Korolëv, Russia
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Ivanova L.D.,RAS Institute of Metallurgy | Petrova L.I.,RAS Institute of Metallurgy | Granatkina Y.V.,RAS Institute of Metallurgy | Mal'chev A.G.,RAS Institute of Metallurgy | And 4 more authors.
Inorganic Materials | Year: 2017

We have studied the thermoelectric properties of p-type Bi0.5Sb1.5Te3 and n-type Bi2Te2.4Se0.6 solid solutions prepared by vacuum hot pressing of mixtures of powders differing in particle size composition. The powders were prepared by mechanically grinding ingots and by ultrarapid melt cooling (melt spinning). Fracture surfaces of samples were examined by scanning electron microscopy. The samples consisted of large, layered particles of the major component (up to hundreds of microns in size) and small flakes (a few to tens of microns in size) of the component prepared by melt spinning. The microstructure of the materials was examined under an optical microscope. On grain boundaries in the p-type materials, we observed telluriumbased eutectic precipitates in the form of a white phase. In some of the n-type samples, the Bi2Te2.4Se0.6 solid solution was found to undergo ordering, resulting in the formation of the ternary compound Bi2Te2Se. The Seebeck coefficient, electrical conductivity, and thermal conductivity of the materials were measured in the temperature range 100–700 K. The addition of 40 wt % powder prepared by melt spinning to hot-pressed p-type samples was shown to have no effect on their thermoelectric figure of merit (ZT)max, which was 1.0 at 350 K. On the addition of 20 wt % powder prepared by melt spinning, we obtained (ZT)max = 1.1 at 550 K in a hot-pressed n-type sample. © 2017, Pleiades Publishing, Ltd.


News Article | February 22, 2017
Site: www.businesswire.com

NEW YORK--(BUSINESS WIRE)--Crystal & Company, a leading insurance brokerage firm headquartered in New York City with 11 regional offices across the country, announces that six of the firm’s esteemed brokers have been recognized for the 2017 Risk & Insurance Power Broker Awards. The renowned Power Broker Awards, bestowed by insurance industry publication Risk & Insurance, commend individuals who stand out among their peers in the areas of risk management and customer service. Risk & Insurance editors and reporters recognize brokers for their problem solving abilities, customer service standards and overall industry knowledge. “It’s an honor to have six of our colleagues recognized for such a prestigious award,” said James W. Crystal, Chairman and CEO of Crystal & Company. “It is a true testament to their capabilities as risk professionals and as dedicated, creative brokers who are able to stand out in a highly competitive insurance industry.” Crystal & Company is the home for talented insurance professionals: creative, committed to their clients and driven to deliver extraordinary results. The company drives the strategy and execution behind insurance and employee benefits programs for businesses that want to be smart about risk. Crystal & Company is the insurance brokerage of choice for leading financial institutions, corporations, and nonprofit organizations. Headquartered in New York City, the firm has 11 regional offices throughout the United States and is an equity owner of Brokerslink, a global broking company with members in more than 95 countries around the world. Visit www.crystalco.com.


Ivanova L.D.,RAS Institute of Metallurgy | Petrova L.I.,RAS Institute of Metallurgy | Granatkina Y.V.,RAS Institute of Metallurgy | Kichik S.A.,Crystal Ltd. | And 2 more authors.
Inorganic Materials | Year: 2015

Halide-doped n-type samples of the Bi2Te2.7Se0.3 solid solution have been prepared by hot-pressing melt-spun powders. The morphology of the powders and fracture surfaces of the hot-pressed samples have been examined by scanning electron microscopy, and the electrical conductivity, Seebeck coefficient, and thermal conductivity of the samples have been measured at room temperature and in the range 100-700 K. The thermoelectric properties of the samples have been compared to those of a sample prepared by extruding a mechanically ground ingot. The highest thermoelectric figure of merit of the materials obtained in this study is ZT ≃ 0.9. © 2015 Pleiades Publishing, Ltd.


Melnikov A.,National University of Science and Technology "MISIS" | Melnikov A.,Crystal Ltd.
Metal Powder Report | Year: 2016

Thermoelectric materials, which directly convert thermal energy into electricity, have become quite popular recently due to the development and world spreading of alternative power energy sources. Nowadays powder metallurgy methods are widely used for production of almost all types of thermoelectric (TE) materials, from low-temperature bismuth-telluride-based materials to high-temperature (operating above 1000K) Cu2-xSe alloys. Historically, crystallization methods were widely used in production [1], for example, Czochralski method, Bridgman method and zone melting method are the most common. However, in case of crystallized materials, we face one disadvantage that is weak mechanical properties. In TE devices working bodies in the devices are bulk TE materials with dimensions about millimeters, so they can be exposed to different shifts or tensile stresses. Therefore, powder metallurgy methods were used to improve mechanical strength, in particular, various sintering methods. Later, it was found that sintering from powders allows to reduce one significant parameter for thermoelectrics - thermal conductivity, and in the 2000s the propagation of powder technologies started over. © 2016 Elsevier Ltd.


