Non-ideal Source Research Articles

Oscillations of the orthogonal mechanism with a non-ideal source of energy in the presence of a load on the operating link

This work studies the features of vibrational motion of an orthogonal mechanism with disturbances, such as restricted power in the presence of a fixed load on the horizontal link. Dynamic and mathematical models were prepared, and the operating conditions’ fields of existence for the vibration mechanism in terms of the driving power were defined. With stable rotational operating conditions of the mechanism, it was shown that the value of the angular rate of the driving link varies about its average value according to the harmonic law. The frequency of the change in the value of the angular rate equals the average value of this rate, and the amplitude is inversely proportional to this value. Therefore, the average value of the angular rate depends on the features of the driving link and the sources of power. The rotational motions of the mechanism are demonstrated to be stable. The librational motions of the mechanism were examined. An amplitude-response curve was built, and the conditions that contribute to the amplitude of driving link’s oscillations were defined. The law of variation of the amplitude of the librational motion was established. The frequency of the oscillations were shown to depend on the amplitude and the parameters of the power and mechanism source.Because the mathematical model provided good practical results, the results of this research can be successfully used during the design of vibration equipment with orthogonal mechanisms.

Decomposition of governing equations in the analysis of resonant response of a nonlinear and non-ideal vibrating system

The dynamic response of a nonlinear system with three degrees of freedom in resonance that is loaded, inter alia, with a non-ideal excitation is investigated. A direct current motor (DC motor) with an eccentrically mounted rotor serves as a non-ideal source of energy. The general coordinate corresponding to the rotor dynamics steadily increases as a result of rotational motion. The decomposition of the equations of motion proposed in the paper allows us to separate the vibration of rotor from its rotations. The presented approach can be used to separate the vibration from rotations in many other mechanical and mechatronic systems. The behaviour of the considered non-ideal system near two simultaneously occurring resonances is examined using the Krylov–Bogolyubov averaging method. The stability analysis of the resonant response is also carried out.

Motion of a motor-structure non-ideal system

Abstract In this paper the generalization to dynamics of a nonlinear oscillator excited with a non-ideal source is studied. The model of the structure-motor system is generalized by assuming that the driving torque is a nonlinear function of the angular velocity and the oscillator is with strong nonlinearity. The oscillator-motor system is assumed as a non-ideal one where not only the motor affects the motion of the oscillator but also vibrations of the oscillator have an influence on the motor motion. The model of the motor-structure system is described with two coupled strong nonlinear differential equations. An improved asymptotic analytic method based on the averaging procedure is developed for solving such a system of strong nonlinear differential equations. The steady state motion and its stability is studied. Results available the discussion of the Sommerfeld effect. A new procedure for determination of parameters of the non-ideal system for which the Sommerfeld effect does not exist is developed. For these critical values of the parameter the Sommerfeld effect is suppressed. As a special case the truly nonlinear oscillator where the order of the nonlinearity is a positive rational number is investigated. In the paper the influence of the order of nonlinearity on the dynamic properties of the system are analyzed. For the motor, with the torque which is the cubic function of the angular velocity, and the truly nonlinear oscillator, with certain order of nonlinearity, the numerical calculation is done. Analytically obtained results are compared with numerical ones. Results show good agreement.

Stress, deformation and diffusion interactions in solids – A simulation study

Equations of diffusion treated in the frame of Manning's concept, are completed by equations for generation/annihilation of vacancies at non-ideal sources and sinks, by conservation laws, by equations for generation of an eigenstrain state and by a strain–stress analysis. The stress-deformation-diffusion interactions are demonstrated on the evolution of a diffusion couple consisting of two thin layers of different chemical composition forming a free-standing plate without external loading. The equations are solved for different material parameters represented by the values of diffusion coefficients of individual components and by the intensity of sources and sinks for vacancies. The results of simulations indicate that for low intensity of sources and sinks for vacancies a significant eigenstress state can develop and the interdiffusion process is slowed down. For high intensity of sources and sinks for vacancies a significant eigenstrain state can develop and the eigenstress state quickly relaxes. If the difference in the diffusion coefficients of individual components is high, then the intensity of sources and sinks for vacancies influences the interdiffusion process considerably. For such systems their description only by diffusion coefficients is insufficient and must be completed by a microstructure characterization.

