Table 1.
RMSE and
Values of PCR and PLSR Models
| PCR | PLSR |
---|
RMSE
| 0.716 | 0.216 |
| 0.603 | 0.964 |
Table 2.
Identified U I Emissions, with Accompanying
of Regression Fit and LoD Values of Calibration Curves from Each Line
line (nm) |
| LoD (wt%) |
---|
409.0 | 0.990 | 0.38 |
502.7 | 0.993 | 0.88 |
591.5 | 0.953 | 1.45 |
682.7 | 0.986 | 0.54 |
Table 3.
Performance Metrics for Calibration Curves Quantifying LiOH Ingrowth from Stofel 2021 [15]
Method | Fit |
| RMSE |
---|
LIBS | Univariate | 0.66 | 13.5 |
PCR | 0.65 | 11.1 |
PLSR | 0.89 | 6.66 |
Raman | Univariate | 0.93 | 5.39 |
PCR | 0.74 | 11.1 |
PLSR | 0.73 | 10.0 |
Fusion | PCR | 0.87 | 6.67 |
PLSR | 0.98 | 2.47 |
Table 4.
Z300 Specifications
Laser | Nd:YAG |
---|
Wavelength
| 1064 nm |
Pulse width
| 1 ns |
Pulse energy
| 5–6 mJ |
Focal length
| 1.5 cm |
Spot size
|
|
Dimensions
|
|
Weight
| 4 lbs |
Bandwidth
| 190–950 nm |
Resolution
| 0.1 nm FWHM |
Table 5.
Comparison of
, RMSE, and LoD Values for Regression Models
Model |
| RMSE | LoD |
---|
PCR | 0.887 | 1.388% | 1.67% |
PLSR | 0.967 | 0.749% | 1.15% |
Table 6.
Summary of Regression Model Performance Parameters
Model |
| RMSEP | LoD |
---|
PCR | 0.8871 | 1.388% | 1.669 % |
PLSR | 0.967 | 0.749% | 1.155% |
Bagged trees |
0.974
| 0.675% | 0.279% |
Boosted trees | 0.964 |
0.272%
| 2.05% |
ANN | 0.936 | 1.059% | 1.086% |
Table 7.
Regression Model Error and Sensitivity Results
Hardware | Model | Parameters |
---|
Laser | Quantel Everbright 250 | 15 Hz rep rate; 10 ns pulse width |
Spectrometer | Catalina Scientific EMU-120/65 |
slit width; 25 mm AS; |
Camera | Andor USB iStar |
pixel CCD |
Delay generator | Berkeley Nucleonics 577 DDG | – |
Table 8.
Hyperparameter Optimization Options for All Models
Model | Hyperparameters | Range | Tuned Value |
---|
Tree | Min. leaf size | 1–144 | 20 |
| Max mum. splits | 1–100 | 61 |
Bag | Min. leaf size | 1–144 | 10 |
| Num. learning cycles | 10–500 | 495 |
Boost | Max num. splits | 1–100 | 34 |
| Num. learning cycles | 10–500 | 180 |
| Learning rate | 0.001–1 | 0.095 |
ET | Min. leaf size | 1–144 | 20 |
| Max num. splits | 1–100 | 5 |
| Num. learning cycles | 10–500 | 300 |
RF | Min. leaf size | 1–144 | 20 |
| Max num. splits | 1–100 | 10 |
| Num. learning cycles | 10–500 | 300 |
SVR | Kernel function | Linear; Gaussian; polynomial | Linear |
| Slack (
) | 0.001–1000 | 200.2 |
| Bandwidth (
) | 0.001–1000 | 454.7 |
| Error (
) | 1.48e-3–148 | 0.362 |
GKR | Bandwidth (
) | 0.001–1000 | 51.14 |
| Regularization (
) | 4.99e-7–0.499 | 1.72e-5 |
| Error (
) | 1.48e-3–148 | 1.51e-3 |
ANN | Layer size | Narrow; medium; wide; bilayer; trilayer | Trilayer |
| Number of neurons | 2–50 | [20;10;10] |
| Activation function | ReLU; sigmoid, tanh | Sigmoid |
| Iteration limit | 1e2-1e4 | 1000 |
| Regularization (
) | 4.99e-7–0.499 | 4.96e-5 |
Table 9.
