Tariq Ali's the Book of Saladin: A Khaldunian Study

The Book of Saladin is Ali's metafictional retelling of the conquest of Jerusalem by Salah ad-Din Ayubbi and the rise of the Ayyubid Dynasty. Ali believes that by acquiring the desired social solidarity (Asabiyyah) and displaying the best elements of the Muslim civilization (Umran), Salah ad-Din raised the Ayyubid Dynasty to its grandeur. The fall of Christians and the rise of the Muslims happened in a cyclic mode; therefore, Ibn Khaldun's cyclic theory of the rise and fall of civilizations from his Muqaddimah suits to the theoretical framework of the present research. The study deconstructs the politics of Eurocentric perceptions about the history of crusades and traces the trajectory of the present socio-political conflicts in the Middle East. This paper concludes that for the sake of global peace, Christians and Muslims must liberate themselves from the roots of their bloody historical clashes especially the painful memories of the crusades.

Tariq Ali's Shadows of the Pomegranate Tree: A Khaldunian Study

Tariq Ali's Shadows of the Pomegranate Tree is the postmodern retelling of what happened to the Muslim civilization in Spain and how the Muslims fell from their grandeur in a cyclic mode of rising and fall. Due to the lack of social solidarity (Asabiyyah) and weak civilization (Umran), the Nasrid Empire in Granada became weak and was overrun by the stronger Christian civilization. Ibn Khaldun's Cyclic Theory of the rise and fall of civilizations from his Muqaddimah is applied as a major theoretical perspective and two of his key concepts, Asabbiyah and Umran are also discussed with reference to Ali's work. Ali's metafiction combines politics as well as the poetics of the postmodern culture and shows the relevance of Khaldunian ideas to the current metamorphosis in the Muslim World. The study deconstructs the Eurocentric notions of Muslim history and finds the trajectory of cultural conflicts of Christian-Muslim civilizations.

TECHNOLOGY OF CYCLIC DISTILLATION IN ALCOHOL PRODUCTION

Alternate changing of the steaming periods and liquid overflow allows to intensify mass transfer between liquid and steam and to reduce the specific consumption of heating steam in the process of separation of multicomponent mixtures. Known methods and models have not found widespread practical use due to the lack of mass transfer in the steam period, fluctuations in steam pressure in the collector, the complexity of constructive solutions to ensure cyclic mode, etc. The authors propose a technology for rectification, which involves the cyclic motion of the liquid without interrupting of the supply of heating steam and the construction of a rectification column for its implementation. The purpose of the work was to research the effectiveness of the proposed technology in the process of rectification of alcohol-containing fractions and to establish the specific flow rate of steam in the impurity concentration column. To ensure a cyclic mode, the column was equipped with movable liquid transfer devices connected to actuating mechanismes, which acted according to the controller program, and perforated (scale-shaped) trays. The primary task was to determine the hydrodynamic mode of operation of the contact devices - the lower and upper the critical vapor velocity of at which the liquid is retained on the plates and there is its entrainment. It is established that the vapor velocity in the free section of the column can reach 1.2 m/s or more, and in the openings of the scales must exceed the first critical velocity of 6.5-7.5 m/s. The weeping of the tray occurs at the vapor velocity in the holes of 1.5-1 m/s. The investigations were carried out in the production conditions of the Chudniv branch of SE “Zhytomyr liquor producer ”. It is experimentally proved that in the process of rectification of alcohol-containing fractions, the main impurities are removed completely, the degree of extraction of higher fusel alcohols is increased by 38%, methanol - by 15.6 %, the multiplicity of concentration of the main impurities is increased by 25 %, the higher alcohols - by 40 %, methanol – by 34 %, acrolein – by 36 %. The costs of heating steam are reduced by 30 % compared to typical installations and do not exceed 13 kg/dal of absolute alcohol introduced with feed. Exempted from the key impurities the bottom liquid of the impurity concentration column should be used for hydroselection in the purifying column.

