Pembuatan dan Karakterisasi Rochelle Salt Crystal

Rochelle Salt is the first synthesis Crystal made by Pierre Siegnette La Rocchelle in France. Rochelle Salt have several characteriztion one of them is piezoelectric effect where the crystal can change the kinetic energy to electrical energy instead this is the one of rewenable source altenative energy. Rochelle Salt can be made with tartar cream and washing soda reacted with distilled water as a solvent. The solution is reacted until there is no more reaction or supersaturation condition. Wait the solution for 2 days until the crystal seed appears. The crystal growth using the method of growing crystal in solution for 1 month until the crystal bigger enough for research to find the piezoelectric effect. Based on the result that have been obtained, Rochelle Salt have piezoelectric effect. Crystal hit using with wooden hitter and metal hitter, the voltage is increase when the crystal is hit by hitter. The piezoelectric also disappear along with time.

Production of single-crystal seeds [001] from nickeltungsten alloys by directional crystallization

The problem of obtaining priming materials from Ni-W alloys arose in connection with the development of technology for casting single-crystal turbine blades of gas turbine engines (GTE) from hightemperature alloys. This technology uses a seed method for producing single-crystal castings with a crystallographic orientation [001] using seedings from alloys of the Ni-W system with a melting point 120–140°C higher than the casting alloy. The use of such primers greatly simplifies the casting process of turbine blades with a single-crystal structure, increases its reliability both in pass-through furnaces of the PMP-2 type and in high-gradient furnaces of the UVNK-9A type. The article presents the results of the study of the influence of temperature-velocity parameters of directional crystallization, namely, the temperature gradient GZ on the structure of the obtained single-crystal seed blanks, as well as the study of effects of tungsten and carbon on the structure of single-crystal seed blanks, and makes recommendations for optimizing the technological process of single-crystal casting of Ni–W seed blanks adjusting the alloy composition for the seed blanks.

Globular pattern formation of hierarchical ceria nanoarchitecture

Dissipative structures often appear as an unstable counterpart of ordered structures owing to fluctuations that do not form a homogeneous phase. Even a multiphase mixture may simultaneously undergo one chemical reaction near equilibrium and another one that is far from equilibrium. Here, we observed in real time crystal seed formation and simultaneous nanocrystal aggregation proceeding from CeIV complexes to CeO2 nanoparticles in an acidic aqueous solution, and investigated the resultant hierarchical nanoarchitecture. The formed particles exhibited two very different size ranges. The hierarchically assembled structures in solutions were CeO2 colloids, viz. primary core clusters (1–3 nm) of crystalline ceria and secondary clusters (20–30 nm) assembled through surface ions. Such self-assembly is widespread in multi-component complex fluids, paradoxically moderating hierarchical reactions. Stability and instability are not only critical but also complementary for co-optimisation around the nearby free energy landscape prior to bifurcation.

Understanding the Reaction Crystallization Process of Glycidyl Trimethyl Ammonium Chloride

Reaction crystallization to produce glycidyl trimethyl ammonium chloride (GTA) via epichlorohydrin with gas-state trimethylamine was investigated. The crystallization process of the GTA gas-liquid reaction was optimized by a seed method. The optimized technology can prepare GTA products with crystal form and purity greater than 97%. The crystallization process of GTA consists of four steps (i.e., addition of seed, dispersion of seed, growth of crystals on the seed surfaces, agglomeration and growth of crystal). Seed method and flow rate are the key factors affecting purity. The purity and particle size of GTA crystals were satisfactory as long as the operation was kept within the defined envelope. The experiments were conducted on a 1 L reactor and successfully scaled-up to 3000 L in industry.

INFLUENCE OF CRYSTAL SEED TECHNIQUE ON RHEOLOGICAL PROPERTIES OF SUCROSE-FREE CHOCOLATE MASSES

Темперирование шоколадных масс – это процесс, обеспечивающий кристаллизацию какао масла в устойчивой β-модификации во избежание жирового поседения готового изделия. Приведены результаты исследований по применению затравочных кристаллов βV-формы при темперировании шоколадной массы с сахарозаменителями инулином и комплексом инулин–стевиозид взамен сахарозы. Установлено, что кристаллы βV-формы обеспечивают получение шоколадной массы с устойчивой β-модификацией какао масла вне зависимости от типа подсластителя. Определены оптимальные режимы процесса затравки кристаллов βV-формы в технологии получения шоколадной массы. Изучено влияние синергизма способа внесения затравки и типа подсластителя на структурно-механические свойства шоколадной массы. Показано, что твердость и реологические параметры шоколадной массы с сахарозаменителями по технологии с затравкой кристаллами βV-формы соответствовали аналогичным параметрам шоколадных масс, изготовленным со стадией традиционного темперирования, при значительном снижении длительности технологического процесса. Tempering chocolate masses is a process that ensures the crystallization of cocoa butter in a stable β-modification in order to avoid fatty bloom of the finished product. Presents the results of studies on the use of βV-form seed crystals in tempering chocolate mass with sweeteners inulin and inulin-stevioside complex instead of sucrose. It was found that crystals of the βV-form provide a chocolate mass with a stable β-modification of cocoa butter, regardless of the type of sweetener. The optimal modes of the process of seed crystals of βV-form in the technology of obtaining chocolate mass have been determined. The influence of the synergy of the method of introducing seeding and the type of sweetener on the structural and mechanical properties of the chocolate mass was studied. It is shown that the hardness and rheological parameters of the chocolate mass with sweeteners using technology with seeding of the βV-form crystals correspond to the same parameters chocolate mass technology with a traditional tempering stage with a significant reduction in the duration of the process.

Growth Diamond on an Impact Lonsdaleite-bearing Diamond from the Popigai Astrobleme

The Popigai astrobleme contains huge reserves of diamonds with unusual properties. In impact diamonds from the Popigai astrobleme, the cubic phase and lonsdaleite are intergrown. In order to study the relationship of lonsdaleite-bearing impact diamonds with diamond, an experimental study of the features of diamond growth on lonsdaleite-bearing fragments was carried out. The experiments were carried out on a high-pressure apparatus of the “BARS” type at 5.5 GPa and 1450 ° C in the Fe-Ni-C system (nickel 36 wt.%). Impact Popigai diamonds were used as seed crystals. As a result of the study, it was found that the newly formed crystals are represented by a cubic phase, while the lonsdaleite in the seed crystals was preserved and the lonsdaleite / diamond ratio did not change. The newly formed cubic diamond in its main properties (Raman spectra, morphology, color, etc.) corresponds to synthetic diamonds grown in the iron-nickel system. The difference between the growth of crystals on seeds of impact diamonds and growth on a single-crystal seed of diamond was that the nucleation of crystals began from different points of the seed of the impact diamond. Multi-headed growth was observed and, as a result, an intergrowth of diamond crystals was formed. Probably, the initial misorientation of the points of nucleation of subindividuals leads to multi-headed growth of crystals in an intergrowth, in contrast to single-crystal growth of diamond on a single- crystal seed.