Timing Diagrams Research Articles

The Effect of Federal Reserves Rate Hikes: A perspective of Financial Market

In recent years, due to the global economic recession caused by the Covid-19 pandemic, the Federal Reserve has increased the interest rate to a historical high level in recent years. In this article, the author plots the diagram of index vs. Time to show the overall economic situation. This article concentrates on the effect of the rate hikes of Federal Reserve. The purpose is guiding the investors and governments to make decision under the challenging situation. Based on the timeline of rate hikes, there are improvement of the overall economy in US. It is a chance for investors to invest the money. There are chances for investors to invest when the US Federal Reserve increase the interest rate. The investors will have more confidence to increase income if the overall economic condition is improved by the rate hike. The government can control the level of the investors confidences to keep stable development of economy by controlling time of rate hikes.

Inf uence of the variable geometry of the diverter nozzle on the metrological characteristics of a calibration unit with weighing devices

This article discusses the issues of improving the metrological characteristics, weight-dimensional and technical and economic indicators of calibration installations with weighing devices due to the introduction of a fl ow switch with a variable nozzle exit geometry into their design. It is assumed that the use of this design of the fl ow switch will solve the problem of fi lling the nozzle exit with water, reduce the dimensions of the hydraulic path, simplify the maintenance procedure, and reduce the cost of installations. A description of the design, principles of operation and a timing diagram of a fl ow switch with a variable nozzle exit geometry are presented. The local hydrodynamic characteristics of the water fl ow by a Pitot tube in the nozzle exit are studied with a change in its width in the mass fl ow rate range from 25 to 550 t/h. The optimal values of the nozzle cut width are experimentally determined depending on the value of the mass fl ow rate of the liquid, at which it is completely fi lled with liquid. A study of the metrological characteristics of a calibration installation with weighing devices, which includes a fl ow switch with a variable nozzle exit geometry, methods of indirect measurements and comparisons using a comparison standard in a wide range of liquid mass fl ow rates, has been carried out. The impact on the metrological characteristics of a calibration installation with weighing devices of the nozzle cut width in the investigated range of liquid fl ow is established. Graphical dependences of the expanded measurement uncertainty of the installation when reproducing the unit of liquid mass fl ow rate on the measurement time interval and on the mass fl ow rate of the liquid are presented. Based on the research results, the optimal values of the nozzle cut width and measurement time intervals were determined depending on the mass fl ow rates of the liquid when using a fl ow switch with a variable nozzle cut geometry. The expansion of the range of operation of weighing devices, which are part of the verifi cation installations with weighing devices, is justifi ed. According to the results of the research, the proposed design of the fl ow switch with a variable geometry of the nozzle exit is recommended for use in the design of new and modernization of installations for calibration with weight devices of fl ow switches.

Modeling and Quantitative-Qualitative Analysis of Two-Dimensional Generators of Chaotic Signals Based on Modular Arithmetic

In this article, by the combined application of the programs E&F Chaos, Past, Fractan, Eviews Student Version Lite, mathematical, numerical and computer modeling of some of the well-known two-dimensional generators of chaotic signals based on modular arithmetic presented in [4] was carried out, and the properties of the obtained chaotic signals were evaluated using nonlinear dynamics methods (time and spectral diagrams, BDS-statistics, Hurst exponent). As a result of the conducted research, it was found that the time and spectral diagrams obtained for the studied two-dimensional generators of chaotic signal based on modular arithmetic have a complex noise-like appearance similar to white noise. The resulting range of BDS-statistics values corresponds to white noise at a certain interval, and persistent processes (black noise) at a certain interval. The resulting range of values of the Hurst exponent is also close to white noise. The results obtained show that two-dimensional generators of chaotic signals based on modular arithmetic can relate to white noise and have more pronounced chaotic properties than classical generators of chaotic signals, on the basis of which they are created. The results obtained complement and expand the knowledge about two-dimensional generators of chaotic signals based on modular arithmetic and open up broad prospects for their use in various practical applications.