DETERMINATION OF HYDRODYNAMIC CHARACTERISTICS OF MASS-EXCHANGE COLUMN APPARATUS OPERATION IN A CYCLIC MODE

The efficiency of operation of perforated trays in a cyclic mode depends on the accepted hydrodynamic modes, which determine the limits of stable operation of mass-exchange column apparatus. There are no general methods of calculating the boundaries of the hydrodynamic modes of perforated trays operate in the cyclic mode. On this basis, the authors were tasked to determine the hydrodynamic modes of operation of mass-exchange column apparatus equipped with perforated trays, the action of which occurs in the mode of controlled cycles of fluid retention on the plates and the overflow of fluid through all holes or slits. Sieve and scaly trays with arched-type scales without overflow devices were selected for study. The aim of the work was to determine the hydrodynamic modes of operation of the sieve and scaly trays without overflow devices in a cyclic mode of retention and overflow of liquid, determination of lower and upper critical velocity of the vapor in the holes of the sieve and scaly trays, the linear velocity of the vapor in the free cross section of the mass-exchange column apparatus and the relative magnitude of the liquid splash to the upper trays. Liquid flow was monitored using a flowmeter RM, air velocity in the free section of the column was monitored using an anemometer MC-13. It was determined that the lower critical air velocity in the bubbling holes was 5.4 m/s; linear air velocity in free column cross section was 0.25 m/s. The velocity of the air in the holes at which the fluid splashes onto the upper plates begins was 8 m/s; thus linear air velocity in free column cross section was equal to 0.7 m/s. Hydrodynamic modes of scaly trays and corresponding values of air velocity in the free section of the column were established. In bubbling mode it was 0.5…0.9 m/s, in the transitional mode it was 0.9…1.3 m/s and in the jet mode, it was 1.3…2.0 m/s. It was determined that the lower critical air velocity in the holes of the trays, below which the drain of liquid is occurs, was 6.5…7.0 m/s. The upper critical air velocity in the holes of the trays above which the liquid splash on the upper trays is observed was 16 m/s. The air velocity in the free cross section of the column was 1.3…1.5 m/s. the relative magnitude of the liquid splash in the mode of steady operation of scaly trays in the bubbling mode does not exceed 0.1 kg/kg of air, in the jet mode, does not exceed 0.2 kg/kg of air. It is proved that intense overflow of liquid through bubbling holes of the perforated trays occurs at air velocities less than the lower critical. For sieve and scaly trays, this velocity should not exceed 1.5-1 m/s. A slight spillage of liquid through the holes of the trays occurs in the range of values of air velocity in the holes of sieve trays of 1.5-5.3 m/s, in the holes of scaly trays of 1,5-6,4 m/s.

ABOUT OF THE DYNAMICS OF FORCED OSCILLATIONS IN NONLINEAR SYSTEMS

The article discusses the issues of determining the effectiveness indicators of an electromagnetic vibration exciter in a dynamic mode of operation. It is established that this system is whole system of electrical and mechanical circuits. In this case, the mechanical part operates in the mode of forced vibrations. The oscillation parameters of the system, such as amplitude, frequency, and phase, largely depend on the parameters of the system load. For the analysis of this system, differential equations describing an electromagnetic vibration exciter have been compiled. For this purpose, the dependence L(x) of the inductance on the displacement is used. The dynamic modes of one of the ways of asynchronous excitation of an electromagnetic vibration exciter are investigated. The accuracy analysis and the evaluation of the results were performed by the Fisher criterion for the regression model. To analysis of transients in the electromagnetic vibration exciter, were used the software packages WinFact and MatLab to simulate and optimize dynamic systems. It is established that the system, depending on the initial conditions in the simulation, goes into one of two very different modes. In this case, the initial zero conditions switch the system into a “cyclic” mode, and in other, non-zero conditions, the system goes into an approximate cyclic mode, characterized by a higher speed of movement of the anchor. The parameters of the steady state cyclic movement are determined by the method of harmonic balance. The obtained results allow us to describe autoparametric oscillations of the electric equivalent circuit. It has been established that the compilation of harmonic balance equations corresponding to a linear system helps simplify the solution of the task of determining the dynamics of forced oscillations. The expressions for determining the tractive force and the current flowing through the circuit are obtained, the wavelet spectra of vibration are constructed using the MatLab software package. As a result, for the mechanical part of a nonlinear system, in fact, it is necessary to solve only harmonic balance equation. The results show that this theoretical model allows a more qualitative and accurate assessment of the observed phenomenon. Based on this, the asymptotic conditions for solving the harmonic balance equations of a nonlinear system are determined. The expressions for the electromagnetic force acting on the anchor are obtained, the conditions for the harmonic balance of the mechanical part of the system are determined. The expressions obtained allow us to construct the amplitude-frequency characteristics of the electromagnetic vibration exciter. In conclusion, not only qualitative, but also quantitative estimates of the observed phenomena were obtained. It has been established that mechanical oscillations of a nonlinear system are insensitive to changes in the supply network and practically have a large amplitude with a constant frequency.