Sample Preparation — the First Step of Successful Research

The overall goal of our research project is to study the unfrozen water mass and mobility in frozen soils. Frozen samples of standard clays with different adsorbed cations will be analyzed to determine their surface potential, micro-fabric, and how they interact with unfrozen water. To be successful, our first step was to develop standard procedures for sample preparation. During the past six months, we have developed and tested a set of methods for preparing clay samples, which included crushing source rocks into clay- sized samples with a suitable grain size distribution and exchanging cations for each type of clay. We experimented with different crushing methods, including using a ball mill, and mortar and pestle. Repeatable hydrometer test results indicated that our final combination of methods will produce clay samples with grain size distributions that are acceptable for future testing. Next, we exchanged the adsorbed cations with Ca2+, Mg2+, K+, and Na+ using chloride salt solutions, and flushed the excess chloride from the soil. Each cation-saturated clay required a different number of flushes due to the changes in surface chemistry. Sample preparation may seem simple, but all great research begins with a sound scientific foundation

Using an NMR Device to Determine Unfrozen Water Content in Frozen Soil

The overall goal of our research project is to study the unfrozen water mass and mobility in frozen soils. During this project, frozen samples of standard clays with different adsorbed cations will be analyzed to determine their surface potential, micro-fabric, and how they interact with unfrozen water. The amount of unfrozen water content at sub-freezing temperatures is measured using a nuclear magnetic resonance (NMR) device. Before using the NMR to test the unfrozen water content, we developed a system to control and stabilize the temperature of the soil sample during the test. We determined that the optimal sample length detected by the NMR is 3.5 cm. Nine duplicate silt samples each with a different moisture content were prepared and tested using the NMR. The result demonstrated a linear relationship between the moisture content of the silt samples and the corresponding NMR signal intensities, thus validating the NMR approach. Future test will be conducted on frozen cation-exchanged clay samples to determine their unfrozen water contents as a function of temperature

Energy Spectrum and Phase Transition of Superfluid Fermi Gas of Atoms on Noncommutative Space

Based on the Bogoliubov non-ideal gas model, we discuss the energy spectrum and phase transition of the superfluid Fermi gas of atoms with a weak attractive interaction on the canonical noncommutative space. Because the interaction of a BCS-type superfluid Fermi gas originates from a pair of Fermionic quasi-particles with opposite momenta and spins, the Hamiltonian of the Fermi gas on the noncommutative space can be described in terms of the ordinary creation and annihilation operators related to the commutative space, while the noncommutative effect appears only in the coefficients of the interacting Hamiltonian. As a result, we can rigorously solve the energy spectrum of the Fermi gas on the noncommutative space exactly following the way adopted on the commutative space without the use of perturbation theory. In particular, different from the previous results on the noncommutative degenerate electron gas and superconductor where only the first order corrections of the ground state energy level and energy gap were derived, we obtain the nonperturbative energy spectrum for the noncommutative superfluid Fermi gas, and find that each energy level contains a corrected factor of cosine function of noncommutative parameters. In addition, our result shows that the energy gap becomes narrow and the critical temperature of phase transition from a superfluid state to an ordinary fluid state decreases when compared with that in the commutative case