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The history of food consumption in Iceland differs in many fundamental ways from that in the rest of Europe. The prominence of domestically produced dairy products, fish, meat and suet, and the insignificance of cereals until the nineteenth century, are among the most unusual features. This paper presents the first attempt to estimate total food consumption in Iceland on the basis of food supply data, covering the period 1770-1940. The data, derived from trade statistics, production statistics and the author's current study of Iceland's GNp, provides information on the level of consumption, on the composition and the nutritional value of the diet, and on the changing patterns of consumption. In general terms, this can be described as a transition from an animal-based to a more grain-based diet. A short discussion on the causes of dietary change, and its effects on the nutrional status of Icelanders and on population growth, concludes the paper.

This paper shows how an extended Kalman filter can be applied to the parameter estimation in continuous time heat exchanger models. The model is based on lumping of the heat exchanger. It is on state space form where the temperature in each section is a model state. By letting the model parameters be functions of the massflows and the temperatures one obtains a model that is capable of accurately describing the dynamics of the heat exchanger for all relevant working conditions. Since the parameters are functions of temperature, the model is nonlinear in the states and an extended Kalman filter is applied to the state estimation. Empirical relations of the heat transfer coefficients are incorporated in the model parameters in order to cope with the massflow and temperature dependence. Some of the parameters in the empirical relations are also estimated, thereby adjusting the formulas to the specific heat exchanger.

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