Pulsed Energy Source Research Articles

Energy analysis of a wireless sensor node powered by a Wiegand sensor

Abstract. This article describes an Internet of things (IoT) sensing device with a wireless interface which is powered by the energy-harvesting method of the Wiegand effect. The Wiegand effect, in contrast to continuous sources like photovoltaic or thermal harvesters, provides small amounts of energy discontinuously in pulsed mode. To enable an energy-self-sufficient operation of the sensing device with this pulsed energy source, the output energy of the Wiegand generator is maximized. This energy is used to power up the system and to acquire and process data like position, temperature or other resistively measurable quantities as well as transmit these data via an ultra-low-power ultra-wideband (UWB) data transmitter. A proof-of-concept system was built to prove the feasibility of the approach. The energy consumption of the system during start-up was analysed, traced back in detail to the individual components, compared to the generated energy and processed to identify further optimization options. Based on the proof of concept, an application prototype was developed.

Obtaining functional-gradient Ti-HA coatings by detonation spraying

Functional-gradient titanium/hydroxyapatite (TiHA) coatings were obtained using detonation spraying technology to improve the structure and mechanical properties. To obtain functional-gradient coatings, pulsed energy sources are best suited, namely, detonation spraying, in which the energy of the explosion of gas mixtures is used as a source of pulsed action. By controlling the modes of detonation spraying, it is possible to vary the temperature and rate of coating deposition; accordingly, it is possible to obtain a certain structuralphase structure of the coatings. The structural-phase state and tribological properties of TiHA detonation coatings were investigated by modern materials science methods: X-ray phase analysis (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDX-mapping), profilometry and ball-disk wear-resistance test. The results showed that the coatings had a continuously gradient elemental composition across the cross-section of the coatings with no boundary between the elemental layers of the coatings. The amount of Ti gradually decreased and the amount of hydroxyapatite gradually increased in the direction from the substrate to the surface of the coatings, which allows to expand the possibilities of using TiHA-coatings for bone implants. Since the surface layer is composed of HA, the resulting functional-gradient coating demonstrates excellent biocompatibility and the ability to create new bone tissue. The excellent mechanical strength of the functionally graded coatings is ensured by the Ti phase.

The evolution of microwave-induced thermoacoustic signal characteristics generated during pulsed microwave ablation

Microwave-induced thermoacoustic (TA) signals are of emerging interest for monitoring microwave ablation (MWA) in real-time. TA signals can be generated using an interstitial ablation antenna with a pulsed microwave energy source. When a microsecond microwave pulse is absorbed by tissue, the tissue undergoes a small-scale temperature rise, inducing a thermoelastic expansion that leads to acoustic generation. TA signal characteristics are linked to the dielectric, thermal, and acoustic properties of the local ablation environment. These relevant properties evolve significantly during the ablation process. We conducted a simulation-based study to examine the evolution of microwave-induced TA signal characteristics generated during pulsed microwave ablation. We experimentally validated our multi-physics simulation model for a spatially uniform temperature profile. Then, using the validated simulation model, we investigated TA signals generated in tissue exhibiting spatially nonuniform temperature profiles that arise during MWA. We find that TA signal characteristics are highly influenced by the local environment temperature within the region of initial TA generation and, thus, contain rich information to be exploited for real-time ablation monitoring.

ЭЛЕКТРОМАГНИТНАЯ КАТАПУЛЬТА ДЛЯ ЗАПУСКА ТЯЖЕЛЫХ ДРОНОВ С МАЛОРАЗМЕРНЫХ СУДОВ

The paper presents the results of mathematical modeling of the operation of a novel electromagnetic catapult design. The main elements of the latter are a single-section multi-rail accelerator with a metal armature and a pulsed energy source based on the powerful pulsed MHD generator and current-increasing transformer. The possibilities of such a scheme for accelerating bodies weighing 7 tons to speeds of about 150 km/h at a maximum permissible acceleration of 15 g are investigated. The mathematical model describes the coordinated operation of the device, starting with connecting of the pulsed MHD generator in idle mode to the primary winding of the transformer and up to the moment when the drone accelerates to a given takeoff speed. Using the proposed model, the efficiency of the electromechanical energy conversion in the developed catapult scheme is tested. The parameters of the main elements of the device, namely the length of the acceleration section of the catapult and the maximum acceleration of the drone, are determined.

