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A new droplet collision and coalescence model was presented, a quick-sort method for locating collision partners was also devised and based on theoretical and experimental results, further advancement was made to the droplet collision outcome. The advantages of the two implementations of smoothed particle hydrodynamics (SPH) method were used to limit the collision of droplets to a given number of nearest droplets and define the probability of coalescence, numerical simulations were carried out for model validation. Results show that the model presented is mesh-independent and less time consuming, it can not only maintains the system momentum conservation perfectly, but not susceptible to initial droplet size distribution as well. [ABSTRACT FROM AUTHOR]

This paper presents a general approach to solution of the complex simulation problem of spindle units (SUs) running on rolling bearings (ball bearings and roller bearings) and proves the necessity of making a complex analysis of their nonlinear tribo-mechanical properties at the development stage. For doing this, we apply SU beam analytical diagrams and develop a complex mathematical model of SUs, which incorporates theparticular models, e.g. elastic-deformation, dynamic and heat models, and the model of the bearing fatigue life. To facilitate practical analysis in design, we develop software and demonstrate its application by examples of the comparative analysis the typical structures of SUs. [ABSTRACT FROM AUTHOR]

According to the World Health Organization reports, tuberculosis (TB) remains one of the top 10 deadly diseases of recent decades in the world. In this paper, we present the modeling, analysis and simulation of a mathematical model of TB transmission in a population incorporating several factors and study their impact on the disease dynamics. The spread of TB is modeled by eight compartments including different groups, which are too often not taken into account in the projections of tuberculosis incidence. The rigorous mathematical analysis of this model is provided, the basic reproduction number ( R 0 ) is obtained and used for TB dynamics control. The results obtained show that lost to follow-up and transferred individuals constitute a risk, but less than the cases carrying germs. Rapidly evolving latent/exposed cases are responsible for the incidence increasing in the short and medium term, while slower evolving latent/exposed cases will be responsible for the persistent long-term incidence and maintenance of TB and delay elimination in the population. The numerical simulations of the model show that, with certain parameters, TB will die out or sensibly reduce in the entire Democratic Republic of the Congo (DRC) population. The strategies on which the DRC's health system is currently based to fight this disease show their weaknesses because the TB situation in the DRC remains endemic. But monitoring contact, detection of latent individuals and their treatment are actions to be taken to reduce the incidence of the disease and thus effectively control it in the population. [ABSTRACT FROM AUTHOR]

The prediction precision of mechanics parameters such as rolling force and torque affects the yield, quality, cost, and benefit of products during the cold strip rolling. The lever arm coefficient is the core linking rolling force and torque, but there is no mathematical model of this in cold rolling. The distribution of rolling pressure and the change rule of lever arm coefficient under different reduction, forward and backward tension stress, deformation resistance, and friction coefficient in cold rolling are illustrated based on 3D (three-dimensional) elastic-plastic FEM (finite element model) simulation. The mathematical model of lever arm coefficient is built according to online measured data processed by BP (back propagation) neural network in the tandem cold rolling plant. The predicted rolling forces calculated on the basis of this model and upper bound method are consistent with online measured values. The proposed model provides valuable guidelines to determine the reduction and check the strength of the equipment such as rolls and stands. [ABSTRACT FROM AUTHOR]

Electronic jamming is the key technology of electronic countermeasure, for which models and simulations are studied on noise jamming, deception jamming, and chaff jamming. In the noise jamming, the simulation analysis of radio frequency noise jamming is conducted and the theoretical models of other forms of noise jamming are built. The simulation analysis of range-gate pull off (RGPO) is carried out in the deception jamming. In addition, theoretical modeling and simulation analysis of chaff jamming are carried out with the Monte Carlo method. Simulation results show that the models are correct and can be used to simulate the statistical characteristics of chaff jamming. With the development and wide application of electronic technology, radar, communication, navigation, and IFF signals constitute a complex electromagnetic environment. It is a must to study electronic jamming technology in the complex electromagnetic environment, which will play an indispensable role in the construction of information team and victory in the countermeasure of information technology. [ABSTRACT FROM AUTHOR]

