Energy Coupling Efficiency Research Articles

Research on virtual water-embodied energy consumption and efficiency accounting in Liaoning

Due to the extensive development model of "focusing on development with high investment" for a long time, the resources input of industry in Liaoning is seriously mismatched with economic output, resulting in serious waste of resources. In view of this, the consumption of virtual water and embodied energy was calculated through the input-output model, and they were incorporated into the undesired super-SBM to compare the virtual water efficiency, embodied energy efficiency and virtual water-embodied energy coupling efficiency of 23 sectors. Finally, we analyzed the dynamic change in coupling efficiency using the Malmquist index model. The results showed that: (1) Food and Tobacco was the largest consumer of virtual water, accounting for 31.3% of total consumption; Petroleum Product Processing was the largest consumer of embodied energy, accounting for 24.4% of total consumption. (2) Regarding the embodied resource transferring pattern, the total industrial transferrable flux decreased by 40.2% (virtual water) and 12.5% (embodied energy) from 2012 to 2018. Smelting and Pressing of Metals was not only an important supplier but also a significant recipient, receiving metal ore resources and transferring them to different equipment manufacturers. (3) On the whole, the embodied energy efficiency was greater than the virtual water efficiency, but neither had reached the production frontier in most sectors. The coupling efficiency of the overall industry showed a "V" trend, but the efficiency value did not reach 1. (4) Although total factor productivity (TFP) and the corresponding decomposition factors were significantly different in 23 sectors, pure technical efficiency (PEC) obviously restricted TFP in most sectors. In addition, scale efficiency (SEC) maintained a stable balanced, especially in heavy manufacturing industry. In contrast, technology efficiency (TC) severely constrained TFP especially in Chemical Products and Production and Supply of Water.

Study on response of metal wire in thermoacoustic imaging

Thermoacoustic imaging (TAI) is an emerging high-resolution and high-contrast imaging technology. In recent years, metal wires have been used in TAI experiments to quantitatively evaluate the spatial resolution of different systems. However, there is still a lack of analysis of the response characteristics and principles of metal wires in TAI. Through theoretical and simulation analyses, this paper proposes that the response of metal (copper) wires during TAI is equivalent to the response of antennas. More critically, the response of the copper wire is equivalent to the response of a half-wave dipole antenna. When its length is close to half the wavelength of the incident electromagnetic wave, it obtains the best response. In simulation, when the microwave excitation frequencies are 1.3[Formula: see text]GHz, 3.0[Formula: see text]GHz, and 5.3[Formula: see text]GHz, and the lengths of copper wires are separately set to 11[Formula: see text]cm, 5[Formula: see text]cm, and 2.5[Formula: see text]cm, the maximum SAR distribution and energy coupling efficiency are obtained. This result is connected with the best response of half-wave dipole antennas with lengths of 11[Formula: see text]cm, 4.77[Formula: see text]cm, and 2.7[Formula: see text]cm under the theoretical design, respectively. Regarding the further application, TAI can be used to conduct guided minimally invasive surgery on surgical instrument imaging. Thus, this paper indicated that results can also guide the design of metal surgical instruments utilized in different microwave frequencies.

Metal microspheres propelled by shock wave based on the fiber structure laser propulsion

An intriguing method of propelling stainless steel (SS, metallic) microsphere by employing the nanosecond laser pulses output from the end face of the fiber was demonstrated, in order to investigate the interaction of nanosecond laser pulses with metal microsphere. Using a two-dimensional model of the shock wave acting on the metal microsphere, the propagation characteristics of shock wave such as propagation distance and pressure have been calculated. Experimentally, we observed that the propulsion efficiency is dependent on the laser pulse energy and the gap distance. The momentum coupling coefficient and the energy coupling efficiency of SS microsphere were analyzed, which showed that metal microsphere has the high propulsion efficiency. In addition, an experiment was performed to remove the SS contamination particles on the surface of the microstructure. Compared with conventional technology, this new method has advantages of high controllability, directional and non-contact, and can be used for the removal of metal pollution particles and the manipulation of metal micromachines.