The Behaviour of Hybrid Aluminium-Steel Resistance Spot Welded Joints in Case of Dynamic Loading

Hybrid joints between aluminium and steel are used sometimes in case of thin sheets for example for a car body. Resistance welding for this joining challenge is not frequently used, but the resistance welded joints basically have good mechanical properties. During resistance spot joining of these hybrid joints, fusion between the two materials cannot occur, but with the right technological parameters an intermetallic compound (IMC) appears in the joint line. The properties of the IMC have significant effect to the joint properties, because the researchers basically investigate this. The original static mechanical tests can show good, comparable results for the joint properties. If we see the dynamic tests basically really difficult to find results in case of spot welding of steels and joining of hybrid aluminium – steel joints. The aim of this paper to show the dynamic properties of these hybrid joints. During our investigation DP600 dual-phase steel was used as the steel part because this grade is frequently used in a car chassis. For the aluminium part, two types of aluminium were applied: non-heat treatable 5754-H22 alloy, and heat-treatable 6082-T6 alloy. The different aluminium alloys have different properties, so different technological parameter combinations were used. To test the resistance of hybrid joints against dynamic loading, instrumented impact tests were performed. This special impact test is considered as an impact-bending test, because the load is perpendicular to the welded point joint. Force – time diagrams of impact tests were shown too in this paper. The intermetallic compound is necessary for joint, but it is very brittle with very big hardness, but in case of dynamic testing this hardness has no significant effect, so these specimens show good result in case of dynamic loading. The two different aluminium – steel joints show different resistance against dynamic loading, and the fracture modes were different too.

Accurate Modeling, Operation Laws and Commutation Timing Matching for Concrete Pumping Systems

The pump system is the heart of the concrete pump truck, and its main function is to deliver high-pressure concrete into the pipeline through the reciprocating motion and cooperation of the main cylinder and the distribution valve driven by the swing cylinder. However, there are currently problems, such as unclear pumping operation rules and mismatched commutation timing, that result in poor pumping efficiency and short life of wear parts such as spectacle plates and cutting rings. To address above problems, based on AMEsim software and system test data, this thesis establishes an accurate simulation model of the pump system with more than 90% precision. Based on this model, the simulation reveals the operating rules of the main cylinder and the swing cylinder during the pumping process; draws the commutation timing diagram of the pumping system; clarifies that the commutation timing has four characteristics: sequential, hysteresis, coupling and cyclic; and proposes an optimization scheme for the commutation timing, i.e., reducing the relief pressure of the main cylinder and shortening the swing time of the distribution valve. The proposed optimization has been proven in the market and significantly improved the life of wearing parts by more than 90%. This study provides technical reference for the structure and parameter optimization of concrete pumping systems.

Автономная станция электроснабжения на основе асинхронного генератора с фазным ротором и преобразователя частоты малой мощности

Currently, asynchronous and synchronous generators with two-link full power frequency converters are the main options to design highly efficient sources of 3-phase voltage with an internal combustion engine (ICE) as a prime mover and a variable speed as a function of the load. It is required to develop and study the effectiveness of the use of an autonomous power supply station with a variable speed based on a low-power frequency converter to reduce its cost with the possibility of saving ICE fuel by controlling the frequency as a function of the load. The description of the power plant and its control system is made at the structural and functional level. The study of its characteristics is carried out by means of computer simulation in the Delphi software package. To assess the potential fuel efficiency of the power plant, a multi-parameter characteristic of the YaMZ-238 internal combustion engine is used. The functional diagram of the power plant, the structural diagram of its control system without the use of a speed sensor are presented. The time diagrams for modeling work on an asymmetric load and its energy characteristics are given. It is shown that the developed power plant allows to provide an effective ICE speed control range of at least 2 with the limitation of the rated power of the converter at the level of 20 % of the rated power of the load. Thus, it creates the preconditions for significant fuel savings. The use of the power supply station in the proposed design makes it possible to reduce its cost by reducing the power of the converter and increase its energy efficiency by controlling the speed of ICE with a satisfactory accuracy of the output voltage under conditions of a significantly asymmetric load. The reliability of the results obtained in the study is confirmed by computer simulation.

