We are not the periphery: barbarian economies and Northern Europe in the exchange patterns of Western Eurasia, 1800 BC - AD 900

University of Ph.D. dissertation. December 2013. Major: History. Advisor: Bernard S. Bachrach. 1 compute4r file (PDF); xi, 708 pages.Examination of long-term exchange patterns involving northern Europe and neighboring regions of western Eurasia reveals that the world of the North has, typically, played an important role both as producer and consumer. Especially in the Carolingian period (AD 700 - 900), the system as a whole can be characterized best as a vast circuit of exchange flows rather than in terms of center - periphery relationships. The major regions participating in the western Eurasian exchange circuit were the North (Scandinavia - Baltic), Latin Christendom, European Russia, Byzantium, and the Islamic world of the Middle East and North Africa. Exchange within the circuit always operated at multiple levels, including elite and non-elite gift giving and resource sharing, but also including independent, professional merchant-adventurers who redistributed goods and materials for profit. This class of entrepreneurs can be analyzed further into long-distance wholesale traders, who linked the top-level nodal places in the system, and others who linked the nodal places with points in the local area down to the capillary level of individual producers and consumers. Typically, members of the mercantile class traveled armed and formed ad hoc aggregations for mutual protection. In the Carolingian Empire, their activities were governed by rules and administrative practices derived, ultimately, from the Late Roman. Commercial exchange can and does operate successfully even in pre-state and non-urbanized societies, i.e., without elite direction or coercion. The evidence shows that pre-commercial societies will incorporate commercial modes of behavior into their socio-economic value systems when opportunity to do so arises. Even "peasants" will behave entrepreneurially, feeding into the larger exchange system both as producers and consumers

Bias-Temperature Instabilities in Silicon Carbide MOS Devices

We have investigated bias-temperature instabilities (BTIs) in 4H-SiC transistors and capacitors under a range of stress conditions. The threshold voltage V TH of nMOS transistors decreases for elevated temperature stress under negative bias, when the surface is accumulated. Devices stressed with the surface inverted do not exhibit significant V TH shifts. Similar results are observed for nMOS and pMOS capacitors stressed in accumulation (measurable shift) or inversion (no significant shift). V TH shifts due to BTI stressed under negative bias correlate strongly with the additional ionization of deep dopants in SiC at elevated temperatures. The charge that leads to BTI lies in interface traps that are more than 0.6 eV below the SiC conduction band, nitrogen-related defects, and O vacancies in the SiO2