Electrical discharge in a non-equilibrium slightly seeded MHD plasma

The effects of ionization relaxation and ionization instability on the electrical discharge in a seeded noble gas have been studied experimentally. Experiments have been made in a simulated MHD channel in which current is applied to each of several electrode pairs with and without a magnetic field present. Experimental results have shown that unsteady current concentration in the ionization relaxation region and ionization instability induce a non-uniform and fluctuating discharge downstream. The effect of unsteady concentrated discharge in the relaxation region is reduced when current is increased. The ionization instability is also reduced when the seed becomes fully ionized. Experimental values of the effective electrical conductivity and Hall coefficient in the flow downstream have shown agreement with the values predicted by the theory for a large current.     

Periodical Oscillation Phenomena Observed in Salt-Water Oscillator Experiments under Small Gravity Conditions

We examined periodical oscillation phenomena that were observed during salt-water oscillator experiments under a small gravity condition. This condition was realized by situating a lower-density gadolinium chloride (GdCl ₃) aqueous solution on a higher-density sodium chloride (NaCl) aqueous solution and applying a downward magnetic force. The GdCl ₃ solution concentration was 0.15 mol/kg (density ρ=1.03×10³ kg/m ³), and the NaCl concentration was varied to (A) 4.35 mol/kg (ρ=1.15×10³ kg/m ³), (B) 3.79 mol/kg (ρ=1.12×10³ kg/m ³), and (C) 2.49 mol/kg (ρ= 1.09×10 ³ kg/m ³). The magnitude of magnetic flux density was varied from 0 to 4.00 T. As the magnetic flux density grew larger, the GdCl ₃ solution was pulled downward by the magnetic force, and upward and downward flows were generated simultaneously at the orifice. These flows were accompanied by a periodical, locally thickened part. The thickened part was only observed when the magnetic force magnitude was small in cases (A) and (B). This flow pattern was not observed in case (C), in which a conventional salt-water oscillation was induced instead (C). In this paper we discuss new experimental results in which the oscillation cycles in cases (A) and (B) are strongly associated with the magnitude of the magnetic force and the density difference in the biphase solutions.     

Effect of high pressure gaseous carbon dioxide on the germination of bacterial spores

Effect of high pressure gaseous carbon dioxide treatment (HGCT) at 6.5 MPa, 35 degrees C on the germination of bacterial spores was investigated. Germination of bacterial spores was estimated by the decrease of heat tolerance. Approximately, 40% of Bacillus coagulans and 70% of Bacillus licheniformis were germinated by HGCT for 120 min at 35 degrees C, respectively. Germination was confirmed by phase contrast microscopy. The effect of hydrostatic pressure treatment (HPT) at 6.5 MPa, 35 degrees C on the germination of B. coagulans and B. licheniformis spores were also investigated. Spores did not germinate by HPT alone at 6.5 MPa for 120 min.     

The rate of an exchange reaction of hydrogen and deuterium in a Mg2Ni bed

Hydrides of intermetallic compounds of Mg₂Ni have a comparatively large isotopic effect in the equilibrium isotherm between hydrogen and deuterium or tritium. An experimental and analytical study is made on the isotopic exchange reaction of hydrogen and deuterium in a Mg₂Ni bed for isotope separation. Values of the first moment, the second moment and a height equivalent to a theoretical plate (HETP) are obtained on the basis of a pulse or a step change of an influent deuterium concentration. It is found that the HETP values have the least at an optimum temperature and linear velocity, and the value is about 3 cm. The activation energy of the isotopic exchange reaction of Mg₂Ni is 18.5 kJ mol⁻¹. Thus the Mg₂Ni bed serves as an effective method for the isotopic separation of hydrogen isotopes.     

Long-term connexin-mediated bystander effect in highly tumorigenic human cells in vivo in herpes simplex virus thymidine kinase/ganciclovir gene therapy

Gene therapy via the herpes simplex virus thymidine kinase (tk) gene and ganciclovir (GCV) treatment eliminates experimental tumors. In this approach, cells expressing the tk gene (tk+) and neighboring tumor cells which do not express the gene are killed. We have demonstrated this bystander effect is enhanced in vitro by gap junctional intercellular communication (GJIC). In order to extend our in vitro results into in vivo situations, we injected into nude mice different ratios of tk+/tk- HeLa cells, either lacking or transfected with connexin43 (Cx43), a gene coding for a gap junction protein. When GCV was administered before tumors were palpable, fewer animals developed tumors, even after a longer period, if the injected cells were mixtures of Cx43(+)-tk+ and Cx43(+)-tk- while tumor growth was not prevented with mixtures of HeLa cells not expressing Cx43, i.e. Cx43(+)-tk+/Cx43(-)-tk-. When GCV was given after the appearance of tumors, the size of the tumors from Cx43- cells was 30% reduced for 3 weeks if 50% of the injected cells were tk+. However, for cells expressing Cx43, the tumor size was 66% reduced if 10% of the cells were tk+. Such a reduction demonstrates a long-term bystander effect which is dependent on Cx43 expression.     

Super TEX-SIM: Interactive textile design and simulation

This paper presents an interactive tool for designing and simulating textile images. It comprises a yarn editor, a textile editor and a texture mapper. These subsystems share a colour editor that can modify the colours of yarn and textile images interactively. We describe how yarn and textile images are generated, and how they are mapped to a target picture read from an image scanner. The user interface in the tool has many useful functions so that users can design textile images without knowledge of computer graphics and programming languages. Several examples of texture mapping are included.     

Polygonal obstacle avoidance method for swarm robots via fluid dynamics

Artificial Life and Robotics - Swarm robots in obstacle environments perform search tasks efficiently while avoiding obstacles. Obstacle avoidance methods are classified by the way obstacles are...