Slope Downwards Research Articles

A Study of Cross Flow Fan with Inner Guide Apparatus

This paper concerns a theoretical and experimental study of cross flow fan with inner guide apparatus. Effects of fan geometry on the performance are investigated. Theoretically, the inner apparatus provides a shockless flow on the inner periphery of the impeller, which has an arbitrary inner blade angle. A series of experiments have been conducted using four types of impellers with different inner blade angles β and inner vanes, whose shapes are identical to theoretical stream lines. One apparatus designed with a single vane and an impeller of β1=100°produced a high and stable performance curve sloping downwards to the flow rate.

Balls Head: the excavation of a Port Jackson rock shelter

Balls Head is a small headland reserve jutting into the north side of Port Jackson west of the Harbour Bridge (Sydney sheet, map No. SI 56-5 grid ref. 420818). It has preserved its bushland appearance and been comparatively little interfered with. Vegetation consists of a mixture of indigenous and introduced trees and shrubs; grassy areas are maintained for the benefit of picnickers. Bedrock is Hawkesbury sandstone, with frequent outcroppings, particularly where the headland slopes steeply down to the Harbour. These outcroppings are in the form of both smooth, steep-sided or flat slabs and the characteristically weathered small rock shelters typical of the Sydney area. Many of the slabs are decorated with Aboriginal rock engravings and axe-grinding grooves, and some of the shelters bear rock paintings and hand stencils (Campbell 1899: 14, 17; Miles 1964: 343). There is not a great deal of other Aboriginal occupation evidence apart from the site under consideration, and thin open shell middens which may be detected beneath some of the grassed-over areas. The rock shelter forming the subject of this paper is approximately 65 feet above mean water-level, of a north-easterly aspect (plate 17). I t is not large: about 35 feet long, 7 feet from the drip-line to the back wall of the shelter, and 6 feet from ground surface to underside of overhang are its maximum dimensions (figs 1 and 2). Occupational deposit stretches from the back of the shelter, out beyond the drip-line for about IO feet, where it then begins sloping downwards in a steep talus. There are faint hand stencils on the rear wall of the shelter and the roof is blackened, perhaps from the fires of the original occupants. The deposit consists of compacted shell midden, looser disturbed material, and less compacted midden. Its maximum depth is 2 feet 9 inches.

Time variation of the depth of a high salinity layer in the Celtic Sea

During July–August 1968, a relatively high salinity layer of 5–10 m thickness was found at a depth of 25–40 m in the Celtic Sea at a point approximately 60 nautical miles † † 1 nautical mile = 1·8532 kilometres. ESE of Cork. The height of this layer from the bottom showed a time variation with tidal period in phase with the tidal height variation. The possibility is discussed whether these variations are due to internal waves or to the layer sloping downwards towards the land so giving rise to a periodic variation of depth at one point due to the to and fro motion of the tide.

The Determination of Pure Rates of Interest in Underdeveloped Rural Areas

T HE determination of interest rates in rural areas throughout the underdeveloped world is best explained in micro-economic terms. The typical village moneylender will either be an outright monopolist, or he will be an imperfect competitor.1 The market for loans will center around the village itself. The farmer will normally only borrow from the one or more moneylenders that the village can support. He will not often have access to a bank or other lending institution. In these circumstances, the moneylender will face a demand curve for his loans which will slope downwards from left to right. The rate of interest will be on the vertical axis and the volume of loans on the horizontal axis.2 He will also have a schedule of costs for lending. This will be compounded of the administration and risk charges on each unit which he lends, together with the opportunity cost of his raw material money. It is this last cost component which corresponds to the pure rate of interest of existing theory. The average cost-of-lending curve will describe the arc familiar to the student of the principles of economics. There will be a certain volume of loans which will maximize the moneylender's net returns. This volume will be at his equilibrium level of lending, and it will determine his most profitable interest charge. It is the opportunity cost of each dollar or rupee which he advances at this equilibrium point which we will analyze here. Questions of average administration and risk charges, as well as of monopoly profit, must be left to other discussions. But it should not be supposed that these are relatively unimportant considerations. Risk and administration costs in particular probably play the major role in forcing high interest rates upon farmers in poor countries.3 If we view the opportunity cost of the lender's money as one of the determinants of his costs, then we could draw a curve representing these charges. It would probably run parallel to the volume of lending axis to begin with and then rise quite sharply as the moneylender adds to his loans. The unit opportunity cost is thus registered on the vertical axis and it forms one of the components of the interest rate which the farmer must ultimately pay. The reasons why the opportunity cost of the money used in a lender's loans will describe such a curve can best be explained under two separate headings. They are: (1) the returns on alternative investments, and (2) liquidity preference.