An important application of the MgAl2O4 spinels nanopowder is its use for the preparation of the transparent ceramic [55–58]. p38 MAPK activation Additional information about this process, properties of magnesium-aluminum spinel, and scanning electron microscope pictures are contained in [59]. Sample preparation The samples of nanofluids containing different mass concentrations

of MgAl2O4 nanopowder in diethylene glycol were prepared by using a two-step method. To disperse of the MgAl2O4 nanopowder in the base fluid, the strictly defined actions were sequentially performed. The first stage was to receive the undispersed nanofluid with desired concentration of nanopowder. It was done by putting VS-4718 chemical structure a predetermined amount of ceramic nanopowder into a glass vessel placed on an analytical balance AS 220/X (Radwag, Radom, Poland). This balance has an accuracy of measurement of 0.1 mg, and its reliability is ensured by an internal calibration. Then, using a pipette, an addition of a pure

diethylene glycol (DG), manufactured by Chempur (CAS: 111-46-6, Piekary Śląskie, Poland), was used to obtain an appropriate weight of sample. In order to achieve a mechanical stirring of components, the sample was placed in a Genius 3 Vortex (IKA, Staufen, Germany) for 30 min. In view of the possibility of emergence of sedimentation of nanoparticles, the sample was inserted into an ultrasound wave bath Emmi-60HC (EMAG, Moerfelden-Walldorf, Germany) for 200 min. At this Liothyronine Sodium time, acting

BX-795 datasheet ultrasonication destroyed agglomerates of nanoparticles and prevented re-agglomeration. A special cooling system which allowed us to maintain the temperature in the bath below 25°C was used. All nanosuspension was performed in temperature less than 25°C. More information about the ultrasound wave bath and cooling system can be found in [60]. It is worth emphasizing that other scientists also use the ultrasonication bath as a method of dispersing of nanoparticles in the base fluid [21, 28, 61–63]. Nanofluids prepared for measurements with this method were stable for several hours. Measuring system Measurements characterizing the influence of pressure and electric field on viscosity of MgAl2O4-DG nanofluids were performed with use of a HAAKE MARS 2 rheometer (Thermo Fisher Scientific, Karlsruhe, Germany). It can be used to perform rotating or oscillating measurements. Furthermore, its modular constructions allow to adjust it for specific applications. This rheometer enables the regulation of torque from 50 nNm to 200 mNm and also the control of angular velocity from 10−5 to 1,500 rpm. The nozzle of the air bearing of the rheometer was connected with a compressor (FIAC Air Compressors, Bologna, Italy). Measurements were controlled using a HAAKE RheoWin Data Manager ver. 4.30.0022 (Thermo Fisher Scientific, Karlsruhe, Germany).