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Mathematics & Statistics

Projects/Programs

Displaying 51 - 75 of 78
Color coded refrigerant bottles

Refrigerants and Working Fluids

Ongoing
We apply a wide range of experimental apparatus to the task of measuring the properties of working fluids. Many of these instruments are the same as those used in our work on standard reference fluids, and our data for working fluids approach the accuracy of the reference fluids. Thermodynamic
Closeup of a plane's jet engine as it flies above the clouds.

Renewable Energy and Fuels

Ongoing
Fuel volatility and chemical characterization. We specialize in the Advanced Distillation Curve (ADC) method, developed at NIST, which is a powerful tool for the measurement of distillation curves to characterize complex fluids. We have applied this to simple hydrocarbons, gasolines, diesel fuels
Staff from the Department of Homeland Security participate in a hands-on exercise as part of the SED short course on experiment design.

Short Courses

Ongoing
Staff members of the Statistical Engineering Division regularly offer short courses on uncertainty analysis, design of experiments, and other topics in statistical metrology at NIST, at conferences open to the public, and at other government agencies. Prospective attendees of short courses at NIST

Special Functions

Ongoing
Special function evaluation is among the more venerable problems of numerical mathematics and remains a staple for engineers, physicists, and scientific computation. What is more, the need for detailed numerical evaluations grows steadily as new quantitative theories are developed for an increasing

Springback

Ongoing
Springback, or the elastic change in shape when a part is released from the manufacturing process, has been a problem for decades and accounts for a significant fraction of the expense that the US auto industry spends each year trying out die sets for new body designs. The inability to predict the
drop

Standard Reference Measurements

Ongoing
State-of-the art property measurements have been the hallmark of the Fluid Properties Group for more than four decades. Many of these measurements have been carried out on one-of-a-kind instruments developed at NIST. In some cases the older instruments are still among the very best of their kind
Breathalyzer

Standards Development to Ensure Reliable Breath Analysis in the Field

Ongoing
Numerous volatile organic compounds (VOCs) have been identified in human breath. These compounds can be produced by the body or by organisms in the body (e.g., bacteria or viruses) and provide a non-invasive window into human health. Inexpensive point-of-care devices are being developed to diagnose

Statistical Methods in Millimeter-Wave Wireless Metrology

Ongoing
DESCRIPTION: One of the measurement solutions is the use of reverberation chambers for free-field testing of wireless devices. A reverberation chamber is an environment for electromagnetic compatibility testing and other investigations. Quantities of interest that have been studied for wireless
DataPlotRelativeErrorBoxplot2

Statistical Methods for Quantitative Imaging

Ongoing
In this project, we have gained valuable experience in the emerging area of developing metrology support for medical image decision making, and we have focused mainly in the area of high resolution CT imaging for lung nodules,using both phantoms and clinical data, in the context of RSNA's QIBA

Statistical Process Monitoring for Autocorrelated Data

Ongoing
DESCRIPTION: Process monitoring is very important for industries. Statistical methodologies have been used to monitor various production process successfully. The majority of statistical process monitoring techniques assume that the process data are free of autocorreation. However, this assumption
Splicing Multiple SRM Correction Factor

Statistical Support for Bioassay Standard Development

Ongoing
Biological assays are procedures that can determine concentration, purity, or biological activity of a substance through scientific experimentation. Fluorescence-based quantification one of the most widely used technique in quantitative clinical and biochemical assays, and it depends on the

Statistics for Ballistics Identification

Ongoing
DESCRIPTION: Statistical Engineering Division has had an ongoing collaboration with NIST's Precision Engineering Division (now Semiconductor and Dimensional Metrology Division) and Office of Law Enforcement Standards (now in the Office of Special Programs) in the field of firearms and tool mark

Statistics for Food and Supplement SRMs

Ongoing
DESCRIPTION: NIST's program of food and reference materials with reliable content values for various nutrients helps the food industry comply with FDA rules and helps consumers in making dietary choices. The Nutrition Labeling and Education Act of 1990 requires that labels on processed foods
testmachine_s

Structure-Property Links in Deformation of Materials

Ongoing
The fundamental physics of the deformation process in metals is controlled by crystal plasticity, a type of non-recoverable strain whose evolution depends on the deformation history of the material (as in all plastic processes), and the relative orientation of the applied load and the crystalline

Surface Roughness

Ongoing
During forming, many alloys develop surface finishes with undesirable features such as orange-peel, banding, or roping. In addition to being cosmetically unacceptable, heterogeneous surface deformation also initiates strain localization that induces necking, tearing, or wrinkling in the part
ghg_test_data3_crop

Surrogate Gas Prediction Model

Ongoing
DESCRIPTION: Since fossil fuels are devoid of 14C, the measured 14C ratio of atmospheric CO 2 (expressed as Delta-C) is the gold standard measurement to determine the fossil fuel enhancement, C ff, to any atmospheric CO 2 measurement. With enough Delta-C measurements, independent, "top-down"

Tension-Compression Testing

Ongoing
The inability to reliably predict the mechanical behavior of new automotive alloys during forming has generated strong demand for more advanced constitutive relationships and property data necessary to calibrate them. There is a particular need for models that incorporate combined kinematic and

Thermodynamic & Kinetic Data for Sustainable Energy

Completed
Knowledge of the thermodynamic, phase equilibria and diffusion properties of potential novel materials can greatly accelerate their development. However, the data needed for new, multi-component materials are often not available. The CALPHAD (Computer Coupling of Phase Diagrams and thermochemistry)

Tunable Compression of Wind Tunnel Data

Ongoing
Variability of Bending Moments The values of the bending moments vary both within each run, and between runs. The between-runs variability provides a standard against which one should assess the severity of any loss of information that a data compression scheme may incur. To assess it, we fitted a
Ultra-dense networks

Ultra-dense Networks

Ongoing
Propagation and system modeling: New propagation models are needed for ultra-dense networks. Driven by legacy cellular systems, most models currently available are tower-to-ground with base stations typically at 30 m and above. Device-to-device links, however, will be ground-to-ground: picocells on

Uncertainty analysis for autocorrelated measurement data

Ongoing
DESCRIPTION: When repeated measurements are autocorrelated, it is not appropriate to use the traditional approach to calculate the uncertainty of the average of the measurements, which assumes that the measurements are statistically independent. We need to develop approaches for assessing

Uncertainty Estimation in Interlaboratory Studies

Ongoing
DESCRIPTION: Data sets consisting of multivariate samples occur increasingly often in applications in particular in in interlaboratory studies known as Key Comparisons in which the key comparison reference value (KCRV) is to be determined. The vector samples, being independent realizations of an