Materials that undergo internal transformations are usually described in solid mechanics by multi-well energy functions that account for both elastic and transformational behavior. In order to separate the two effects, physicists use instead phase-field-type theories where conventional linear elastic strain is quadratically coupled to an additional field that describes the evolution of the refe...

Optical sensors are increasingly applied in laser material processing to monitor and control the lasermaterial interaction zone. Dynamic models, relating the sensor signals (e.g. as temperature or molten area) to the process inputs (e.g. laser power or beam velocity), provide the basis for the design and tuning of a feedback controller. These models can show nonminimum phase (NMP) behavior. Thi...

Given the proposed importance of membrane tension in regulating cellular functions, we explore the effects of a finite surface tension on phase equilibrium using a molecular theory that captures the quantitative structure of the phase diagram of the tensionless DPPC/DOPC/Cholesterol lipid bilayer. We find that an increase in the surface tension decreases the temperature of the transition from l...

We study the phase behavior of solutions consisting of positive and negative ions of valence z to which a third ionic species of valence Z > z is added. Using a discretized Debye-Hückel theory, we analyze the phase behavior of such systems for different values of the ratio Z̄ ≡ Z/z. We find, for Z̄ > 1.934, a three-phase coexistence region and, for Z̄ > 2, a closed (reentrant) coexistence loop at ...

We have performed a combined experimental and theoretical study of the thermodynamic properties of semifluorinated alkanes. In particular, the liquid density of perfluorohexylhexane (F6H6) and perfluorohexyloctane (F6H8) has been measured as a function of temperature from 273.15 to 353.15 K and at four temperatures as a function of pressure up to 600 bar. The results were interpreted using the ...

C. Bernard, T. Blum, C.E. DeTar, Steven Gottlieb, U.M. Heller, J.E. Hetrick , Beat Jegerlehner , K. Rummukainen , R.L. Sugar, D. Toussaint, and M. Wingate, Department of Physics, Washington University, St. Louis, MO 63130, USA Physics Department, Brookhaven National Laboratory, Upton, NY 11973, USA Physics Department, University of Utah, Salt Lake City, UT 84112, USA and Zentrum für interdiszip...

We investigated the phase behavior of double-tail lipids, as a function of temperature, headgroup interaction and tail length. At low values of the head-head repulsion parameter a(hh), the bilayer undergoes with increasing temperature the transitions from the subgel phase L(c) via the flat gel phase L(beta) to the fluid phase L(alpha). For higher values of a(hh), the transition from the L(c) to...

Ceramides were isolated from the pig stratum corneum (SC) and mixed in varying molar ratios with either cholesterol or with cholesterol and free fatty acids. The phase behavior of the mixtures was studied by small-(SAXD) and wide-angle (WAXD) X-ray diffraction. Ceramides alone did not exhibit a long range ordering. Upon addition of cholesterol to ceramides, lamellar phases were formed and a hex...

Molecular-dynamics simulations are used to study the phase behavior of a single linear multiblock copolymer with blocks of Aand B-type monomers under poor solvent conditions, varying the block length N , number of blocks n, and the solvent quality (by variation of the temperature T ). The fraction f of A-type monomers is kept constant and equal to 0.5, and always the lengths of A and B blocks a...

We report molecular dynamics simulations of a system of repulsive, polymer-tethered colloidal particles. We use an explicit polymer model to explore how the length and the behavior of the polymer (ideal or self-avoiding) affect the ability of the particles to organize into ordered structures when the system is compressed to moderate volume fractions. We find a variety of different phases whose ...