Phase Transformations and Shape Memory Effect in Alloys of Zr-Ni-Co System

Intermetallic compounds of ZrNi-ZrCo cross-section undergo martensitic phase transformation, which is accompanied by the imperfect shape memory effect at elevated temperatures. Martensitic transformation is also taking place in one of the constituents for the in-situ composites of ZrCo-Zr2Co-Zr2Ni-ZrNi region. High temperature shape memory behavior of Zr-Ni-Co composite material shows improvement in shape recovery comparing to quasibinary intermetallic compounds of ZrNi-ZrCo cross-section.

Perawatan apeksifikasi pada gigi permanen muda insisivus pertama kiri atas yang non-vital Apexification treatment of non-vital young permanent left central insicivus

Imperfect young permanent teeth caused by caries or trauma could become necrotic before it’s growth anddevelopment completed, thus causes imperfect shape of the root canal and an opened apex. Difficulty in treatment ofroot canal caused by the absence of apical stop, that makes obturation cannot be accomplished because fillingmaterials will be pushed to periapex. The purpose of this case report was to report the treatment of anterior teethwhich diagnosed as necrotic with apexification. The material filling is calcium hydroxide with strong base natureand give antimicrobacterial effect and tissue liquefaction. The result of the treatment was closure of the apex, thetissue surrounding tooth is in normal range or that absence of radiolusency which is a sign of healing at theperiapical.The conclusion is young permanent tooth which experienced pulp necrotic can be treated withapexification treatment

Creep Buckling of a Complete Spherical Shell

The creep buckling behavior of a complete spherical shell which is subjected to a uniform external pressure is investigated using a perturbation method of analysis. The spherical shell has an arbitrary initial imperfect shape and is made from a material which creeps according to the generalized Norton’s law. It turns out that the critical mode number of the deformed profile is identical to that obtained previously by various authors for the linear elastic instability of complete spherical shells. It also appears that the resistance to creep buckling of complete spherical shells is greater than the resistance of a long cylindrical shell having the same R/h ratio and material properties.