Synthesis and properties of magnetic fluids produced on the basis of magnetite particles

Environmental express monitoring of territory and water bodies at various stages of construction and improvement

“…Basic parameters of any condensed media by which a change in its aggregative state (a temperature increase, the presence of other substances, whether dissolved or not) can be instantly established are longitudinal T1 and transverse T2 relaxation times [1,12,16,17,22,23]. Nuclear magnetic spectrometers allow one to perform non-contact measurements of relaxation times of a liquid medium, both in the stationary and flowing state [1,17,[22][23][24].…”

“…The only condition for their application is the presence of a sufficient number of nuclei with magnetic moments in the medium under study, such as fluorine, lithium, sodium, carbon, boron, chlorine, phosphorus, etc. [17,[22][23][24]. Now there exists a very large number of condensed media containing protons or nuclei of other elements with large magnetic moments, which can be analyzed by NMR spectrometers [17,[21][22][23][24].…”

“…To avoid errors in determining the degree of deviation of the condensed medium state from the normal one, it is necessary to measure two relaxation constants T1 and T2 because mixtures of water, oil, alcohol-containing, and acidic products with hazardous substances frequently have T1 equal to T2 of the initial medium in some temperature interval. The knowledge of only T1 (without T2) for the mixtures also makes it impossible to determine the degree of deviation from the normal state of the medium because there are media and also mixtures in which different structural arrangements of one medium or mixture have different T1 [12,23].…”

“…The design and operation principle of small-sized NMR spectrometers and relaxometers have been considered in detail by the authors [11,12,16,17] and other scientists [21][22][23]. By measuring the air temperature with a standard device with high accuracy, it is possible to compare the values of relaxation times T1 and T2 of the medium measured by the NMR spectrometer with the basic values to instantly draw a conclusion about its state [11,12,16,17].…”

“…Nuclear magnetic spectroscopy relying on the use of nuclear magnetic resonance (NMR) allows one to solve the majority of the tasks associated with a rapid reliable express control of the state of condensed matter, including the tasks arising at environmental monitoring because it is highly precise and does not affect chemical properties and structure of the material being examined [11,12,16,17,[21][22][23].…”