Listening to pulses of radiation: design of a submersible thermoacoustic sensor

Nowadays, various collaborations are creating immense machines to try to track and understand the origin of high-energy cosmic particles (e.g., IceCube, ANTARES, Baikal-GVD, P-ONE). The detection mechanism of these sophisticated experiments relies mainly on an optical signal generated by the passage of charged particles on a dielectric medium (Čerenkov radiation). Unfortunately, the dim light produced by passing particles cannot travel too far until it fades away, creating the necessity to instrument large areas with short spacing between sensors. The range limitation of the optical technique has created a fertile ground for experimenting on the detection of acoustic signals generated by radiation—thermoacoustics. Despite the increased use of the thermoacoustic technique, the instrumentation to capture the faint acoustic signals is still scarce. Therefore, this work has the objective to contribute with information on the critical stages of an affordable submersible thermoacoustic sensor: namely the piezoelectric transducer and the amplifying electronics. We tested the sensor in a 170,{textit{l}} non-anechoic tank using an infrared (lambda =1064,hbox {nm}) Q-switched Nd:YAG laser as a pulsed energy source to create the characteristic signals of the thermoacoustic phenomena. In accordance with the thermoacoustic model, a polarity inversion of the pressure signal was observed when transiting from temperatures below the point of maximum density of water to temperatures above it. Also, the amplitude of the acoustic signal displayed a linear relationship with pulse energies up to (51.1 pm 1.7),hbox {mJ} (R^2 sim 0.98). Despite the use of cost-effective parts and simple construction methods, the proposed sensor design is a viable instrument for experimental thermoacoustic investigations on high-energy particles.

Probe Pulse Conditions and Solidification Parameters for the Dissimilar Welding of Inconel 718 and AISI 316L Stainless Steel

The present work addresses the weldability of dissimilar materials Inconel 718 and AISI 316L stainless steel through metallurgical and mechanical characterization of the joint. The 3D heat transfer model analyzes the solidification behavior for a pulsed arc energy source. However, intermetallic formation deteriorates the welded joint properties and promotes solidification cracking in the weld zone. We attempt to join these dissimilar materials without using any filler materials and allowing solidification with the use of a pulse current. The use of a pulse current during microplasma arc welding assists in the formation of a beneficial microstructure that produces strong welds. Since the solidification parameters (G·R and G/R) largely define the weld microstructure, their effect on the weld joint properties is investigated herein. With an increase in the pulse current, the (G/R) decreases and enables the formation of an equiaxed solidified structure in the weld zone. A reduction in the amount of various intermetallic phases is observed in the equiaxed regions compared to amount present in areas with a columnar structure. The tensile strength of the joint is superior to that of AISI 316L stainless steel, and failure is observed in the heat-affected zone of this material. The best joint efficiency herein of 108 pct and elongation of 35.3 pct is achieved for the welding condition having the lowest (G/R) value. An improvement in the elongation is achieved for the weld joint with a reduction in the (G/R) value.

Numerical and Analytical Estimation of Parameters of Pulsed Energy Sources Which Do Not Lead to Locking of Supersonic Flow in Channels of Variable Section

In this paper the pulse energy supply into the channel of variable cross section was studied. The approximate formulas were obtained for the value of the input energy, corresponding to the maximal distance which the shock wave from a pulsed power source reached upstream, as well as full power, energy supply period corresponding to the conditions of closing the channel. The applicability of the analytical relationships is confirmed by numerical calculations based on the Euler equations in a quasi one-dimensional approximation

Ceramic to metal joining by using 1064 nm pulsed and CW laser energy source

A novel joining method for ceramic and metallic layers is proposed using laser drilling and surface tension driven liquid metal filling. A high intensity laser beam irradiated a 500 μm thick ceramic filter, and the irradiated laser drilled the ceramic layer. The pulsed or CW laser transmitted through the ceramic layer irradiated the bottom metallic layer; the molten metallic layer then filled the drilled ceramic holes by the capillary force between the liquid metal and ceramic layer. As process variables, average laser power, pulse duration, and the number of pulses were used. The scattering optical properties were also studied for both green and red lasers. There was no significant difference between the colors and the estimated extinction coefficients were −26.94 1/mm and −28.42 1/mm for the green and red lasers, respectively.