Astigmatism and spherical aberrations as main causes for degradation of ultrafast laser-induced cavitation in water

The generation of cavitation bubbles in water by focused laser pulses has been thoroughly studied, particularly due to the wide range of applications in biomedical fields, in particular for ophthalmic laser surgery. The presence of optical aberrations in any optical system deteriorates the precision of light focusing and may reduce the laser interaction efficiency in transparent media. In this paper, we analyze the influence of several controlled optical geometrical aberrations in the formation and dynamics of cavitation bubbles in water caused by laser-induced optical breakdown using femtosecond laser pulses. The maximum cavitation bubble diameter reduces with increasing aberrations, showing a drop of the energy coupling efficiency, ultimately leading to the absence of cavitation bubble. The study reveals that the secondary astigmatism and spherical aberrations degrade more rapidly the beam concentration than the other aberrations studied here (namely astigmatism first and second, coma, spherical and trefoil). The cavitation energy threshold becomes equally increased. This observation relates very well to numerical simulations evaluating the laser fluence at and around the focusing plane in the presence of aberrations. These results open the door to more controlled ultrafast laser assisted surgeries and processing in transparent media.

Experimental Study on Electrical Explosion Behavior of Six Metal Wires in Air and Vacuum

Experimental investigations have been carried out to establish a correlation of energy coupling efficiency in fast electrical explosion of different metals with known electrical and thermophysical properties. To cover a wide range of metal properties, in the present study, five metals (Au, Cu, Al, W, and Ti) are considered from two well-known groups (refractory and non refractory) and palladium is included as sixth metal having intermediate properties between these two. Comparative study is carried out for the same circuit parameters (current rate <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\approx 90 \times 10^{9}$ </tex-math></inline-formula> A/s) to explore electrically exploding wire (EEW) behavior of these metals in two different media: air and vacuum. Temporal evolution of self-emitted light around these metal wires is analyzed as a qualitative measure for energy diversion from the metal core to outer corona and is recorded using streak camera for both media. In air, refractory and non refractory metals are seem to exhibit different behavior as inferred from voltage profiles, time of burst, temporal optical emission profiles, and overheating factor (the ratio of energy deposited till burst to the enthalpy of atomization). Overheating in air is found to depend inversely on the enthalpy of atomization and resistivity for refractory and non refractory metals, respectively. Pd has shown mixed electrical and optical characteristics of both groups (refractory and non refractory) in air as well as in vacuum. On changing the surrounding medium from air to vacuum, overheating is found to decrease for all metals; interestingly, their drop is observed to depend on the speed of sound at room temperature in that particular metal. Using these experimental outcomes, the possible mechanisms responsible for energy diversion in the explosion of wires of different materials along with their correlation to surrounding medium are discussed in this work. In the present study, the electrical characteristics of gold have been found to be most favorable for efficient energy coupling and hence for high-energy-density applications irrespective of the surrounding medium.

Simulation of a novel wind–wave hybrid power generation system with hydraulic transmission

The mutual compensation of offshore wind energy and wave energy provides a cost-effective solution to offshore power supply. Herein, a novel wind–wave hybrid power generation system with hydraulic transmission is proposed, which consists of a wave energy harvesting part, a wind energy harvesting part, an energy coupling part, and a control part. This system removes the conventional electric regulation components and significantly reduces the negative interaction between the two energy harvesting parts. First, the working principles of the hybrid system, individual wind power generation system, and individual wave power generation system are introduced, and relevant numerical models are established. Next, simulation models of the three systems are established via AMESim and MATLAB/Simulink. Finally, the output power, generator speed, system pressures, and internal flow rates of the hybrid system are compared with those of two individual power generation systems to evaluate the complementary energy performance. Relative to the individual wave power generation system and individual wind power generation system, the hybrid system exhibits enhanced stability of the output power (by 69.42% and 21.03%, respectively) and enhanced stability of the generator speed (by 63.78% and 39.32%, respectively). Furthermore, the hybrid system exhibits a high energy coupling efficiency between 80.34% and 99.12%.

