A Modeling and Rendering Method for Snow by Using Metaballs

The display of natural scenes such as mountains, trees, the earth as viewed from space, the sea, and waves have been attempted. Here a method to realistically display snow is proposed. In order to achieve this, two important elements have to be considered, namely the shape and shading model of snow, based on the physical phenomenon. In this paper, a method for displaying snow fallen onto objects, including curved surfaces and snow scattered by objects, such as skis, is proposed. Snow should be treated as particles with a density distribution since it consists of water particles, ice particles, and air molecules. In order to express the material property of snow, the phase functions of the particles must be taken into account, and it is well-known that the color of snow is white because of the multiple scattering of light. This paper describes a calculation method for light scattering due to snow particles taking into account both multiple scattering and sky light, and the modeling of snow.     

Fracture toughness of sea ice

Linear elastic fracture mechanics, which has been applied to fragile substances and successfully used for studying the brittle fracture of metallic materials, was utilized to gain an understanding of the fracture phenomena of sea ice.The present paper reports the first results of investigations into the fracture-toughness value of sea ice, which was analyzed experimentally as a function of strain rate on the basis of the stress-intensity-factor concept.The fracture toughness, K_IC, of sea ice, which was measured by an in-situ three-point bending test on notched specimens, shows almost constant value if the strain rate is less then 10^?3 s^?1 and decreases with increasing strain rate if the strain rate exceeds 10^?3 s^?1. K_IC data show considerably less scatter than existing data such as the compressive, tensile and flexural strengths.It was confirmed in the present study that the linear elastic-fracture-mechanics concept is effective for analyzing the fracture phenomena of sea ice. Moreover, the K_IC value was shown to be closely related to sea-ice structures (e.g. the size of crack-like flaws such as brine cells).It is also suggested that the fracture-toughness test might prove to be a standard testing method to obtain the sea-ice strength, since once K_1C and crack-like flaw sizes are determined, the less-scattered critical-fracture stress can be calculated.     

Crystallization characteristics of an amorphous Nb81Si19 alloy under high pressure and formation of the A15 phase

Amorphous Nb-19 at% Si alloy, prepared by rapid quenching from the molten state, was annealed while being subjected to a pressure of 10 GPA. X-ray diffraction investigations on the alloy specimens quenched to ambient conditions have shown that pressure greatly alters the crystallization characteristics and the cubic A15 (Nb₃Si)-phase forms in preference to the tetragonal Nb₃Si-phase at temperatures in the range from 710° C to 800° C. Up to 680° C, the component atoms do not show any tendency towards ordering upon crystallization and the body-centred tetragonal solid solution forms; while, at 830° C, niobium atoms diffuse to form the body-centred cubic Nb precipitates. Superconducting properties have been measured for the single-phase A15 structure with the lattice parametera=0.5155 nm with the results that the transition temperature,T _C, is 3.4 K and the temperature coefficient of the upper critical field,H _C2, is 1.2 MA m^–1 K^–1 (15 kOe K^–1).     

Phosphorus Recovery from Dehydrated Water Sludge by Incineration Using Alkali Metal Compounds

In order to recover the phosphorus from the waste water sludge,the dehydrated sludge was mixed with the reagent of NaOH,KOH or Na2CO3,and incinerated at 750℃ or...     

Phosphorus Recovery from the Ash of Sewage Sludge Using NaOH by Heat Treatment-II—Reuse of the Alkali Water Generated by Phosphorus Recovery

The phosphorus recovery from the incinerated ash using NaOH by the heat treatment,was investigated.In this method,non-reacted NaOH containing alkali water was g...     

Abnormal myelination in a patient with ring chromosome 18

BACKGROUND: Most adult anatomical texts state that the deep inguinal ring is situated midway between the anterior superior iliac spine and the pubic tubercle. The aim of this study was to determine if this was true in prepubescent children. METHODS: A total of 107 inguinal ligaments and canals were measured during inguinal operations in 80 children (68 boys, age range 1-118 months). RESULTS: The length of the inguinal ligament increased from a median of 4.3 cm (range 3.6-6.8) at less than 1 year of age to 7.5 cm (range 6.7-10.1) at over 4 years of age. The internal ring was situated medial to the midpoint of the inguinal ligament throughout childhood. The ratio of internal ring to public tubercle over inguinal ligament length was 42% (range 27-58) at less than 2 years; and 34% (range 25-46) at over 4 years. The inguinal canal remained short (median 1 cm (range 0.7-1.1) at less than 2 years, and median 1.1 cm (range 0.7-2.3) at over 4 years) suggesting that growth of the inguinal region in this age group occurs outside the canal. CONCLUSIONS: These results have implications for the siting of incisions, and question the necessity of opening the inguinal canal in children.     

Light scattering from ferroelectric domains in LiTaO3

When a He-Ne 0.633 μm laser light passes through an as-grown LiTaO₃ single crystal, the Tyndall phenomenon is observed along the beam path. The scattered light intensity distribution was measured in the plane perpendicular to the incident beam. Results were discussed from the viewpoint of very small ferroelectric domains using light scattering theory. It was concluded that light scattering centers in LiTaO₃ are ferroelectric multi-domains of size in order of one wavelength.     

Stabilization of oscillating modes in a LiNdP4O12laser

Suppression of mode competition in a LiNdP4O12(LNP) laser is reported. The stabilization of the oscillating modes was achieved with a quartz quarter-wave plate placed within an optical resonator without any external modulation.     

Anisotropy in the resistive superconducting transition under magnetic fields in single crystal Pb2Sr2Ho0.5Ca0.5Cu3O8

Anisotropie properties of the single crystal Pb₂Sr₂Ho_0.5Ca_0.5Cu₃O₈ have been investigated by measuring the electrical resistivity in theab-planeρ _ab (H, θ,T), which depends on the angleθ between theab-plane and the magnetic-field direction, in various constant fieldsH perpendicular to the current direction. All the angle-dependent values ofρ _ab (H, θ,T) at a constant temperature are scaled to be on one curve as a function of reduced field. The anisotropic parameter γ≡(m _c ^* /m _ab ^* )^1/2 is estimated as 12–13, which is larger than that of YBa₂Cu₃O₇ and much smaller than that of Bi₂Sr₂CaCu₂O₈. It has been concluded that the anisotropy does not always depend on the thickness of the blocking layer but seems to depend on the overlap of the electronic wave functions along thec-axis. Anisotropy in the pinning potential has also been discussed from the resistive tail in the temperature dependence ofρ _ab (H,θ,T).