Resource pulses can increase power acquisition of an ecosystem

Pulsing is prevalent in nature. As resource pulse has been recognized as one of the major factors influencing ecosystem structures and processes, it is important to investigate why nature pulses and what benefits an ecosystem obtains from pulsed resources. The main question of this study was that if a system could be exposed to either constant external resources or pulsed external resources of the same temporal average intensity, which resources would maximize power acquisition of a system. To answer the question, this study tested how matching of pulsed resources affects total empower acquisition of a system using numerical simulation models and a refined dynamic emergy accounting method. A producer–consumer model system was built and simulated by varying phases and frequencies of pulsed energy sources. It was hypothesized that matching of frequency and phase among two or more pulsed energy sources increases the empower acquisition of a system, compared with a system under constant energy sources. The simulation results showed that in systems of two energy sources, matching phases and frequencies of the pulsed energy sources involved in primary production is critical to increase total empower acquisition and consumer energy storage. The primary mechanism was that the matching of pulsed resources in phase and frequency promotes energy acquisition of primary producers that is further efficiently transferred for the production of consumers. Energy acquisition of consumers was strongly correlated with total empower acquisition of the system presumably because the consumers are in the high energy hierarchical position controlling the producers thus contributing to the total empower acquisition through the system.

Synthesis of generators of pulsed currents with parametric variation of the resistance of the discharge circuit

An approach to the synthesis of pulsed capacity nonlinear parametric energy sources upon varying the discharge circuit’s resistance in time according to the pressure at the point of the working medium allowing for the constructive features of the electrode system and electrical conductivity of water is suggested.

Resonant interaction of periodic pulsed energy source with shock-wave structure in transonic flow past airfoil

The interaction of a periodic pulsed energy source with a closing shock wave that arises near an airfoil in transonic flight regimes has been studied. The evolution of the shock-wave structure near a symmetric airfoil is analyzed based on a numerical solution of two-dimensional nonstationary equations of gasdynamics. A resonance interaction mechanism is established that leads to a significant (by an order of magnitude) decrease in the wave drag of the airfoil.

Gasdynamic effects of periodic energy input into a divergent channel

The influence of the space-time characteristics of a pulsed energy source on a supersonic flow through a divergent channel is considered. It is found that low-frequency energy sources used for generating the thrust may provide a considerably higher specific force than continuous energy input. The influence of the duration of periodically applied energy pulses on the specific force is shown to be nonmonotonic. Short pulses provide a much higher specific force compared with steady energy input. The nonuniformity of the energy input distribution along the channel is found to have a noticeable effect on the specific force.

Influence of a periodic pulsed energy source on the regime of supersonic flow past a body

A two-dimensional nonstationary problem on the interaction of a trace developed behind a periodic pulsed energy source and a body occurring in a supersonic flow is considered. The results of numerical calculations are compared to the available experimental data.

Numerical modeling of vortex/shock wave interaction and its transformation by localized energy deposition

Three-dimensional unsteady Euler simulations are presented for the interaction of a streamwise vortex with an oblique shock of angle β = 23.3° at Mach 3 and 5. The flowfield features are analyzed for weak, moderate and strong interaction regimes. The details of the free recirculation zone at conditions of subsonic and supersonic flow on the vortex axis are considered. The vortex breakdown under conditions of a subsonic vortex core is characterized by a continuous growth and gradual degeneration of the region, unlike the supersonic core condition wherein a steady recirculation zone is achieved. The possibility of using a localized steady and pulsed periodic energy deposition on the vortex axis for stimulating the breakdown is demonstrated for various interaction regimes. It is shown that the formation of a subsonic wake downstream of an energy source lying on the vortex axis contributes to a more significant growth of the dimensions of the recirculation zone compared to the case when the vortex core remains supersonic. The possibility of achieving the effects similar to the steady case is demonstrated by the effect of a pulsed periodic energy source on the flow under consideration for corresponding equivalence parameters.

