Accelerator system and method of accelerating particles

An accelerator system and method that utilize dust as the primary mass flux for generating thrust are provided. The accelerator system can include an accelerator capable of operating in a self-neutralizing mode and having a discharge chamber and at least one ionizer capable of charging dust particles. The system can also include a dust particle feeder that is capable of introducing the dust particles into the accelerator. By applying a pulsed positive and negative charge voltage to the accelerator, the charged dust particles can be accelerated thereby generating thrust and neutralizing the accelerator system

Simulation of Electrospray Emission Processes for Highly Conductive Liquids

An electrohydrodynamic numerical model is used to explore the electrospray emission behavior of both moderate and high electrical conductivity liquids under electrospray conditions. The Volume-of-Fluid method, incorporating a leaky-dielectric model with a charge relaxation consideration, is used to conserve charge to accurately model cone-jet formation and droplet breakup. The model is validated against experiments and agrees well with both droplet diameters and charge-to-mass ratio of emitted progeny droplets. The model examines operating conditions such as flow rate and voltage, with fluid properties also considered, such as surface tension, electrical conductivity, and viscosity for both moderate and high conductivity. For high conductivity and surface tension, the results show that high charge concentration along with the meniscus and convex cone shape results in a higher charge-to-mass ratio of the emitted droplets while lower conductivity and surface tension tend towards concave cone shapes and lower charge-to-mass droplets. Recirculation flows inside the bulk liquid are investigated across a range of non-dimensional flow rates, and electric Reynolds numbers. For high conductivity liquid emission at the minimum stable flow rate, additional recirculation cells develop near the cone tip suggesting the onset of the axisymmetric instability.Comment: submitted to Journal of Fluid Mechanic

Cold plasma treatment for biomedical applications: using aluminum foam to reduce risk while increasing efficacy

Plasma medicine is an emerging and innovative interdisciplinary research field combining biology, chemistry, physics, engineering, and medicine. However, the safe clinical application of cold atmospheric plasma (CAP) technology is still a challenge. Here, we examine the use of aluminum (Al) foam with three pores-per-inch (PPI) ratings in clinical plasma applications. Al foams can filter sparks to avoid damage from high voltage discharge during surgery and efficiently deliver reactive species generated in CAP to the target. The sparks appear and plasma intensity increases at the foam/discharge interface, which just slightly increases the interface temperature without changing the interface microstructure during a 30-minute treatment. After CAP penetrated the Al foams, N2, N2+, *OH, O, and He emission peaks were characterized, and the highest values appeared using Al foams with 10 PPI. CAP with and without Al foam intermediating was used to treat deionized water, and the results indicate CAP in combination with 10 PPI Al foam led to much higher ROS concentration than CAP alone. For melanoma cell experiments, CAP with and without Al foam had a similar effect on cell viability after 30-second treatment, while CAP with the 10-PPI Al foam had much higher killing efficiency than CAP alone after 60-second treatment. In summary, 10-PPI Al foam can not only prevent damage to tissues resulting from high discharge voltage during clinical surgery but also increase the delivery efficiency of reactive species generated in plasma for biomedical applications

Magnetically Shielded Miniature Hall Thruster: Design Improvement and Performance Analysis

ABSTRACT: Magnetic shielding has been shown to dramatically reduce discharge channel wall erosion of high powered Hall thrusters, thereby increasing their useful lifetimes. However, unique challenges exist for developing a low power magnetically shielded Hall thruster. A previously tested 4 cm magnetically shielded miniature Hall thruster demonstrated low performance of its magnetic circuit, resulting in an asymmetric field topology, low thrust, and low efficiency. A 6 cm magnetically shielded Hall thruster was developed to improve upon the 4 cm design. The 6 cm device, which generated a symmetric and fully shielded field topology, was tested at 30 operating conditions ranging from 160 W to nearly 750 W. Visual observation of the plasma and discharge channel during and after operation was used to assess the level of magnetic shielding that was achieved. Hall2De plasma simulations were also used to offer further evidence of magnetic shielding. Thrust stand measurements provided thrust, anode specific impulse, and anode efficiency data at each operating condition. Pole face erosion, which is believed to be associated with the 6 cm thruster's non-optimized magnetic shielding field topology and strength, identify the near-term challenges to resolve before long lifetimes and high efficiencies can be achieved in low power Hall thrusters

