The University of Edinburgh natural history class lists 1782-1800

In 1779 Revd Dr John Walker was appointed to be the University of Edinburgh’s Professor of Natural History. Because of the institutional structure of the university, he took care to keep detailed class lists from 1782 to 1800. These are extant in the University of Edinburgh’s Special Collections Department. As many of the students on the lists would go on to have a profound impact on the practice of nineteenth century natural history, I have compiled them into a table so that they can be used as a reference tool for those interested in the study of natural history in Edinburgh during the late eighteenth century. The table is arranged into columns that state the student’s name, degree, year of attendance and geographic origin. To help the reader better understand the table, I have written a brief introductory essay that addresses Walker’s organisation of the course and the types of students who attended the lectures. It also identifies the prominent role played by chemistry in Edinburgh’s natural history community and discusses the foundation of the Student Natural History Society of Edinburgh

Elements, principles and the narrative of affinity. Mi Gyung Kim : affinity that illusive dream : a genealogy of the chemical revolution

In the 18th century, the concept of ‘affinity’, ‘principle’ and ‘element’ dominated chemical discourse, both inside and outside the laboratory. Although much work has been done on these terms and the methodological commitments which guided their usage, most studies over the past two centuries have concentrated on their application as relevant to Lavoisier’s oxygen theory and the new nomenclature. Kim’s affinity challenges this historiographical trajectory by looking at several French chemists in the light of their private thoughts, public disputations and communal networks. In doing so, she tells a complex story which points to the methodological and practical importance of industrial and medical chemistry. The following review highlights the advantages and snares of such an approach and makes a few historiographical points along the way

Zero sound in a single component fermion - Bose Einstein Condensate mixture

The resonant dynamics of mediated interactions supports zero-sound in a cold atom degenerate mixture of a single component fermion gas and a Bose-Einstein condensate (BEC). We characterize the onset of instability in the phase separation of an unstable mixture and we find a rich collective mode structure for stable mixtures with one undamped mode that exhibits an avoided crossing and a Landau-damped mode that terminates.Comment: 4 pages, 2 figure

Tinjauan Kekuatan Beton pada Usia Muda dengan Penambahan Polypropylene Fibre

Dewasa ini pemakaian beton sangat berkembang pesat pada kegiatan kontruksi, dikarenakan beton memiliki kelebihan mudah dibentuk sesuai keinginan, memiliki kuat tekan yang baik dan lain – lain. Tetapi beton memiliki kelemahan pada sifat yang getas dan kuat tarik yang rendah, sehingga kontruksi beton diberi tulangan untuk mengatasi pada bagian tarik. Maka diperlukan beton khusus untuk meningkatkan kuat tarik maupun kuat lentur yaitu beton serat. Beton serat adalah beton dengan bahan tambah serat. Dalam penelitian ini campuran beton menggunakan bahan tambah polypropylene fibre, sehingga diharapkan dapat meningkatkan kualitas beton pada umumnya dan khususnya pada kuat tarik belah dan kuat lentur. Polypropylene fibre menggunakan produk dari Sika dengan diameter 18 mikron dan panjang 12 mm. Pengujian ini meliputi pada kuat tekan, kuat tarik belah dan kuat lentur. Untuk pengujian kuat tekan dan kuat tarik belah menggunakan benda uji silinder dengan diameter 15 cm dan tinggi 30 cm, sedangkan kuat lentur menggunakan benda uji balok dengan panjang 60 cm, lebar 15 cm dan tinggi 15 cm. Benda uji terdiri dari tiga buah silinder dan tiga buah balok untuk masing - masing pengujian. Dari pengujian slump dapat disimpulkan tidak ada Perubahan berarti dalam penggunanan polypropylene fibre. Dan dari pengujian kuat tekan, kuat tarik belah dan kuat lentur di dapatkan nilai optimum pada beton normal ditambah polypropylene fibre. Pada kuat tekan terjadi peningkatan sebesar 4,44 % dibandingkan beton normal (N), sedangkan pada kuat tarik belah terjadi peningkatan sebesar 16,96% dibandingkan beton normal (N), dan pada kuat lentur terjadi peningkatan sebesar 16,47 % dibandingkan beton normal (N)

Membrane amplitude and triaxial stress in twisted bilayer graphene deciphered using first-principles directed elasticity theory and scanning tunneling microscopy

Twisted graphene layers produce a moir\'e pattern (MP) structure with a predetermined wavelength for given twist angle. However, predicting the membrane corrugation amplitude for any angle other than pure AB-stacked or AA-stacked graphene is impossible using first-principles density functional theory (DFT) due to the large supercell. Here, within elasticity theory we define the MP structure as the minimum energy configuration, thereby leaving the height amplitude as the only unknown parameter. The latter is determined from DFT calculations for AB and AA stacked bilayer graphene in order to eliminate all fitting parameters. Excellent agreement with scanning tunneling microscopy (STM) results across multiple substrates is reported as function of twist angle.Comment: to appear in Phys. Rev.