Microstructure and Mechanical Properties of Low-Pressure Cold-Sprayed (LPCS) Coatings

In low-pressure cold spraying, compressed air is used as a process gas. The most important process parameters are temperature and pressure. In the Low-Pressure Cold Spraying (LPCS) system in this study, the maximum preheating temperature is 650 °C and pressure is 9 bar. Powders used in LPCS process contain alumina with metallic powders; therefore LPCS is the method to spray soft metallic coatings with ceramic hard phase for different application areas, e.g., thick coatings and coatings for electrical and thermal conduction and corrosion protection applications. The aim of this study was to investigate microstructure, denseness, and mechanical properties of LPCS Cu, Ni, and Zn coatings. LPCS coatings seemed to be dense according to Scanning Electron Microscope (SEM) studies but corrosion tests were needed to identify the existence of porosity. Through-porosity was observed in structures of the LPCS coatings. Bond strengths of LPCS Cu and Zn coatings were found to be 20-30 MPa, and hardness was high indicating reinforcement and work hardening.</p

Determination of the quark coupling strength vertical bar V-ub vertical bar using baryonic decays

In the Standard Model of particle physics, the strength of the couplings of the b quark to the u and c quarks, vertical bar V-ub vertical bar and vertical bar V-ub vertical bar, are governed by the coupling of the quarks to the Higgs boson. Using data from the LHCb experiment at the Large Hadron Collider, the probability for the Lambda(0)(b) baryon to decay into the p mu(-)(nu) over bar (mu) final state relative to the Lambda(+)(c)mu(-)(nu) over bar (mu) final state is measured. Combined with theoretical calculations of the strong interaction and a previously measured value of vertical bar V-ub vertical bar, the first vertical bar V-ub vertical bar measurement to use a baryonic decay is performed. This measurement is consistent with previous determinations of vertical bar V-ub vertical bar using B meson decays to specific final states and confirms the existing incompatibility with those using an inclusive sample of final states