Method, systems, and techniques for determining the age of an underground space are provided. In some embodiments, determining the age of an underground space comprises taking soil samples from a plurality of surface locations within a second underground space, analyzing the soil samples from the plurality of surface locations to determine an amount of a chemical compound for each soil sample, and determining an age of the second underground space using one or more relationships based on amounts of the chemical compound measured in a plurality of soil samples taken over a period of time in a first underground space and a baseline amount of the chemical compound at one or more locations remote from both the first underground space and the second underground space.

Method, systems, and techniques for determining the age of an underground space are provided. In some embodiments, determining the age of an underground space comprises taking soil samples from a plurality of surface locations within a second underground space, analyzing the soil samples from the plurality of surface locations to determine an amount of a chemical compound for each soil sample, and determining an age of the second underground space using one or more relationships based on amounts of the chemical compound measured in a plurality of soil samples taken over a period of time in a first underground space and a baseline amount of the chemical compound at one or more locations remote from both the first underground space and the second underground space.

Color quantification of chemical test pads and titration of analytes can be performed under different lighting conditions. In one embodiment, the lighting condition is estimated under which a digital image is captured and utilized to select a set of reference colors from which the quantified color is compared to determine the titration. In another embodiment, a plurality of comparisons are made with different lighting conditions with the result having the highest confidence level being selected to determine the titration.

Color quantification of chemical test pads and titration of analytes can be performed under different lighting conditions. In one embodiment, the lighting condition is estimated under which a digital image is captured and utilized to select a set of reference colors from which the quantified color is compared to determine the titration. In another embodiment, a plurality of comparisons are made with different lighting conditions with the result having the highest confidence level being selected to determine the titration.

Systems for quantifying one or more target analyte concentrations in a process solution are provided and can be used, for example, in methods for quantifying a target analyte concentration. These systems and methods include continuous and batchwise automated titration methods that use titration chemistries to measure the target analyte concentration in the process solution using a multiwavelength detector. The methods provide for efficient and robust automated titration methods for a variety of target analytes and can include methods that analyze more than one analyte and that provide for a dynamic range for measurement of more than one target analyte concentration.

Systems for quantifying one or more target analyte concentrations in a process solution are provided and can be used, for example, in methods for quantifying a target analyte concentration. These systems and methods include continuous and batchwise automated titration methods that use titration chemistries to measure the target analyte concentration in the process solution using a multiwavelength detector. The methods provide for efficient and robust automated titration methods for a variety of target analytes and can include methods that analyze more than one analyte and that provide for a dynamic range for measurement of more than one target analyte concentration.

Color quantification of chemical test pads and titration of analytes can be performed under different lighting conditions. In one embodiment, the lighting condition is estimated under which a digital image is captured and utilized to select a set of reference colors from which the quantified color is compared to determine the titration. In another embodiment, a plurality of comparisons are made with different lighting conditions with the result having the highest confidence level being selected to determine the titration.

Color quantification of chemical test pads and titration of analytes can be performed under different lighting conditions. In one embodiment, the lighting condition is estimated under which a digital image is captured and utilized to select a set of reference colors from which the quantified color is compared to determine the titration. In another embodiment, a plurality of comparisons are made with different lighting conditions with the result having the highest confidence level being selected to determine the titration.

An article, system, and method is provided for the filtration of blood wherein the blood is removed, contacted with a filter substrate operatively associated with a filter structure, and the filtered blood is subsequently returned to a receiver. Methods for removing iron from the liquid fraction of blood and for determining whether a substrate is capable of selectively retaining 2,2-dipyridyl (DP)-Fe.sup.2+ complexes are also disclosed.

An article, system, and method is provided for the filtration of blood wherein the blood is removed, contacted with a filter substrate operatively associated with a filter structure, and the filtered blood is subsequently returned to a receiver. Methods for removing iron from the liquid fraction of blood and for determining whether a substrate is capable of selectively retaining 2,2-dipyridyl (DP)-Fe.sup.2+ complexes are also disclosed.