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Contaminant Removal Capabilities of Wetlands Constructed to Treat Coal Mine Drainage
Published in Gerald A. Moshiri, Constructed Wetlands for Water Quality Improvement, 2020
In this study, a dilution factor was calculated from differences in concentrations of magnesium (Mg) between influent and effluent water samples.6 The dilution factor was then used to separate changes in contaminant concentrations due to dilution from those due to biological and chemical processes. Magnesium was considered a good indicator of dilution in these systems for several reasons. In northern Appalachia, concentrations of magnesium in coal mine drainages are generally greater than 50 mg/L, while concentrations in rainfall, surface runoff, and shallow groundwater are less than 5 mg/L. Magnesium appears to be chemically and biologically conservative in constructed wetlands. MgSO4 does not precipitate in wetlands because the compound is highly soluble (710,000 mg/L).7 MgCO3 generally forms only under evaporative conditions.8Processes that remove Mg from coal mine drainage are negligible relative to the high Mg loadings that most constructed wetland sites in northern Appalachia receive. The average Mg loading of sites described in this study is 7000 g/m2/year. Uptake of dissolved Mg by plants likely accounts for only 10 g/m2/year, while sorption of Mg by cation exchange processes may account for a total of 50 to 100 g/m2.
Laboratory Analytical Methods and Data Interpretation
Published in Rong Yue, Fundamentals of Environmental Site Assessment and Remediation, 2018
Sometimes, the samples need to be diluted due to high concentrations that exceed the instrument calibration range. For example, if the calibration range is set for 1–20 ppb, a sample concentration at 40 ppb will be out of range. In this case, the sample will need to be diluted by a factor of two (i.e., 20 ppb) down to the calibration range to continue quantification of the concentration. The dilution factor is used to measure how many times the sample is to be diluted and should be reported in the laboratory reports. It should be noted that a high dilution factor also results in elevated reporting limits for non-detected compounds in a given sample that requires dilution.
Rhodium(I) complexes with N-heterocyclic carbene ligands: synthesis, biological properties and catalytic activity in the hydrosilylation of aromatic ketones
Published in Journal of Coordination Chemistry, 2021
Naceur Hamdi, Ichraf Slimani, Lamjed Mansour, Faisal Alresheedi, Ismail Özdemir, Nevin Gürbüz
Duplicate plate counts were performed for each sample of colony-forming units (CFUs) activity which was used for viable cells of microorganisms or plants. All cell units (dead and alive), including area units, are counted as cellular units using a hemocytometer. However, only viable cells will be counted. According to the test, CFU/mL (per milliliter) represents liquids, whereas CFU/g (per gram) represents solids. The miles and Misra method will be used to calculate CFU, which is helpful for crucial microbiological load and magnitude of the infection in blood and alternative samples. For example, the dilution factor calculated the colonies to obtain the number of microorganisms (CFU) per cc or gram of sample. The colonies per cubic centimeter should be no more than two and replicate the method's precision. The following formula is a measurement used to calculate the CFU/mL value:
Ejector diluter behavior assessment and dilution factor accuracy improvement
Published in Particulate Science and Technology, 2023
Ondřej Červený, Pavel Vybíral, Luděk Mareš, Jiří Hemerka, Jakub Ondráček, Petr Roztočil
The ejector diluter is a device used for work and measurement with aerosols of high concentrations. There can be several reasons for the use of a diluter. Using a diluter under laboratory conditions, we are able to simulate the exhaust aerosol transformations that would occur in the ambient environment. However, these transformations may not always be desirable, due to the formation of new particles by nucleation (Pyykönen et al. 2007; Woo et al. 2019). Second, some aerosol sensors such as optical particle counters, have a limited working range of concentrations and temperatures. With the use of a dilution system, we can meet these requirements. The diluter can also find use during the process of aerosol generation (Liu and Chen 2014). The diluter is defined by the nominal dilution factor (e.g. 1/10), or by a calibration curve under the given conditions. There are applications where knowledge of the exact dilution factor plays an important role, for example in the case of emission measurements, where the goal is to determine the total concentration of undiluted aerosol. Such a case was described, e.g. by Wong, Chan, and Leung (2003), where the authors used two different dilution methods for characterization of diesel exhaust particle number and size distribution. Also Giechaskiel et al. (2014) and Lee and Bae (2016) described the use of diluters for exhaust aerosol measurements. An ejector/porous diluter was also used for continuous measurement of PM2.5 and PM10 emissions from a coal-fired power plant (Shin, Woo, et al. 2020). This more sophisticated dilution device for continuous measurement and its development was described in further detail by Shin et al. (2019) and Shin, Seo, et al. (2020). Because within exhaust pipes the pressure can vary during the measurement, Tzamkiozis et al. (2013) developed a dilution system independent of the inlet pressure. General information on diluters and their applications in the field of aerosols was summarized by Mölter and Schmidt (2018).