Similarities and differences in the construction of dispersion laws for charge carriers in semiconductor crystals and adiabatic potentials in molecules

Using the group theory and the method of invariants, it is shown how the vibronic potential can be written in a matrix form and the corresponding adiabatic potentials can be found. The molecule having $D_{3d}$ symmetry is considered herein as an example. The symmetries of normal vibrations active in Jahn-Teller's effect were defined. $E-E$ vibronic interaction was considered to obtain vibronic potential energy in a matrix form and thus the adiabatic potential. Significant differences are shown in the construction of a secular matrix $D(\vec{k})$ for defining a dispersion law for charge carriers in the crystals and the matrix of vibronic potential energy, which depends on the normal coordinates of normal vibrations active in Jahn-Teller's effect. Dispersion law of charge carriers in the vicinity of $\Gamma$ point of Brillouin zone of the crystal with $D_{3d}^2$ symmetry was considered as an example.Comment: 8 page

Internet of Things for Sustainable Human Health

The sustainable health IoT has the strong potential to bring tremendous improvements in human health and well-being through sensing, and monitoring of health impacts across the whole spectrum of climate change. The sustainable health IoT enables development of a systems approach in the area of human health and ecosystem. It allows integration of broader health sub-areas in a bigger archetype for improving sustainability in health in the realm of social, economic, and environmental sectors. This integration provides a powerful health IoT framework for sustainable health and community goals in the wake of changing climate. In this chapter, a detailed description of climate-related health impacts on human health is provided. The sensing, communications, and monitoring technologies are discussed. The impact of key environmental and human health factors on the development of new IoT technologies also analyzed

Internet of Things in Agricultural Innovation and Security

The agricultural Internet of Things (Ag-IoT) paradigm has tremendous potential in transparent integration of underground soil sensing, farm machinery, and sensor-guided irrigation systems with the complex social network of growers, agronomists, crop consultants, and advisors. The aim of the IoT in agricultural innovation and security chapter is to present agricultural IoT research and paradigm to promote sustainable production of safe, healthy, and profitable crop and animal agricultural products. This chapter covers the IoT platform to test optimized management strategies, engage farmer and industry groups, and investigate new and traditional technology drivers that will enhance resilience of the farmers to the socio-environmental changes. A review of state-of-the-art communication architectures and underlying sensing technologies and communication mechanisms is presented with coverage of recent advances in the theory and applications of wireless underground communications. Major challenges in Ag-IoT design and implementation are also discussed

High Temperature Magnetic and Thermal Properties of (PbySn1−y)2P2S6(Pb_ySn_{1-y})_2P_2S_6 Chalcogenides

The results of study of Pb influence on high temperature magnetic and thermal properties of the chalcogenides $(Pb_ySn_{1-y})_2P_2S_6$ are presented. The increasing Pb content shifts phase transition to the ferroelectric state at about 337 K towards lower temperatures while magnetic field till 3 T has no influence on this transition. The measured susceptibility and magnetisation data are discussed

Tricritical Lifshitz point in the temperature-pressure-composition diagram for (PbySn1-y)2 P2(SexS1-x)6 ferroelectrics

The heat capacity of Sn2P2S6 ferroelectric crystals has been measured under quasihydrostatic pressures up to 0.7 GPa. The analysis of the heat-capacity and literature data for the birefringence shows that the tricritical point of Sn2P2S6 is in the 0.20–0.25 GPa range. Moreover, in the approximation of a linear change in the free-energy expansion coefficients, with respect to concentration and pressure, thermodynamic trajectories have been constructed for (PbySn1−y)2 P2(SexS1−x)6 solid solutions. We have thereby identified the region of the T-p-y-x diagram for (PbySn1−y)2 P2(SexS1−x)6 showing the tricritical Lifshitz point

Modeling and Improvement of Saddling a Stepped Hollow Workpiece with a Profiled Tool

A new technological process of forging massive stepped hollow rings has been investigated based on modeling. This process implies the saddling of a hollow blank with a stepped deforming tool. We have devised a procedure of experimental modelling based on the law of geometrical similarity. The procedure makes it possible to establish regularities of change in the shape of a hollow workpiece and in the formation of surface defects while deforming with a stepped tool. The varied parameter was a relative height of the ledge (diameter ratio) of the original workpiece. Based on the research results, we determined the taper of rings, which forms during forging in line with a new technique. The study involved blanks made of lead and steel.Modeling allowed us to determine that the deformation with a stepped tool could lead to the emergence of taper on a ring. These results can be explained by the fact that the process of deformation of the ledge of a hollow workpiece is accompanied by a more intense deformation of the ring in a tangential direction than in the ledge, due to the difference in thicknesses of the stepped hollow workpiece. An increase in the degree of ledge deformation leads to an increase in its diameter. Macrostructural investigation of the wall of a stepped ring has allowed us to establish that the process of forging a stepped hollow workpiece with a ledge die leads to the formation of a fibrous structure that coincides with the profile of the stepped part. Such a location of fiber rules out the possibility of its cutting in the process of machining. Based on the results from experimental modeling, it was determined that it becomes possible to forge stepped hollow rings, which extends the technical possibilities of saddling massive parts for responsible purpose

Determining the Deformed State in the Process of Rolling Conical Shells with A Flange

Obtaining conical shells by forging is an important and relevant task in energy and heavy engineering. Existing processes of their manufacture come down to simplifying the configuration of such billets. The result is the increased material's consumption while the internal fiber is cut during machining, which also leads to a decrease in mechanical properties. A new forging technique necessitated a study into the shape change of the billet and the distribution of deformations in the process of rolling. A finite-element method was used to investigate the process of rolling out the step hollow billets. Based on the study results, the forging's taper was established, obtained during the forging process. A research procedure involving the finite-element method was devised to study the operation of conical shells' rolling, which made it possible to determine a change in the shape and size of a hollow forging when rolled out by a step tool. A parameter has been proposed to quantify the formation of taper in the process of rolling a billet with a flange. Based on the study results, a step-wise distribution of the intensity of logarithmic deformities in the body of a forging was established when conical shells were rolled out. It was found that the step deformation leads to an increase in the uneven distribution of deformations on the part of the protrusion and ledge. Maximum deformations of 1.0...1.2 occur at the inner and outer surfaces of the step billet's protrusion. Dependences of the shape change in a step billet for the investigated ratios of sizes and rolling modes have been established. It was found that the maximum taper is obtained at a deformation degree of 15 %. It was determined that the degree of compression in the ledge and protrusion is leveled after 3 deformation runs of the step bille