Remote control your miniRUEDI

Setting up a remote control for the miniRUEDI is easy with the right software. So far, we really like DWService! It’s open source, and you can use if for free. The DWService system works by installing an «agent» software on the miniRUEDI computer, which connects to an account on the DWService website. The website allows screen sharing, file uploads and downloads, shell access, a text editor, and other useful remote management tools for the miniRUEDI computer.

Connecting the agent to the DWService website requires a code, which is generated from the DWService account. To this end, you’ll either create your own account (it’s free!), or you can ask us to create a code for you from our DWService account.

Here’s how to install and configure the DWService agent software on the miniRUEDI computer:

  1. Connect the miniRUEDI computer to the internet.
  2. Download and and save the installer file (do not “open as text”).
  3. Install the DWService agent by using the installer (run the commands in a Terminal window):
    1. Change to the directory where you downloaded the installer file. For example:
      cd /home/ruedi/Downloads/
    2. Make sure the installer file is executable:
      chmod +x dwagent.sh
    3. Run the installer file with admin permissions (you may have to enter the admin password), using your DWService code. For example, if your code is 123-456-789:
      sudo ./dwagent.sh -silent key=123-456-789
  4. Once the installation of the DWService agent is completed, the miniRUEDI computer should be accessible via the internet using the DWService website.

New Software!

We spent some time to revamp the miniRUEDI software for instrument control and gas analysis!

The new software is not only prettier but is also easier to configure. You don’t need to write Python code anymore (but you still can!).

If you want to try the new software with your miniRUEDI, please get in touch with us.

Understanding PCE contamination of groundwaters

In their recent recent paper, Chrisitan Moeck and his Eawag colleagues used a miniRUEDI to study the groundwater flow and perchloroethylene (PCE) transport in an urban aquifer system. They used dissolved He concentrations measured with a miniRUEDI to establish a relationship with 3H/3He groundwater ages, which allowed them to characterize the water flow and provided conceptual understanding of the groundwater system. The combination of the groundwater age data (miniRUEDI He, 3H/3He) with hydrochemical data, water isotopes (18O and 2H), and PCE concentrations showed the spatial inter-aquifer mixing between artificially infiltrated groundwater and water originating from regional flow paths. Furthermore, the correlation of groundwater age with PCE concentration explained the spatial distribution of PCE contaminations within groundwater system. In addition, faults were observed to provide preferential flow paths that lead to elevated PCE concentrations.

Full paper: C. Moeck, A.L. Popp, M.S. Brennwald, R. Kipfer, M. Schirmer: Combined method of 3H/3He apparent age and on-site helium analysis to identify groundwater flow processes and transport of perchloroethylene (PCE) in an urban area. J. Contaminant Hydrology, doi: 10.1016/j.jconhyd.2021.103773

From Snow to Groundwater

Oliver Schilling (Université Laval and Centre for Hydrogeology and Geothermics) and his colleagues used a miniRUEDI for on-site quantification of dissolved He, Ar, Kr, N2, O2 and CO2 in groundwaters of a boreal catchment in Canada. The gas data allowed them to quantify the contribution of snowmelt to groundwater recharge, to analyze the temporal recharge dynamics, and to identify the primary recharge pathways. Furthermore, they observed a systematic depletion of N2 in groundwater, which provides insights into the biological N‐fixation in boreal forest soils.

Full paper: O. S. Schilling, A. Parajuli, C. Tremblay Otis, T. U. Müller, W. Antolinez Quijano, Y. Tremblay, M. S. Brennwald, D. F. Nadeau, S. Jutras, R. Kipfer, R. Therrien. Quantifying groundwater recharge dynamics and unsaturated zone processes in snow‐dominated catchments via on‐site dissolved gas analysis. Water Research, doi: 10.1029/2020WR028479

Lake Kivu will not explode anytime soon, says miniRUEDI

Fabian Bärenbold and his coworkers studied the gases in Lake Kivu in East Africa, which is well known for its huge reservoir of CH4 and CO2 dissolved in the deep waters. In view of the ongoing and planned extraction of CH4 for energy production, Fabian Bärenbold and his colleagues used a miniRUEDI and other gas analysis techniques (gas chromatography, laser spectrometery, and a total dissolved gas pressure). The measurement results show good agreement within 5–10%. The CH4 and CO2 dioxide concentrations in Lake Kivu are very similar to earlier results observed during the past few decades, which indicates that the risk for a limnic gas erruption of Lake Kivu has not increased.

