A Design Method for a Variable Combined Brake System for Motorcycles Applying the Adaptive Control Method

The variable combined brake system (VCBS) is a mechanism for motorcycles to simultaneously activate the front and rear brake systems by using one brake lever or pedal. The purpose is to reduce the risk of rollover accidents due to misuse of the front brake when panic braking. Due to its ability in a wide variation range of braking force distribution (BFD) ratios between the front and rear wheels, the VCBS can simultaneously achieve high braking effort and driving comfort performances, provided that the BFD ratio is designed appropriately. This paper aimed to develop the design method for the VCBS. A mathematical model of the VCBS mechanism is derived, and a parameter matching design method that applies adaptive control theory is proposed. A prototype of VCBS is designed and built based on the proposed method. The straight-line braking test results show that the motorcycle equipped with the VCBS prototype effectively obtained a high braking performance in deceleration. The obtained maximum deceleration is an average of 6.37 m/s2 (0.65 g) under an average handbrake lever force of 154.29 N. For front brake failure, maximum deceleration is obtained at an average of 3.38 m/s2 (0.34 g), which is higher than the homologation requirement of 2.9 m/s2.

PHYSICAL AND COMPOSITIONAL CHARACTERISTICS OF CHESTNUT FRUITS

The objective of this study was investigationofphysical and compositional fruits characteristics of six chestnut cultivars. The fruits belonging to these cultivars were subjected to physical and chemical composition determinations, and the obtained results were comparatively analysed. It can be noticed that there are significant differences between cultivars for all the analysed traits. A high variability was found between cultivars in terms of nutrients content. The moisture content of chestnuts analysed in this study ranged from 51.63% to 58.42%. The protein content recorded values between 5.40 and 7.18% fresh matter. The polyphenols content in cultivars taken under analysis was between 1.65 and 19.60 mg GAE/g, which is a very large variation range between different cultivars. The obtained values of antioxidant activity of chestnuts are high, ranging from 0.73 to 9.90 mg Trolox/g of fresh substance, revealing also a wide variation range. Among the individual phenolic compounds, elagic and gallic acids were determined in higher amounts. The results of this study have shown that chestnut fruits contain significant concentrations of primary and secondary metabolites that are known for their positive effects on human health.

Определение расходных характеристик сопловых аппаратов с сверхзвуковыми прямоугольными соплами при моделировании переменных режимов малорасходных турбин

В работе приводятся обобщающие зависимости коэффициентов расхода сопловых аппаратов с сверхзвуковыми прямоугольными соплами в широком диапазоне изменения определяющих геометрических и режимных параметров, базирующиеся на экспериментальном материале по коэффициентам расхода для транс- и дозвуковых решеток профилей. Получены эмпирические формулы, учитывающие влияние степени конфузорности, относительной высоты сопел и числа Рейнольдса на коэффициент расхода соплового аппарата. Показано слабое влияние на коэффициент расхода относительного шага сопел в области его оптимальных значений определенных по минимуму потерь кинетической энергии и числа Маха. Переменные режимы работы сопла учитываются зависимостью относительного коэффициента расхода в функции от числа Рейнольдса. Полученные в работе эмпирические зависимости позволяют использовать их при моделировании переменных режимов и многорежимной оптимизации малорасходных турбин.The research introduces generalizing functions of mass flow rates in supersonic rectangular nozzle diaphragms in wide variation range of controlling geometry and duty parameters, based on experimental material on the mass flow rates for trans- and subsonic cascades. Empirical functions which take into account influence of convergence ratio, the relative height of the nozzles and the Reynolds number on the mass flow rate of nozzle diaphragms are obtained. It is shown that the relative nozzle step in the area of its optimal values determined from the minimum kinetic energy loss and Mach number slightly effects on the mass flow rate. Variable duties of the nozzle are taken into account by the dependence of the relative mass flow rate from the Reynolds number. The empirical dependences obtained in the paper allow using them in modeling variable duties and multimode optimization of low-consumption turbines.

Heavy metals as indicators of dynamics of the circulation of substances on recultivated lands of the Western Donbass

The biological cycle of matter in artificial plantations of forest rehabilitation sites of the Western Donets Basin was studied. The content and patterns of microelements’ migration in plants, tree waste, litter and soils are determined. Manganese, copper, lead, chromium, nickel and titanium were under investigation. The dependence between the microelements content in tree waste, litter and soil and their main physicochemical characteristics as well as the correspondence of forest growing conditions to the optimal limits of the elements’ content in soil for plants normal development are characterized. The factors influencing the trace elements content in the fill-up reclaiming layer are analyzed. The reasons for the wide variation range of the microelements content in the leaves of experimental trees, and the possibility of using different ground types and plantation patterns are explained. It makes possible to estimate the importance of the biological stage of rehabilitation for the preventing technogenic influence on the environment.

Hypersonic Cruise Vehicle Attitude Control Based on NESO

Hypersonic cruise vehicles traverse abroad flight envelope, severe interference and aerodynamic parameters of great uncertainty. Aiming at these problems, the attitude control system is divided into two first-order subsystem based on the backstepping, which improved by introducing the command filter and the error signal correction. simplifies the solution of pseudo control of derivative, and considering the attenuation and noise on the system state. The aerodynamic parameters wide variation range and disturbances were classified into two subsystems uncertainties, and two sets of nonlinear extended state observer (NESO) were used to estimate them. The backstepping controller based on NESO was designed with combined estimated value and backstepping method. Additionally used fuzzy logic to tuning the NESO parameters. Simulation results show that the method can track the control signal accurately, and has good robustness against parameter uncertainty.