Stable Mode Operation Research Articles

Модернизация насадочных ректификационных колонн с применением математической модели разделения многокомпонентной смеси

The scientific and technical problem of mathematical modeling and calculation of separation of hydrocarbon mixtures in industrial columns with chaotic and regular nozzles is solved. Multicomponent transfer is calculated using a matrix of volumetric mass transfer coefficients, and the reverse (longitudinal) mixing of steam and liquid flows by Pekle numbers with back-mixing coefficients. The task of developing options for upgrading the stabilization column of the oil and gas condensate mixture at an oil refinery is considered. Calculated profiles of concentrations of key components in the mixture are presented. The required height of the nozzle layer has been determined. After upgrading the column with a new nozzle, a stable mode of operation of the unit is provided in the specified range of loads and the composition of the mixture. We also solved the problem of designing two industrial columns in the technological scheme for the separation of benzene from stable condensate (gasoline fraction). As a result of calculations based on a mathematical model, the operating and structural characteristics of columns with the use of chaotic metal nozzles "Injekhim-2012"were established.

Visual experimental investigation on stable operating process of the plane-radial rotating detonation engine

Using visual observation methods, assisted by synchronous measurement of dynamic pressure and ion tracks, the flow field structures of stable operating modes in plane-radial rotating detonation engine (RDE) are revealed, and the influences of injection conditions on the RDE stable operating range are analyzed. The flow field structures of single-wave mode, symmetric dual-wave mode and triple-wave mode are observed. Typical structures such as rotating detonation wave (RDW), oblique shock wave, combustion products, deflagration surface and contact discontinuity are obtained in the flow fields. Obvious reactants pre-combustion ahead of detonation wave is found in the combustor, and low-frequency oscillation phenomenon is gained under specific conditions. With the increase of wave-head number in combustor, the detonation-wave height and parameters decrease. The RDW propagating velocity and pressure peak are higher in single-wave operating mode, but the flow fields in multi-wave mode are more stable. Both the RDW velocity and pressure peak increase generally with equivalence ratio. Keeping the equivalent ratio (ER) fixed, as the mass flow rate increases, the number of detonation wave in combustor increases, and the operating mode transforms from single-wave mode to multi-wave mode. Keeping the mass flow rate fixed, when the equivalent ratio deviates from stoichiometric ratio, the operating mode varies from multi-wave mode to single-wave mode. Additionally, with the mass flow rate increasing, the ER upper and lower limits of multi-wave mode decrease linearly, and the operating range of dual-wave mode remains unchanged. Mass flow rate has little influence on the ER lower limit of the RDE stable operation, which is approximately ER=0.55 in this structure.

Analysis of capability for improvement of basic mathematical model of electrode of ferro-alloy furnace

The article analyzes the Mathematical Model of The Self-Baking Electrode which is defined as basic. Its advantages and disadvantages are determined. Criterias for creating more advanced mathematical model for equalizing the thermal field of the Electrode are proposed.
 The problem of calculating the thermal field is solved by the the method of elementary heat balances of electrode. For this goal the simulated area is divided into annular (cylindrical) elements along the radius and height of the electrode.The calculation of the temperature field of the electrode is carried out in two stages: I – with boundary conditions and currents for the parts of the electrode facing to the center of the smelting furnace; II – with boundary conditions and currents for the parts of the electrode facing to the lining. 
 The mathematical model takes into account an effect of the ribs and the hood on the distribution of electric current and Joule’s Heat over the cross section of the Electrode. In case heating ferromagnetic materials under impact of an electromagnetic field, the magnetic permeability at first decreases relatively slowly, and then droping down sharply as a certain temperature (Curie Point) is reached. The material loses its magnetic properties completely and goes into into a paramagnetic state.
 The value of the electrode current changes according to the graph from the starting value to the working value and then remains constant. The current density of the electrode along the radius is unequal due to the action of the surface effect, as well as due to existence of a metal hood and ribs, the electrical conductivity of which is higher than conductivity of special carbon paste.
 The goal of the work is to create modern mathematical model of the secondary current network of electric smelting furnace which could improve baking conditions of the Electrode and to reach the state of its temperature field to equable. This would create a stable mode of operation of the furnace.The paper analyzes the main features of the mathematical model of the secondary network of the smelting furnace, identifies the stages of development and formulates the main assumptionssimplifications that could be accepted wile creating this model.

