Synthesis of Chlorinated and Non-chlorinated Polyols from Model Cross-Metathesis Modified Triacylglycerols

Three pure triacylglycerols (TAG) containing decenoic acid (D), and stearic acid (S), were hydroxylated into chlorinated and non-chlorinated polyols and studied in detail. D is a fatty moiety that can result from the cross metathesis of small olefins with common vegetable oils such as soybean oil. A fundamental understanding relating chemical composition and derived structure, particularly the number and position of the hydroxyl groups, to physical properties was established allowing us to add some perspective to the growing body of knowledge on industrially relevant polyol and polyurethane systems produced with metathesis-modified TAG (MTAG). The hydroxyl value, crystallization and melting behaviors, thermal degradation behavior of the polyols were directly related to their peculiar shortened and primary functionality inherited from the parent MTAG. The effect of regiochemistry on the physical properties of the polyols was investigated with the chromatography fractions of the trichlorinated polyol of propane-1,2,3-triyl tris(dec-9-enoate), giving an unhindered insight into the role of short and terminal functionality of MTAG polyols that will help select the optimal isomer composition for designer polyurethane materials.     

The Standard Model of the Heterostructure for Microwave Devices

A methodology of the selection of the initial materials, architecture and synthesis of heterostructures based on domestic materials and technologies as applied to specific types of microwave components needs to be developed. As the nomenclature expands, the requirements on energy consumption, overall dimensions and weight, frequency range, noise, values of working temperatures, and other characteristics of microwave components have significantly increased. Specific examples of power amplifiers for various applications (wireless communication systems and location systems) are considered. It is shown that in order to implement such developments, it is necessary to apply modern methods of multilevel computer modeling using various methods of optimization and widely use the tested technical solutions. The final result of this development is the creation of a set of basic physical models of the heterostructures, including those based on the solution of optimized problems by choosing the initial material, substrate material, layer composition, their sequences, layer thicknesses, impurity contents, and their distribution by the layer thickness. All this makes it possible to form an acceptable level of mechanical stresses and high values of the electrophysical characteristics in the heterostructure. The initial data set in the form of a library of basic models of the heterostructures will make it possible to significantly accelerate the development of various microwave components and optoelectronic components in the system of instrument and technological design and improve the characteristics of the devices and economic rates.     

Factors associated with the likelihood of injury resulting from collisions between four-wheel drive vehicles and passenger cars

The specific effects of vehicular type on the likelihood of an injury occurring are relatively unexplored. This study sought to assess the relative risk of injury to occupants of four-wheel drive vehicles and their counterparts in passenger cars.Data for 1143 occupants from all of the 454 crashes in Oklahoma, in 1995 that involved a four-wheel drive vehicle were used. Multiple logistic regression analysis determined the association between potential predictive factors and vehicular injury. Odds ratios revealed occupancy in a passenger car to be a major predictor of the likelihood of injury. Other factors include the driver being female, driving too fast, travel on curved or level roadways, and being hit laterally or from the rear.     

Identifying key structural indicators of mechanical strength in networks of fat crystals

The mechanical properties of edible fats can be influenced by a series of factors, including the amount of solids, the polymorphism of the solid-state, as well as the microstructure of networks of polycrystalline particles created upon crystallization. This work demonstrates that for binary mixtures of the high-melting fraction of milk fat (HMF) with cocoa butter as well as for mixtures of HMF with the middle-melting fraction of milk fat, changes in the storage shear modulus (G′) are mostly controlled by the solid fat content (SFC), and the material’s microstructure. The SFC, in turn is a function of the phase behavior of the mixtures in the solid state. Experimental techniques used in the characterization of the different levels of structure are presented in this work. A model developed to explain mechanical properties of these materials taking into account all levels of structure is proposed. The polymorphism of the solid state did not seem to influence the mechanical properties of the fats, indicative of this material being structured as a network of weakly-attractive polycrystalline particles. Moreover, the mass fractal dimension of the network was closely related to the polymorphism of the solid state.     

Comparison of experimental techniques used in lipid crystallization studies

Four methods were used to monitor the crystallization behavior of anhydrous milk fat (AMF), milk fat triacylglycerols (MF-TAG), and MF-TAG plus diacylglycerols (MF-DAG). The crystallization process was monitored by measuring the solid fat content, turbidity, and scattering intensity of the crystallizing material, as well as by imaging using polarized light microscopy combined with digital image processing. In general, induction times followed the order MF-DAG>AMF>MF-TAG for all techniques. However, the absolute value for the induction times differed substantially; on average 3 min by microscopy, 7 min by light-scattering spectroscopy, 13 min by turbidimetry, and 25 min by pulsed nuclear magnetic resonance. Microscopic imaging coupled to image processing proved to be the most sensitive method, suitable for the study of early events in the crystallization of fats.     

Characterization of soapstock and deodorizer distillates of vegetable oils using gas chromatography

Soapstock and deodorizer distillates are complex lipid mixtures that are produced in significant amounts by the vegetable oil refining process. These mixtures contain components such as fatty acids, sterols, squalene and tocopherols that have important commercial value and therefore their characterization and quantification are of interest. We describe here the development of a simple gas chromatography (GC) method based on a silylation derivatization technique coupled with the use of a medium polar column to separate the different classes of fatty compounds in these waste streams. This method is suitable for GC coupled with either a flame ionization detector or a mass spectrometer.     

Lipid‐derived monoamide as phase change energy storage materials

One of the major shortcomings of current organic phase change materials (PCMs) is their relatively low melting points, typically below 80°C, which limits their integration into thermal energy storage (TES) systems. The present work was aimed at developing lipid‐derived PCMs with increased melting points which would be suitable for TES applications requiring higher melting points without compromising other key properties such as enthalpy. The introduction of an amide group into the structure of linear saturated fatty acids was used as a means to increase intermolecular interactions and therefore crystallization and melting points. A series of six linear monoamides with differing chain length and symmetry about the amide group were investigated for thermal stability, thermal transition, flow behavior, and crystal structure to establish the structure‐property relationships relevant to TES. The presence of the highly polar amide group in the aliphatic fatty acid–derived molecules resulted in notable improvement in performance compared with the analogous monofunctional molecules: Increases in melting points (79°C‐96°C) and high enthalpies of fusion (155‐201 J/g) were recorded. Fundamental relationships between structure, processing, and macroscopic physicochemical properties, never before elucidated, were revealed in the study. The study revealed a step‐like variation of macroscopic properties: a surprising outcome of the competition between intermolecular attractions, symmetry effects, and mass transfer limitations. The predictive structure‐function relationships established in this work will allow the straightforward engineering of monoamide architectures that can extend the range of organic PCMs and deliver thermal properties desirable for TES applications.     

Factors Determining the Relevance of Creating a Research Infrastructure for Synthesizing New Materials in Implementing the Priorities of Scientific and Technological Development of Russia

Russian Microelectronics - In the modern world, knowledge and advanced technologies determine the effectiveness of the economy, and they can radically improve the quality of life of people,...     

Mathematical Modeling of a Self-Learning Neuromorphic Network Based on Nanosized Memristive Elements with a 1T1R-Crossbar-Architecture

Russian Microelectronics - Artificial neural networks play an important role in the modern world. Their main field of application is the tasks of recognizing and processing images, speech,...     

Simulation of Hall Field Elements Based on Nanosized Silicon-on-Insulator Heterostructures

Russian Microelectronics - This article is devoted to the issues of numerical simulation of field Hall sensors (FHSs) based on the silicon-on-insulator (SOI) structure with two control gates. To...