Pixel source follower glow in HxRG detector

AbstractThe Atmospheric Remote‐Sensing Infrared Exoplanet Large‐survey (ARIEL) space mission is dedicated to the study of the exoplanets' atmosphere. To do so, the payload module is made of two instruments. The ARIEL InfraRed Spectrometer instruments is one them, it will perform spectroscopic measurements from the near‐infrared domain to the long‐wave infrared domain. The instrument relies on the use of two H1RG detectors. During early phases of instrument development dark current measurements have been done on an 8 m cutoff detector operated in window mode. These measurements revealed an unexpected level of dark current. This observation triggered a joint series of tests at the European Space Agency technical center and at the Astrophysics Department of the Atomic Energy Commission. As demonstrated in this paper, the excess of dark current originates from the collection, by the photosenstive layer, of light emitted by the source follower transistor of the pixel unit cell. This effect is referred as glow. Based on experimental results, this glow is studied as a function of the detector operating conditions (temperature, biases, timing diagram). These results also show that for the range of operating temperatures considered, the dark current performance of the detector is limited by the glow.

A Single-Cycle Forward-Flybaсk Stabilized DC-DC Voltage Converter Part. 2. Power Stage Control Device

The article addresses the development of a single-cycle single-transistor forward-flyback DC voltage converter. The article’s second part shows the features of constructing a secondary power supply source based on a single-cycle single-transistor forward-flyback power converter stage considered in the article’s first part [1]. The power supply is constructed as a closed-loop automatic control system responding to mismatch of the output voltage from its setpoint value based on the principle of subordinate current control. The PWM controller initial starting scheme with its subsequent auxiliary feeding from the power transformer additional windings is proposed. The results of studying the scheme carried out using computer simulation in the OrCAD software are presented. The proposed scheme allows the device to remain operational even with a relatively poor coupling coefficient between the transformer’s power and auxiliary feed windings. In the OrCAD software, a simulation computer model was developed for a secondary power supply source based on the new structure of a single-cycle single-transistor forward-flyback power converter stage with the proposed method for starting the PWM controller. Based on the results obtained from studying the processes running in the secondary power supply source, time diagrams confirming the circuit operability are presented. The simulation has shown that a sufficiently large output power can be obtained on a single-cycle single-transistor forward-flyback power converter stage.

A Device for Decreasing Loss in Electric Networks Containing Unbalanced Nonlinear Load

Matters concerned with controlling the operating modes of low-voltage electric networks are discussed. Thus, 0.4 kV electric networks are characterized by significant emission of additional current sequences generated by unbalanced nonlinear load. A versatile compensating device filtering additional power flows caused by unproductive fundamental and higher harmonic current components is proposed as a technical means minimizing the undesirable consequences of additional current load. A method and calculation software were developed, using which the operating mode of a 0.4 kV electric network section was studied with the possibility to incorporate a simulation model of the proposed device. The compensating device parameters are calculated proceeding from the unbalanced power consumption in the network section considered. By using the MATLAB software package, time diagrams visualizing the variation of the studied indicators have been obtained. The economic efficiency of the proposed versatile device for decreasing electric energy loss has been estimated.

Universal Behavior of Fractal Water Structures Observed in Various Gelation Mechanisms of Polymer Gels, Supramolecular Gels, and Cement Gels.

So far, it has been difficult to directly compare diverse characteristic gelation mechanisms over different length and time scales. This paper presents a universal water structure analysis of several gels with different structures and gelation mechanisms including polymer gels, supramolecular gels composed of surfactant micelles, and cement gels. The spatial distribution of water molecules was analyzed at molecular level from a diagram of the relaxation times and their distribution parameters (τ-β diagrams) with our database of the 10 GHz process for a variety of aqueous systems. Polymer gels with volume phase transition showed a small decrease in the fractal dimension of the hydrogen bond network (HBN) with gelation. In supramolecular gels with rod micelle precursor with amphipathic molecules, both the elongation of the micelles and their cross-linking caused a reduction in the fractal dimension. Such a reduction was also found in cement gels. These results suggest that the HBN inevitably breaks at each length scale with relative increase in steric hindrance due to cross-linking, resulting in the fragmentation of collective structures of water molecules. The universal analysis using τ-β diagrams presented here has broad applicability as a method to characterize diverse gel structures and evaluate gelation processes.