Efficiency of hydrodynamic energy transfer to an arbitrarily thick flat layer of material during pulsed ablation

We obtained a general analytical solution of the problem of hydrodynamic energy transfer to a flat layer of material with an arbitrary initial thickness when ablation—the evaporation of material and the formation of a pressure gradient under the action of an external pulsed energy source—takes place at one of its surfaces. The solution was obtained in the form of a dependence of the fraction of the source energy transferred to the nonevaporated part of the layer on the intensity and duration of the energy source as well as on the initial layer thickness and density. The solution includes, as limiting cases, the previously obtained solutions for the hydrodynamic transfer coefficient during the ablation acceleration of a thin layer, through which the travel time of a shock or acoustic wave is much shorter than the duration of the energy source, and for the ablation loading efficiency when a shock wave propagates through a semiinfinite layer.

Report of a new technique for enhanced non‐invasive skin rejuvenation using a dual mode pulsed light and radio‐frequency energy source: selective radio‐thermolysis

Report of a new technique for enhanced non‐invasive skin rejuvenation using a dual mode pulsed light and radio‐frequency energy source: selective radio‐thermolysis

Characterization of a high-intensity bipolar-mode pulsed ion source for surface modification of materials

A high-intensity pulsed ion source of TEMP-type series, operating in bipolar mode, has been developed as a unique pulsed energy source to produce a high-intensity pulsed ion beam (HIPIB) for surface modification of materials. To generate the ion beam, a specially shaped bipolar pulse, consisting of a first negative pulse and a second delayed positive pulse both of nanosecond width, is formed by a double coaxial pulse-forming line (PFL) powered with a Marx generator and supplied to a magnetically insulated ion diode (MID) by a self-magnetic field. It is found that the efficient generation of a HIPIB is mainly dependent on the delay time of the bipolar pulse, adjusted by pressure ratio in the two gas switches of a PFL, and the anode–cathode (A–K) gap distance in the self-magnetic field MID. The delay time determines the effective area on the anode surface for plasma generation and the A–K gap distance ensures the stability of the process. A proper delay time and a proper A–K gap distance are obtained by a series of experimental investigations. Under delay time from 30 to 280 ns and several different A–K gap distances, the typical wave forms of the bipolar pulses at a dc charging voltage of 45 kV to Marx generator are illustrated to clarify the effects of delay time and A–K gap distance on the ion beam generation. The proper A–K gap distance is not uniform, varied from 6 to 8 mm, and the corresponding proper delay time is 250 ns. The most efficient plasma generation leads to a maximum output of HIPIB with a peak ion current density of 350 A cm−2 and a beam pulse width of 75 ns (full width at half maximum), at an accelerating pulse of 220 kV with a pulse width of 100 ns.

DPL model analysis of non-Fourier heat conduction restricted by continuous boundary interface

Dual-phase lag (DPL) model is used to describe the non-Fourier heat conduction in a finite medium where the boundary at x=0 is heated by a rectangular pulsed energy source and the other boundary is tightly contacted with another medium and satisfies the continuous boundary condition. Numerical solution of this kind of non-Fourier heat conduction is presented in this paper. The results are compared with those predicted by the hyperbolic heat conduction (HHC) equation.

Heating of matter in the inner cavity of a target by a pulsed energy source

A two-dimensional model is proposed for describing plasma formation when a pulsed energy source acts on a planar layer of matter which either has free surfaces or is bounded on one or both sides by thermally insulating infinitely heavy walls with apertures for injecting radiation. Conditions are found for efficient heating of matter in the inner cavity of a target by a radiation or ion beam under conditions of minimal energy losses associated with hydrodynamic expansion of matter through a radiation-injection aperture. A version of a model is suggested for describing the formation of a plasma in a low-density absorber of the kind used in inertial-confinement thermonuclear fusion targets with internal injection of laser radiation.

The performance of high-field magnets with optimized internal reinforcement

For the performance analysis of pulsed high-field magnets with internal reinforcement, analytical equations are derived for the optimum distribution of the reinforcement in long coils without external reinforcement. Among others, the relation between the stress in the reinforcement, the obtainable magnetic field and the filling factor of the conductor are established. By adjusting the amount of reinforcement for each layer of conductor, optimal use is made of the material strength. Therefore, this type of magnet is a good candidate for obtaining high magnetic fields up to 100 T. Moreover, it is shown that these magnets give the longest pulse duration when used in combination with an energy-limited high-power pulsed energy source.