Optical and mass spectral characterization of the electrospray ionization/corona discharge ionization interface

The interchange between electrospray ionization (ESI) and corona discharge ionization (CDI) with respect to applied bias on the needle is customarily placed at the point where light production begins at the tip of the needle. If a liquid sample is flowing through a needle that is observed to produce light, the ionization process is assumed to be harsher and the term coronaspray ionization has been coined to describe this hybrid ionization mechanism. In this work, the transition between ESI and CDI is investigated with respect to applied bias through optical and mass spectrometric measurements. As a function of applied bias potential, the optical signal at the tip of the needle was recorded simultaneously with the resultant ionization products. In this effort, the production of ions from an electrospray ionization needle has been demonstrated to produce light regardless of bias if ions are also formed. With this understanding, an ESI/CDI needle was designed to allow the bias to be temporarily pulsed over the ‘onset’ voltage necessary for ionization and the rise and decay of the optical signal was measured. Positive mode CDI onset to a stable discharge state within 0.05 ms, while positive ESI required 1.9 ms to reach a stable condition. In the negative mode, the stability of the ionization process was highly variable in both ESI and CDI modes, though CDI was generally faster to reach the stable mode of operation. When the resultant ions were investigated, the effect of increased bias on an ESI needle was found to be species-dependent. Recognizing that the range of compounds probed was limited, for those examined, it appears that stable, non-labile species may be investigated via ESI under extremely high biases while labile species demonstrate a narrow range of stable biases before significant fragmentation occurs.

Gas Discharge Atmospheric Pressure Systems for the Biomedical Use

The analysis of world literature is carried out, which indicates the intensive development of the scientific and technical field “Plasma in Medicine” based on the use of different gas-discharges for biomedical purposes. The atmospheric pressure plasma discharge systems have the favorite features and are very suitable for medical physiotherapy, bactericide treating and even for sterilization. The systems with non-thermal plasma are in the most use and one of their applications is generation of gas ozone. The given paper is devoted to looking for atmospheric pressure discharge modes, which are more suitable for ozone therapy equipment taking into account the peculiarities of such type of electronic apparatus. As practice shows, for the generation of ozone, discharges with a secondary-emission cathode and non-thermal plasma are most preferable, and of these two types of discharges are discharges with a dielectric barrier and corona discharges with uncoated metal electrodes. The article focuses on the appropriateness of the use of a corona discharge for ozone therapy equipment. This is justified by the fact that the corona discharge ozonizers have certain design advantages over the ozonizers on the discharge with dielectric barriers, namely that the advantages of the ozonizers on the corona discharge are the absence of a expensive barrier and low resistance to the gas flow, so there is no need to significantly increase the pressure at the ozonizer oxygen inlet, and possibility of power supplying the ozonizer with DC voltage. Also, ozonizers on the corona discharge have a lower cost. From the literature and the authors' own practice, there is a wide variety of configurations of electrode systems for creating the corona discharge, but they always have electrodes with a small radius of curvature of the surface: threads, wires, nets, various pointed needles, serrated electrodes. The article considers the physical mechanism of maintaining the corona discharge of a unipolar or bipolar type and notes the role of secondary electron emission of the cathode. All types of corona discharge are capable of generating ozone because discharge electrons have the energy required to dissociate oxygen molecules in a non-thermal gas environment. Then a free oxygen atom attaches to an oxygen molecule to form a metastable ozone molecule. It is noted that the corona discharge and ozone generation were studied in detail mainly in unipolar point-of-plane or wire-in-pipe systems. The data on ozone generation in bipolar discharge is not enough to develop an ozone therapy apparatus, although this form of discharge is interesting because it requires relatively small values of the supply voltage and operates at a direct current. Based on the review of the prospects for the use of bipolar corona discharge in biomedical apparatus and practical considerations of the realistic and expanded future usage of bipolar corona equipment in the ozone therapy, the tasks have been formulated to be solved. It is necessary to thoroughly study the characteristics of the developed equipment and the influence of various external operational factors and physico-chemical processes in the ozonizer electrode system on them. It is necessary to ensure that the parameters of the equipment are maintained during operation, which means that during the eight-hour working day and with the total time between failures of at least 1000 hours. Also, it is necessary to take into account the effect of the decomposition of ozone molecules at elevated temperatures and not to allow excessive heating of the ozonizer. These requirements must be met by choice of the configuration and materials of the electrode system and must be experimentally verified. It is proposed to ensure the linearity of the calibration characteristics of the ozonizer and to formalize it mathematically to simplify the setting and maintenance of stable operating modes of ozone equipment. It is necessary to prove its therapeutic efficacy, including for sterilization treatment, with the participation of medical specialists.

