Dynamics of metal ions during laser-produced plasmas was studied. A 1064 nm, Nd: YAG laser pulse was used to ablate pure Al, Fe, Co, Mo, and Sn samples. Ion flux and velocity were measured using Faraday cup ion collector. Time-of-flight measurements showed decreasing ion flux and ion velocity with increasing atomic weight, and heavy metal ion flux profile exhibited multiple peaks that was not observed in lighter metals. Slow peak was found to follow shifted Maxwell Boltzmann distribution, while the fast peak was found to follow Gaussian distribution. Ion flux angular distribution that was carried out on Mo and Al using fixed laser intensity 2.5 × 10¹⁰ W/cm² revealed that the slow ion flux peaks at small angles, that is, close to normal to the target ∼0° independent of target's atomic weight, and fast ion flux for Mo peaks at large angles ∼40° measured from the target normal, while it completely absents for Al. This difference in spatial and temporal distribution reveals that the emission mechanism of the fast and slow ions is different. From the slow ion flux angular distribution, the measured plume expansion ratio (plume forward peaking) was 1.90 and 2.10 for Al and Mo, respectively. Moreover, the effect of incident laser intensity on the ion flux emission as well as the emitted ion velocity were investigated using laser intensities varying from 2.5 × 10¹⁰ W/cm² to 1.0 × 10¹¹ W/cm². Linear increase of fast ion flux and velocity, and quadratic increase of slow ion flux and velocity were observed. For further understanding of plume dynamics, laser optical emission spectroscopy was used to characterize Sn plasma by measuring the temporal and spatial evolution of plasma electron density N_e and electron temperature T_e. At 3.5 mm away from the target, plasma density showed slow decrease with time, however electron temperature was observed to decrease dramatically. The maximum plasma density and temperature occurred at 0.5 mm away from target and were measured to be 8.0 × 10¹⁷ cm⁻³ and 1.3 eV, respectively.

Structural damage due to high flux particle irradiation can result in significant changes to the thermal strength of the plasma facing component surface (PFC) during off-normal events in a tokamak. Low-energy He+ ion irradiation of tungsten (W), which is currently the leading candidate material for future PFCs, can result in the development of a fiber form nanostructure, known as “fuzz”. In the current study, mirror-finished W foils were exposed to 100eV He+ ion irradiation at a fluence of 2.6 ×1024ionsm−2 and a temperature of 1200K. Then, samples were exposed to two different types of pulsed heat loading meant to replicate type-I edge-localized mode (ELM) heating at varying energy densities and base temperatures. Millisecond (ms) laser exposure done at 1200K revealed a reduction in fuzz density with increasing energy density due to the conglomeration and local melting of W fibers. At higher energy densities (∼ 1.5MJm−2), RT exposures resulted in surface cracking, while 1200K exposures resulted in surface roughening, demonstrating the role of base temperature on the crack formation in W. Electron beam heating presented similar trends in surface morphology evolution; a higher penetration depth led to reduced melt motion and plasticity. In situ mass loss measurements obtained via a quartz crystal microbalance (QCM) found an exponential increase in particle emission for RT exposures, while the prevalence of melting from 1200K exposures yielded no observable trend

Kinetics of ion and neutral atom emission features were compared for nanosecond laser-produced plasmas generated from several metal targets (i.e., Al, Ti, Zr, Nb, Ta) and an alloy containing all of these as principal alloying elements. Plasmas were produced by focusing 6 ns, 1064 nm pulses from an Nd:YAG laser on the targets of interest in a vacuum. A Faraday cup was used for collecting ion temporal features while spatially and temporally resolved emission spectroscopy was used for measuring the optical time of flight of various neutral atomic transitions. Our results highlight that most probable ion and atom velocities decay with increasing atomic mass. Trends for ions from the alloy target represent a weighted average where all ions contribute. For both ions and atoms, velocities decrease with increasing heat of vaporization and melting temperature, consistent with the thermal mechanisms that contribute to nanosecond laser ablation. Kinetic energies for neutral atoms from pure metal targets have some variability with atomic mass, whereas kinetic energies for atoms from the alloy target are more similar. These more similar kinetic energies observed for neutral atoms in the multi-element plasma may be attributed to collisions between species from all elements in the Knudsen layer.

As cancer continues to be one of the world's leading killers, efforts to replace expensive and invasive therapies that cause harmful side effects led to the exploration of cold atmospheric plasma (CAP) and electroporation (EP) as efficient and selective treatments for the ablation of cancerous tissues. CAP acts by producing reactive oxygen and nitrogen species within irradiated cancer cells, initiating the intrinsic apoptosis pathway through oxidative stress. Another treatment that is also emerging is EP, which compromises plasma membrane stability, resulting in the transmembrane mass transfer or, in extreme electrical field exposure, cell death. The combination of these two methods has not been thoroughly investigated. Although the apoptotic pathway and its components' responses to cold plasma have been previously explored, there is still a lack of knowledge in the mode of signal propagation and the timeframe in which affected cells begin to feel the plasma's effects. It has been previously observed that the addition of EP to treatments augments the plasma effects, increasing cancer cell death events. This study tracked apoptotic events through time using flow cytometry and real-time fluorescent microscopy following cold plasma, EP, and a combined plasma/ EP treatment. Flow cytometry analysis of CAP and EP+CAP treated cells suggest that both treatments are effective at killing cancer cells within a short timeframe, with the combined treatment possessing higher killing potential. A 48-h time lapse of treated and untreated live cells reveals that the first 8 h after CAP treatment shows the highest rate of cell death, but the imaging performed on the EP+CAP treatment was largely inconclusive. These treatment methods represent promising emerging technologies in the ongoing battle against cancer but require further investigations.

Thermophilic anaerobic digestion (TAD) of solid organic wastes for biogas production offers dual human-health and environmental benefits: source-separated waste management with reduced pathogen burden and renewable energy generation with reduced greenhouse-gas emissions. This study investigated a “Techno-Economic Assessment (TEA)” of an industrial-scale TAD process integrated with combined heat and power (CHP) generation and alternative digestate-management strategies. Two processing capacities, 7000 tons/year (Case I) and 2000 tons/year (Case II), were evaluated under four digestate-management scenarios using economic assumptions. For Case I, the total capital investment (TCI), including working capital equivalent to 5% of fixed capital investment, was estimated at $4.055 million, while the annual operation and maintenance (O&M) cost was estimated at $0.434 million. Scenario 1, involving solid–liquid separation with recovery of separated compost and liquid digestate, generated an annual revenue of $1.070 million, a 20-year net present value (NPV) of $0.869 million, a discounted payback period of 12.3 years, and an internal rate of return (IRR) of 13.2%. Scenario 2, based on direct utilization of whole digestate, produced the highest modeled economic return, with an NPV of $5.998 million and an IRR of 30.1%; however, its feasibility depends strongly on securing a reliable whole digestate offtake market. In contrast, Scenarios 3 and 4 resulted in negative NPVs under the base-case assumptions. A normalized one-at-a-time sensitivity analysis identified process-cycle duration and effective throughput, liquid digestate netback, tipping fee, CHP energy value, methane yield, capital cost, processing capacity, and discount rate as the principal economic drivers. Zero-revenue digestate cases produced negative NPVs for Scenarios 1 and 2, with estimated break-even plant-gate netbacks of $0.134/gal for liquid digestate and $0.121/gal for whole digestate. Overall, industrial TAD can be economically feasible, but commercial viability depends on feedstock supply, reactor productivity, internal energy demand, digestate offtake, heat utilization, and site-specific waste-management revenue.