Characterization of the light scattering by ensembles of randomly distributed soot aggregates

Soot particles formed in combustion processes commonly exist in the form of ensembles of randomly distributed aggregates of small, nearly spherical monomers. In this paper, these randomly distributed aggregates are numerically generated using a combination of the cluster–cluster aggregation algorithm with the Monte Carlo method. Moreover, an efficient and accurate numerical method is presented for characterizing the light scattering by these complex soot particles illuminated by plane wave and Gaussian beam. This method exploits the unique features of the hybrid finite element-boundary integral method and, more importantly, the unique features of soot aggregates. It is designed in such a manner that it first decomposes the original problem into many sub-regions, where each primary particle is regarded as a sub-region, and then it employs the edge-based finite element method to deal with each sub-region. The sub-regions communicate through the near-field Green’s function. To reduce computational burdens, an iterative domain decomposition method in combination with parallel conjugate gradient method is adopted to solve the coupling system of equations. As an illustration, we present some of our preliminary numerical results. The results are expected to provide useful insights into the optical properties of soot particles formed in combustion processes.     

Theory of nonlinear dynamic stability for composite laminated plates

In this paper,the general equations of dynamic stability for composite laminatedplates are derived by Hamilton principle.These general equations can be used to considerthose different factors that affect the dynamic stability of laminated plates.The factors aretransverse shear deformation,initial imperfections,longitudinal and rotational inertia,andply-angle of the fiber,etc.The solutions of the fundamental equations show that someimportant characteristics of the dynamic instability can only be got by the considerationand analysis of those factors     

Monte carlo simulations of microemulsions

Summary We describe the Larson-Stauffer model of a microemulsion and report results which strongly indicate that this is a successful model. Particular attention is paid to the structure of the surfactant which appears to be the decisive factor for modelling a microemulsion. We study the kinetics of micelle formation, the miscibility gap of oil and water, the coexistence of various phases, the segregation of three phases (oil rich, water rich and the bicontinuous surfactant rich) as a function of temperature, the relative interaction strengths of hydrophobic and hydrophilic monomers of the surfactant with oil and water, and concentration of surfactant. The model is capable of describing most of the observed properties of a microemulsion. In addition, we are now in the position to study the properties of ?designer? surfactant,e.g., ?bola-form?. Paper presented at the I International Conference on Scaling Concepts and Complex Fluids, Copanello, Italy, July 4–8, 1994.     

Thermal Equilibrium Reached by Interaction Between Two Identical Systems

In this work we show that tending to thermal equilibrium in one system, at least in certain cases, is associated with the coherent dynamical evolution of this system in interaction with another identical system. The temperature varying effect with time is manifestly shown in our analyses.     

Operators of observables for a neutral particle with anomalous magnetic moment in an electromagnetic field

The explicit form of operators of kinetic momenta and spin projection for a neutral particle with an anomalous magnetic moment in constant homogeneous electromagnetic field is found. The possible applications of the obtained results in neutrino physics are considered.     

Dynamic compressive responses of intact and damaged ceramics from a single split Hopkinson pressure bar experiment

A novel dynamic compressive experimental technique has been developed based on a split Hopkinson pressure bar. This new method dynamically loads the ceramic specimen by two consecutive stress pulses. The first pulse determines the dynamic response of the intact ceramic materiaal and then crushes the specimen, and the second pulse determines the dynamic compressive constitutive behavior of the ceramic rubble. Precise pulse shaping ensures that the specimen deforms at nearly constant strain rates under dynamic stress equilibrium during the loading by both stress pulses. Pulse shaping also controls the amplitudes of loading pulses, the values of strain rates, the maximum strains in the rubble specimens, and the proper separation time between the two loading pulses. The feasibility of the new technique is demonstrated by the experimental results obtained on an AD995 alumina.     

Dynamic Capacity Studies of CIM (Convective Interaction Media)® Monolithic Columns

The characterization of CIM^® DEAE monolithic columns in terms of dynamic binding capacity is presented in this paper. Breakthrough experiments were performed for capacity determination. Bovine serum albumin (BSA) was used as a model protein. It is shown that CIM^® monolithic columns have good batch‐to‐batch reproducibility as well as long‐term stability. The experiments performed under different linear velocities demonstrated that the dynamic capacity is unaffected at least up to a linear velocity of 2450 cm/h. Furthermore, the breakthrough curve slope is constant, indicating that the capacity would remain constant at even higher linear velocities. The adsorption isotherm of BSA dissolved in 20 mM Tris‐HCl buffer shows a constant capacity of around 30 mg/mL of support down to a concentration of 20 μg/mL. The capacity is substantially influenced by the ionic strength; however, 20% of the maximal capacity is still preserved at 0.3 M NaCl.     

Olive-Derived Triterpenes Suppress SARS COV-2 Main Protease: A Promising Scaffold for Future Therapeutics

SARS CoV-2 pandemic is still considered a global health disaster, and newly emerged variants keep growing. A number of promising vaccines have been recently developed as a protective measure; however, cost-effective treatments are also of great importance to support this critical situation. Previously, betulinic acid has shown promising antiviral activity against SARS CoV via targeting its main protease. Herein, we investigated the inhibitory potential of this compound together with three other triterpene congeners (i.e., ursolic acid, maslinic acid, and betulin) derived from olive leaves against the viral main protease (M^pro) of the currently widespread SARS CoV-2. Interestingly, betulinic, ursolic, and maslinic acids showed significant inhibitory activity (IC₅₀ = 3.22–14.55 µM), while betulin was far less active (IC₅₀ = 89.67 µM). A comprehensive in-silico analysis (i.e., ensemble docking, molecular dynamic simulation, and binding-free energy calculation) was then performed to describe the binding mode of these compounds with the enzyme catalytic active site and determine the main essential structural features required for their inhibitory activity. Results presented in this communication indicated that this class of compounds could be considered as a promising lead scaffold for developing cost-effective anti-SARS CoV-2 therapeutics.     

Dynamic Visualization of Free Radicals at Single Oxygen Bubbles using Chemiluminescence

The generation of free radicals is a key process in the formation and the collapse of the bubbles in water, however, the direct and dynamic observation of the radicals in this process at single bubbles has never been achieved. Here, the hydroxyl (OH^.) and oxygen (O₂^.−) radicals at single oxygen bubbles are continuously traced using chemiluminescence (CL), in which these radicals at the bubble react with the surrounding luminol in the solution emitting the light. Varied increase trends of luminescence are observed in the generation of a bubble, floating, short parking at the water/air interface and the final explosion, revealing the complexity in the distribution of radicals at the bubble unprecedentedly. Despite more radicals are observed at the bubble generated at a deep position under the water for the stabilization, almost the same amount of radicals are included in the bubbles that is independent on the water pressure during the production of the bubble. This rich information collected from the dynamic study of bubbles illustrates the complicated generation and distribution process of radicals at the bubbles, and will facilitate the understanding of the function about the bubbles.     

Double-Network Heparin Dynamic Hydrogels: Dynagels as Anti-bacterial 3D Cell Culture Scaffolds

Double cross-linked dynamic hydrogels, dynagels, have been prepared through reversible imine bonds and supramolecular interactions, which showed good pH responsiveness, injectability, self-healing property and biocompatibility. With the further encapsulation of heparin, the obtained hydrogels exhibited good anti-bacterial activity and promotion effects for 3D cell culture.