Analysis of Stable Modes of a Scalable Coupled Oscillator Array

This brief proposes a scalable array of actively coupled oscillators based on vertex-shared expansion of multiple sub-arrays. We analytically prove that as a result of this proposed scaling, the expanded array preserves the stable operating modes of the sub-arrays. In addition, we verify the expected transient and steady-state behaviour of the scaled structure using time-domain simulation. Furthermore, we demonstrate that the proposed topology is resilience to element-to-element variation as the dimensions scale. This offers a promising solution for large scale signal distribution in phased arrays.

Choice of Parameters for the Electrodrive Diagnostic System of Hybrid Vehicle Traction

Abstract When operating a hybrid vehicle (HEV), it is important to reduce maintenance and repair costs. The HEV electric drive (ED) consists of electronic, electrical and mechanical parts and is considered a complex diagnostic model. The availability of an electrical part greatly simplifies the process of monitoring and obtaining information about the state of the system. In order to create a hybrid diesel-electric propulsion system (HDEPS), the choice of structural and functional parameters as diagnostic ones is justified, the control points are chosen, and the necessary accuracy and unambiguity of measurements are determined. Qualitative evaluations of the electrical processes occurring in the power supply circuit of ED from a high-voltage accumulator battery for the selection of diagnostic parameters according to the criteria of sensitivity, informative character, stability and manufacturability of measurements are presented. It has been revealed that during HDEPS diagnostics both stable and transient modes of operation of electric machines should be considered; for analysis of ED technical state it is necessary to have information about current mode of HDEPS load; for measurement of instantaneous values of supply voltage and consumption current it is necessary to select the sensors with short response time and linear conversion function. In terms of sensitivity to structural changes in the circuit and parametric deviations, it is necessary to choose, as diagnostic parameters, the voltage or current, depending on the mode of operation of the ED and the point of measurement of the electrical value. The obtained results are the basis for creating a new system of diagnostics of electric power supply HDEPS in this direction.

BaCe0.7–xZr0.2Y0.1FexO3–δ derived from proton-conducting electrolytes: A way of designing chemically compatible cathodes for solid oxide fuel cells

