Nowadays, the interaction of oil droplets with gas bubbles plays an important role in many industrial, environmental and biological processes. Therefore, in this paper, the outcome of a collision between a silicon oil droplet and an air bubble in water has studied in order to identify the effective parameters in this process. For this purpose, an especial setup was built and four series of experiments in both dynamic (in which the relative velocity of collision is equal to the bubble velocity due to the Buoyancy force) and static conditions were carried out. The results of these experiments were presented and discussed in the form of several tables and pictures. In these experiments, a high-speed camera and image processing were used to gain a better understanding about bubble-drop Coalescence qualitatively, and to obtain some quantitative information such as contact time, velocity, and kinetic and interfacial energies of bubbles and drops during the impact. The results of this study show that in addition to the spreading coefficient, the kinetic energy of bubble/droplet in the collision and their contact time, are also determinative parameters in the determination of the outcome of a collision. In the dynamic and static states, the effect of kinetic energy and contact time are more effective, respectively.

The Laplacian spectrum of a graph is obtained by taking the difference of the adjacency spectrum from the diagonal matrix of degrees. If a graph has a unique Laplacian spectrum,  it means that  it can be identified by this spectrum, it is called $DLS$. In this article,  we first introduce the graph resulting from the integration of a starlike tree and a multi-wheel graph at the vertices with the maximum degree of these two graphs. Then, we check whether it is $DLS$.

In this research, effect of bicomponent mixed surfactant was studied on drop interface Coalescence phenomenon in ambient temperature. First basic chemical system was water and toluene and 0.01 gr of sodium dodecyle sulfate (SDS) and the second basic system was water and toluene and 0.01 gr of cethyl trimethy amonium bromide (CTAB). Various weight fractions of second surfactant including 2-heptanol (non-ionic) and aniline (cationic) added to each of these systems, respectively, in order to study the effect of mixed surfactant on Coalescence time. It was shown that chemical systems including mixture of nonionic/anionic surfactant increased Coalescence time. However, chemical systems including mixture of nonionic/cationic surfactant decreased Coalescence time. If a mixture of anionic/cationic surfactant was considered, in terms of being weak or powerful cationic surfactant, Coalescence time would have been decreased in the later and for mixture of ctionic/ctionic surfactant, Coalescence time increased in small diameter and decreased in further diameter. Effect of sodium chloride (NaCl) on selected systems, including 40% CTAB in the basic system of water and toluene and SDS, 40% 2-heptanol in basic system of water and toluene and CTAB and 40% 2-heptanol in basic system of water and toluene and SDS was considered and it was shown that in general, Coalescence time decreases