Neural Network-Based Control Algorithm for DSTATCOM Under Nonideal Source Voltage and Varying Load Conditions

Distribution static compensator (DSTATCOM) is the optimal choice of power quality (PQ) compensator in a three-phase four-wire distribution system for the mitigation of PQ problems. The performance of the PQ compensator under varying load and nonideal source conditions relies on the control strategy. A neural network-based p-q control algorithm is proposed in this paper for the DSTATCOM, which comprises of a four-leg voltage-source converter with a dc capacitor. The proposed control strategy implements five artificial neural network controllers for, the conversion of nonideal voltage source into ideal sinusoidal voltage, the extraction of dc component p of load real power supplied to the load, maintenance of the voltage across the capacitor, and mitigation of neutral current. The performance of the proposed neural network-based p-q control strategy for DSTATCOM is evaluated under various possible source and load conditions by simulating in MATLAB/Simulink environment, and the results obtained through the simulation are validated experimentally by a prototype developed in the laboratory. Both the experimental and simulation results prove that the performance of the proposed neural network-based control strategy is superior to the conventional method.

Theoretical Analysis of the Fluctuation Theorem Applied to Electric Circuits

We carry out a theoretical analysis of the fluctuations in the Johnson—Nyquist noise in an RC electric circuit being driven by a non-ideal constant current source. Using the appropriate Langevin equation, we derive the fluctuation theorem for the system. This analysis exhibits some interesting features. Firstly, the average of the dissipation function is not necessarily just an instantaneous entropy production, i.e. the work being done on the circuit by the external power source divided by the ambient temperature. Secondly, by appropriate selection of the values for the circuit components, the transient response of the system can be made identical to the nonequilibrium steady state response. In the limit of an ideal current source, the average of the dissipation function reduces to the entropy production. Our analysis accurately reproduces published experimental results.

English

The unconfined aerosols of propylene oxide (PO) are formed by dispersing the fuel in air. These aerosols undergo detonation by suitable initiation and produce high impulse blast. Tri-nitro Toluene (TNT) equivalence is an important parameter used to represent the power of explosive materials and compare their relative damage effects wrt TNT. The parameters commonly used for estimation of TNT equivalency are total energy of explosive source and properties of resulting blast wave, viz., blast peak overpressure and positive impulse. In the present study, the unconfined aerosols of 4.2 kg PO were formed by breaking open the cylindrical canister with the help of axially positioned central burster charge and then detonated using a secondary explosive charge after a preset time delay. The resulting blast profiles were recorded and the blast parameters were analysed. Being a non-ideal explosive source, the TNT equivalency depends on fraction of total energy utilised for blast formation, the rate of energy release, cloud dimensions, and concentration of fuel. Hence, various approaches based on energy release, experimental blast profiles, triangulated blast parameters, and ground reflected blast parameters were considered to determine the TNT equivalency of unconfined PO aerosols. It was observed that the TNT equivalency is not a single value but vary with distance. The paper provides various options for weapon designer to choose a suitable approach for considering TNT equivalency. The scaling laws established from the experimental data of unconfined aerosols of PO for blast peak over pressure and scaled impulse help in predicting the performance for different values of fuel weight and distance. Defence Science Journal, Vol. 64, No. 5, September 2014, pp.431-437, DOI:http://dx.doi.org/10.14429/dsj.64.6851

On nonlinear dynamics behavior and control of a new model of a magnetically levitated vibrating system, excited by an unbalanced DC motor of limited power supply

We analyze new results on a magnetically levitated body (a block including a magnet whose bottom pole is set in such a way as to repel the upper pole of a magnetic base) excited by a non-ideal energy source (an unbalanced electric motor of limited power supply). These new results are related to the jump phenomena and increase of power required of such sources near resonance are manifestations of a non-ideal system and they are referred as the Sommerfeld effect, which emulates an energy sink. In this work, we also discuss control strategies to be applied to this system, in resonance conditions, in order to decrease its vibration amplitude and avoiding this apparent energy sink.

Tight asymptotic key rate for the Bennett-Brassard 1984 protocol with local randomization and device imprecisions

Local randomisation is a preprocessing procedure in which one of the legitimate parties of a quantum key distribution (QKD) scheme adds noise to their version of the key and was found by Kraus et al. [Phys. Rev. Lett. 95, 080501 (2005)] to improve the security of certain QKD protocols. In this article, the improvement yielded by local randomisation is derived for an imperfect implementation of the BB84 QKD protocol, in which the source emits four given but arbitrary pure states and the detector performs arbitrarily-aligned measurements. Specifically, this is achieved by modifying an approach to analysing the security of imperfect variants of the BB84 protocol against collective attacks, introduced in [Phys. Rev. A 88, 012331 (2013)], to include the additional preprocessing step. The previously known improvement to the threshold channel noise, from 11\% to 12.41\%, is recovered in the special case of an ideal BB84 implementation and becomes more pronounced in the case of a nonideal source. Finally, the bound derived for the asymptotic key rate, both with and without local randomisation, is shown to be tight with the particular source characterisation used. This is demonstrated by the explicit construction of a family of source states and optimal attacks for which the key-rate bound is attained with equality.

