Magnetic suspensions

L. Nelik and co-workers. Proceedings of NMSM Magnetic Suspension Technology Conference, Hampton, Va., 1991. 

Rubotherm PrSzisionsmeBtechnik GmbH Technical Information on Magnetic Suspension Balances (1993). 

V. Nonlinear Susceptibilities of Magnetic Suspensions Interplay of Mechanical and Magnetic Degrees of Freedom... 

Let us introduce a unit vector v of the particle axis. In general, the order parameter is given by the second-rank tensor pik oc (v/ y) — 8a, but in the uniaxial case it reduces to a scalar parameter p = (Pi)- Note that in a magnetic suspension p is a quantity independent of in in a standard polarization setup the measured intensity of light is proportional to p2. 

V. NONLINEAR SUSCEPTIBILITIES OF MAGNETIC SUSPENSIONS INTERPLAY OF MECHANICAL AND MAGNETIC DEGREES OF FREEDOM... 

Equations (4.329) for a solid assembly and (4.332) for a magnetic suspension are solved by expanding W with respect to the appropriate sets of functions. Convenient as such are the spherical harmonics defined by Eq. (4.318). In this context, the internal spherical harmonics used for solving Eq. (4.329) are written Xf (e, n). In the case of a magnetic fluid on this basis, a set of external harmonics is added, which are built on the angles of e with h as the polar axis. Application of a field couples [see the kinetic equation (4.332)] the internal and external degrees of freedom of the particle so that the dynamic variables become inseparable. With regard to this fact, the solution of equation (4.332) is constructed in the functional space that is a direct product of the internal and external harmonics ... 

Other techniques that have been introduced recently in association with adsorption manometry include the use of a magnetic suspension balance (Dreisbach et al., 1996) and a rotational pendulum (Keller, 1995). 

We used excess adsorption isotherms for N2, CH4, Ar, CgHg and n-C4Hio on an activated carbon (F30-470 from Chemviron Carbon) at 303, 323, 343, 363 and 383 K. These data have been measured using a magnetic suspension balance specially instrumented to perform simultaneous high pressure and high temperature adsorption isotherms measurements. The experimental apparatus and the data are presented elsewhere [11,12,13]. 

Oecomposilion ol Ca-Oxalate recorded with a magnetic suspension balance lor thermogravimetric measurements equipped with a mass spectrometer for reaction gas analysis... 

Figure 2. Scheme of a thermogravimetrical apparatus equipped with magnetic suspension balance. Typical thermogram of the decomposition of Ca-Oxalate with reaction gas tinalysis by mass spectromety. 

Dispersion of magnetic suspensions may be effected by subjecting the suspension to a high frequency magnetic field [109]. For the Autometrics PSM 200, 400 Hz was selected at a peak field strength of 800 Oersted [110]. 

The experimental set-up consists of a home-made manometric adsorption apparatus coupled to a Rubotherm three-position magnetic suspension balance. The introduction part of this home-made set-up is designed to work at 473 K and 10 MPa. During the... 

Dreisbach F. and LOsch, H.W., Magnetic suspension balance for simultaneous measurement of a sample and the density of the measuring fluid. J. Therm. Anal. Chem. 62 (2000) pp. 515-521. 

Adsorption equilibria and uptakes were gravimetrically measured with two balances, i.e., Cahn 1100 microbalance and Magnetic Suspension Balance (Rubotherm Co.). Adsorbents were loaded and regenerated in the balance under the flow of ultra high purity Helium gas at ISO 3S0 C, then adjusted to the measuring temperature and evacuated to 10 mmHg by using a turbo molecular pump. Adsorbates used were as follows propane (min.99.5), isobutane (min.99.5%), n-butane (min.99.S%), 1-butene (min.99.5%), isobutene (min.99.5%) and t-2-butene (min.99.8%). 

The high pressure-high temperature adsorption isotherms have been measured using a RUBOTHERM magnetic suspension balance The adsorption isotherms and the detail of the experimental procedure are presented elsewhere [11,12] Considering the measurement accuracy of each sensor (mass, temperature and pressure), the relative errors on the adsorbed mass and on the pressure are estimated respectively to 0 3 and 0 5 % the temperature is measured with an accuracy of 0 1 K The main cause of experimental error is not the lack of accuracy of the sensors but rather the buoyancy effect on the adsorbent sample on the one hand and on the adsorbed phase on the other hand The first contibution is taken into account by... 

Wagner W, Kleinrahm R, Losch HW et al. (2003) Density. Hydrostatic balance densimeters with magnetic suspension couplings. Bellows volumetry. Absolute density standards. In situ density measurements. In Goodwin ARH, Marsh KN, Wakeham WA eds) Experimental thermodynamics, vol VI measurement of the thermodynamic properties of single phases, IUPAC. Elsevier, Amsterdam... 

Fig. 1 shows the solubility of CO2 in LDPE, HDPE, PP, ethylene-ethylacrylate copolymer (EEA), and PS, which were measured at temperatures from 150°C to 200° C and pressure up to 12 MPa using a magnetic suspension balance (MSB). As shown in Fig. 1, the solubility of gases in polymers increases as the saturation... 

The Rubotherm system provides gravimetric sorption measurements carried out in a closed measuring cell completely thermostated up to 700 K or down to 77 K without temperature differences or corrosive parts inside the whole measuring cell with pressures up to 100 MPa and a mass sensitivity down to 1 gg using a magnetic suspension balance to measure mass transfer under controlled environments (14). 

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