The present study describes the rational engineering, preparation and characterisation of new mixed ionic-electronic conductors (MIECs) having great potential for application in solid oxide fuel cells (SOFCs) based on proton-conducting electrolytes. The developed MIECs are derived from promising Ba(Ce,Zr)O 3 -materials doped with iron as a transition element: BaCe 0.7–x Zr 0.2 Y 0.1 Fe x O 3–δ (x = 0–0.7, Δx = 0.1). The comprehensive analysis of the functional properties (crystal structure, densification, microstructure, defect structure, thermal expansion behaviour, electrical conductivity) indicate that a moderate iron content is beneficial in order to achieve a certain compromise. In detail, the gradual Fe-doping results in an enhancement of transport properties (including, ionic-electronic conductivity level) and deterioration of mechanical characteristics (an increase of average thermal expansion coefficient values). The composition with x = 0.6, identified as more optimal, was used as a cathode for an intermediate-temperature SOFC; this cathode displays a satisfactory polarisation resistance level, 0.21 Ω cm 2 at 700 °C, without the use of any additional electroactivation technique. The obtained results indicate that BaCe 0.7–x Zr 0.2 Y 0.1 Fe x O 3–δ MIECs having one of the highest chemical compatibility with state-of-the-art proton-conducting electrolytes can be considered as advanced electrodes for designing new solid oxide electrochemical devices with prolonged and stable operation mode. • BaCe 0.7–x Zr 0.2 Y 0.1 Fe x O 3–δ (BCZYFx) materials were prepared for the first time. • The BCZYFx materials are single-phase across the entire x range (0 = x ≤ 0.7). • Fe-doping leads to an increase in both ionic and electronic conductivities (at x ≥ 0.4). • At the same time, TECs values increase and chemical strain becomes more pronounced. • BCZYF0.6 with an optimal combination of properties was utilised as a SOFC cathode.

Magnetic field design for miniature pulse Penning ion source

Magnetic field configuration for a miniature pulse Penning ion source was designed in this work. The amplitude-time characteristics of discharge and extracted currents were investigated as a function of gas pressure for various magnetic field magnitude and configuration An effect of magnetic field configuration on the Penning’s discharge modes and characteristics of the extraction current impulse were experimentally shown. Stable operation modes of the ion source were found in this work. Also the appropriate ranges of working gas pressure and magnetic field configuration were demonstrated, at which the current pulse of the extracted ions had a quasi-rectangular form. For better understanding real magnetic fields distributions of within the discharge cell magnetic field have been calculated in COMSOL software.

Theoretical investigation of pulse-to-pulse instabilities in a synchronously pumped femtosecond optical parametric oscillator

A singly resonant synchronously pumped optical parametric oscillator (SPOPO) based on the experimental setup of J. Opt. Soc. Am. B 36, 131 (2019)JOBPDE0740-322410.1364/JOSAB.36.000131 is studied theoretically. Stable, oscillatory, and chaotic operation modes of the SPOPO are investigated. The need of the self- and cross-phase modulation terms in the theoretical model for the explanation of the instabilities is demonstrated. The theoretical values of the wavelengths of the signal spectrum maxima are found. The evidence of chaos by the calculation of the Lyapunov exponent is provided. The possibilities to avoid the instabilities are discussed.

Traction control and diagnostics of electric and unmanned vehicles on roller stands

The authors of the article analyze the possibilities of correct diagnostics of unmanned and electric vehicles on modern power and inertia roller stands. The purpose of this work is to improve the quality of monitoring the technical condition of wheeled vehicles by providing highly informative and stable test modes of operation in the process of their diagnostics. To achieve this target, we have developed test methods for wheeled vehicles, the implementation of which it is proposed to use a hybrid designed stand allows to measure force and power to the drive wheels of the vehicle, and temporal and kinematic parameters of the process of its functioning. The study proved that, to ensure a highly stable and test modes of operation of wheeled vehicles in the process of control of technical condition and diagnosis, you should use hybrid stands.

