Relationship between the energy distribution of electrostatic field change and lightning activity

A lightning strength parameter α (denoted as LSP or LAIDO), which is used for characterizing the phenomena of lightning activity, has been proposed, where α is defined by the characteristic energy obtained from the energy distribution of a radiated field component E in the electrostatic field changes produced by lightning discharge. Here, it is observed that the energy distribution of E_γ components is Maxwellian type. To prove more clearly the forementioned assumption from another viewpoint, changes of the amplitudes of the electrostatic field component E_S were measured and their distribution functions constructed. In the cloud-to-ground lightning discharges, the E_S components have a positive sign in the changes. However, those changes in the intercloud discharges are observed with either a negative or positive change depending on the distance between the striking point and the observation site. Therefore it is necessary to sum the numbers of occurrences of both positive and negative components for constructing an energy distribution of the E_S component. A fieldmill and a pair of doughnut-shaped electrostatic antennas are used in measuring the changes of the E_S component. As a result it is found that the changes of the amplitudes of the E_S components have a Maxwelliantype energy distribution. A characteristic energy β is defined which is obtained from the component of the electrostatic fields as a measure of LSP. Based on comparison of α and β it is clarified that β has the same characteristic nature with α. The lightning activity could be estimated from β.     

Potent preventive action of alpha-carotene against carcinogenesis: spontaneous liver carcinogenesis and promoting stage of lung and skin carcinogenesis in mice are suppressed more effectively by alpha-carotene than by beta-carotene

Although beta-carotene has been considered to be a key cancer preventive agent in green and yellow vegetables, other types of carotenoids, such as alpha-carotene, may also contribute to anticarcinogenic action, since these carotenoids usually coexist with beta-carotene and are detectable in human blood and tissues. In this study, we compared the inhibitory effect of natural alpha-carotene, obtained from palm oil, with that of beta-carotene on spontaneous liver carcinogenesis in C3H/He male mice. The mean number of hepatomas per mouse was significantly decreased by alpha-carotene supplementation (per os administration in drinking water at a concentration of 0.05%, ad libitum) as compared with that in the control group (P < 0.001, Student's t test). On the other hand, beta-carotene, at the same dose as alpha-carotene, did not show any such significant difference from the control group. Furthermore, we also compared the antitumor-promoting activity of alpha-carotene with that of beta-carotene against two-stage mouse lung carcinogenesis (initiator, 4-nitroquinoline 1-oxide; promoter, glycerol). alpha-Carotene, but not beta-carotene, reduced the number of lung tumors per mouse to about 30% of that in the control group (P < 0.001, Student's t test). The higher potency of the antitumor-promoting action of alpha-carotene compared to beta-carotene was confirmed in other experimental systems; e.g., alpha-carotene was also found to have a stronger effect than beta-carotene in suppressing the promoting activity of 12-O-tetradecanoylphorbol-13-acetate on skin carcinogenesis in 7,12-dimethylbenz[a]anthracene-initiated mice. These results suggest that not only beta-carotene, but also other types of carotenoids, such as alpha-carotene, may play an important role in cancer prevention.     

Emission mechanism in phosphorescent and fluorescent OLED utilizing energy transfer from exciplex to emitter

This paper discusses the effectiveness of energy transfer from an exciplex to an emitter in both phosphorescent and fluorescent organic light‐emitting diodes. This energy transfer enhances the efficiency, lowers the drive voltage, and extends the lifetime. The increase in the quantum efficiency of a fluorescent organic light‐emitting diode using this mechanism is also analyzed.     

Synthesis of Highly Oriented Lithium Niobate Thin Film from Neutralized Aqueous Precursor Solution

Lithium niobate thin films with a c -axis orientation were synthesized from a neutralized aqueous precursor solution that was derived from lithium niobium double alkoxide. Lithium niobium hydroxide solution that was prepared by dissolving precipitates, through the complete hydrolysis of lithium niobium double alkoxide with water, was weakly basic. The hydroxide solution was neutralized with acetic acid to give neutralized homogeneous lithium niobium hydroxide solution. The film that was prepared at 500°C from the neutralized precursor solution had a smooth surface texture without cracks and pores. A pole-figure pattern indicated that the crystalline film was twinned, with rotation by 60° oriented along the c -axis.     

Co-existing handednesses of lamella twisting in one spherulite observed with scanning microbeam wide-angle X-ray scattering

In poly(ε caprolacton) (PCL)/poly(vinyl butyral) (PVB) blend which forms band spherulite, some straight lines along the radial direction of the spherulites are observed under polarized optical microscope (POM). By using microbeam scanning WAXS, we have investigated the handedness of lamella twisting on the left and right sides of the straight line. As a result, we have observed that the manner of periodic change of 110 reflection in WAXS is reversed between left and right sides of the straight line with respect to the direction of the X-ray beam scanning. This result clearly shows that the straight line observed under POM is the boundary line of handedness in band spherulite, and further, that both handednesses co-exist within one spherulite. It also implies that the lamellae growing from one nucleus are twisted cooperatively only with neighboring lamellae but not with all lamellae in the spherulite of PCL/PVB.     

