Photochemical aerosol forming potential of polluted air as a function of photochemical reactivity of hydrocarbons

We introduce a new term, “Photochemical aerosol forming potential, PAFP” defined by the latent faculty of an air parcel in which gaseous reactants can be converted photochemically to particulates.

This paper presents the results of laboratory tests which were conducted to evaluate PAFP in both simulated pollution air systems containing SO2, NO2 and/or hydrocarbons (HC) and real atmospheric air. The concentration of aerosol particles formed photochemically during a certain fixed irradiation time, in which the aerosol formation is dominant rather than aerosol growth, is adopted here as an indicator of PAFP level. Eight different HCs were chosen by taking into consideration their chemical properties (paraffin, olefin or aromatic) and photochemical reactivity ranking based on gas‐phase reaction.

PAFP was influenced in a very complicated way by both kind and concentration of gaseous reactions in the system. The most dominant reactant in photochemical aerosol formation was found to be SO2. The similar tendencies were obtained for the real atmospheric air under the sunlight.     

Design study on reactor structure of Pb–Bi-cooled direct contact boiling water fast reactor (PBWFR)

Pb–Bi-cooled direct contact boiling water small fast reactor (PBWFR) can produce steam by direct contact of feedwater with primary Pb–Bi coolant above the core, and circulate Pb–Bi coolant by means of buoyancy of steam bubbles. The PBWFR is capable of eliminating components of the cooling system such as primary pumps and steam generators, and thereby making the reactor system simple and compact. The specifications of the PBWFR are as follows: the fuel is Pu–U nitride; the core height is 75 cm; the core diameter is 278 cm; the average burnup is 80 GWd/t; the refueling interval is 10 years; the rated electric power is 150 MWe; the rated thermal power is 450 MWt; the core outlet/inlet temperatures are 460 °C/310 °C, respectively; and the operating steam pressure is 7 MPa. The reactor structure design has been formulated, where reactor vessel sizes are 4200 mm (ID) × 19,750 mm (H), the guard vessel is a closed type, the upper structure is made of chimneys, and the core support structure is hung up. An ultrasonic flow meter is installed inside the vessel. The seismic evaluation, design of refueling procedure and cost evaluation have been performed.     

The influence of heat transfer and friction on the impulse of a detonation tube

In the present study, we experimentally and numerically investigated the influence of heat transfer and friction on the performance of a single-shot detonation tube open at one end. Two kinds of specific impulse measurement were carried out with various tube lengths and levels of surface roughness, one by using a ballistic pendulum arrangement and the other by integrating the pressure history measured at the thrust wall. These measurements revealed the degree to which potential impulse can be exploited by the detonation tube after the impulse losses due to various wall loss mechanisms such as heat transfer and friction. The detonation tube obtained 89%, 70%, and 64% of the theoretical ideal impulse for electropolished tubes at a ratio of tube length to diameter (L/D) of 49, 103, and 151, respectively. The impulse losses due to shear stress on the side wall of the detonation tube were found to have a dominant influence on the performance of the detonation tubes of L/D = 103 and 151, but the loss was remarkably small for L/D = 49 relative to that of the longer tubes. In addition to the experiments, a simplified one-dimensional gas-dynamic model was developed by considering heat transfer and friction as wall loss mechanisms and validated by the experimental results. This simplified model was found to predict the experimental results very well, especially in the range of L/D 103–151.     

Carbothermal Reduction of the Molybdenum Oxide/Phenanthroline Complex

Samples of an MoO₃/phenanthroline complex and an MoO₃/carbon black mixture were heated below 1400°C in nitrogen to characterize the carbothermal reduction process of the complex. The conversion of crystalline phases by carbothermal reduction followed substantially the same process in both samples but occurred at a temperature 100° to 150°C lower in the complex than in the carbon black mixture. Two possible explanations for this difference are theorized: (1) The complex may provide more intimate contact between the MoO₃ and the intercalated reducing material. (2) The intercalated reducing agents may have a higher reactivity than does the carbon black.     

Receiving antennas in a compressible plasma

The receiving voltages and the receiving maximum available powers of a dipole antenna and a loop antenna immersed in an isotropic compressible plasma are obtained for both an electromagnetic and an electron-plasma wave incidence by making use of the reciprocity theorem.     

Water sensor with optical fiber

In optical-fiber networks, it is important to monitor water which seeps into splice enclosures. The fibers have residual stress at splicing points, and when water is present, this adversely affects fiber lifetime. A water sensor which has a simple structure for monitoring water at splicing points has been developed. This water sensor causes optical loss due to fiber bending when water seeps into splicing enclosures. The design method using a fiber-bending model and sensor performance are described     

Endoscopic appearances of hemorrhagic peptic ulcers and efficacy of H2-receptor antagonists

BACKGROUND/AIMS: In this retrospective study, we compared the effects of histamine H2-receptor antagonists to those of antacids and anticholinergics in patients with hemorrhagic ulcers with various endoscopic appearances of bleeding. PATIENTS AND METHODS: Patients with hemorrhagic ulcers (n = 376) were examined by emergency endoscopy and were treated with 1) antacids and anticholinergic drugs or 2) H2-receptor antagonists. RESULTS: In ulcer patients with oozing or fresh red coagulation, H2-receptor antagonists ceased further hemorrhage more effectively (65.9% of the cases) than antacids and anticholinergic drugs (46.7%). In patients with projectile bleeding, both of the treatments failed to stop hemorrhage. There were no significant differences in favorable outcome in the patients only with old black coagulation between antacid and anticholinergic drugs-treated group and H2-receptor antagonists-treated group (94.4% and 93.8%, respectively). CONCLUSIONS: The results suggest that H2-receptor antagonists are more effective than antacids and anticholinergic drugs in patents with peptic ulcer with fresh coagulation or oozing, but not with projectile bleeding or old black coagulation. The results also indicate that endoscopic appearances of peptic ulcer bleeding are good predictors for the effects of medication.     

A new architecture of photonic ATM switches

A photonic asynchronous transfer mode (ATM) switch architecture for ATM operation at throughputs greater than 1 Tbit/s is proposed. The switch uses vertical-to-surface transmission electrophotonic devices (VSTEPs) for the optical buffer memory, and an optical-header-driven self-routing circuit in contrast with conventional photonic ATM switches using electrically controlled optical matrix switches. The optical buffer memory using massively parallel optical interconnections is an effective solution to achieve ultra-high throughput in the buffer. In the optical-header-driven self-routing circuit, a time difference method for a priority control is proposed. For the optical buffer memory, the write and read operations to and from the VSTEP memory for 1.6 Gbit/s, 8-bit optical signal are confirmed. The optical self-routing operation and priority control operation by the time difference method in the 4×4 self-routing circuit were performed by 1.6-Gbit/s 256-bit data with a 10-ns optical header pulse     

Acoustic behavior of the incommensurate state of Rb2Zncl4 by brillouin scattering?

Temperature dependence of elastic stiffness constant C₁₁ was studied from 60 to -100°C by Brillouin scattering and refractive index measurements. It is found that C₁₁ decreases with decreasing temperature over the incommensurate phase and its temperature gradient becomes more or less flat at several degrees above the incommensurate-commensurate transition point T_c, where the dis-commensurate structure appears. This unusual temperature dependence of C₁₁ seems to be attributable to the incommensurately modulated structure of Rb₂ZnC1₄.