Hybridized synergy effect among TiO2, Pt and graphite silica on photocatalytic hydrogen production from water–methanol solution

The photocatalytic production of hydrogen gas from aqueous methanol solution was performed using powdered mixtures of graphite silica (GS) and platinized TiO₂ (Pt/TiO₂) or those of GS, Pt and TiO₂. The addition of GS to Pt/TiO₂ resulted in the decrease of the amount of H₂ gas, whereas the addition of GS to mixtures of TiO₂ and Pt led to the incremental production of H₂ gas. This effect is attributed to the aggregation of GS, TiO₂ and Pt in suspension. The new additional electron transfer process of TiO₂ → Pt → GS caused the increment of the amount of hydrogen gas.     

Transient thermal stresses in a finite solid circular cylinder due to a cylindrical surface heat source over the lateral surface

An exact solution is given for the determination of transient thermal stresses in a traction-free, finite solid, circular cylinder subjected to a cylindrical surface heat source over the lateral surface and having a heat loss to a surrounding medium over the entire boundary surface. The problem is formulated in terms of thermo-elastic displacement potential and Love's function, and the solution rigorously satisfies traction-free boundary conditions on both the lateral and end surfaces of the cylinder.

The problem is of considerable technological importance, particularly to certain nuclear reactor analyses related to the behavior of fuel elements and control rods during power transients.

Numerical calculations are carried out for various combinations of Biot's number and the ratio of length to diameter of the cylinder. The results obtained are compared with those of an infinite, solid, circular cylinder and of a solid circular disc.     

Photocatalytic Cancer (HeLa) Cell-Killing Enhanced with Cu–TiO2 Nanocomposite

The metallic Cu nanoparticles have been successfully deposited on the heterogeneous TiO₂ surface by the borohydride reduction of copper nitrate in water/CH₃CN mixture under Ar atmosphere. The catalytic activity of the Cu–TiO₂ nanocomposite was evaluated by the application to a photocatalytic cancer cell-killing under UV–visible light irradiation. Based on the obtained results, a plausible mechanism was proposed.     

Synthesis and physiological activity of ureas and amides with carvone residues

The synthesis and herbicidal activity of ureas and amides with carvone residues were examined. (S)-(+)-(1) and (R)-(-)-Carvone(2) were converted to the respectively, primary amines(3) and (4) by oximation and reduction with LiAlH(4). Primary amine derivatives were further converted into the urea and amide compounds (3a) approximately (3e) and (4a) approximately (4e). The herbicidal activity of products (3a) approximately (3e) and (4a) approximately (4e) towards weeds found in a paddy field and field was measured in the pot. Products (3a) showed a particularly strong inhibitory effect on the growth of Amaranthus retroflexus(AR) and Setaria viridis(SV).     

Development of an Mg2Si Unileg Thermoelectric Module Using Durable Sb-Doped Mg2Si Legs

Mg₂Si unileg structure thermoelectric (TE) modules, which are composed only of n-type Mg₂Si legs, were fabricated using Sb-doped Mg₂Si. The Mg₂Si TE legs used in our module were fabricated by a plasma-activated sintering method using material produced from molten commercial doped polycrystalline Mg₂Si, and, at the same time, nickel electrodes were formed on the Mg₂Si using a monobloc plasma-activated sintering technique. The source material used for our legs has a ZT value of 0.77 at 862 K. The TE modules, which have dimensions of 21 mm × 30 mm × 16 mm, were composed of ten legs that were connected in series electrically using nickel terminals, and the dimensions of a single leg were 4.0 mm  × 4.0 mm × 10 mm. From evaluations of the measured output characteristics of the modules, it appeared that the electrical resistance of the wiring that is used to connect each leg considerably affects the power output of the unileg module. Thus, we attempted to reduce the wiring resistance of the module and fabricated a module using copper terminals. The observed values of the open-circuit voltage and output power of the Sb-doped Mg₂Si unileg module were 496 mV and 1211 mW at ΔT = 531 K (hot side: 873 K; cool side: 342 K).     

