Hopewellian Traits in Florida

1938 ◽  
Vol 3 (4) ◽  
pp. 327-332 ◽  
Author(s):  
E. F. Greenman
Keyword(s):  
Copper Plate ◽  
Crystal River

The resemblance of certain objects from the Crystal River Mound in Florida to others taken from mounds of the Hopewell culture in Ohio was first noted by Shetrone in 1931. Willoughby discussed a certain type of design on a round copper plate, interpreted by him as representative of the foot of a bear, and commented upon the presence of such Hopewell-like objects as plummets of shell, stone, and copper, copper ear spools, and conjoined copper tubes. The resemblances between these widely separated mound groups are much more numerous than have been listed in any publication up to the present date, but the Crystal River Mound and other related mounds in Florida have been denied inclusion in the Hopewellian culture for the reason that most of the pottery found in them is not of the Hopewell type.

Heat transfer from a chemically oxidized or anodized copper plate to liquid helium

2005 ◽  
Vol 48 (21-22) ◽  
pp. 4652-4656 ◽  
Author(s):  
Qiang Chen ◽  
Bingjun Gao ◽  
Jinglin Chen ◽  
Yu Wu ◽  
Shen Wang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Liquid Helium ◽  
Copper Plate

Prediction of Surface Profile Evolution of Workpiece and Lapping plate in Lapping Process

2021 ◽  
pp. 1-34
Author(s):  
Zhichao Geng ◽  
Ping Zhou ◽  
Lei Meng ◽  
Ying Yan ◽  
Dongming Guo
Keyword(s):  
Optical Glass ◽  
Removal Rate ◽  
Surface Profile ◽  
Copper Plate ◽  
Modeling Method ◽  
Plate Interface ◽  
Inclination Angles ◽  
Material Removal Rate Model ◽  
The Right ◽  
Evolution Modeling

Abstract Lapping has a history of hundreds of years, yet it still relies on the experience of workers. To improve the automaticity and controllability of the lapping process, a modeling method of friction and wear is developed to predict the surface profile evolution of the workpiece and lapping plate in the lapping process. In the proposed method, by solving the balance equations of resultant force and moment, the inclination angles of the workpiece can be calculated, thus more accurate contact pressure distribution of the workpiece/lapping plate interface can be calculated. Combined with the material removal rate model, the continuous evolution process of the workpiece and lapping plate can be predicted in the lapping process. The modeling method was validated by a lapping test of a flat optical glass (Φ 100 mm) with a composite copper plate. The results show that the proposed method can predict the evolution of the surface profile of the workpiece and lapping plate with high accuracy. Consequently, the lapping plate can be dressed at the right time point. Benefit from this, in the validation test the PV value of the workpiece (with 5 mm edge exclusion) was reduced from 5.279 μm to 0.267 μm in 30 min. The proposed surface profile evolution modeling method not only improves the lapping efficiency but also provides an opportunity to understand the lapping process.

DETERMINATION OF CORROSION INFLUENCE ON FUEL METAL, OBTAINED FROM SECONDARY POLYMER RAW MATERIALS

2021 ◽  
pp. 48-56
Author(s):  
K. Сhevchenko ◽  
A. Grigorov ◽  
I. Sinkevich
Keyword(s):  
Raw Materials ◽  
Petroleum Products ◽  
Copper Plate ◽  
Water Soluble ◽  
Synthetic Fuels ◽  
Laboratory Setup ◽  
Corrosive Effect ◽  
Preliminary Preparation ◽  
Sulfur Containing

The article proposes to determine the corrosion effect on fuel metals under dynamic conditions, when washing the prepared copper plate of a certain size, a significant amount of fuel at a certain speed and temperature of the study. This approach will significantly reduce the duration of the study (up to 100 minutes) and is closer to the real conditions of contact of the fuel with a metal surface, in comparison with the standardized method, which is widely used today. Using the proposed laboratory setup, the study was subjected to fuel (200–360 °C), which was obtained by thermal destruction of secondary polymer raw materials, in particular polypropylene. The obtained results showed that the investigated fuel, despite the temperature, the amount of circulating fuel and its water content, does not have a corrosive effect on the copper plate, which can be explained by the absence of corrosive substances in the fuel: water-soluble mineral acids and alkalis, active sulfur compounds and organic acids. However, it should be kept in mind that in polyolefin raw materials, in the form of contamination, there may be products made of other materials, such as rubber and polyvinyl chloride. This can happen when the sorting technology is violated or during the preliminary preparation of raw materials and, in turn, will contribute to the increase in sulfur-containing and chlorine-containing compounds in the fuel, which are characterized by high corrosion activity and should be necessarily removed from the fuel. Note that the fuel obtained from secondary polymer raw materials, in the absence of sulfur-containing and chlorine-containing compounds, is quite promising for the creation on its basis of modern synthetic fuels, analogues of classic petroleum products.

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