A hybrid discrete-continuum model of tumor growth in the avascular phase considering capillary points is established. The influence of the position of capillary points on tumor growth is also studied by simulation. The results of the dynamic tumor growth and the distribution of oxygen, matrix-degrading enzymes, and extracellular matrix-concentration in the microenvironment with respect to time are shown by graphs. The relationships between different oxygenated environments and the numbers of surviving, dead, proliferative, and quiescent tumor cells are also investigated. [ABSTRACT FROM AUTHOR]

Water penetration behavior in the polymer melt is an important part of water-assisted injection molding (WAIM) technology. Based on the traditional injection molding model, an improved WAIM mathematical model was proposed, in which shear stress transportation κ- ω turbulent model was used to reflect the turbulent characteristics of water and predict the cooling of the melt by the water. In addition, the free interface of water/melt two-phase flow was tracked by volume of fluid, and the distribution of temperature, velocity, and pressure were calculated by computational fluid dynamics method. The results showed that in the long straight water channel, water penetration was uniform and smooth, and wall thickness difference is small. However, it was easy to produce water fingering in variable cross-section and L-shaped water channels. The fingering could effectively be reduced by the smooth transition of size and fillet. Reasonable fillet radius made the distribution of residual wall thickness of the inner and outer relatively uniform, but the wall thickness difference was inevitable. The fast cooling of the melt by the water was verified, so the cycle time could be shortened effectively. [ABSTRACT FROM AUTHOR]

Glioblastoma (GBM), a highly aggressive (WHO grade IV) primary brain tumor, is refractory to traditional treatments, such as surgery, radiation or chemotherapy. This study aims at aiding in the design of more efficacious GBM therapies. We constructed a mathematical model for glioma and the immune system interactions, that may ensue upon direct intra-tumoral administration of ex vivo activated alloreactive cytotoxic-T-lymphocytes (aCTL). Our model encompasses considerations of the interactive dynamics of aCTL, tumor cells, major histocompatibility complex (MHC) class I and MHC class II molecules, as well as cytokines, such as TGF-β and IFN-γ, which dampen or increase the pro-inflammatory environment, respectively. Computer simulations were used for model verification and for retrieving putative treatment scenarios. The mathematical model successfully retrieved clinical trial results of efficacious aCTL immunotherapy for recurrent anaplastic oligodendroglioma and anaplastic astrocytoma (WHO grade III). It predicted that cellular adoptive immunotherapy failed in GBM because the administered dose was 20-fold lower than required for therapeutic efficacy. Model analysis suggests that GBM may be eradicated by new dose-intensive strategies, e.g., 3 × 108 aCTL every 4 days for small tumor burden, or 2 × 109 aCTL, infused every 5 days for larger tumor burden. Further analysis pinpoints crucial bio-markers relating to tumor growth rate, tumor size, and tumor sensitivity to the immune system, whose estimation enables regimen personalization. We propose that adoptive cellular immunotherapy was prematurely abandoned. It may prove efficacious for GBM, if dose intensity is augmented, as prescribed by the mathematical model. Re-initiation of clinical trials, using calculated individualized regimens for grade III–IV malignant glioma, is suggested. [ABSTRACT FROM AUTHOR]

A mathematical model is developed to describe autowave processes in a catalytic fixed bed, which takes into account changes in coefficients of interphase heat and mass transfer and thermal conductivity of the catalytic bed, depending on the current values of system parameters. The behavior of the phase trajectories of the dynamic system is studied by methods of qualitative and numerical analysis, and an effective technique is proposed for searching for a phase trajectory corresponding to the autowave solution of the problem. Numerical studies of the mathematical model of autowave processes are performed, and the effect of system parameters on technological characteristics of the process, such as the maximum temperature and wave-propagation velocity, is considered. [ABSTRACT FROM AUTHOR]

Mathematical simulation of impact‐induced deep penetration of an absolutely rigid spherical particle into an ideally plastic medium is performed; the law of particle motion and the distance covered by the particle are determined. The problem for a particle whose size varies owing to attrition is solved. [ABSTRACT FROM AUTHOR]