Linear mass experiments

Linear Mass Experiments. Using long strips of natural rubber (60 cm X 2 mm X 0.5 mm) coated with a 15% PAA solution in NMP, the mass per unit length of the sample was obtained as a function of temperature. The technique involves measuring the tension on the sample and the time of flight of a traveling wave on the sample (M. Chipalkatti,... 

In vivo experiments can also be utilized to estimate mass transfer coefficients. Under the condition of steady-state blood concentrations of drug, a linear mass transfer coefficient can be estimated from [10]... 

The mass/time curve measured at T(isothermal) = 160°C shows a non-linear mass loss effect during the first 250 minutes, see Figure 2.2. No further mass losses were detected during the remaining 750 minutes of this experiment. This mass loss effect of about 0.3 %wt. is assumed to be caused by the evaporation of an oligomeric fraction. 

The TGA experiments at T(isothermal) > 190°C show a continuous, nearly linear with the time, decreasing sample mass after the first (non-linear) mass losses due to evaporation of the oligomers fraction. The slopes of the linear part of these curves increase with isothermal measuring temperatures. This effect is thought to be caused by the thermal degradation of the polymer matrix. The mass/time curves were extrapolated, subsequently, as indicated in Figure... 

Mass transfer coefficients can also be estimated from in vivo experiments. Under the condition of steady-state drug concentrations in blood, a method was derived to estimate a linear mass transfer coefficient. Another method, referred to as the moment method, was derived by Gallo et al. to estimate linear mass transfer coefficients for non-eliminating organs. By using Monte Carlo methods it was demonstrated that the method was both accurate and precise. 

Concentration/separation of sample solutes is one of most important functions in micro- and nanofluidic systems. TGF has proved to be a promising technique that can achieve concentration and separation in microfiuidic devices. However, so far very limited experimental and theoretical investigations have been reported. Experimentally, it is highly desirable to develop various microfiuidic structures that can be utilized by the TGF technique to cmicentrate different samples. Furthermore, more experiments should be carried out to characterize the thermoelectrical properties of buffers and samples so as to obtain the temperature-dependent electroosmotic mobility and electrophoretic mobility, as well as buffer conductivity, viscosity, and dielectric permittivity for each individual sample and buffer solution. In addition, the development of reliable, accurate, high-resolution, experimental techniques for measuring fiow, temperature, and sample solute concentration fields in microfiuidic channels is needed. Theoretically, the model development of TGF is still in its infancy. The models presented in this study assume the dilute solute sample and linear mass flux-driving forces correlations. However, when the concentrations of the sample solute and the buffer solution are comparable, the aforementioned assumptions break down. Moreover, the channel wall zeta potential in this situation may become nonconstant. More comprehensive models should be developed to incorporate the solute-buffer and solute-channel wall... 

The poor activity for methanol oxidation of PtRuSn was also reported for the eatalyst obtained by ethylene glycol reduction [80]. Contradictory results were presented regarding the effect of Mo. The addition of Mo to PtRu with 1 1 0.5 and 1 1 1 PtRuMo atomic ratios, coupled with thermal treatment at 673 K in Ha atmosphere, improved the methanol oxidation current density in linear voltammetry experiments, e.g., at 0.5 V vs. RHE the mass activity for PtRuMo (1 1 1) at 293 K was 1 A gpt" [121]. However, longer-term DMFC experiments were not presented. Many of these studies lack fundamental insights into the observed eleetrocatalytic effects... 

The linear dependence of C witii temperahire agrees well with experiment, but the pre-factor can differ by a factor of two or more from the free electron value. The origin of the difference is thought to arise from several factors the electrons are not tndy free, they interact with each other and with the crystal lattice, and the dynamical behaviour the electrons interacting witii the lattice results in an effective mass which differs from the free electron mass. For example, as the electron moves tlirough tiie lattice, the lattice can distort and exert a dragging force. 

The competitive adsorption isotherms were determined experimentally for the separation of chiral epoxide enantiomers at 25 °C by the adsorption-desorption method [37]. A mass balance allows the knowledge of the concentration of each component retained in the particle, q, in equilibrium with the feed concentration, < In fact includes both the adsorbed phase concentration and the concentration in the fluid inside pores. This overall retained concentration is used to be consistent with the models presented for the SMB simulations based on homogeneous particles. The bed porosity was taken as = 0.4 since the total porosity was measured as Ej = 0.67 and the particle porosity of microcrystalline cellulose triacetate is p = 0.45 [38]. This procedure provides one point of the adsorption isotherm for each component (Cp q. The determination of the complete isotherm will require a set of experiments using different feed concentrations. To support the measured isotherms, a dynamic method of frontal chromatography is implemented based on the analysis of the response curves to a step change in feed concentration (adsorption) followed by the desorption of the column with pure eluent. It is well known that often the selectivity factor decreases with the increase of the concentration of chiral species and therefore the linear -i- Langmuir competitive isotherm was used ... 

In these experiments, it might be anticipated that, with high concentrations of vapour in the air, the rate of evaporation would no longer be linearly related to the partial pressure difference because of the contribution of bulk flow to the mass transfer process (Section 10.2.3), although there is no evidence of this even at mole fractions of vapour at the surface as high as 0.5. Possibly the experimental measurements were nol sufficiently sensitive to detect this effect. 

In mass spectrometers, ions are analysed according to the ml7. (mass-to-charge) value and not to the mass. While there are many possible combinations of technologies associated with a mass-spectrometry experiment, relatively few forms of mass analysis predominate. They include linear multipoles, such as the quadrupole mass filter, time-of-flight mass spectrometry, ion trapping forms of mass spectrometry, including the quadrupole ion trap and Fourier-transform ion-cyclotron resonance, and sector mass spectrometry. Hybrid instruments intend to combine the strengths of the component analysers. 

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