Reaching 30% energy coupling efficiency for a high-density-carbon capsule in a gold rugby hohlraum on NIF

In the laser-driven indirect drive scheme for inertial confinement fusion, the energy coupling efficiency from the hohlraum to the capsule is typically ∼10% due to limited capsule sizes in order to attain quasi-round implosions with currently available laser energy in cylindrical hohlraums. Recent experiments at the National ignition Facility (NIF) showed ∼30% energy coupling efficiency to aluminum capsules by using a rugby-shaped hohlraum to accommodate larger capsules. This paper reports the first experiment at the NIF demonstrating ∼30% energy coupling to a 3 mm-diameter high-energy-density carbon capsule in a rugby hohlraum with a two-shock laser pulse shape. By comparing the measured bang time with a simulated hydrodynamic scaling, ∼430 kJ coupling is inferred with 1.36 MJ laser drive. The symmetry of the hot spot was observed to be more oblate than simulations predicted. X-ray images taken at late time show strong emission at the laser entrance hole of the rugby hohlraum, indicating a closure earlier than expected, which could contribute to the oblate hot spot shape. Implementing wavelength detuning or modifying the hohlraum shape to tune the symmetry in future experiments would allow symmetric implosions while maintaining the high energy coupling.

Effects of confining layer and ablating layer on laser-induced shock wave characteristics during laser shock processing by PVDF gauge

The PVDF sensor is used to obtain the time variation curves of the shock wave pressure in the four states of the laser shock peening with or without confining layer and with or without ablating layer, the effects of confining layer and ablating layer on shock wave characteristics are analyzed. The results show that the confining layer limits the plasma expansion area, and the inverse bremsstrahlung absorption effect is enhanced, so that the peak pressure and pulse width of the shock wave are increased to 10 times and 2 times that under the condition of the without confining layer; The ablating layer significantly increases the peak pressure of the shock wave by improving the laser energy coupling efficiency. However, the influence of the ablating layer on the peak pressure tends to saturate with the increase of power density, the difference of the peak pressure is only 8.5% when the laser power density is 4.53GW/cm2. In addition, the ablating layer complicates the shock wave propagation process, and the shock wave curve presents a multi-peak structure.

An investigation on physical phenomena of water-jet assisted underwater wet laser welding technique under continuous and pulsed mode operation

This work presents the development and demonstration of a novel underwater wet laser welding technique, where unlike the conventional underwater wet laser welding, a water-jet parallel to the weld pool surface was introduced inside the water environment. The water flow was found to enhance the removal of water vapour formed at the laser-water-workpiece interface without creating hindrance to the molten weld bead, resulting in lower energy loss due to absorption and scattering, thus enhancing the laser energy coupling efficiency to the material. The process was studied for bead-on-plate welding on 4 mm stainless steel (SS) sheets using a 2 kW Yb-Fiber laser (wavelength 1.07 µm), with water column height of 5–15 mm, and a parallel water jet of speed 2–3 m/s, under continuous (CW) and pulsed mode (modulated power) laser operation. The major objective of the work was to study the effect of water flow and mode of laser operation on the formation and growth of vapour layer at the processing zone and investigate its effect on laser energy coupling efficiency. Further, their effect on weld bead geometry and microstructure was investigated. Welding operation with modulated laser power was found to produce higher weld depth compared to CW mode with same average laser power due to lower scattering loss and better energy coupling under pulsed mode operation. The micro-structural investigation has showed the formation of finer grains and oxide or carbide precipitation in case of underwater welding, indicating the enhanced cooling phenomena in this technique.

Three dimensional low-mode areal-density non-uniformities in indirect-drive implosions at the National Ignition Facility

To achieve hotspot ignition, an inertial confinement fusion implosion must achieve high hotspot pressure that is inertially confined by a dense shell of DT fuel. This requires a symmetric implosion having high in-flight shell velocity and high areal density at stagnation. The size of the driver and scale of the capsule required can be minimized by maintaining a high efficiency of energy coupling from the imploding shell to the hotspot. Significant 3D low mode asymmetries, however, are commonly observed in indirect-drive implosions and reduce the coupling of shell kinetic energy to the hotspot. To better quantify the magnitudes and impacts of shell density asymmetries, we have developed new analysis techniques and analytic models [Hurricane et al., Phys. Plasmas 27(6), 062704 (2020)]. To build confidence in the underlying data, we have also developed an analytic neutron transport model to cross-compare two independent measurements of asymmetry, which shows excellent agreement across shots for mode-1 (ℓ = 1). This work also demonstrates that asymmetry can introduce potential sampling bias into down-scattered ratio measurements causing the solid-angle-average and uncertainty-weighted-average down-scattered ratios to differ significantly. Diagnosing asymmetries beyond mode-1 (ℓ &amp;gt; 1) presents significant challenges. Using new diagnostic instruments and analysis techniques, however, evidence of significant Legendre mode P2 (ℓ = 2, m = 0) and additional 3D asymmetries (ℓ &amp;gt; 1, m ≠ 0) are beginning to emerge from the high precision activation diagnostic data (real-time nuclear activation detectors) and down-scattered neutron imaging data.

