Pumping various chemical substances

Measures when pumping various chemical substances... 

In the assessment of placental toxicology of any foreign chemical substances, there are two major areas of concern what the placenta does to xenobiotics and what xenobiotics do to the placenta (Myllynen et ai, 2005). In the former area the major topics of concern are the entry and possible storage of substances in placental cells and through the placenta, aided perhaps by various transporters and efflux pumps the distribution and binding of compounds in placental cells and biotransformafion of substances by intracellular enzymes. Metabolic activation and production of reactive intermediates by placental enzymes link these areas with toxicodynamics of placental toxicants. In the latter area, effects of compounds on placental blood flow and vasculature and the presence of membrane and intracellular receptors, enzymes, and other potential targets for foreign substances are important areas of inquiry for placental toxicity. 

Secondary recovery, infill drilling, various pumping techniques, and workover actions may still leave oil, sometimes the majority of the oil, in the reservoir. There are further applications of technology to extract the oil that can be utilized if the economics justifies them. These more elaborate procedures are called enhanced oil recovery. They fall into three general categories thermal recoveiy, chemical processes, and miscible methods. All involve injections of some substance into the reservoir. Thermal recovery methods inject steam or hot water m order to improve the mobility of the oil. They work best for heavy nils. In one version the production crew maintains steam or hot water injection continuously in order to displace the oil toward the production wells. In another version, called steam soak or huff and puff, the crew injects steam for a time into a production well and then lets it soak while the heat from the steam transfers to the resei voir. After a period of a week or more, the crew reopens the well and produces the heated oil. This sequence can be repeated as long as it is effective. 

Boerhaave also brought together different genres of experiments on air to devise a consistent picture of its nature and operations. He was familiar with Boyle s and Mariotte s experiments with the air-pump, which characterized the elasticity of air, as well as with Hales s experiments on the fixation of air. On the one hand, this elastic medium functioned as an instrument of many chemical operations. On the other hand, air particles exhibited a tendency towards a union. The air fixed in bodies seemed to take up a very small space when divided into smaller particles of its proper substance, but it expanded considerably when these particles were collected together. Boerhaave s discussion of air, like the one on fire, is remarkable for the facility with which he mixed different genres of instrumental practices to create a coherent ontology of these supposedly elementary bodies. He discussed various effects... 

The previous example showed that pumping from an observation well screened over the complete thickness of the aquifer results in a mixture of different types of water. This is problematic for the evaluation of natural attenuation processes since the concentrations of various substances such as contaminant, electron acceptors and other chemical parameters have to be considered. The mixing of waters with different redox conditions during the measurement can lead to microbial and chemical reactions which falsify the true conditions within the aquifer. 

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