Stability mechanism of crystalline CO2 and Xe.

We explore the phase behaviors of simple molecular crystals in order to investigate the molecular basis of the stability mechanism relative to their liquid counterparts. The free energies of the face centered cubic crystals of Xe and CO2 are calculated as a collection of oscillators, and those of the liquids are from an equation of state via molecular dynamics simulations. The vibrational free energy in the solid is separated into the harmonic and anharmonic terms.

Spontaneous Mode Switching of Self-Propelled Droplet Motion Induced by a Clock Reaction in the Belousov-Zhabotinsky Medium.

Interfacial chemical dynamics on a droplet generate various self-propelled motions. For example, ballistic and random motions arise depending on the physicochemical conditions inside the droplet and its environment. In this study, we focus on the relationship between oxidant concentrations in an aqueous droplet and its mode of self-propelled motion in an oil phase including surfactant.

Oscillation of Speed of a Self-Propelled Belousov-Zhabotinsky Droplet.

Self-propelled objects can become potential biomimetic micromachines, but a versatile strategy is required to add the desired functions. Introducing a characteristic chemical reaction is a simple answer; however, the problem is how the chemical reaction is coupled to the self-propelled motion. We propose a strategy to select the chemical reaction so that its product or intermediate affects the driving force of a self-propelled object.

Pulse-density modulation control of chemical oscillation far from equilibrium in a droplet open-reactor system.

The design, construction and control of artificial self-organized systems modelled on dynamical behaviours of living systems are important issues in biologically inspired engineering. Such systems are usually based on complex reaction dynamics far from equilibrium; therefore, the control of non-equilibrium conditions is required. Here we report a droplet open-reactor system, based on droplet fusion and fission, that achieves dynamical control over chemical fluxes into/out of the reactor for chemical reactions far from equilibrium.

Photoexcited chemical wave in the ruthenium-catalyzed Belousov-Zhabotinsky reaction.

The excitation of the photosensitive Belousov-Zhabotinsky (BZ) reaction induced by light stimulation was systematically investigated. A stepwise increase in the light intensity induced the excitation, whereas a stepwise decrease did not induce the excitation. The threshold values for the excitation were found to be a function of the initial and final light intensities, time variation in light intensity, and the concentration of NaBrO(3).

Analysis of the bromate-sulfite-ferrocyanide pH oscillator using the particle filter: toward the automated modeling of complex chemical systems.

This study was aimed at identifying a quantitatively accurate reaction model of the bromate-sulfilte-ferrocyanide (BSF) pH oscillator by using the simulation-based model estimation algorithm known as the particle filter. The Rbai-Kaminaga-Hanazaki (RKH) model proposed for the BSF system was extended by adding the protonation equilibrium of SO42-, for which the particle filter analysis was carried out to optimize the rate constants involved with reference to the measured pH oscillation data. The extended RKH model with the optimized rate constants almost completely reproduced the measured pH oscillations and the state diagram, showing the validity of the present analysis.

Phase wave between two oscillators in the photosensitive Belousov-Zhabotinsky reaction depending on the difference in the illumination time.

To investigate the nature of the phase wave between two connected oscillators, the photosensitive Belousov-Zhabotinsky (BZ) reaction was examined for two connected circular reaction fields, which were drawn by using computer software and then projected on a filter paper soaked with BZ solution by using a liquid-crystal projector. The difference in the time at which illumination was terminated between the two circles (Deltat(0)) was changed to control the time at which the phase wave was induced. When Deltat(0) was small (0-3 s), the phase wave normally propagated on the two circles in one direction.

Congener profiles of PCB and a proposed new set of indicator congeners.

In this study, a new method for calculating total PCB and toxic equivalents (TEQ) of coplanar PCB (Co-PCB) was proposed, called the 'PCB dual method'. This method analysed various kinds of technical PCB, samples contaminated by technical PCB and byproduct PCB. In the PCB dual method, a data set of 15 indicator congeners was utilized for the calculations, having IUPAC nos.

PCB decomposition and formation in thermal treatment plant equipment.

In this study we investigated both the decomposition and unintentional formation of polychlorinated biphenyl congeners during combustion experiments of refuse-derived fuel (RDF) and automobile shredder residue (ASR) at several stages in thermal treatment plant equipment composed of a primary combustion chamber, a secondary combustion chamber, and other equipments for flue gas treatment. In both experiments, the unintentional formation of PCB occurred in the primary combustion chamber at the same time as the decomposition of PCB in input samples. By combusting RDF, non-ortho-PCB predominantly formed, whereas ortho-PCB and symmetric chlorinated biphenyls (e.

Solvent sublation and spectrometric determination of iron(II) and total iron using 3-(2-pyridyl)-5,6-bis(4-phenylsulfonic acid)-1,2,4-triazine and tetrabutylammonium bromide.

Solvent sublation has been studied for the separation and determination of trace iron(II) in various kinds of water samples. A strongly magenta-colored anionic [Fe(FZ)3](4-) complex was formed at pH 5.0 upon adding 3-(2-pyridyl)-5,6-bis(4-phenylsulfonic acid)-1,2,4-triazine (ferrozine, FZ) to the sample solution.

Chemosensitive running droplet.

Chemical control of the spontaneous motion of a reactive oil droplet moving on a glass substrate under an aqueous phase is reported. Experimental results show that the self-motion of an oil droplet is confined on an acid-treated glass surface. The transient behavior of oil-droplet motion is also observed with a high-speed video camera.