###### Analysis of crack propagation in a “pull-out” test

compression test performed on the same samples. Photograph from these tests are shown in Fig. 4 . On the left side, the displacement sensor is visible, which measures the vertical deformations, and on the right side, there is the extensometer that measures the horizontal deformations. It is mounted on steel plates glued to the opposite sides of samples. Figure 4 Compression with extensometer test. The Young modulus was calculated from the below equation: (3.1) E = h ⋅ κ A $$E=\frac{h\cdot \kappa }{A}$$ where, h is the

###### Method for Assessment of Changes in the Width of Cracks in Cement Composites with Use of Computer Image Processing and Analysis

scale-invariant keypoints, International Journal of Computer Vision, 2004, 60 (2), 91-110. [5] KANELLOPOULOS A., QURESHI T.S., AL-TABBAA A., Glass encapsulated minerals for self-healing in cement based composites, Construction and Building Materials, 2015, 98, 780-791. [6] PAWLIK P., MIKRUT S., Wyszukiwanie punktów charakterystycznych na potrzeby zdjęć lotniczych, Automatyka, 2006, 10 (3), 407-411. [7] SZELĄG M., FIC S., Analiza rozwoju spękań klastrowych w zaczynie cementowym modyfikowanym mikrokrzemionką, Budownictwo i

###### A note on the differences between Drucker-Prager and Mohr-Coulomb shear strength criteria

equivalent measure of principal stress ratio. Introducing equations (8) - (10) into the definitions of invariants the following relations are obtained: I 1 = 3 p − a q , $${{I}_{1}}=3p-aq,$$ (12) J 2 = q 2 3 ( a 2 + 3 ) , $${{J}_{2}}=\frac{{{q}^{2}}}{3}\left( {{a}^{2}}+3 \right),$$ (13) J 3 = 2 a 27 q 3 ( − a 3 + 9 ) . $$ {{J}_{3}}=\frac{2a}{27}{{q}^{3}}\left( -{{a}^{3}}+9 \right).$$ (14) Finally the Lode angle θ ϵ 〈-π/6, π/6〉 is introduced by

###### The impact of medium frequency pulsed magnetron discharge power on the single probe Langmuir measurements and resulted plasma parameters

induced secondary electron emission coefficient, ISEE(Ti) = 0.11, ISEE(Cu) = 0.08 electron per ion, for argon ion energy of about 500 eV [ 39 ]. With the ISEE(Cu) being lower than ISEE(Ti), the discharge voltage is higher in case of copper sputtering ( Fig. 1 ). Taking into account invariant discharge current pulses (constant amplitude, duration time) one can conclude that higher energy is delivered to the magnetron source with each pulse while sputtering copper than titanium. To keep the same average discharge power, the number of pulses in a group has to be lower in