MODELING OF A CONTROLLED ELECTROMAGNETIC VIBRATION DRIVE WITH A VARIABLE RESONANT FREQUENCY

The technology for the production of high-quality concrete products includes the vibration of the concrete mixture at various frequencies. For this, an electromagnetic vibration drive can be used, which has high reliability, durability and controllability. For its effective application, it is necessary to adjust the resonance frequency of the oscillating system in order to ensure the near-resonance mode of operation at different frequencies. This is possible by using devices with adjustable stiffness, in particular, controlled dynamic vibration absorbers with nonlinear elastic elements. In the article the electromagnetic, electromechanical, mechanical, and energy processes in a controlled vibration system, which includes an electromagnetic vibrator and a vibration absorber with conical springs, the stiffness of which is regulated by compression using a press, have been investigated. Using the circle-field method, a mathematical and simulation model of electromagnetic and electromechanical processes in the vibrator has been developed. For this purpose, numerical calculations of the magnetic field in the vibrator have been performed and, based on the obtained results, the functional dependences between the electromagnetic force, magnetic flux, magnetomotive force and the size of the air gap have been determined. A model of the mechanics of the oscillating system, processes in the vibration absorber press drive and processes in the control system has been also developed. The built simulation models were combined into a general model in the Simulink environment, by means of which the time diagrams of the processes have been obtained. The modeling results show that the system provides a smooth transition from one vibration frequency to another while maintaining the specified amplitude of the working body oscillations and near-resonance mode with high energy efficiency. References 12, figures 10, tables 3.

Brouwer's Intuition of Twoity and Constructions in Separable Mathematics

ABSTRACT My first aim in this paper is to use time diagrams in the style of Brentano to analyze constructions in Brouwer's separable mathematics more precisely. I argue that constructions must involve not only pairing and projecting as basic operations guaranteed by the intuition of twoity, as sometimes assumed in the literature, but also a recalling operation. My second aim is to argue that Brouwer's views on the intuition of twoity and arithmetic lead to an ontological explosion. Redeveloping the constructions of natural numbers and systems sketched in an appendix to Brouwer's Cambridge lectures, I observe that the only plausible way he can make some elementary arithmetic in his separable mathematics is by allowing for the same canonical number to be determined by multiple separable entities, resulting in an overabundant mathematical ontology.

An Intriguing Array of Extrudate Patterns in Long‐Chain Branched Polymers During Extrusion

AbstractThe present study highlights a range of surface and volume extrudate patterns that can be detected during the extrusion flow of long‐chain branched polymers. Thus, four linear low‐density polyethylenes (LDPEs) have been extruded using a single‐screw extruder coupled to an inline optical imaging system. The selected LDPEs are selected to outline the influence of molecular weight and long‐chain branching on the types of melt flow extrusion instabilities (MFEI). Through the inline imaging system, space–time diagrams are constructed and analyzed via Fourier‐transformation using a custom moving window procedure. Based on the number of characteristic frequencies, peak broadness, and whether they are surface or volume distortions, three main MFEI types, distinct from those typically observed in linear and short‐chain branched polymers, are identified. The higher molecular weight, low long‐chain branching LDPEs exhibited all three instability types, including a special type volume instability. Independently of the molecular weight, higher long‐chain branching appeared to have a stabilizing effect on the transition sequences by suppressing volume extrudate distortions or limiting surface patters to a form of weak intensity type.