Melnikov A.A.,National University of Science and Technology | Kostishin V.G.,National University of Science and Technology | Alenkov V.V.,Crystal Ltd.
Journal of Electronic Materials | Year: 2016

Real operating conditions of a thermoelectric cooling device are in the presence of thermal resistances between thermoelectric material and a heat medium or cooling object. They limit performance of a device and should be considered when modeling. Here we propose a dimensionless mathematical steady state model, which takes them into account. Analytical equations for dimensionless cooling capacity, voltage, and coefficient of performance (COP) depending on dimensionless current are given. For improved accuracy a device can be modeled with use of numerical or combined analytical-numerical methods. The results of modeling are in acceptable accordance with experimental results. The case of zero temperature difference between hot and cold heat mediums at which the maximum cooling capacity mode appears is considered in detail. Optimal device parameters for maximal cooling capacity, such as fraction of thermal conductance on the cold side y, fraction of current relative to maximal j′ are estimated in range of 0.38–0.44 and 0.48–0.95, respectively, for dimensionless conductance K′ = 5–100. Also, a method for determination of thermal resistances of a thermoelectric cooling system is proposed. © 2016 The Minerals, Metals & Materials Society


Melnikov A.A.,National University of Science and Technology "MISIS" | Tabachkova N.Y.,National University of Science and Technology "MISIS" | Kichik S.A.,Crystal Ltd. | Marakushev I.S.,Crystal Ltd. | And 2 more authors.
Journal of Electronic Materials | Year: 2015

The melt spinning technique is a process for obtaining materials based on ultrafast cooling and solidification of a melt in contact with a liquid-cooled rotating wheel. In this work, p-Bi0.5Sb1.5Te3 powders were obtained and compacted by spark plasma sintering at various temperature conditions, and the changes in their structural and dimensional characteristics were investigated. It is shown that the sintering temperature conditions significantly affect the structure of the material, causing active recrystallization processes even at short sintering times (5 min to 10 min). Material obtained in this work has slight preferential orientation of (0 0 1) planes perpendicular to the pressure axis, which disappears with increasing sintering time. Power factor values for all samples were greater for current direction perpendicular to the pressure axis, which corresponds to compacted nonspun material. It is shown that annealing in vacuum negatively affects the material, reducing the power factor for all current directions. © 2014, The Minerals, Metals & Materials Society.


Melnikov A.A.,National University of Science and Technology "MISIS" | Kostishin V.G.,National University of Science and Technology "MISIS" | Kichik S.A.,Crystal Ltd | Alenkov V.V.,Crystal Ltd
Journal of Nano- and Electronic Physics | Year: 2014

Thermoelectric melt spun p-Bi0,5Sb1,5Te3 powders were obtained and their structural properties were studied. It was established that the crystallites constituting the powder particles are nanofragmented. Powders were compacted by vacuum hot pressing and spark plasma sintering. Thermoelectric characteristics of obtained samples were investigated in 100 K-700 K temperature range. The samples prepared by above methods posses low thermal conductivity while retaining values of the Seebeck coefficient and electrical conductivity comparable to conventional crystallized materials, thereby thermoelectric efficiency ZT reaches 1.05-1.15 at 330-350 K. © 2014 Sumy State University.


NEW YORK--(BUSINESS WIRE)--Crystal & Company, a leading insurance brokerage firm headquartered in New York City with 11 regional offices across the country, is pleased to announce Sandy Crystal, Executive Vice President, and Linda Bourn, Executive Managing Director of Family Enterprise Risk Practice, will participate in the upcoming Family Wealth Report Fintech Summit. The summit, which will be held on February 28 in New York City, will highlight the role technology has played in the financial services industry and how family offices in particular can benefit from leveraging financial technologies. Presentations from a number of experts across industries will offer insight into the technological advantages and challenges family offices face as the fintech landscape evolves. Sandy leads the firm’s Financial Institutions Group and oversees the company’s commercial brokerage operations which consist of Commercial Insurance Services, Employee Benefits Services and the Management and Professional Risk Group. His panel will discuss how to mitigate potential cybersecurity threats that can affect digital family offices. Linda Bourn will leverage over 20 years of experience advising family businesses to explain the challenges, benefits and risks associated with the digital family office. “As a third-generation family owned and operated business, we at Crystal & Company understand the unique needs of family offices,” said Crystal. “We continue to adapt to a changing technology landscape, developing risk management services and tailoring solutions to meet our clients’ complex needs.” Crystal & Company is the home for talented insurance professionals: creative, committed to their clients and driven to deliver extraordinary results. The company drives the strategy and execution behind insurance and employee benefits programs for businesses that want to be smart about risk. Crystal & Company is the insurance brokerage of choice for leading financial institutions, corporations, and nonprofit organizations. Headquartered in New York City, the firm has 11 regional offices throughout the United States and is an equity owner of Brokerslink, a global broking company with members in more than 95 countries around the world. Visit www.crystalco.com.

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