Burning Grain Research Articles

Passos/Santa Comba Mountain in the context of the late prehistory of northern Portugal

This paper summarizes the results of archaeological work carried out during the past eight years on the Passos/Santa Comba Mountain in northern Portugal. The more important sites there are thirteen painted rock shelters. One of them, Buraco da Pala, was occupied for three millennia, making it reasonable to assume that it played a part in different social, economic and symbolic systems. It was used for settlement purposes between the late sixth/early fifth millennium BC and the beginning of the third. A high number of burnt cereal grains shows the introduction of farming in the interior of northern Portugal. Buraco da Pala was used as a granary and storage was carried out in large pottery vessels that occupied most of the usable space in the shelter. These levels provide evidence both for the intensification of agricultural production in this area during the Chalcolithic period and for different ways of symbolically appropriating the surrounding territory.

Une maison à absides sur l'oppidum de Gailhan (Gard) au milieu du V s. avant J.-C. La question du plan absidial en Gaule du Sud

A mid 5th century house, built on an apsis plan, has been excavated on the Plan de la Tour oppidum, near Gailhan. The walls were partly made of mud, supported by stakes, and partly of stone. A partition divided the inside into two rooms and the northern room was used as a store-room (crushed vases, burnt grains of cereals). Until today, the presence of the apsis plan, in prehistoric South Gaul, had only been attested on coast sites, precociously and intensively exposed to Hellenic influence, associated to the use of raw brick (La Monédière, near Bessan, Hérault, and Saint-Blaise, near Saint-Mitre-les-Remparts, Bouches-du-Rhône, 6th or early 5th century B.C.), thus pleading in favour of a Hellenic origin. But, possibly, the Gailhan house, located in the inland of Languedoc, in an indigenous society, within the reach of the Massaliete market stream, and built according to a technology traditional of that area, has been built on an indigenous plan which was already known in Eastern Languedoc during the Chalcolithic Age, and in the inland of Gaul since the Bronze Age. That hypothesis remains to be confirmed by future excavations in South Gaul, where our knowledge of the plans of early Iron Age perishable houses is very limited, whereas the plans of Bronze Age houses are still totally unknown.

Carry-over grain stocks as an emergency fuel

In a typical year, the U.S. has carry-over stocks of grain with a total energy content of 0.5–1.0 quad (10 15Btu). These stocks could serve as an emergency supply of solid fuel which could provide a partial substitute for coal in coal power plants. The technical feasibility of burning grain in coal plants has already been demonstrated. Although the stocks would be a costly substitute for coal, they would be cheaper than some alternate power sources.

High-Frequency Combustion Instability in Solid Propellant Rockets. Part 2

A theory of unstable high-frequency oscillations in solid propellant rockets is advanced with the mechanism of self-excitation based on the following simplified model. Both the rate of primary decomposition of solid propellant element and the rate of activation of the intermediate products during the time lag are assumed to depend upon the gas oscillations. Both interactions are expressed in terms of the instantaneous pressure according to power law with exponent n and m, respectively. The dependence of the rate of decomposition on drifting velocity is shown to be not of fundamental importance in determining the stability of oscillations in the combustion chamber. Analysis shows that a simplified over-all pressure index of interaction S = m — (n/2) must be bigger than certain minimum value if unstable oscillation is to be possible. Unstable oscillation further requires the time lag to be in proper range. The most unstable mode is shown to be the fundamental spiral mode, and its tangential component with exactly the acoustical frequency is the one which is most easily observed at finite magnitudes because of its rapid amplification. Several configurations of the propellant grain with radial burning surfaces have been investigated. Rod grain becomes more stable while other grain shapes become less stable in the course of firing. Rod grain is the most stable while tubular grain is the most unstable configuration. The stabilizing effect of inserting a nonburning solid rod into tubular grain is verified by the theory. Several other aspects have also been treated. Solid rocket with end burning grain also becomes less stable in the course of operation. Both the spiral and the longitudinal modes in rocket with endburning grain are briefly investigated.

Ukrudtsfrø som næringsmiddel

Seeds of weeds as food in the fore-Roman lron AgeAmong the objects found in 1949 in the ruins of a burnt house on Gørding Heath was a small pottery vessel containing, in addition to sand and earth, about 95 ccs of burnt grain and seeds. The house site can be dated by means of its ceramic contents to the second division of the Celtic Iron Age. A statistical investigation of the vegetable remains showed there to be 65 ccs of barley and 30 ccs of seeds of weeds.The barley is the naked type of six-row nodding barley, Hordeum tetrastichum Kcke., which predominated in Denmark and presumably in the remainder of northern and western Europe throughout the period up to approximately the commencement of our era. At that time this type of barley appears to have been gradually superseded by the husked type, which had achieved some degree of importance in Denmark even as early as the Later Bronze Age. Naked barley has never since regained its supremacy among Danish barley types, although it is known to have been cultivated in the 18th century. That it is still possible to grow it in Danish latitudes is shown by the fact that it has been cultivated - rather experimentally than commercially -in Jutland during the last few decades. For example the author saw a field of ripe naked barley in Central Jutland in 1937. The size of the grains of the Gørding barley is much less than that of modern barley, while even compared with other Iron Age barley it is small, suggesting that the ploughland belonging to the village was very poor.Vessels of the size of the one here described, which hold about a quart, occur regularly in Iron Age graves and must be looked upon as table vessels as they are too small for storage of foodstuffs. The seeds found in this vessel must therefore be considered as a meal, or as the remains of one. When it is taken into consideration that certain of the species of seeds found belong to plants which do not occur in cornfields, and when it is further recalled that only quite small quantities of weeds would be harvested together with sicklereaped corn, the conclusion cannot be avoided that the weeds were gathered for their own sake and the seeds deliberately added to the corn. That the seeds of certain weeds have been gathered is shown by the discovery of unmixed stores of Pale Persicaria, White Goosefoot and Corn Spurry in burnt Iron Age houses in Jutland. The impressions of the seeds of these plants and of Black Bindweed are similarly frequently found in Iron Age pottery. The seeds of the seventeen other species are presumably only present because these plants grew together with those collected. No large quantity of seeds of weeds could be collected from corn fields, but rather from these fields after the harvest or, perhaps most likely, from first year's fallow, where the annuals would have favourable conditions for growth until the grasses and other perennials reached a sufficient predominance in numbers to squeeze them out.The stomach contents of the two bodies found in the bogs at Borremose and Tollund show that their meals had consisted partly of seeds of weeds. In those two cases there was no evidence of the quantitative relationship of corn and seeds; but here we have an example which suggests the probability that uncultivated plants supplied about a third of the meal. Together with the evidence of the bodies this little find gives a basis for the conclusion that the gathering of weed seeds played a very important role in the Iron Age in Jutland. Circumstances made it necessary for the population to supplement the insufficient yield of their ploughlands by a partial reversion to the ancient practice of food-gathering, which up to the discovery of agriculture was the only way in which mankind could furnish itself with vegetable food.Hans Helbaek