Optimization Simulation of Match between Technical Actions and Music of National Dance Based on Deep Learning

In the match between technical movements and music of folk dance, the most important thing is to extract features effectively. DL algorithm is one of the most efficient methods to extract video features at present. In this study, the DL method is applied to the matching optimization of technical movements and music in folk dance. Using DL to train the corresponding relationship between the technical movements and music of national dance, the given dance movements and corresponding movements are adapted to the musical beat points. To better reflect the degree of correlation between music and movement changes, the change rate of feature value is used instead of feature value itself in correlation calculation. The matching degree between this method and genetic theory method and spatial skeleton timing diagram method is compared. The experiment shows that the matching method of technical movements and music of national dance optimized by DL can achieve 95.78% accuracy, and the matching synchronization of technical movements and music of national dance can reach 96.17%. Therefore, the method proposed in this study can fully reflect the synchronization of music and movement changes, and the optimized movement matching method matches the national dance technical movements—music matching quality is better. This study expands a new perspective for the research of dance and music matching technology. It has certain practical and theoretical significance.

Comparison of RSW technologies on DP steels with modified instrumented Charpy impact test

In recent decades the toughness of welded structures becomes more and more important. This trend is particularly valid for the advanced high-strength steels (AHSS), which have reduced toughness comparing to the low-strength structural steels. Dynamic characteristics of the welded joints of the newly developed high-strength steel sheets required by the automotive industry have been neglected, with welding procedures being optimized on the static joint properties, mainly on the tensile-shear force. Up to the present time, testing of dynamic properties of the spot-welded joints has been performed by increased testing speed during tensile testing. The authors have developed a new dynamic testing method and designed new testing equipment for impact bending, which can give a numeric result to characterize the resistance of spot-welded joints against dynamic load. In this paper, this method will be used to evaluate resistance spot-welded joints made on DP600 and DP800 steels with three different technological parameters, comparing long-time welding, short-time welding, and two-pulse welding. The different parameters cause different weld nugget sizes, failure modes, impact energies, and force–time diagrams. All test results show that bigger weld nugget diameters cause better impact energies and impact forces, but the differences are not perfectly correlated.

Experimental study on post-fire mechanical properties of Grade 12.9 high-strength bolts

This paper aims to experimentally investigate the post-fire mechanical properties of Grade 12.9 high-strength bolts. To evaluate the effects of elevated temperatures and the bolt diameter on the post-fire mechanical properties, seven different diameters of the Grade 12.9 bolts were heated based on a standard temperature–time diagram with the ranges of 20 to 900 °C. Upon air-cooling and reaching room temperature (a heating and cooling cycle), 105 bolt specimens were subjected to the standard tensile test. The experimental results, including the post-fire stress–strain curve, yield strength, tensile strength, modulus of elasticity, and ductility, were presented. The results indicated that changes in mechanical properties were noticeable for temperatures higher than 400 °C. Although the post-fire modulus of elasticity did not significantly change, the post-fire yield and tensile strengths decreased substantially if the maximum temperature exceeded 400 °C. After heating up to 900 °C and then cooling down and reaching ambient temperature, Grade 12.9 steel bolts showed a 60% reduction in strength. The comparison of the results showed that the effect of diameter on the post-fire yield and tensile strengths of Grade 12.9 bolts was insignificant and could be neglected, but on elastic modulus and ductility, the diameter effect needs to be considered. In addition, the scanning electron microscope (SEM) images indicated that the elevated temperatures remarkably changed the microstructural characteristics of the Grade 12.9 bolts. Finally, based on the test results, the prediction equations of the post-fire mechanical properties of the Grade 12.9 high-strength bolts were proposed.

Особенности эмиссии и полевая электронная спектроскопия оксидного термокатода

The results of a study of the emission characteristics and gas release of oxide thermocathode by the method of time diagrams in the temperature range of 678÷885 °C and emission currents from 0.08 to 1.3 mA are presented, a directly proportional dependence of the partial pressures of the released gases CO and CO2 on the cathode emission current is established. The energy spectra of the emitted electrons of oxide thermocathode at a temperature of ~600 °C were measured, corresponding to the "spotted cathode" model. The dynamics of changes in the energy spectrum of the emitted electrons of the “spotted cathode” is presented, showing the existence of stages of activation, growth and deactivation of the emission of “spots” with an increase in the emission voltage.

