Here are some free apps developed by engineers and researchers at the National Institute of Standards and Technology (NIST).
âNanolithography Toolbox: This platform-independent software package gives users a way to generate layouts for lithography patterns. Those patterns can then be used to design small devices with complex curves and aggressively scaled critical dimensions by designers working with NIST’s NanoFab at the Center for Nanoscale Science and Technology (CNST). The Toolbox uses the freely available Java-based (JGDS) library for encoding shapes to GDSII objects. Using parameterized shapes as building blocks, the toolbox lets users quickly and easily design and lay out nanoscale devices of arbitrary complexity through scripting and programming. The app also offers many parameterized shapes, including structure libraries for micro- and nanoelectromechanical systems (MEMS and NEMS) and nanophotonic devices. The toolbox also lets users precisely define the number of vertices for each shape or create vectorized shapes using Bezier curves. Users have parameterized control for designing smooth curves with complex shapes. The Toolbox is useful for a broad range of design tasks in fabricating microscale and nanoscale devices. The software can be modified and distributed and is public domain, so it is not subject to copyright protection.
For more information or to download the app, click here.
âEVAP-COND: This software package contains NIST’s simulation models for a finned-tube evaporator and condenser. The “tube-by-tube” modeling scheme lets users specify complex refrigerant circuits, model refrigerant distribution between these circuits, and account for non-uniform air distribution. Simulation results include local parameters for each tube including inlet and outlet quality, temperature, enthalpy, entropy, pressure drop, mass flow rate for refrigerant, and inlet and outlet temperature for air. The condenser model can simulate operations above the critical point. And users can model behaviors with 15 refrigerants and refrigerant mixtures: R22, R32, R116, R134a, R152a, R290, R404A, R407C, R410A, R507A, R600a, R717, R744, R1234yf, and R1234ze(E). Version 4.0 also features the option for optimizing refrigerant circuitry based on computational intelligence methods. The software works with Windows XP, Windows 7, Windows 8, and Windows 10.
To download EVAP-COND, click here.
Factory Design and Improvement (FDI) Activity Model: This app lets users model the activities and systems involved in setting up new factories and improving or modifying existing factories. It helps manufacturers throughout the factory’s entire lifecycle from planning to operation. Data that needs to be collected to help in making decisions throughout the activities is clearly defined and analyzed. The model also highlights the relationships between implemented technologies in the context of a standard enterprise control hierarchy, ANSI/88 Batch Control. Note, other aspects of a manufacturing enterprise, including product development and design and operational control, are beyond the scope of this model. And activities related to physical construction of the factory are not covered.
To download the FDI activity model, which runs on AIØ, click here.
âTimebase Correction App: This software package, used with high-speed sampling oscilloscopes, can correct both random and systematic timebase errors using measurements of two quadrature sinusoids made simultaneously with a waveform of interest. Users find the estimated sinusoid by minimizing the average “distance” between the samples and sinusoid. If the user assumes, for illustrative purposes, that there is no additive noise, he can estimate the total time error due to timebase distortion and jitter by drawing a horizontal line between each measurement (circles) and the distorted sinusoid. The length of each line represents the difference between the nominal (oscilloscope) time at which the measurement was taken and the time as determined by the distorted sinusoidal fit. The time that each line intersects the distorted sinusoid is the corrected time for each sample.
Once the timebase error is known, it can be applied to a simultaneously measured signal of interest if the timing errors of the simultaneous measurements are sufficiently correlated. The software lets users correct random and systematic timebase errors using measurements of two quadrature sinusoids made simultaneously with a waveform of interest.
NIST maintains a library of free apps it has developed for engineers and researchers. For a complete look at it, click here.