Full paper: Fabian Bärenbold, Bertram Boehrer, Roberto Grilli, Ange Mugisha, Wolf von Tümpling, Augusta Umutoni, Martin Schmid. No increasing risk of a limnic eruption at Lake Kivu: Intercomparison study reveals gas concentrations close to steady state. PLOS, doi: 10.1371/journal.pone.0237836

Deconvolution and compensation of MS interferences

For many gas species (e.g., He, Ar, Kr, N2, O2, CO2) the partial pressures measured with the miniRUEDI can usually be calibrated by simple peak-height comparison relative to ambient air or gas standard with well known partial pressures. However, depending on the composition of the analysed gases, the ion currents measured at certain m/z ratios may result from overlapping ion currents of multiple species (for example CH4, O2 and N2 at m/z=15 and 16; or Ne, Ar and H2O at m/z=20).

We developed a method that extends the miniRUEDI peak-height comparison in order to resolve such overlap interferences. The method uses spectral deconvolution and was incorporated in the ruediPy software toolbox. The deconvolution method substantially improves the analytical accuracy in situations where mass-spectrometric interferences cannot be avoided.

Full details are availalble in the original publication: M.S. Brennwald, Y. Tomonaga, R. Kipfer: Deconvolution and compensation of mass spectrometric overlap interferences with the miniRUEDI portable mass spectrometer, MethodsX, 2020, doi: 10.1016/j.mex.2020.101038

Running on Batteries

We frequently get asked how to run the miniRUEDI on batteries for field work at remote locations with no mains power.

Here are the basics to run the miniRUEDI on batteries:

  • The miniRUEDI runs on a voltage of 24 V.
  • The miniRUEDI draws about 2 A current during normal operation, and up to about 5 A or slightly more during startup of the pumps.
  • You need a fuse. Batteries do not like short circuits or similar mishaps. A 10 A rating should be fine.
  • Unplug the 24 V connections of the main power supply unit in the miniRUEDI, and connect the batteries to the miniRUEDI instead.

There are many ways to set up a battery power supply, but here is a simple setup that uses two simple «12 V car batteries»:

The capacity of the batteries determines how long they will be able to supply power to the miniRUEDI. Two of the typical «12 V car batteries» with a capacity rating of 60 Ah may last up to a full day before they need to be recharged.

In-situ monitoring of noble gases in groundwater during rock fracking

Clement Roques and his colleagues published a paper in Nature Scientific Reports, where they used a miniRUEDI to study changes of dissolved-gas concentrations in groundwater in response to hydraulic stimulation and fracturing of the reservoir rocks (Nature Scientific Reports, 10, 6949, 2020). The miniRUEDI was installed on-site to continuously analyse the dissolved-gas concentrations of the groundwater. The high-frequency He and Ar measurements indicate that trapped fluids were mobilized from the rocks in response to the fracking. The miniRUEDI revealed the nature and evolution of the fracture network and flow paths, and showed the effect of the fracking procedures on groundwater quality.

Full paper: “In situ observation of helium and argon release during fluid-pressure-triggered rock deformation.” Sci Rep 10, 6949 (2020). https://doi.org/10.1038/s41598-020-63458-x

Eawag News article: https://www.eawag.ch/en/news-agenda/news-portal/news-detail/observing-how-fissure-systems-are-formed-thanks-to-the-gas-sniffer/

miniRUEDI goes sailing

Researchers from the Max Planck Institute for Chemistry (Germany) installed a miniRUEDI on the Eugen Seibold, the world’s greenest research vessel. Since May of 2019, the innovative yacht has been sailing the high seas, and the miniRUEDI is set up to continuously analyse the dissolved gas concnetration in the surface water. By gradually gathering data on the various marine provinces, the climate geochemists at the Max Planck Institute for Chemistry in Mainz will be able to chart a detailed description of the world’s oceans, characterising their current properties and even reconstructing how they change over time.