Characterization of Solid‐State Reaction of Barium Carbonate and Titanium Dioxide by Spatially Resolved Electron Energy Loss Spectroscopy

A mixture of ultrafine submicrometer‐sized BaCO₃ powder and TiO₂ (rutile) powder was calcined in air at 700°C, 800°C, and 900°C, and then quenched to liquid nitrogen temperature in each case. The cross‐sectional quenched specimens were characterized by spatially resolved electron energy‐loss spectroscopy (SR‐EELS). The energy‐loss near‐edge structures (ELNES) were sequentially extracted at 1.3 to 5.3 nm in width from SR‐EELS image obtained from the rectangularly cut SR‐EELS slit aperture put on the synthesized BaTiO₃ layer and TiO₂ rutile powder. The ELNES of Ti‐L_2,3 edges and Ba‐M_4,5 edges clearly show fine structure changes from the surface of BaTiO₃ layer to the TiO₂ bulk region reflected from crystallinity of synthesized BaTiO₃, lattice distortion of TiO₂ caused by Ba diffusion, and lattice misfit between BaTiO₃ and TiO₂ without formation of Ba₂TiO₄ and other titanate phases.     

One-step and large scale synthesis of non-metal doped TiO2 submicrospheres and their photocatalytic activity

Without using an external precursor a simple and one-step method for the synthesis of C-doped TiO₂ submicrospheres has been developed via hydrolysis of titanium tetraisopropoxide in pure methanol followed by calcination under air at 500 °C. Also, with the addition of d-glucose and NH₄OH solution during the hydrolysis process, C- or N-doped and C, N co-doped TiO₂ submicrospheres can be prepared by the same method. The size of the submicrosphere was homogeneous ranging from 300 to 400 nm. The resulting submicrospheres were characterized by FE-SEM, TEM, XRD, XPS and UV–vis diffuse reflectance spectroscopy. The C- or N-doped and C, N co-doped submicrospheres showed obvious absorption in the wavelength up to around 650, 500 and 650 nm, respectively. The activity of the photocatalysts was evaluated by the hydroxyl radical formation under visible light irradiation. Finally, the mechanism of sphere formation is discussed.     

Energy-less respiration monitoring device using thermo-sensitive film

We propose an easy-to-use energy-less respiration monitoring device for monitoring the breathing flow using a thermo-sensitive film. Thermo-sensitive film less than 0.01 mm thick with thermo-sensitive ink and a base film were wrapped over the aperture and partially produced in the tube for monitoring the breathing status. The aperture used as the respiration monitoring area, also worked as thermal isolation to shorten the response time and to decrease thermal capacity in the monitoring area. The response time was investigated using a response evaluation device (designed and produced using MEMS technology) to follow the temperature change with the breathing cycle of 0.3 Hz. The response time depended on the thickness of both the ink and the base film and decreased with the decrease of the thickness due to thermal capacity reduction. The obtained minimum response time was 373 ms when the ink thickness was 6.8 μm and the base film thickness was less than 5.0 μm. The color of the ink at the breathing monitoring area formed on the aperture successfully changed from blue to transparent according to the temperature change of the airflow.

     

The Use of Transition-Metal Silicides to Reduce the Contact Resistance Between the Electrode and Sintered n-Type Mg2Si

The electrical and thermoelectric characteristics of n-type Mg₂Si equipped with electrodes of Ni and the transition-metal silicides CoSi₂, CrSi₂, TiSi₂, and NiSi were examined. To form the electrodes on the Mg₂Si matrix, a monobloc sintering method, i.e., simultaneous sintering of the electrode material during Mg₂Si sintering, was used. To obtain dense electrodes and to keep an appropriately low sintering temperature for the Mg₂Si matrix, a Ni binder was used for the CoSi₂, CrSi₂, and TiSi₂ monobloc sintering. The mixture ratio between the transition-metal silicide and the Ni was 50:50 in wt.%. The room-temperature I?CV characteristics of the fabricated CoSi₂, CrSi₂, and TiSi₂ electrodes with the Ni binder and NiSi electrodes were considered to be adequate for practical applications in as much as ohmic contacts were obtained. The contact resistance at the Mg₂Si/electrode interface decreased by 35% and 28%, respectively, for the CoSi₂ and CrSi₂ electrodes compared with our standard Ni electrode. The thermoelectric power output was measured at the practical operating temperature of 600?K, with ??T?=?500?K. The observed output powers for 3.0?mm?×?3.0?mm?×?7.5?mm samples equipped with CoSi₂, CrSi₂, and NiSi electrodes were 153?mW, 149?mW, and 125?mW, respectively, representing increases of 27%, 24%, and 4%, respectively, compared with the 120?mW measured for the sample with Ni electrodes.