Impact of neutron energy on asteroid deflection performance

In the future, a hazardous asteroid will find itself on a collision course with Earth. For asteroids of moderate size or larger, a nuclear device is one of humanity’s only technologies capable of mitigating this threat via deflection on a timescale of less than a decade. This work examined how the output neutron energy from a nuclear device standoff detonation affects the deflection of a notional asteroid that is 300 meters in diameter and composed of silicon dioxide at a bulk density of 1.855 g/cm3. 14.1 MeV and 1 MeV neutron energy sources were modeled in MCNP to quantify the energy deposition in the asteroid target. The asteroid’s irradiated region was discretized in angle by tracing the rays emanating from the point of detonation and in depth by considering the neutron mean-free-paths. This high-fidelity approach was shown to deviate from previous analytic approximations commonly used for asteroid energy deposition. 50 kt and 1 Mt neutron yields of the energy deposition mappings were imported into a hydrodynamic asteroid model in ALE3D to simulate the deflective response due to blow-off ejecta. Underexplored in literature, changing the neutron energy was found to have up to a 70% impact on deflection performance due to induced differences in the energy deposition profile and in the energy coupling efficiency. The magnitude of energy deposition accounted for most of the observed variation in the asteroid velocity change, making the coupling efficiency more significant than the spatial profile characteristics. These findings are vital for determining the optimal source neutron energy spectrum for asteroid deflection applications.

Effects of mixed laser beam irradiation with different wavelengths on fast electron generation

In fast ignition laser fusion, a high-intensity picosecond laser heats a compressed dense core to achieve ignition. It is theoretically expected that the energy coupling efficiency from the heating laser to the compressed core becomes higher as the wavelength of the heating laser is shorter. This prediction is ready to be experimentally demonstrated using second harmonic generation at Institute of Laser Engineering (ILE), Osaka University. Fundamental and converted second harmonic waves irradiate a target simultaneously in the experiment because crystals for wavelength conversion is installed after a final optical system. In addition, the polarization of the second harmonic wave becomes perpendicular to the original fundamental wave after the wavelength conversion. These features make laser-plasma-interactions complicated. Therefore, three-dimensional particle-in-cell simulations have been conducted to investigate effects of conversion to short wavelength and mixed-beam irradiation with different wavelengths. Simulation results show that the temperature of the generated fast electrons decreases for second harmonic conversion compared to the case of pure fundamental wave and the laser propagates deeper as the wavelength conversion efficiency becomes high. In the case of mixed-beam irradiation, it is found that the second harmonic wave drills the plasma and guides the fundamental wave to the deep region, where pure fundamental wave cannot reach.

Proton beams from intense laser-solid interaction: Effects of the target materials

We report systematic studies of laser-driven proton beams produced with micrometer-thick solid targets made of aluminum and plastic, respectively. Distinct effects of the target materials are found on the total charge, cutoff energy, and beam spot of protons in the experiments, and these are described well by two-dimensional particle-in-cell simulations incorporating intrinsic material properties. It is found that with a laser intensity of 8 × 1019 W/cm2, target normal sheath acceleration is the dominant mechanism for both types of target. For a plastic target, the higher charge and cutoff energy of the protons are due to the greater energy coupling efficiencies from the intense laser beams, and the larger divergence angle of the protons is due to the deflection of hot electrons during transport in the targets. We also find that the energy loss of hot electrons in targets of different thickness has a significant effect on the proton cutoff energy. The consistent results obtained here further narrow the gap between simulations and experiments.

