NMR data for 90+ natural sesquiterpenes possessing triquinane cores were examined with the help of a relatively fast parametric/DFT hybrid computational method, DU8+. Thirteen of these compounds, ...i.e., approximately 14% of the sample, required structure correction. This rate of misassignment is similar to the percentage of misassigned halogenated sesquiterpenes reported previously.
A series of experiments in a thin layer geometry performed at the HYKA test site of the KIT. Experiments on different combustion regimes for lean and stoichiometric H2/air mixtures were performed in ...a rectangular chamber with dimensions of 200 × 900 x h mm3, where h is the thickness of the layer (h = 1, 2, 4, 6, 8, 10 mm). To model a gap between a fuel cell assembly and a metal housing, three different layer geometries were investigated: (1) a smooth channel without obstructions; (2) a channel with a metal grid filled 25% of chamber length and (3) a metal grid filled 100% of chamber length. The blockage ratio of metal grid has changed from 10 to 60% of cross-section. Detail measurements of H2/air combustion behavior including flame acceleration (FA) and DDT in closed rectangular channel have been done. Five categories of flame propagation regimes were classified. Special attention was paid to analysis of critical condition for different regimes of flame propagation as function of layer thickness and roughness of the channel. It was found that thinner layer suppresses the detonation onset and even with a roughness, the flame may quench or, in thicker layer, is available to accelerate to speed of sound. The detonation may occur only in a channel thicker than 4 mm.
•Combustion regimes for hydrogen/air mixtures (4–30%H2) in a closed thin layer geometry.•The layer thickness from 1 to 10 mm models a gap between fuel cell assembly and its housing.•An effect of metal grid and wall roughness on flame dynamics.•Five categories of flame propagation regimes depending on mixture reactivity and a layer thickness.
•Methods of cancer treatment and their limitations are described.•Approaches to mathematical modeling of cancer are presented.•Ways of treatment optimization via modeling are considered.•Detailed ...models and optimization methods are given.•Modern understanding of cancer and its origin is discussed.
Despite significant advances in oncological research, cancer nowadays remains one of the main causes of mortality and morbidity worldwide. New treatment techniques, as a rule, have limited efficacy, target only a narrow range of oncological diseases, and have limited availability to the general public due their high cost. An important goal in oncology is thus the modification of the types of antitumor therapy and their combinations, that are already introduced into clinical practice, with the goal of increasing the overall treatment efficacy. One option to achieve this goal is optimization of the schedules of drugs administration or performing other medical actions. Several factors complicate such tasks: the adverse effects of treatments on healthy cell populations, which must be kept tolerable; the emergence of drug resistance due to the intrinsic plasticity of heterogeneous cancer cell populations; the interplay between different types of therapies administered simultaneously. Mathematical modeling, in which a tumor and its microenvironment are considered as a single complex system, can address this complexity and can indicate potentially effective protocols, that would require experimental verification. In this review, we consider classical methods, current trends and future prospects in the field of mathematical modeling of tumor growth and treatment. In particular, methods of treatment optimization are discussed with several examples of specific problems related to different types of treatment.
In this paper flame instabilities are analyzed utilizing the Sivashinsky equation in order to derive the flame wrinkling factor. This is a synthetic variable representing the excess of flame surface ...which is obtained for a wide range of hydrogen concentrations, considering the Darrieus–Landau and the Thermo-Diffusive instabilities, and also taking into account the effect of acceleration. Additionally, the time for the development of the cellularity is also analyzed. The study is carried out for a wide range of hydrogen–air mixtures as well as for a large domain of accelerations. Models representing both the wrinkling factor and the time of development of the instabilities are obtained.
•Flame instability model (DL, RT, TD) based in Sivashinsky equation.•Model based in the calculation of the wrinkling factor.•Evolution and dynamics of the wrinkling factor analyzed.
Abstract
The article is devoted to optimization of the mean-square approximation procedures for iterated Ito stochastic integrals of multiplicities 1 to 4 based on multiple Fourier-Legendre series. ...The mentioned stochastic integrals are part of strong numerical methods with convergence orders 1.0, 1.5, and 2.0 for Ito stochastic differential equations with multidimensional non-commutative noise. We show that the lengths of sequences of independent standard Gaussian random variables required for the mean-square approximation of iterated Ito stochastic integrals can be significantly reduced without the loss of the mean-square accuracy of approximation for these stochastic integrals.
The aim of this study is to scientifically substantiate an integrated methodology for assessing the socioeconomic efficiency of integrated investment projects (IIP) based on the principles of ...sustainable development and international approaches to assessment with a case study of IIP for creating innovative infrastructure in the Far Eastern Federal District (FEFD) of Russia. The object of the study is complex investment projects for the development of innovative infrastructure, implemented in the FEFD. The subject of the study is a set of forecast socioeconomic effects and consequences of implementing the IIP for the development of innovation infrastructure in the FEFD. The article discusses the main directions and instruments of state policy to support IIP in the FEFD, as well as approaches to evaluating such projects. The features and problems of methodological support for assessing the social (economic) efficiency of IIP are revealed. The scientific novelty of the research is the following: existing domestic and foreign methodological approaches to achieving the goal set in it were adapted, the corresponding tools were modified, and experimental calculations were performed with a case study of the project of the Russky innovative scientific and technological center, making it possible to obtain quantitative estimates of the social effectiveness of the project in the context of types of generated effects. The results of the study will make it possible to improve the validity of decisions on implementing budget investments and provision of state support measures for individual projects; they will form a systemic basis for prioritizing a portfolio of existing and future projects (reorienting state support to projects with maximum social impact) and will contribute to improving the structure of initiated projects in favor of more socially effective options for their implementation.
A model of a redundant repairable system of the rank structure is considered. Its time operation is determined by distributions of general form. In order to evaluate the gradient of the probability ...of system failure in a given time interval, the fast simulation method is proposed. A numerical example illustrates the application of this method to assess how the repair rates of components of different types affect the reliability of the entire system.
This paper presents results of experimental investigations on spherical and cylindrical flame propagation in pre-mixed H2/air-mixtures in unconfined and semi-confined geometries. The experiments were ...performed in a facility consisting of two transparent solid walls with 1 m2 area and four weak side walls made from thin plastic film. The gap size between the solid walls was varied stepwise from thin layer geometry (6 mm) to cube geometry (1 m). A wide range of H2/air-mixtures with volumetric hydrogen concentrations from 10% to 45% H2 was ignited between the transparent solid walls. The propagating flame front and its structure was observed with a large scale high speed shadow system. Results of spherical and cylindrical flame propagation up to a radius of 0.5 m were analyzed. The presented spherical burning velocity model is used to discuss the self-acceleration phenomena in unconfined and unobstructed pre-mixed H2/air flames.
•We study spherical and cylindrical H2/air flames in un- and semi-confined geometries.•A large-scale shadowgraphy for high-speed applications used to measure visible flame.•Mixture specific flame acceleration observed for spherical flame propagation.•A spherical burning velocity S(sph) for undisturbed flame propagation was derived.•The model is in agreement with experimental data for spherical flame propagation.
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