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Watercolor portrait of Justo Karell working at a café tableJusto E. Karell
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justokarell@gmail.com (preferred)(203) 524-2311

Simulations

Fluids

Coming soon

Plasmas

3D rendering of plasma confined by magnetic field coils inside a tokamak fusion reactor
Magnetic confinement of plasma in a tokamak, the kind of regime I work on simulating: the interplay between poloidal field coils (the orange loops) and a hot plasma core.
3D visualization of a Hall-effect ion thruster showing the annular discharge channel, ion pathlines, and magnetic field structure
A reduced-order Hall-effect ion thruster model. Xenon is singly ionized inside the annular discharge channel and accelerated by the crossed E×B fields; the visualization overlays the solved ion-density field, fluid-derived ion pathlines, and the radial magnetic-field profile. It is a browser prototype, not a PIC or HallThruster.jl backend, so its outputs are proxies, not validated engineering predictions.

Ion Engine Engineering Workbench

An interactive, browser-based workbench for the reduced-order Hall-effect ion thruster model above. Adjust voltage, flow, magnetic field, and channel geometry and watch the discharge current, thrust, and efficiency proxies update. It is a prototype, not validated engineering output.

Open the workbench →

Industrial

  • ScrapSim routing map showing numbered collection stops and vehicle routes across Stamford, Noroton, and Old Greenwich, Connecticut
    ScrapSim: Food Scrap Route Optimization and Planner

    A decision-support simulator for municipal food-scrap drop-off programs. Collection locations accumulate uncertainly and have finite capacity; vehicles have finite payload; processing facilities have finite storage and throughput. ScrapSim formulates the coupled operating problem, when to empty locations, how to route vehicles, and where to process material, as a stochastic inventory-routing problem with dynamic downstream processing inventories. At each replanning time it observes current inventories and an arrival forecast and decides which locations to service, how to route, and which facilities to use, minimizing expected transportation, labor, overflow, and downstream-congestion cost. The running software does not solve the full stochastic mixed-integer problem exactly; it implements a rolling-horizon anticipatory heuristic that uses Monte Carlo scenarios to estimate overflow risk, a marginal-value rule to select locations, and a road-network routing service to build executed routes. The mathematical formulation and the approximating algorithm are kept separate by design.

  • WellFed Simulator interface showing a donor business and selected nonprofit connected by a route on a map, with trip details and tax savings per trip
    WellFed: Food Donation Tax Savings Simulator

    A food rescue logistics simulator. It models donors, recipient agencies, and the vehicles between them over a service region, so you can see how routing, vehicle count, pickup windows, and donation size drive the cost per pound of rescued food, and where a program stops closing the resource gap efficiently.