Use Wear on Bone and Antler Tools from the Mackenzie Delta, Northwest Territories

1994 ◽  
Vol 59 (2) ◽  
pp. 316-334 ◽  
Author(s):  
Genevieve M. LeMoine

A series of experiments making and using bone and antler tools show that functional identifications of these tools can be made with confidence in some circumstances. Using principles from the field of tribology, the experiments demonstrate that different uses leave different microscopic traces on bone and antler. They also show that when the materials used are similar, the wear produced will be similar. In particular, wet materials, including snow, ice, wet hide, and wet antler all produce nearly identical microscopic patterns. Other groups of similar materials, such as bone, antler, and wood, or fish scales and hair, present the same problem. Although differences can be detected, these may not be preserved on archaeological tool specimens. Application of the experimental results to bone and antler tools from the Mackenzie Delta illustrates that functional identifications of tools can be made with confidence, despite the problem of similar microscopic patterns, when other lines of evidence (ethnographic and historical accounts, distribution of wear) are taken into account. When such information is lacking, functional identifications are more difficult and must be made with more caution.

1897 ◽  
Vol 60 (359-367) ◽  
pp. 336-337 ◽  

The wave-length of sound in gaseous and in liquid ethyl oxide (sulphuric ether) has been determined by the two first-mentioned of the authors, by means of Kundt’s method, between limits of temperature ranging from 100° C. to 200° C., and of pressure ranging from 4000 mm. to 31,000 mm. of mercury, and of volume ranging from 2·6 c. c, per gram to 71 c. c. per gram. Making use of the same apparatus throughout, the results obtained are to be regarded as comparative, and, by careful determination of the pitch of the tone transmitted through the gas, it is probable they are approximately absolute. The sections of the complete memoir deal with (I) a description of the apparatus employed, (II) the method of ascertaining the weights of ether used in each series of experiments, (III) determinations of the frequency of the vibrating rod, (IV) the calculations of the adiabatic elasticity and tables of the experimental results, and (V) a mathematical discussion of the results. The last section is due to Mr. Rose-Innes.


2002 ◽  
Vol 14 (03) ◽  
pp. 127-130 ◽  
Author(s):  
MING-CHUNG LEE ◽  
CHING-LUNG LIN ◽  
CHIU-LIN HUANG

Silicone fluid is applied to reduce the friction of medical device in this study. Several factors, which might affect the friction of Arterial-Venous Fistula (A. V.F.) Needles, were investigated by a series of experiments. The experimental results showed that a better condition for the coating is using 10/90-weight ratio of MDX4/n-hexane silicone solution and dipping for 1.5 seconds. Two-step coating with an interval of 20 minutes also was examined to give an improvement in the lubricity of needles. It was observed that increased DC 360 concentration in coating solution displays more excellent friction reduction properties. Experimental consequences also showed that the lubricity of needles coated with DC 360 (350cst) is superior to that of coated with DC 360 (12,500cst).


1993 ◽  
Vol 30 (3) ◽  
pp. 506-514 ◽  
Author(s):  
E.G. Hivon ◽  
D.C. Sego

Saline permafrost has a detrimental impact on the performance of foundations. Increased pore-water salinity decreases the strength and increases the deformation susceptibility of permafrost and foundations installed in permafrost. A data base of the distribution of saline permafrost in the Northwest Territories shows high pore-water salinities beneath coastal communities and at locations along the upper Mackenzie Valley and within the Mackenzie Delta. Salinity of inland sites is usually low. High salinities are usually associated with ice-poor materials and are linked with previous marine submergence associated with glacial events. Key words : permafrost, saline distribution, measurements, Quaternary geology.


Symmetry ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 1486
Author(s):  
Zhinan Gou ◽  
Zheng Huo ◽  
Yuanzhen Liu ◽  
Yi Yang

Supervised topic modeling has been successfully applied in the fields of document classification and tag recommendation in recent years. However, most existing models neglect the fact that topic terms have the ability to distinguish topics. In this paper, we propose a term frequency-inverse topic frequency (TF-ITF) method for constructing a supervised topic model, in which the weight of each topic term indicates the ability to distinguish topics. We conduct a series of experiments with not only the symmetric Dirichlet prior parameters but also the asymmetric Dirichlet prior parameters. Experimental results demonstrate that the result of introducing TF-ITF into a supervised topic model outperforms several state-of-the-art supervised topic models.


1983 ◽  
Vol 105 (3) ◽  
pp. 259-267 ◽  
Author(s):  
A. G. Dawson ◽  
W. C. Thomas ◽  
D. Waksman

An analytical and experimental investigation was undertaken to evaluate an alternative method for measuring the thermal degradation of materials used in flat-plate collectors. This test method is based on measuring the temperature of the absorber under a no-flow condition before and after prolonged exposure. The primary material properties of interest are cover transmittance, solar absorptance and infrared emittance of the absorber, and thermal conductivity of insulation. The advantages and limitations of the proposed test method are compared with those for the currently used method, which is based on measuring the energy output from collectors. Experimental results from both outdoor and indoor tests are presented. Steady-state and transient analytical models are developed to evaluate the proposed test method and interpret experimental results. While the measurements required in the proposed method are simpler than those used to measure energy output, other factors, such as nonisothermal absorbers, variations in environmental conditions, and transient response, must be reconciled.


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