Tree-Based Regression Model RMSEP and LoD Values
Model | Tree | Bag | Boost | ET | RF |
---|
RMSEP
| 0.475% | 0.394% | 0.422% | 0.394% | 0.391% |
LoD
| 0.366% | 0.025% | 0.256% | 0.006% | 0.018% |
Table 10.
SVR, GKR, and ANN Model Test Regression Error and Sensitivity Results
Model | SVR | GKR | ANN |
---|
RMSEP
| 0.611% | 0.329% | 0.399% |
LoD
| 0.098% | 0.015% | 0.017% |
Table 11.
Description of Sites Surveyed and Associated Test Parameters
Site | Debris Type | Yield | HOB | # Samples |
---|
1 | Particle | 500 t |
| 11 |
2 | Deposition | 500 t |
| 10 |
3 | Particle | 22 t |
| 9 |
4 | Deposition | 30 kt |
| 8 |
5 | Particle | 18 t |
| 10 |
6 | Particle/deposition | 44 kt |
| 18 |
Table 12.
Average Elemental Concentrations (%) Measured with Handheld Libs Device at Each Site, Compared to Trinity Debris Composition Determined by LA-ICP-MS
Site | Na | Mg | Al | Si | K | Ca | Ti | Cr | Mn | Fe | Ba | Li |
---|
1 | 3.01 | 0.18 | 27.7 | 11.3 | 13. 5 | 3.16 | 0.09 | 0.14 | 0.11 | 1.68 | 0.04 | 0.01 |
2 | 4.85 | 0.45 | 17.8 | 6.08 | 15.7 | 7.88 | 0.09 | 0.08 | 0.12 | 3.4 | 0.09 | 0.02 |
3 | 8.98 | 4.25 | 13.61 | 32.9 | 25.3 | 3.81 | 1.32 | 2.50 | 0.09 | 7.92 | 0.49 | 0.01 |
4 | 2.30 | 0.42 | 19.3 | 41.3 | 10.7 | 2.14 | 0.19 | 0.34 | 0.03 | 0.97 | 0.16 | 0.004 |
5 | 2.23 | 0.35 | 9.90 | 17.1 | 9.62 | 4.35 | 0.04 | 0.03 | 0.12 | 9.49 | 0.05 | 0.02 |
6 | 2.90 | 0.61 | 15.9 | 42.5 | 18.0 | 2.64 | 0.43 | 1.14 | 0.15 | 5.70 | 0.29 | 0.006 |
Trinity | 2.68 | 1.13 | 15.0 | 66 | 4.32 | 6.87 | 0.42 | 0.01 | 0.08 | 2.27 | 0.1 | – |
Table 13.
XRF Univariate Calibration Fit Metrics: MAPE and LoD for Each Emission Peak
Peak | MAPE | LoD |
---|
| 9.8 % | 0.002% |
| 8.3% | 0.008% |
Table 14.
Random Forest Hyperparameters and Tuned Values
Hyperparameter | Search Values | Tuned Value |
---|
# of trees | 100–1000 | 1000 |
# Predictors per split | 10–1000 | 1000 |
Minimum # of leaves | 1–100 | 1 |
# of splits | 10–1000 | 1000 |
Table 15.
Fit Parameters for Each Data Set Type, Regression Method, and Evaluated Environmental Condition
| | Humidity | Temperature |
---|
Data Set | Method |
| RMSE |
| RMSE |
---|
LIBS | PLSR | .84 | 11.48 | .66 | 8.42 |
| Random forest | .88 | 8.10 | .73 | 3.47 |
Raman | PLSR | .70 | 15.2 | .43 | 11.9 |
| Random forest | 98 | 3.90 | .74 | 4.65 |
Fusion | PLSR | .91 | 8.22 | .65 | 8.04 |
| Random forest | .98 | 3.79 | .85 | 3.37 |