Резонансный электромагнитный вибровозбудитель колебаний с обратной связью

A number of modern technological processes can be significantly intensified due to the use of vibrations with a wide range of oscillation frequencies and amplitudes. In many cases, electromagnetic vibration exciters (EMVE) can serve as the most effective vibration source. Direct conversion of electric energy into mechanical vibration energy opens the possibility for developing devices controlled by electrical methods. However, the oscillatory processes in the circuits containing electromagnetic exciters have been studied to an insufficient extent as applied to vibration engineering. This is connected with the complexity of the effects caused by the nonlinearity of vibration exciter electromagnets and power source on the vibration processes, i.e., a nonlinear dependence of the vibration amplitude and phase on the system parameters and a nonlinear dependence of inductance from the armature displacement. The results from theoretical and experimental studies of oscillating electromechanical systems (EMC) built on the basis of an EMVE with feedback, and the development of methods for analyzing resonant EMVE circuits with a view to obtain the optimal characteristics in low-frequency oscillation modes (LFO) demonstrate the possibilities of economically efficient consumption of electric energy and the performance of the EMVEs used in different industry branches. With the introduction of feedback proportional to the control frequency and the output voltage amplitudes of the EMVE power supply source, it becomes possible to automatically adjust the vibration frequency to the resonance frequency of the elastically suspended EMVE load-carrying member for maintaining constancy of vibration velocity amplitudes and, hence, the system performance. To achieve a stable resonance operation mode of the electromagnetic vibration exciter, the voltage proportional in phase between the inverter output voltage and the load-carrying member motion speed are analyzed. The study results have shown that, owing to the feedback effect that adjusts the driving frequency in phase toward tuning to resonance, a rational EMVE operation mode can be secured.

Solution of the problem of optimum power distribution of individual compensating devices for a group of asynchronous motors for a stable operating mode and for a smoothly changing load

Residential and industrial buildings with large territorial dimensions, have mainly radial power supply schemes, which feed a large number of small and medium capacity 0.4 kV induction motors. For their power supply copper or aluminum cables of small cross-section (with high active resistance) are used. Calculations of electricity losses in such lines show significant values. In order to reduce active power losses in 0.4 kV cable lines, the optimization problem of minimizing active power losses in the radial power supply circuit is solved by optimal distribution of reactive power of a given value between compensating devices. The single-line scheme of power supply of a group of pumps of technological installation of petrochemical production is considered, the mathematical model of the optimization problem on criterion of minimum of active losses in power lines from reactive power flow is made, which limitations are presented as a system of linear algebraic equations. Results of distribution of optimum values of reactive power between compensating devices of asynchronous motors at maintenance of the set tg φ are received. The quantitative estimation of active power loss reduction in power lines at use of capacitor units, which reactive power is optimally distributed, is given.

The control system simulation technology for optimization and determination of the feasible parameters domain

This paper focuses on the simulation technology for optimization of the automatic control system (ACS) parameters vector to be tuned and to provide a stable operating mode eliminating self-oscillations. A hybrid approach (synthesis of optimal control methods and simulation research) for designing ACS using genetic algorithms is presented, which allows taking into account constraints when searching for the optimal solution. Simulation of the ACS was performed using the software tools MATLAB / Simulink / Global Optimization Toolbox. It is shown that the proposed technology for determining the domain of recommended tuning parameters is effective for computer-aided design of ACS, it allows to significantly improve the quality of control and reduce the time spent on pre-setting developed controllers.