Guidelines for the use of flow cytometry and cell sorting in immunological studies (third edition)

The third edition of Flow Cytometry Guidelines provides the key aspects to consider when performing flow cytometry experiments and includes comprehensive sections describing phenotypes and functional assays of all major human and murine immune cell subsets. Notably, the Guidelines contain helpful tables highlighting phenotypes and key differences between human and murine cells. Another useful feature of this edition is the flow cytometry analysis of clinical samples with examples of flow cytometry applications in the context of autoimmune diseases, cancers as well as acute and chronic infectious diseases. Furthermore, there are sections detailing tips, tricks and pitfalls to avoid. All sections are written and peer‐reviewed by leading flow cytometry experts and immunologists, making this edition an essential and state‐of‐the‐art handbook for basic and clinical researchers.DFG, 389687267, Kompartimentalisierung, Aufrechterhaltung und Reaktivierung humaner Gedächtnis-T-Lymphozyten aus Knochenmark und peripherem BlutDFG, 80750187, SFB 841: Leberentzündungen: Infektion, Immunregulation und KonsequenzenEC/H2020/800924/EU/International Cancer Research Fellowships - 2/iCARE-2DFG, 252623821, Die Rolle von follikulären T-Helferzellen in T-Helferzell-Differenzierung, Funktion und PlastizitätDFG, 390873048, EXC 2151: ImmunoSensation2 - the immune sensory syste

Ion–surface interactions in plasma-facing material design

A multi-scale simulation framework for ion-solid interactions in plasma-exposed materials provides crucial insight into advancing fusion energy and space electric propulsion. Leveraging binary-collision approximation (BCA) simulations, the framework uniquely predicts sputter yields and analyzes material transport within volumetrically complex materials. This approach, grounded in the validated BCA code TRI3DYN, addresses key limitations in existing models by accurately capturing ion-solid interaction physics. A case study is presented, highlighting the framework’s ability to replicate experimental sputter yield results, underscoring its reliability and potential for designing durable materials in harsh plasma environments. Insights into sputtering transport phenomenology mark a significant advancement in material optimization for improved resilience in plasma-facing applications

Simulation of electrospray emission processes for low to moderate conductivity liquids

The leaky-dielectric model is incorporated in the Finite Volume Method (FVM) code, OpenFOAM, to investigate the electrospray emission behavior of low to moderate conductivity liquids. This work extends FVM modeling to moderate conductivities by employing a new interface interpolation scheme that is devised in the volume of fluid method to ensure charge conservation for accurate reproduction of charge accumulation and resulting meniscus shape in the cone-to-jet region and jet breakup. The model results agree well with experiments and scaling laws for droplet diameter and total current for low and moderate conductivity fluids, i.e., heptane and tributyl phosphate, respectively. The droplet diameter is shown to increase as the dimensionless flow rate increases or the electric Reynolds number decreases. The results are also consistent with a parametric investigation of the meniscus shape and the maximum charge density for key operating conditions (flow rate and extraction potential) and liquid properties (conductivity, surface tension, viscosity, and relative permittivity). These results show that the new interface interpolation scheme provides accurate results for a wide range of conductivities, fluid properties, and operating conditions. The results also provide valuable physical insight for varying liquid conductivity in the electrospray emission process. In particular, low dimensionless flow rate or high electric Reynolds number leads to the emergence of convex-outward menisci associated with a high charge density in the cone-to-jet region, resulting in high jetting velocity and high specific charge droplets