High-robustness intravascular photoacoustic endoscope with a hermetically sealed opto-sono capsule.

The prevailing open-structure intravascular photoacoustic (IVPA) endoscope emits a gradually deformed laser beam with exposed optical or acoustical components bearing pollution and damage in arterial lumen. Deformed laser beam scanning, which causes a low excitation efficiency and serious deterioration of the transverse resolution, is a current big obstacle to the application of photoacoustic endoscopy in intravascular imaging. Hence, the stable and reliable IVPA endoscope is indispensable. In this letter, we designed a high-robustness intravascular photoacoustic (HR-IVPA) endoscope with a hermetically sealed opto-sono capsule. The distal end of the opto-sono capsule was integrated with miniaturized optics, including a customized C-Lens and a customized total-reflection prism (TRP). The TRP was first applied to a side-viewing IVPA endoscope, featuring a high-throughput energy coupling efficiency of 90% and a cut-off free damage threshold. The optical path structure of the endoscope, optimized using optical simulation tools, overcame the ambiguous focus shift caused by chromatic dispersion and achieved a waist size of 20 µm as well as a focus depth of 4 mm in water at the wavelength of 1200 nm. The mass phantom experiments demonstrated that the HR-IVPA endoscope afforded repeatable IVPA images with a relatively constant signal-to-noise ratio (SNR) of about ∼41.8 dB and a transverse resolution of about ∼23 µm. The imaging experiments of the stent and lipid further demonstrated the robustness and validated the imaging ability of the HR-IVPA endoscope, which opens a new avenue for improving the endoscopic imaging capability, strengthening the credible detection of atherosclerotic cardiovascular disease.

On the Energy Coupling Efficiency of AGN Outbursts in Galaxy Clusters

Abstract Active galactic nucleus (AGN) jets are believed to be important in solving the cooling flow problem in the intracluster medium (ICM), while the detailed mechanism is still under debate. Here we present a systematic study on the energy coupling efficiency η cp, the fraction of AGN jet energy transferred to the ICM. We first estimate the values of η cp analytically in two extreme cases, which are further confirmed and extended with a parameter study of spherical outbursts in a uniform medium using hydrodynamic simulations. We find that η cp increases from ∼0.4 for a weak isobaric injection to ≳0.8 for a powerful point injection. For any given outburst energy, we find two characteristic outburst powers that separate these two extreme cases. We then investigate the energy coupling efficiency of AGN jet outbursts in a realistic ICM with hydrodynamic simulations, finding that jet outbursts are intrinsically different from spherical outbursts. For both powerful and weak jet outbursts, η cp is typically around 0.7–0.9, partly due to the nonspherical nature of jet outbursts, which produce backflows emanating from the hot spots, significantly enhancing the ejecta–ICM interaction. While for powerful outbursts a dominant fraction of the energy transferred from the jet to the ICM is dissipated by shocks, shock dissipation only accounts for ≲30% of the injected jet energy for weak outbursts. While both powerful and weak outbursts could efficiently heat cooling flows, powerful thermal-energy-dominated jets are most effective in delaying the onset of the central cooling catastrophe.

Visibility Graph Power Geometric Aggregation Operator and Its Application in Water, Energy, and Food Efficiency Evaluation.

In the real decision-making process, there are so many time series values that need to be aggregated. In this paper, a visibility graph power geometric (VGPG) aggregation operator is developed, which is based on the complex network and power geometric operator. Time series data are converted into a visibility graph. A visibility matrix is developed to denote the links among different time series values. A new support function based on the distance of two values are proposed to measure the support degree of each other when the two time series values have visibility. The VGPG operator considers not only the relationship but also the similarity degree between two values. Meanwhile, some properties of the VGPG operator are also investigated. Finally, a case study for water, energy, and food coupling efficiency evaluation in China is illustrated to show the effectiveness of the proposed operator. Comparative analysis with the existing research is also offered to show the advantages of the proposed method.