КОМПЛЕКСНЫЕ РЕШЕНИЯ ПО ПОВЫШЕНИЮ ЭФФЕКТИВНОСТИ РАЗРАБОТКИ МНОГОПЛАСТОВЫХ ГАЗОВЫХ И ГАЗОКОНДЕНСАТНЫХ МЕСТОРОЖДЕНИЙ

Актуальность. С целью снижения капитальных затрат и сокращения времени выработки запасов газа и конденсата многопластового газоконденсатного месторождения актуальной задачей является обоснование технологии одновременной разработки различных по ресурсно-энергетическому потенциалу и/или фильтрационно-емкостным свойствам эксплуатационных объектов с подачей газа в одну газосборную сеть. Решение этой задачи актуально как на стадии проектирования, так и в зрелой стадии разработки месторождения на режиме истощения пластовой энергии. В условиях резкого различия ресурсно-энергетического потенциала и фильтрационно-емкостных свойств разрабатываемых объектов низконапорные скважины при определенном противодавлении в системе сбора газа прекращают фонтанирование и переводятся в бездействующий фонд до снижения линейного давления к необходимому уровню. Цель: обоснование комплексных технологических решений, направленных на повышение эффективности разработки многопластовых газовых и газоконденсатных месторождений с единой газосборной сетью. Объекты: многопластовые газовые и газоконденсатные месторождения, содержащие в геологическом разрезе разобщенные и различные по ресурсно-энергетическому потенциалу и фильтрационно-емкостным свойствам выделенные эксплуатационные объекты. Методы: анализ текущего состояния разработки газовых эксплуатационных объектов Губкинского месторождения, аналитические расчеты технологических режимов работы низконапорных скважин, проведение опытно-промышленных испытаний на газовых скважинах Губкинского месторождения, технико-экономический анализ результатов применения предложенных технологий. Результаты. Произведен анализ текущего состояния Губкинского месторождения, характеризуемого высокой дифференциацией текущих пластовых давлений по продуктивным пластам. Предложены комплексные решения по обеспечению совместной разработки эксплуатационных объектов с подачей газа в общую газосборную сеть, обеспечивающие устойчивые режимы работы скважин и основанные на регулировании устьевого давления различными техническими устройствами. Произведена технико-экономическая оценка влияния представленных комплексных технологических решений на эффективность разработки нижнемеловых пластов Губкинского месторождения.

Исследование пусковых свойств вихрекамерных дизелей средств коллективного спасения экипажей морских судов магнитной обработкой топлива

The paper considers the diesel engines as the hearts of the lifeboat power plants 
 of all types of vessels: sea, river and mixed navigation, according to the International Convention on the Protection of Human Life at Sea - SOLAS. In the Russian Federation there are two types 
 of engines produced for this purpose: 4-9.5/11 (“Kaspiy 30”) with vortex-chamber mixing and 
 4-9.5/11 (“Kaspiy 40”) with a combustion chamber in piston and volume-film mixing. The Kaspiy 40 engine is characterized by good starting properties and does not require additional acceleration of the launch. The Kaspiy 30 engine, due to the design of the combustion chamber, must be equipped with a fuel mixture heating device in the combustion chamber, which must work before the engine reaches a stable mode of operation. This device is glow plugs powered by a rechargeable battery and connected sequentially, so that failure of one plug entails the inoperability of the entire chain. If the rescue operation is necessary, the lifeboat engines must be started on deck without 
 a coolant (sea water) in the cooling system and must work for at least 10 - 15 minutes until the crew gets into the boat and the boat is launched, after which the cooling system will take the sea water. If the glow plug system fails, especially when the ambient temperature is low, the start of the engine in the prescribed time may not take place at all. There has been studied the effect of magnetic treatment of fuel before the launch and during the launch on the activation energy of fuel molecules and their reaction in the combustion without external heat

WAYS TO REDUCE THE INFLUENCE OF LONGITUDINAL OSCILLATIONS OF VEHICLES WITH UNIT VARIABLE WEIGHT

Practical recommendations are given on the operation of wheeled tractors with units of variable mass (trailed and / or semi-trailer tanks) without constructive modernization of the unit itself. Since during the performance of transport work on a wheeled tractor, there are longitudinal vibrations that occur when a fluid oscillates in a tank, it becomes necessary to combat them. Thus, the most popular tie-go-coupling devices that are used when coupling agricultural units are considered. It is highlighted that the priority is a hydroficated hook, which constructively consists of a damping mechanism. It is also noted that among the most desirable transmissions that modern wheeled tractors can be equipped with are infinitely variable double-flow and hydrovolume-mechanical ones. The main advantage of which, in contrast to transmissions of analogs, is the presence of a hydraulic link, with the help of which the mechanical oscillations of a unit of variable mass are reduced, coming in through transmission units. Since, for the tractor industry, the diesel engine of the internal combustion engine still remains the main driving power unit, an electronic fuel management system is presented, which differs from the similar ones in the control algorithm. The main video window of which is the method of microcontroller speed control of the crankshaft, which is based on the fact that to achieve an equilibrium (stable) mode of operation, the required position of the fuel rail is set, which positively depends on the position of the fuel supply control body and negatively on the current crankshaft rotation frequency making any design changes to the fuel equipment, allows to improve the performance of the diesel.

