Nanoparticle Generation in Glowing Wire Generator: Insight into Nucleation Peculiarities

The paper studies nanoparticle formation in a glowing wire generator (GWG), in which the gas carrier flows around heated metal wire, producing aerosols from a vapor released from the surface. The device has been customized, enabling the use of a double-wire in different orientations in regard to the gas flow. Such alterations provided different effective distances between wires enabling investigation of their mutual influence. Concentration of particles produced in the GWG at different parameters (applied voltage and a gas flow) was carefully measured and analysed. Different regimes of a nanoparticle nucleation were identified that resulted from the applied voltage variation and the gas flow direction. In particular, independent nucleation of nanoparticles on both parts of the wire occurred in the wire plane’s configuration perpendicular to the gas flow, whilst dependent nucleation of nanoparticles was observed at a certain specific set of parameters in the configuration, in which the wire plane was parallel to the gas flow. Two corresponding functions were introduced in order to quantify those nucleation regimes and they tend to zero when either independent or dependent nucleation occur. The peculiarities found ought to be considered when designing the multi-wire GWGs in order to further extend the device’s range for industrial applications.

Cryopreservation of semen of initial forms and chimeras of birds of two breeds: Sussex light and Poltava clay

Purpose: evaluation of the quality of seed chimer and source forms before and after cryopreservation.Materials and methods. For research, the breed of Sussex chickens and Poltava clay. Using these rocks, chimeras were obtained by the method of transplantation of blastodermal cells. An assessment of the quality of sperm of the roosters was carried out under a microscope at a temperature of 42 degrees. At various times, the activity of native sperm and its concentration was determined. Cryoconservation was carried out in small granules. The defrosting of the granules was produced on a heated metal plate at a temperature of 60 ° C.Results. A comparative analysis of the volume of the ejaculate showed that Himer on average it was somewhat larger than that of the initial forms. The activity of sperms in native genital cells was sufficiently high in all studied samples, and was 80% or more. The concentration of sperm retained the same trend and practically did not differ from each other in all studied samples. The activity of frozen-fatty seed of the initial breeds and their chimer was significantly different. The maximum activity was observed in the Sussex breed and reliably below (p≤ 0.01) it has the remaining experimental groups. The activity of frozen-fatty seed turned out to be equal in chimeric organisms and Poltava clay, although Himer recipients were sussexes. It should be noted that the swing of oscillations according to the degree of activity of frozen-fatty seed in chimeric birds was significant (from 10 to 40 points), and the number of observations is small.Conclusion. The study assess the quality of seed chimer and the source forms before and after cryopreservation. It was demonstrated that after defrosting the activity of frozen-fatty seed of the initial rocks and their chimer was different.

Errors Related to General Relativity, Repulsive Gravitation and the Question of Black Holes

Galileo and Newton considered gravity to be independent of temperature, while Einstein claimed that the weight of metal will increase as temperature increases. Further, Maxwell maintained that charge is unrelated to gravity. Experiments show, however, that the weight of a metal piece is reduced as its temperature increases. Thus, charge-initiated repulsive gravitation exists. In fact, repulsive gravity has been demonstrated by the use of a charged capacitor hovering over Earth. Further, it is expected that a piece of heated metal would fall more slowly than a feather in a vacuum. Einstein developed an invalid notion of gravitational mass, and failed to establish the unification of gravitation and electromagnetism since he overlooked repulsive gravitation. Moreover, photons are a combination of the gravitational wave and the electromagnetic wave. For electromagnetic energy is invalid, and is in conflict with the Einstein equation. The non-linear Einstein equation has no bounded dynamic solution, Space-time singularity theorems are based on an invalid implicit assumption that all the couplings have a unique sign. Since gravity is no longer always attractive, the existence of black holes is questionable. The fact that Penrose was awarded the 2020 Nobel Prize in Physics for the derivation of black holes is due to that the Nobel Prize Committee for Physics did not sufficiently understand the physics of general relativity. A distinct characteristic of Penrose's work, as usual, is that it is not verifiable.

Thermotaxis of Janus particles

The interactions of autonomous microswimmers play an important role for the formation of collective states of motile active matter. We study them in detail for the common microswimmer-design of two-faced Janus spheres with hemispheres made from different materials. Their chemical and physical surface properties may be tailored to fine-tune their mutual attractive, repulsive or aligning behavior. To investigate these effects systematically, we monitor the dynamics of a single gold-capped Janus particle in the external temperature field created by an optically heated metal nanoparticle. We quantify the orientation-dependent repulsion and alignment of the Janus particle and explain it in terms of a simple theoretical model for the induced thermoosmotic surface fluxes. The model reveals that the particle’s angular velocity is solely determined by the temperature profile on the equator between the Janus particle’s hemispheres and their phoretic mobility contrast. The distortion of the external temperature field by their heterogeneous heat conductivity is moreover shown to break the apparent symmetry of the problem. Graphic abstract

A differential emissivity imaging technique for measuring hydrometeor mass and type

The Differential Emissivity Imaging Disdrometer (DEID) is a new evaporation-based optical and thermal instrument designed to measure the mass, size, density, and type of individual hydrometeors and their bulk properties. Hydrometeor spatial dimensions are measured on a heated metal plate using an infrared camera by exploiting the much higher thermal emissivity of water compared with metal. As a melted hydrometeor evaporates, its mass can be directly related to the loss of heat from the hotplate assuming energy conservation across the hydrometeor. The heat-loss required to evaporate a hydrometeor is found to be independent of environmental conditions including ambient wind velocity, moisture level, and temperature. The difference in heat loss for snow versus rain for a given mass offers a method for discriminating precipitation phase. The DEID measures hydrometeors at sampling frequencies up to 1 Hz with masses and effective diameters greater than 1 µg and 200 µm, respectively, determined by the size of the hotplate and the thermal camera specifications. Measurable snow water equivalent (SWE) precipitation rates range from 0.001 to 200 mm h−1, as validated against a standard weighing bucket. Preliminary field-experiment measurements of snow and rain from the winters of 2019 and 2020 provided continuous automated measurements of precipitation rate, snow density, and visibility. Measured hydrometeor size distributions agree well with canonical results described in the literature.

Effect of phase dispersivity and grain size on hardness of steel vessels at outlet of rolling-press line

The hot production technology of round vessels made of 50 steel on rolling-press line is studied. It is shown that processing by cooled deforming tool leads to uneven distribution of temperature and phase composition along the height of the vessels metal. Oil quenching did not allow the uniformity of structure and hardness to be formed in the unevenly heated metal of the vessels. The study of the microstructure and its phase components made it possible to establish the reasons for the deviations of the hardness along the height, measured by Rockwell method in the bottom and top parts of vessel about 32 and 24 HRC respectively.

3D Transient Spray Cooling Heat Transfer Simulation for Metallic Slabs of Various Alloys

Water spray cooling is widely used in many industrial processes to control the surface dissipation of a material ported at high temperatures. To predict heat transfer and obtain the rate of required temperature distributions of the surface, it is necessary to understand the basic spray cooling dynamics and a more precise estimation of the heat transfer rate. This paper is about a three-dimensional simulation to estimate the transient heat transfer obtained locally by water spray to reduce the temperature of heated metal. The use of water spraying is a practical and flexible process. It is possible to vary, in space, time, and in large proportions the flux of extracted heat and controls the density of the flow of water which is a key element and very simple to achieve. Globally, the aim of this study is to simulate the spray cooling of different metal slabs for various alloys (steel, cast iron, titanium, nickel) by mainly comparing cooling in maps of iso-surfaces and in curves (at starts and globally) obtained after estimation of the heat flux.