Versatile direct push profiler for the investigation of volatile compounds near the water table
Bibliographic record
Abstract
The collection of representative samples of dissolved volatile compounds requires particular care to ensure that degassing does not occur during sampling, particularly for sites where the water table is deep. Furthermore, the investigation of physical and chemical processes involving volatile components can be enhanced by collecting vadose zone gas samples above the water table and collecting water samples very close to the water table. Here we describe the design and operation of a direct push profiler that allows the collection of gas and water samples from one hole. The profiler is capable of collecting water samples close to the water table and preserves the integrity of the samples collected from below deep water tables with respect to volatile compounds. The versatility of the profiler is due to the incorporation of a small‐diameter bladder pump into the tip of a Waterloo profiler. Laboratory testing shows that samples collected from 10 cm below the water table and at 9 m depth below ground surface show no signs of degassing. Field measurements made at a petroleum spill site near Bemidji, Minnesota, provide a comparison of profiler results to samples collected from an existing well cluster, demonstrating the ability of the profiler to obtain representative samples under field conditions. Furthermore, the field tests demonstrate the utility of the direct push profiler in terms of obtaining high‐resolution, high‐quality data through the vadose zone and into the upper few meters of the aquifer.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.004 | 0.002 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".