Similarity parameters clarified in the conditions of gas wells operation with water phase of various mineralization

Determining the effect of the fluid properties extracted from the reservoirs together with the produced gas on the pressure loss in wellbores is an urgent task for many fields and underground gas storages. The similarity parameters clarification of gas-liquid flows in pipes and creation of new modeling methods based on them make it possible to increase the degree of validity of the assigned technological modes at all stages of operation of field facilities containing a liquid phase in the products. Previous experimental studies have made it possible to establish an unambiguous dependence of pressure losses in the well on the amount of fluid represented by condensation water. However, the question of the effect of fluid properties on pressure losses in the path of formation mixture movement from the bottom to the installation of integrated gas treatment remains open. The article describes experimental studies of gas-liquid flows with liquids of high density, allowing us to make appropriate changes to the calculation formulas. Based on the methods of similarity and dimensions, corrections to the parameters included in the calculated relationships are concretized, conclusions of new formulas are given that take into account the influence of the liquid phase density on pressure losses in well bores. The structure of a new similarity parameter, the clarified Buzinov parameter, is substantiated, which allows us to most accurately calculate the stable operating modes of gas wells in fields and underground gas storage with an aqueous phase of various salinity. Relations for quantitative estimates of the effect of reducing pressure losses in gas-liquid flows due to wetting of the inner surface of elevator pipes are presented for the first time.

Energy, exergy, economic, and environmental analysis of an integrated system of high-temperature heat pump and gas separation unit

A novel integrated system consisting of a high-temperature heat pump providing 120–130 °C heat and a gas separation unit was developed to recover the industrial waste heat and replace the low-pressure steam used in traditional refinery process. An energy, exergy, economic, and environmental analysis was carried out to evaluate the performance of such integrated system according to its operational data of the project. Energy and exergy analyses provide an insight into the quantity and quality of the energy conversion of the integrated system. The results show that the coefficient, which evaluates the performance of the system in a stable operation mode, are 8.05 and 4.45 in the presence and absence of the waste heat recovery mechanism, respectively. The total exergy efficiency decreases from 34.57% to 33.03% in the ambient temperature range of −10–40 °C. When an electricity price of 0.109 $/kW·h and a steam price of 22.361 $/t are considered, the annual net profit of the integrated system measures a minimum of 187.4*103 $/year and 169.8*103 $/year, the payback period measures a maximum of 2.21 years and 2 years, with and without considering the penalty cost induced by emission reductions. Assuming a 8000 h/year operating time, the reduction of CO2, SO2, and NOx emissions reaches 3348 t, 101 t, and 50 t, respectively. These results indicate that the integrated system operates with a high performance and provides significant economic and environmental benefits.

Gated-Dynode photomultiplier tube assembly for the boronated scintillator detector of the ISS-CREAM experiment

Abstract We present the design of a four-photomultiplier tube (PMT) assembly for measuring light generation in the Boronated Scintillator Detector (BSD) of the Cosmic Ray Energetics And Mass experiment for the International Space Station (ISS-CREAM). The light produced in the scintillator includes a contribution from the capture of thermalized neutrons produced in cosmic ray interactions, as well as delayed fluorescence, in the range of several microseconds following the incident cosmic ray impact. The BSD is held in an insensitive state until a cosmic-ray trigger causes a rapid turn on of the PMTs to detect late light signals, several microseconds after the trigger. The design includes two pulsed high-voltage supplies, which serve to gate the first two dynodes of the Hamamatsu R1924A PMTs used in the assembly. When the dynode gates are held in the “off” state, this scheme is shown to suppress >10 5 photons from injection into the tube’s multiplier stage, while being capable of rapid switching into a stable operating mode in less than 1 μ s. This mitigates any backgrounds from afterpulsing that might otherwise be present in the PMT response following the cosmic ray incidence.