Behavioral non-ideal Model of 8-bit Current-Mode Successive Approximation Registers ADC by using Simulink

In this paper a new non-ideal model of 8-bit Current Mode Successive Approximation Analog-Digital Converter (CM-SAR-ADC) has been proposed, the main blocks of CM SAR ADC are a current sample and hold, a current comparator, SAR logic register and current steering digital to analogue converter (DAC). The model is implemented in Matlab Simulink environment with non ideals factors such as switching noise, clock feed through, charge injection, flicker noise, clock jitter, settling error, and the effect of MOS transistor mismatch in the current sample and hold(S/H) and in the current steering DAC models, the delay time and the current offset are introduced as non-ideal sources to the current comparator model. The comparisons of the simulation results using 8-bits CM SAR ADC with ideal and non-ideal models confirmed the effects of the non ideality sources on the parameters of the ADC.

Heralded linear optical quantum Fredkin gate based on one auxiliary qubit and one single photon detector

Linear optical quantum Fredkin gate can be applied to quantum computing and quantum multi-user communication networks. In the existing linear optical scheme, two single photon detectors (SPDs) are used to herald the success of the quantum Fredkin gate while they have no photon count. But analysis results show that for non-perfect SPD, the lower the detector efficiency, the higher the heralded success rate by this scheme is. We propose an improved linear optical quantum Fredkin gate by designing a new heralding scheme with an auxiliary qubit and only one SPD, in which the higher the detection efficiency of the heralding detector, the higher the success rate of the gate is. The new heralding scheme can also work efficiently under a non-ideal single photon source. Based on this quantum Fredkin gate, large-scale quantum switching networks can be built. As an example, a quantum Beneš network is shown in which only one SPD is used.

NON-LINEAR ENERGY HARVESTING SYSTEM EFFICIENCY COMPARISON FROM PERIODIC TO NON-IDEAL EXCITATION

Dynamics of a non-linear energy harvesting is affected by excita- tion source and to explore efficiency it is necessary to understand which region offers more energy and the influence of a forced periodic vibration related to ambient non-ideal and power source. A bistable Duffing oscillator coupled to piezoelectric layers and electric load configuring a non-linear energy harvesting is excited by periodic resonant vibration and the system behaviour and energy availability is compared to non-ideal excitation. The chaos via Lyapunov expo- nent were determined and Runge-Kutta forth order was applied to determine displacement, velocity, phase portrait and output voltage. As main conclusion it was possible to identify a more efficient coupling of cantilever configuration to non-ideal power source than resonant periodic excitation. Considering the kinetic energy available for the coupled system to be converted into electricity it was possible to verify an increase around then times of energy offered to the harvesting system from non-ideal vibration compared to periodic resonant

Memory-assisted measurement-device-independent quantum key distribution

A protocol with the potential of beating the existing distance records for conventional quantum key distribution (QKD) systems is proposed. It borrows ideas from quantum repeaters by using memories in the middle of the link, and that of measurement-device-independent QKD, which only requires optical source equipment at the userʼs end. For certain memories with short access times, our scheme allows a higher repetition rate than that of quantum repeaters with single-mode memories, thereby requiring lower coherence times. By accounting for various sources of nonideality, such as memory decoherence, dark counts, misalignment errors, and background noise, as well as timing issues with memories, we develop a mathematical framework within which we can compare QKD systems with and without memories. In particular, we show that with the state-of-the-art technology for quantum memories, it is potentially possible to devise memory-assisted QKD systems that, at certain distances of practical interest, outperform current QKD implementations.

Design Guidelines of In0.53Ga0.47As and Si Tunneling Field-Effect Transistors

In this paper, the impacts of the source doping profile, effective oxide thickness (EOT), gate alignment, and trap density at the source junction on key characteristics of In0.53Ga0.47As- and Si-based tunneling field-effect transistors (TFETs) were comprehensively analyzed through Sentaurus simulations with calibrated models, which can provide some guidelines for device and process design. The simulations show that the EOT and the gate alignment should be carefully designed and controlled for both Si and In0.53Ga0.47As TFETs fabrication. The EOT needs a tighter control in In0.53Ga0.47As TFETs, a suitable gate-source underlap can optimize the performance of device considering a non-ideal source doping profile. Moreover, the trap density at the source junction plays more significant impacts in In0.53Ga0.47As TFETs than Si TFETs.

A dual-modal retinal imaging system with adaptive optics.