Analysis of Exchange Power in the Power System of an Unmanned Aerial Vehicle with a BlDC Engine

The purpose of this work is the analysis of the power supply system of unmanned aerial vehicle. One of the most important tasks of this system is to ensure the smallest possible losses in order to achieve greater endurance of the aircraft, which means – the ability to complete the mission. The presence of an inactive component of consumed power obviously reduces the efficiency of the entire unmanned aerial vehicle. Considering also that due to the influence of wind, speed changes and other factors, the power system spends a significant amount of time in the transition mode, the impact of this phenomenon becomes even more significant. Thus, the phenomenon of the occurrence of exchange power in the power supply system of an unmanned aerial vehicle is analyzed. One of the most common solutions for unmanned aerial vehicles is the use of a BLDC motor, which is a further development of DC motors and was created with the aim of improving their basic characteristics. This type of engine has gained its popularity due to numerous advantages: high reliability, efficiency, speed and others. The principles of control of the BLDС engine are given. The unmanned aerial vehicle power supply system, built on the basis of a buck converter and a bridge inverter, was analyzed. An equivalent circuit of the converter is built, taking into account the losses in the electric circuit. On its basis the relations for determining the value of exchange power in the power supply system are derived. With the help of these expressions, it is possible to determine the value of the exchange energy at an arbitrary time interval in the real power supply system of the aircraft. A model of the power supply system of an unmanned aerial vehicle with a BLDC engine was built in the Matlab Simulink software environment. A time diagram is obtained, on the basis of which it is possible to draw a conclusion about the content of exchange power in the converter circuit. To minimize this phenomenon, it is necessary to develop a compensation system or an intelligent control system.

Segmented continuously varying pulse interval sequence design for extremely high-resolution spaceborne sliding spotlight SAR

ABSTRACT Synthetic aperture radar (SAR) is an active microwave remote sensing device used to obtain high-resolution SAR images.With the development of SAR, extremely high-resolution SAR (i.e. resolution reaching 0.1 m) plays an increasingly important role in applications such as target recognition. In extremely high-resolution spaceborne SAR, the variation of slant range history becomes extremely severe, resulting in echoes of interest overlapping with transmitted pulses and nadir echoes when transmitting the pulses at constant pulse intervals (PIs), further causing the loss of echo data. Although a continuously varying pulse interval (CVPI) system can expand the tolerance of slant range variation to some extent, overlap still occurs when the variation in slant range exceeds a certain threshold. Thus, this paper proposes segmented CVPI sequence design methods to solve the data acquisition problem in the situation of severe variation in slant range history. The timing diagram- and strip layering diagram-based segmented CVPI sequence design methods, which are suitable for the acquisition of spaceborne SAR data with any variation of slant range, are given. The characteristics of the two methods are analysed. Finally, several computer simulations indicate that the echoes generated by the proposed methods are not overlapped, which verifies the validity of the proposed methods.

Water Masses at the Surface of the Indian Ocean

Water masses in the surface layer of the ocean are harder to define in terms of hydrographic properties because they undergo large seasonal and interannual variations. Therefore, single TS-combinations cannot be used to define surface water masses. The solution to the definition of surface water masses is the temperature/salinity time diagram (TS-time diagram) and/or the temperature/chlorophyll time diagram (TC-time diagram). This work establishes a systematic definition of regional water masses in the surface layer of the tropical Indian Ocean based on TC-time and TS-time diagrams of mean and standard deviation for 5° squares. This classification is based on an analysis of the ratios between semi-annual and annual amplitudes of temperature and a multiple regression analysis between temperature, salinity, and chlorophyll, with Ekman pumping, components of pseudo-stress wind, wind magnitude and net-down-freshwater-flux. Four water masses are identified for the surface of the Indian Ocean: The Arabian Sea Surface Water (ASSW), the Bay of Bengal Surface Water (BBSW), the Equatorial Indian Surface Water (EISW) and the Southern Indian Surface Water (SISW). The geographical representation of the water masses agrees well with the theoretical frame of reference.