Generation of quasi-monoenergetic ions using optimized hollow nanospheres

For ultra-high-intensity lasers irradiating nanometer-sized targets, Coulomb explosion (CE) is one of the main ion acceleration schemes. Previous studies have shown that the CE of solid nanospheres can produce quasi-monoenergetic ions. However, the development of optimized hollow nanospheres has yet to be achieved. Currently, the technology for the production of various types of hollow nanospheres has already been established. Still, the applications of hollow nanospheres are more inclined toward energy storage. This study shows that CE-based ion acceleration is another plausible application for these hollow nanospheres. Different nanosphere designs were analyzed using simple analytical models, which showed the possibility of using them to produce quasi-monoenergetic ions. This was then confirmed using one-dimensional particle–particle simulations in spherical coordinates. Overall, the results showed that hollow nanospheres are viable targets that can be used for the production of quasi-monoenergetic ions via spherical CE. Furthermore, the new proposed target design substantially improved the energy coupling efficiency.

Experimental Research on Impulse Coupling Characteristics and Plasma Plume Dynamics of a Nanosecond Pulsed Laser Irradiated Aluminum Target

The impulse generated by ablating aluminum targets was investigated in this study using the micro-impulse measurement method with a torsion pendulum, and the plasma plume characteristics were researched using fast photography and optical emission spectroscopy. The experiment was carried out with a pulsed laser with a wavelength of 1064 nm and a pulse duration of 8.7 ns. The fluence varied from 5.69 J/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> to 33.67 J/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . The impulse coupling coefficients were obtained from the impulse measurements and the images of the plasma plume were recorded with a gate width of 500 ns. The results indicated that the variation of the impulse coupling coefficient was affected by the change of the laser fluence and the decline of the coefficient at high fluence was because of the plasma shielding effect. The intense radiation region located above the target surface in the corresponding plume was evident. Additionally, the differential coupling coefficient was presented and compared with the impulse coupling coefficient. The plasma temperature and the electron number density were estimated with the Boltzmann plot method and the Stark broadening method, respectively, using optical emission spectroscopy. Furthermore, the relative energy coupling efficiency was deduced from the plume front positions to determine the influence of the plume expansion dynamics on the impulse coupling. The obtained results showed that the variation trend of efficiency versus the laser fluence was similar to that of the impulse coupling coefficient.

Improvement of Acetaldehyde Production in Zymomonas mobilis by Engineering of Its Aerobic Metabolism.

Acetaldehyde is a valuable product of microbial biosynthesis, which can be used by the chemical industry as the entry point for production of various commodity chemicals. In ethanologenic microorganisms, like yeast or the bacterium Zymomonas mobilis, this compound is the immediate metabolic precursor of ethanol. In aerobic cultures of Z. mobilis, it accumulates as a volatile, inhibitory byproduct, due to the withdrawal of reducing equivalents from the alcohol dehydrogenase reaction by respiration. The active respiratory chain of Z. mobilis with its low energy-coupling efficiency is well-suited for regeneration of NAD+ under conditions when acetaldehyde, but not ethanol, is the desired catabolic product. In the present work, we sought to improve the capacity Z. mobilis to synthesize acetaldehyde, based on predictions of a stoichiometric model of its central metabolism developed herein. According to the model analysis, the main objectives in the course of engineering acetaldehyde producer strains were determined to be: (i) reducing ethanol synthesis via reducing the activity of alcohol dehydrogenase (ADH), and (ii) enhancing the respiratory capacity, either by overexpression of the respiratory NADH dehydrogenase (NDH), or by mutation of other components of respiratory metabolism. Several mutants with elevated respiration rate, decreased alcohol dehydrogenase activity, or a combination of both, were obtained. They were extensively characterized by determining their growth rates, product yields, oxygen consumption rates, ADH, and NDH activities, transcription levels of key catabolic genes, as well as concentrations of central metabolites under aerobic culture conditions. Two mutant strains were selected, with acetaldehyde yield close to 70% of the theoretical maximum value, almost twice the previously published yield for Z. mobilis. These strains can serve as a basis for further development of industrial acetaldehyde producers.

Simple Analysis of the Laser-to-Core Energy Coupling Efficiency with Magnetized Fast Isochoric Laser Heating

Simple Analysis of the Laser-to-Core Energy Coupling Efficiency with Magnetized Fast Isochoric Laser Heating