Cryptosporidium parvum oocyst inactivation in field soil and its relation to soil characteristics: analyses using the geographic information systems

The need exists to understand the environmental parameters that affect inactivation of Cryptosporidium parvum oocysts in soil under field conditions. The inactivation of C. parvum oocysts placed in the natural environment was studied at a dairy farm in western New York State, USA. Seventy sampling points were arranged in a grid with points 150 m apart using the Geographic Information System. The sampling points were distributed among three distinct areas: woodland, corn field and pasture. Purified oocysts were inoculated into chambers filled with soil from each sampling point, and buried in the surface of each respective sampling point. To compare C. parvum oocyst survival with another organism known to survive environmental stresses, Ascaris suum eggs were also placed in soil contained in chambers and buried at the same sampling points as the oocysts. As controls oocysts and eggs in distilled water were also placed at each sampling point. Oocyst and egg viability, soil pH and percent gravimetric water content were measured at all sampling points at 0, 60 and 120 day sampling periods. Soil organic content was determined for each sampling point. At 120 days after placement, mean viability of C. parvum oocysts was 10% although at a few sampling points, 30% of oocysts were still potentially infective; whereas 90% of A. suum eggs were viable at all sampling points. Statistically significant differences were not observed among the three different sampling areas, and no statistically significant predictors were found by regression analysis. Results exemplified the heterogeneity of soil parameters and oocyst viability across a landscape; such results make predictive models for C. parvum inactivation problematical. The long-term survival of C. parvum oocysts in soil under field conditions, as this study demonstrated, emphasizes their potential as a risk to contaminate surface waters.     

Loading pattern optimization for a PWR using Multi-Swarm Moth Flame Optimization Method with Predator

ABSTRACT

This paper aims to propose a new methodology for optimizing fuel loading pattern in a nuclear reactor which is important for its higher safety and economic efficiency. Previous researches have proposed various methodologies to decide better loading patterns automatically. However, the processes still require manual operations of engineers to automatically design actual loading patterns. Swarm intelligence algorithm has currently gained interest as a solution to seek the patterns. Although these methodologies generate better patterns, they sometimes struggle with getting out from local optima and fails to complete the optimization. Large and multimodal solution space sometimes captures worse solutions due to local optima. The conventional methodologies struggle with setting proper parameters to get out from local optima. This research focuses on Multi-Swarm Moth Flame Optimization with Predator (MSMFO-P), an improved Moth Flame Optimization (MFO) by applying the concepts of predator and multi-swarm, as new methodologies. The method of MSMFO-P was applied to solve a loading pattern problem and compared with the conventional optimization methods such as simulated annealing (SA), Hybrid genetic algorithm (GA), and particle swarm optimization (PSO). The results of our experimental works indicated that MSMO-P generates better loading patterns than the conventional methodologies.     

New aspects in the unfolding of the nilpotent singularity of codimension three

This paper is concerned with three-dimensional vector fields and more specifically with the study of dynamics in unfoldings of the nilpotent singularity of codimension three. The ultimate goal is to understand the dynamics and bifurcations in the unfolding of the singularity. However, it is clear from the literature that the bifurcation diagram is very complicated and a complete study is far beyond the current possibilities, not only from a theoretical point of view but also from a numerical point of view, despite recent developments of computational methods for dynamical systems. Since all complicated dynamical behaviour is known to be of small amplitude, shrinking to the singularity for parameter values tending to the bifurcation parameter, the aim in this paper is especially to focus on a different aspect that might be interesting in the study of global bifurcation problems in the presence of such a nilpotent singularity of codimension three. The notion is introduced of 'traffic regulator' and the specific sets called the 'inset' and 'outset', which give a new framework for studying a transition map in a cylindrical neighbourhood of the singularity that contains all the non-trivial dynamics that can bifurcate from the singularity, focusing on the domains on which the transition map is defined. A list is also given of open problems which are believed to be helpful for future investigation of the bifurcations from the nilpotent triple zero singularity in 3.     

Synthesis of polypyridine-graft-PEG copolymer for protein repellent and stable interface

Polypyridine grafted with poly(ethylene glycol) (Py-g-PEG) have been synthesized. Radical copolymerization of methyl-terminated PEG macromonomer with 4-pyridylmethyl methacrylate homogeneously proceeded and the obtained copolymer spontaneously adsorbs from aqueous solution onto gold surfaces, where the pyridine parts act as the multipoint anchor to the surface and the PEG parts provide the strong steric repulsion between the chains. As a result, the highly protein repellent and stable surface was constructed through multipoint pyridine attachment as compared with singlepoint pyridine attachment. Py-g-PEGs thus synthesized are promising material to functionalize metal and semiconductor material and to self-assemble into micelle in biotechnological and biomedical field.