(e) TEM and (f) SEM images of the Fe3O4 buy TPCA-1 nanoplates prepared under the condition of EG/H2O = 5:1. The diameter is about 80 to 10 nm, and the thickness is about 5 nm. The typical magnetic hysteresis loop of the Fe3O4 nanoplates obtained in EG/H2O = 1 is depicted in Figure 6a. It exhibits a ferromagnetic behavior with saturation magnetization (M s), remanent magnetization (M r), and coercivity (H c) values of ca. 71.6 emu/g, 18.4 emu/g, and 152.2 Oe, respectively. It is well known that the saturation magnetization and the coercive field of bulk Fe3O4 are about 85 to 100 emu/g and 115 to 150 Oe, respectively [38]. Selleck C188-9 From the results, it can be seen that the saturation magnetization value is lower than that of bulk Fe3O4.

The reduced value might be due to the spin canting of surface Fe atoms [39–41]. Compared with bulk magnetite,

the as-prepared nanoplates exhibit enhanced coercivity. The enhanced coercivity may be attributed to the large sharp anisotropic nature of the nanoplates which represents the barrier for particle remagnetization [42]. According to our earlier study, hysteresis loss of magnetite in AC magnetic field with low frequency and high amplitude can be assumed to be proportional to coercivity [43]. Thus, the as-prepared Fe3O4 nanoplates with enhanced coercivity may have enhanced hysteresis loss in AC magnetic field. We investigated the SAR coefficient of the Fe3O4 nanoplates by time-dependent calorimetric measurements. The frequency and amplitude of the magnetic Carnitine palmitoyltransferase II field are 180 kHz and 0.95 kA/m, respectively. The temperature versus time curves of Fe3O4 nanoplate-based KU55933 mw ferrofluids are shown in Figure 6b. According to the curves, the SAR for the nanoplates was calculated using the following equation [43, 44]: where C is the sample-specific heat capacity which is calculated as

a mass weighted mean value of magnetite and water. For magnetite, C mag = 0.937 J/g K, and for water C wat = 4.18 J/g K. ΔT/Δt is the initial slope of the time-dependent temperature curve. m Fe is the iron content per gram of the Fe3O4 suspension solution. The obtained SAR value is 253.7 ± 27.3 W/g. This value is very high compared to the reported values of Fe3O4[43, 45] and indicates that this material is likely to be very suitable for application in tumor magnetic hyperthermia. Figure 6 The Fe 3 O 4 nanoplates obtained in EG/H 2 O = 1. (a) Magnetic hysteresis loop measured at room temperature for the Fe3O4nanoplates (EG/H2O = 1:1). (b) Temperature versus time curves of Fe3O4 nanoplates (EG/H2O = 1:1) dispersed in aqueous solution under an AC magnetic field (0.95 kA/m, 176 kHz). Conclusions In summary, ultrathin single-crystalline Fe3O4 nanoplates can be synthesized facilely on a large scale by a hydrothermal route of Schikorr reaction. The experimental results showed that the concentration of EG played a key role in the information and adjustment of the thickness of the nanoplates.

For water-based nanofluids, values of the average Nusselt number and average skin friction coefficients are constant after 100 s, i.e., steady state can be achieved after 100 s for water-based nanofluids. Similarly, for EG-based nanofluids, the steady state

is achieved after nearly 160 s. This implies that the water-based nanofluids achieve a steady state earlier than the EG-based nanofluids. The reason for this behavior is the higher values of effective thermal diffusivity and lower values of volumetric heat capacity ratio of water-based nanofluids than EG-based nanofluids, as given AZD0530 in Table 3. Figure 3 Comparison between (a, b, c, d) Al 2 O 3 + H 2 O and Al 2 O 3  + EG at 324 K. Table 3 Properties of six different types of nanofluids Ganetespib nanofluid α eff(10−7) σ Preff RaKeff μ nf Nuavg Cfavg(103) Al2O3 + H2O 2.6100 0.9266 3.1656 101.6234 9.1980 × 10−4 13.1848 4.7330 TiO2 + H2O 2.5443 0.9234 3.2048 104.3849 9.1980 × 10−4 13.2042 4.7204 CuO + H2O 2.9179 0.9519 2.5879 91.3187 9.1980 × 10−4 12.5223 4.8192 Al2O3 + EG 1.8052 1.0160 73.4908 139.8607 1.6100 × 10−2 12.1085 8.1741 TiO2 + EG 1.7409 1.0096 75.2862 145.0326 1.6100 × 10−2 12.1394 8.1421 CuO + EG 2.1278 1.0711 57.4017 118.6878 1.6100 × 10−2 GSK1120212 in vivo 11.1641 8.3152 ε = 0.72, diameter of Cu powder = 470 μm, length of plate = 0.04 m, permeability = 7 × 10−9,

T (ambient) = 293 K, T w  = 324 K, d p  = 10 nm, ϕ =0.04. To find the percentage increase in heat transfer using nanofluids in porous media, two types of nanofluids have been used for calculations of Osimertinib molecular weight the average Nusselt number and average skin friction coefficients at steady state, and the calculated values are compared with the case of pure fluid in porous media. The values of parameters taken in the calculations are given in Table 3. From Figure 3a and Table 4, it is clear that the value of the average Nusselt number at the steady state for the EG-based nanofluid is lesser than that of the water-based nanofluid, but the percentage increase in the value

of the average Nusselt number is much more in the case of the EG-based nanofluid. Table 4 Average Nusselt number and average skin friction coefficients for Al 2 O 3  + H 2 O and Al 2 O 3  + EG Nanofluid Φ Nuavg Percentage increase in Nuavgat steady state Cfavg (103) Percentage increase in Cfavgat steady state Al2O3 + H2O 0 11.7178 12.11% 4.4865 6.34% Al2O3 + H2O 0.05 13.1371   4.7711   Al2O3 + EG 0 9.8380 23.16% 7.8077 5.06% Al2O3 + EG 0.05 12.1162   8.2028   ε = 0.72, diameter of Cu powder = 470 μm, length of plate = 0.04 m, permeability = 7 × 10−9, T (ambient) = 293 K, T w  = 324 K, d p  = 10 nm. Figure 3c,d depicts the variation of local Nusselt number and local skin friction coefficients along the length of the plate at steady state.