Microhardness testing procedure and effect of composition on the microhardness of brittle materials

1964 ◽  
Vol 2 (2) ◽  
pp. 123-127 ◽  
Author(s):  
V. N. Vigdorovich ◽  
A. Ya. Nashel'skii
2012 ◽  
pp. 209-221 ◽  
Author(s):  
Zbigniew Ranachowski ◽  
Daria Jóźwiak - Niedźwiedzka ◽  
Mariusz Dąbrowski ◽  
Jolanta Wołowicz ◽  
Maciej Sobczak ◽  
...  

2002 ◽  
Vol 149 (1) ◽  
pp. 27-35 ◽  
Author(s):  
J.M Antunes ◽  
A Cavaleiro ◽  
L.F Menezes ◽  
M.I Simões ◽  
J.V Fernandes

Author(s):  
B. J. Hockey

Ceramics, such as Al2O3 and SiC have numerous current and potential uses in applications where high temperature strength, hardness, and wear resistance are required often in corrosive environments. These materials are, however, highly anisotropic and brittle, so that their mechanical behavior is often unpredictable. The further development of these materials will require a better understanding of the basic mechanisms controlling deformation, wear, and fracture.The purpose of this talk is to describe applications of TEM to the study of the deformation, wear, and fracture of Al2O3. Similar studies are currently being conducted on SiC and the techniques involved should be applicable to a wide range of hard, brittle materials.


2002 ◽  
Vol 18 (1) ◽  
pp. 78-84 ◽  
Author(s):  
Eva Ullstadius ◽  
Jan-Eric Gustafsson ◽  
Berit Carlstedt

Summary: Vocabulary tests, part of most test batteries of general intellectual ability, measure both verbal and general ability. Newly developed techniques for confirmatory factor analysis of dichotomous variables make it possible to analyze the influence of different abilities on the performance on each item. In the testing procedure of the Computerized Swedish Enlistment test battery, eight different subtests of a new vocabulary test were given randomly to subsamples of a representative sample of 18-year-old male conscripts (N = 9001). Three central dimensions of a hierarchical model of intellectual abilities, general (G), verbal (Gc'), and spatial ability (Gv') were estimated under different assumptions of the nature of the data. In addition to an ordinary analysis of covariance matrices, assuming linearity of relations, the item variables were treated as categorical variables in the Mplus program. All eight subtests fit the hierarchical model, and the items were found to load about equally on G and Gc'. The results also indicate that if nonlinearity is not taken into account, the G loadings for the easy items are underestimated. These items, moreover, appear to be better measures of G than the difficult ones. The practical utility of the outcome for item selection and the theoretical implications for the question of the origin of verbal ability are discussed.


2000 ◽  
Vol 10 (PR9) ◽  
pp. Pr9-811-Pr9-816 ◽  
Author(s):  
O. A. Plekhov ◽  
D. N. Eremeev ◽  
O. B. Naimark

TAPPI Journal ◽  
2013 ◽  
Vol 12 (11) ◽  
pp. 21-26 ◽  
Author(s):  
CHAO TIAN ◽  
LINQIANG ZHENG ◽  
QINGXIAN MIAO ◽  
CHRIS NASH ◽  
CHUNYU CAO ◽  
...  

The Fock test is widely used for assessing the reactivity of dissolving pulp. The objective of this study was to modify the method to improve the repeatability of the test. Various parameters that affect the repeatability of the Fock test were investigated. The results showed that Fock reactivity is dependent on testing conditions affecting the xanthation between cellulose and carbon disulfide, such as the moisture content of the pulp sample, sodium hydroxide (NaOH) concentration, xanthation temperature, carbon disulfide dosage, and xanthation time. The repeatability of the test was significantly improved using the following modified testing procedure: air dried sample in the constant temperature/humidity room, xanthation temperature of 66°F (19°C) in a water bath, xanthation time of 3 h, NaOH concentration of 9% (w/w), and 1.3 mL carbon disulfide.


2020 ◽  
Vol 7 (54) ◽  
pp. 205-217
Author(s):  
Mnaku Honest Maganya

AbstractTanzania, like most other developing countries, faces numerous economic challenges in striving to achieve sustainable economic growth and development through taxation. In the literature, the debate on how effective taxes are as a tool for promoting economic growth and economic development remains inconclusive, as various research have reported mixed effects of tax on economic growth. This article investigates the effect of taxation on economic growth in Tanzania using the recently developed technique of autoregressive distributed lag model (ARDL) bounds testing procedure for the period from 1996 to 2019. Various preliminary tests were conducted including stationary tests as well as the pair-wise Granger causality test. According to the results obtained, domestic goods and services (TGS) taxes are positively related to GDP growth and are statistically significant at 1% level. Income taxes, on the other hand, were found to be negatively related to GDP growth and to be statistically significant at 5% level. The pair-wise Granger causality results indicated that there is bidirectional Granger causality between TGS and GDP growth at 1 % significance level. The government should aim at growing, nurturing and sustaining tax base to positively drive economic growth even further.


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