An adaptive optics scanning laser ophthalmoscope (AO-SLO) is adapted to provide optical coherence tomography (OCT) imaging. The AO-SLO function is unchanged. The system uses the same light source, scanning optics, and adaptive optics in both imaging modes. The result is a dual-modal system that can acquire retinal images in both en face and cross-section planes at the single cell level. A new spectral shaping method is developed to reduce the large sidelobes in the coherence profile of the OCT imaging when a non-ideal source is used with a minimal introduction of noise. The technique uses a combination of two existing digital techniques. The thickness and position of the traditionally named inner segment/outer segment junction are measured from individual photoreceptors. In-vivo images of healthy and diseased human retinas are demonstrated.

Non-ideal mechanical system with an oscillator with rational nonlinearity

In this paper the generalized form of a non-ideal system which contains a pure nonlinear oscillator and a non-ideal energy source is studied. In the non-ideal oscillator-motor system there is an interaction between the motions of the oscillator and those of the motor, as the motor has an influence on the oscillator and vice versa. The mathematical model of the system is represented with two coupled nonlinear differential equations. The averaging method for solving these differential equations is based on the application of the Ateb function, which is the exact solution of the pure nonlinear oscillator. Using the obtained approximate solution, the resonant motion of the system is considered. Significant attention is paid to the steady-state motion and to the Sommerfeld effect. The influence of the order of nonlinearity on the dynamics of the nonideal system is evident. In the paper the procedure for determination of the parameters for suppression of the Sommerfeld effect of the non-ideal system is also given.

Electromechanical control of vibration on a plate submitted to a non-ideal excitation

This paper deals with the enhancement of electromechanical control of vibration on a thin plate submitted to non-ideal excitation. Modelling of the systems displays the non-ideal source used as external excitation above the structure on a particular surface and control force acting at specific points under the structure. The electromechanical device is composed by a RL circuit with a saturated inductance and stings connected to the plate is used as connection between the structure and the controller. Routh–Hurwitz criteria are used to obtain the stability condition of the controlled system and some dynamics exploration leads us to the condition for which the amplitude of vibration is reduced in the mechanical structure.

Experimental Measurement-Device-Independent Quantum Key Distribution

Quantum key distribution is proven to offer unconditional security in communication between two remote users with ideal source and detection. Unfortunately, ideal devices never exist in practice and device imperfections have become the targets of various attacks. By developing up-conversion single-photon detectors with high efficiency and low noise, we faithfully demonstrate the measurement-device-independent quantum-key-distribution protocol, which is immune to all hacking strategies on detection. Meanwhile, we employ the decoy-state method to defend attacks on a nonideal source. By assuming a trusted source scenario, our practical system, which generates more than a 25 kbit secure key over a 50km fiber link, serves as a stepping stone in the quest for unconditionally secure communications with realistic devices.

Positive Feedforward Control for Multimodule Output-Series Power-Conversion Systems With Individual Nonideal Sources

This paper presents a positive feedforward control (PFFC) for a multimodule output-series (MMOS) system with individual nonideal sources. By adding PFFC-loop regulation into the conventional negative feedback control loop, the power module can easily harvest the maximum power from the source, and the output voltage of the converter can be slowly decreased when the input voltage is kept constant. In MMOS applications, an automatic master-loop regulation (AMLR) control is proposed to achieve voltage allocation among the individual power modules; however, this scheme has some drawbacks because its output voltage and power decrease immediately when the power of any one source is insufficient for the converter's needs. By utilizing the characteristics of the PFFC loop, the output voltage of the individual modules can be effectively allocated for managing the output power of the MMOS system. In this paper, the characteristics of the PFFC-loop regulation are derived through dc analysis. An experimental prototype is implemented for three forward modules with individual nonideal sources, and the characteristics of the PFFC loop are verified. By adding the proposed PFFC loop to AMLR, the measured power rating of the experimental MMOS system can be increased by about 20%.

On an Energy Exchange Process and Appearance of Chaos in a Non-ideal Portal Frame Dynamical System

The dynamics of a structure excited by a non-ideal excitation device, such as a DC motor with limited power capacity, is considered in this paper. When non-ideal excitation sources are attached to structures that consume energy at levels similar to the source power capacity, some characteristic phenomena such as jumps can occur. These behaviors are related to the Sommerfeld effect, where a part of the excited system behaves as energy sink. One of the problems often faced by designers of such structures is how to drive a system through resonance and avoid this “energy sink”. The basic structural model proposed in this paper is a simple portal frame driven by a non-ideal power source (NIPF). The vibrations absorption (in resonance, nonlinear and chaotic) is also analyzed by means of a nonlinear sub-structure known as a nonlinear energy sink (NES). An energy exchange process between NIPF and NES in the passage through resonance as well the suppression of chaos are investigated.