Andrey V. Smirnov

Plasma processing and deposition of powdered metal oxides consisting of hollow spherical particles

Features of the plasma processing of agglomerated metal oxide powders and the deposition of coatings of these powders, which consist of hollow spherical particles are considered in a particular case of powdered zirconium dioxide. It is shown that the formation of zirconia splats (melt drops spread over and solidified on a substrate surface) during the collision of hollow drops with the substrate has a more stable character as compared to the case of continuous (dense) particles of the same mass. Advantages of using hollow powders in the thermal spraying of coatings are discussed.

Spreading and Solidification of Hollow Molten Droplet under Its Impact onto Substrate: Computer Simulation and Experiment

The peculiarities of plasma treatment of agglomerated (spray dry) YSZ powder and subsequent plasma spraying of produced HOSP powder (consisting of the hollow spherical particles) are analyzed. Formation of splats of hollow YSZ droplets deserves a special attention within thermal spraying. In this case, immediately prior to particle—substrate collision, we have a droplet that consists of a liquid shell enclosing a gas cavity heated to a temperature close to the melt temperature. The paper presented includes the results of computer simulation and model experiments carried out under full control of the key physical parameters: temperature, velocity, external diameter of droplet, thickness of its shell, and temperature of polished substrate. It was shown that formation of splats of hollow droplets proceeds in a manner more stable compared to the case of “dense” molten particles obtained from fused and crushed compacts, and this provides superior coating‐substrate interface.

Hydrodynamic features of the impact of a hollow spherical drop on a flat surface

Physical model experiments devoted to visualization of the collision of a hollow liquid drop with a flat surface are described. A new phenomenon is discovered, according to which the impact leads to the formation of a central counter jet of the liquid. A simple theoretical model is proposed for predicting the dynamics of the hollow liquid drop spreading on the surface. The results of calculations satisfactorily agree with the data of model experiments.

Development of Laminar Plasma Shielded HF-ERW Process: Advanced Welding Process of HF-ERW 3

High frequency - electric resistance welded (HF-ERW) pipe has been successfully used for many years for a number of applications. The benefits of HF-ERW pipe are considerable, including a higher dimensional tolerance and lower prices than seamless pipe and UO pipe. The conventional weld seam produced by HF-ERW, however, often has a relatively low toughness. We have developed an automatic heat input control technique based on ERW phenomena that relies on optical and electrical monitoring methods and has been shown to result in a significant improvement in the toughness. Shielding of the weld area must also be considered as a key factor in the formation of a sound weld. It has been shown that an inert cold gas (e.g., at room temperature) shielding technique is effective for maintaining a stable low oxygen state in the weld area that inhibits the formation of penetrator, a pancake oxide inclusions. Compared to the cold gas shielding technique, high temperature gas shielding, due to its higher kinetic viscosity coefficient, should make it easier to sustain a higher laminar flow, thus leading to a rather low air entrainment in the shielding gas. In addition, plasma is a much higher temperature state (∼6000 K), and the dissociated gases can react with the entrained oxygen; plasma jets should, therefore, enhance the overall shielding effects. Moreover, oxides on the strip edges can be expected to melt and/or be reduced by the high temperature plasma jets. Nippon Steel has developed a plasma torch that can generate a long and wide laminar argon – nitrogen – (hydrogen) jet. This paper describes the results obtained from our investigation of the effects of a plasma jet shield on the weld area of high strength line pipe with a yield strength grade of X65. Preliminary attempts in applying this novel shielding technique has been found, as expected, to demonstrate extremely low numbers of weld defects and a good low temperature toughness of the HF-ERW seam.Copyright

Proposition and Predication

Subject-predicate linkage and its role in language and metaphysics is the point where the immanent logic of thought and its relation to reality uncover themselves. The logic of predication displays itself in language in the elementary proposition. For Indo-European languages, the core predication formula is “S is P.” It is backed by a universal intuition of a closed space, as exemplified by Euler diagram. The formal logic based on that type of the subject-predicate linkage may be called substance-based logic. The “S is P” construction is not possible in natural Arabic. This language uses an alternative predication formula for connecting subject to predicate, which in the terminology of traditional Arabic grammar is designated as “S isnād P” where isnād literally means “leaning.” This Arabic elementary proposition reflects the basic intuition of the flux, the intuition of continuous process of flowing. The logic based on of this type of subject-predicate linkage is referred to as process-based logic.

