Simultaneous additions of SrO and A1203 to ZrOZ(12 mol% CeO,) lead to the in situ formation of strontium aluminate (Sr0.6A1203) platelets (~0 . 5 pm in width and 5 to 10 pm in length) within the Ce-TZP matrix. These plateletcontaining Ce-TZP ceramics have the strength (500 to 700 MPa) and hardness (13 to 14 GPa) of Ce-TZP/AI2O3 while maintaining the high toughness (14 to 15 MPa-m'") of Ce-TZR Optimum room-temperature properties are obtained at SrO/A1203 molar ratios between 0.025 and 0.1 for Zr02(12 mol% CeOz) with starting A1203 contents ranging between 15 and 60 ~01%. The role of various toughening mechanisms is discussed for these composite ceramics. [
Against a background of recent work in the history of geography and of geographical knowledge, the paper considers evidence for the place of geography within British universities before the formal establishment of the first departments of geography. Attention is paid to geography's discursive connections with other subjects within given university curricula, and to the values placed upon its teaching by contemporaries. The paper argues that extant historiographies for British geography should be revised in the light of such evidence. More importantly, the paper raises questions about the sites and intellectual spaces in which geography has been situated and about the content, nature and purpose of writing geography's 'disciplinary' history.key words geography historiography Britain universities
This article examines the ways in which geographers have written about the history of geography in the early modern period ( c. 1600–1850). It is argued that geography was a clearly defined practice in that period, but that a century of writing about the period by geographers has consistently effaced that definition. This practice began with modern geography's ‘founding fathers’, of whom Mackinder, Hartshorne and Sauer are considered. They developed an ‘essentialist’ historiography – postulating what geography is as a science ‘in essence,’ judging geography's history in the light of this essence and placing the early modern period in a precritical era. This model proved highly influential with historians of geography, and even contemporary work has not escaped from its framework to take on board the alterity of the early modern conception of geography.
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