The Finer Points of a Culture’s Thought: Guest Editor’s Introduction

Imagine: On a warm sunny day you wade into the crystal clear water of a lake or a river. Taking a stick, conduct an experiment as old as mankind itself. You bring the stick to the surface of the water and touch it; the stick is suddenly broken, although—despite the break—it keeps sinking into the water. So where is the break? We will never find it examining the stick itself, i.e. the very thing that has seemingly been broken. Nor it is in the water: it is limpid and insubstantial, embracing and releasing without changing anything that gets sunk into it. And yet the break is there, and it is quite palpable. It becomes even more palpable if—in order to survive —we need to use this stick, sharpened and turned into a crude spear, to impale the fish swimming nonchalantly through the water. Then the refraction effect ceases to be a figment of imagination or a conundrum to guess at leisure—it becomes a factor which is necessarily to be taken into account, with maximum precision, to avoid blunders that would lead to starvation. To the conventional mode of thought, otherness is only otherness inasmuch as it is unknown; so it would be sufficient to get to know the length and breadth of it to make it your own, something that is close and thoroughly familiar. However, the task of grasping otherness could be viewed as a mere accumulation of data only when both the data gatherer

Microstructure and morphology of powder particles TiC-NiCr, synthesized in plasma jet, at high-energy actions on components of initial composition Ti-C-NiCr

The results of experiments on in-situ synthesis of the microspherical, in particular hollow, cermet powder TiC– 30vol.%NiCr at processing of the Ti-C-NiCr agglomerates in argon-helium plasma jet flowing out into controlled atmosphere are presented. Preparation of the agglomerates consisted of the following stages: (i) high-energy treatment of the initial powders Ti and NiCr in planetary mill with their subsequent uniform mixing with glass black powder, (ii) preparation of dough from mechanically mixed powders and binder, and their granulation using the extrusion method, (iii) drying and classification of granules by the sizes.

The collective cognitive unconscious and its role in logic, language, and culture

The notion of the collective cognitive unconscious (CCU) is introduced. The hypothesis is formulated that data from the external world are processed proceeding from intuitively adopted assumptions, which substantiate for a subject of cognition the sense and justifiability of any statement or semantic construction. These intuitions are of mass character and are transmitted within a culture. The CCU is probably supported by neuronal mechanisms. It is potentially a universal faculty of man as a generic creature, although it is always realized in one of its possible variants. CCU explications in Western and Arabic–Muslim cultures are demonstrated as spatial visualization and a metaphor of flux. Three major functions of the CCU are considered: specifying the intuitive background for the substantiation of formal logic, the logic of language, and the logic of culture. Since the CCU is potentially universal for humans but is actually always accomplished as a variant and cannot be realized as an invariant, this determines the justifiability of the strategy of panhuman and not common-to-humankind understanding of culture and civilization. The question is posed about the necessity to return the category of panhuman into the field of theoretical discourse.

Current status of the space mission Millimetron

Millimetron is a planned space observatory working in millimeter, submillimeter and far infrared bands with 10-m actively cooled mirror. It will operate in two modes. In the single dish mode with very high sensitivity Millimetron will address the key problems of cosmology, star and planet formation, interstellar medium and galaxy evolution left open by previous missions. The second mode is the Space-Earth radio interferometer with extremely high angular resolution and it is aimed at observations of the sub horizon scale structures of black holes.

Spreading and solidification of metal-melt droplets under conditions of substrate submelting. Theory and model experiment

Spreading and solidification of metal-melt droplets upon their collision with a surface are of particular interest for thermal spraying, molding, melt spinning for obtaining amorphous and microcrystal powders, etc. The scenarios of the formation of splats (spread and solidified particles on the substrate) can be significantly different and are determined by thermophysical properties of materials of the particle and substrate, as well as by key physical parameters (KPPs): velocity up0, size Dp, and temperature Tp0 of the droplet and substrate Tb0 and the state of its surface. An attempt was made to theoretically and experimentally study the formation of splats for the case in which the substrate is submelted in the spot of the contact with the particle in the process of spreading and solidification of metal-melt droplets.