A conduction-cooled stage for high-resolution Cryo-SEM

The goal is to examine with high resolution cryo-SEM aqueous particulate suspensions used in coatings for printable paper. A metal-coating chamber for cryo-preparation of such suspensions was described previously. Here, a new conduction-cooling system for the stage and cold-trap in an SEM specimen chamber is described. Its advantages and disadvantages are compared to a convection-cooling system made by Hexland (model CT1000A) and its mechanical stability is demonstrated by examining a sample of styrene-butadiene latex.In recent high resolution cryo-SEM, some stages are cooled by conduction, others by convection. In the latter, heat is convected from the specimen stage by cold nitrogen gas from a liquid-nitrogen cooled evaporative heat exchanger. The advantage is the fast cooling: the Hexland CT1000A cools the stage from ambient temperature to 88 K in about 20 min. However it consumes huge amounts of liquid-nitrogen and nitrogen gas: about 1 ℓ/h of liquid-nitrogen and 400 gm/h of nitrogen gas. Its liquid-nitrogen vessel must be re-filled at least every 40 min.

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Analysis of the efficiency of hydrocarbon propellant cooling using liquid nitrogen and a combination of recuperative heat exchangers

Engineering Journal Science and Innovation ◽

10.18698/2308-6033-2020-3-1965 ◽

2020 ◽

Author(s):

A.A. Aleksandrov ◽

I.V. Barmin ◽

A.V. Zolin ◽

V.V. Chugunkov

Keyword(s):

Heat Exchanger ◽

Liquid Nitrogen ◽

Coming Out ◽

Heat Exchangers ◽

Cooling System ◽

Design Parameters ◽

Nitrogen Gas ◽

Double Pipe ◽

The Cost ◽

Pipe Heat

The paper describes the propellant cooling system using liquid nitrogen and a combination of recuperative heat exchangers, including sections of the double pipe heat exchanger and a twisted heat exchanger located in a tank with antifreeze, cooled by nitrogen gas coming out of the sections of the double pipe heat exchanger. Mathematical models of cooling processes for two variants of movement of propellant and liquid nitrogen in the channels of the double pipe heat exchanger sections are considered. Their using makes it possible to analyze the efficiency of propellant cooling operations depending on its mass, design parameters of the system tanks and heat exchangers, consumption characteristics of nitrogen and propellant, as well as to predict the required mass of liquid nitrogen and the time of propellant cooling during the operation of launching complex propellant-feed systems. Calculated dependences and simulation results of propellant and antifreeze cooling in a tank with a twisted heat exchanger are presented. The influence of variants of arranging propellant cooling processes and liquid nitrogen consumption on the efficiency of the cooling system is analyzed. Comparing to the available systems the capability of reducing the cost of liquid nitrogen are identified as well as reducing time of the propellant cooling operations by means of equipping launch complexes.

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A Liquid Nitrogen Cooled Stage for STEM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100052237 ◽

1974 ◽

Vol 32 ◽

pp. 444-445

Author(s):

Louis T. Germinario

Keyword(s):

Electron Microscope ◽

High Resolution ◽

Liquid Nitrogen ◽

Room Temperature ◽

Objective Lens ◽

Thermal Drift ◽

Specimen Holder ◽

Resolution Capability ◽

Focal Position

A liquid nitrogen stage has been developed for the JEOL JEM-100B electron microscope equipped with a scanning attachment. The design is a modification of the standard JEM-100B SEM specimen holder with specimen cooling to any temperatures In the range ~ 55°K to room temperature. Since the specimen plane is maintained at the ‘high resolution’ focal position of the objective lens and ‘bumping’ and thermal drift la minimized by supercooling the liquid nitrogen, the high resolution capability of the microscope is maintained (Fig.4).

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Compact counter-flow cooling system with subcooled gravity-fed circulating liquid nitrogen

Physica C Superconductivity ◽

10.1016/j.physc.2010.05.231 ◽

2010 ◽

Vol 470 (20) ◽

pp. 1895-1898 ◽

Cited By ~ 7

Author(s):

Yu. Ivanov ◽

A. Radovinsky ◽

A. Zhukovsky ◽

A. Sasaki ◽

H. Watanabe ◽

...

Keyword(s):

Liquid Nitrogen ◽

Cooling System ◽

Counter Flow

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High resolution, portable gamma spectrometer not requiring liquid nitrogen cooling for field use for nuclear security and safeguards applications

2008 IEEE Nuclear Science Symposium Conference Record ◽

10.1109/nssmic.2008.4775207 ◽

2008 ◽

Author(s):

A. Kh. Khusainov ◽

T. A. Antonova ◽

V. V. Lysenko ◽

V. G. Muratov ◽

A. M. Pirogov ◽

...

Keyword(s):

High Resolution ◽

Liquid Nitrogen ◽

Gamma Spectrometer ◽

Nuclear Security ◽

Liquid Nitrogen Cooling

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Design of a very low temperature induction motor for liquid nitrogen gas pump

2013 International Conference on Electrical Machines and Systems (ICEMS) ◽

10.1109/icems.2013.6713175 ◽

2013 ◽

Author(s):

Boem Jin Kim ◽

Ki Wook Lee ◽

Gwan Soo Park

Keyword(s):

Low Temperature ◽

Induction Motor ◽

Liquid Nitrogen ◽

Nitrogen Gas ◽

Temperature Induction ◽

Very Low Temperature

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CFD-Assisted Optimization of Chimneylike Flows to Cool an Electronic Device

Journal of Electronic Packaging ◽

10.1115/1.4002009 ◽

2010 ◽

Vol 132 (3) ◽

Cited By ~ 3

Author(s):

Varghese Panthalookaran

Keyword(s):

Heat Transfer ◽

Natural Convection ◽

Energy Efficient ◽

Electronic Device ◽

Cooling System ◽

Electronic Devices ◽

Cost Effective ◽

Transfer Rates ◽

Slot Opening ◽

Convection Cooling

Natural convection cooling provides a reliable, cost-effective, energy-efficient and noise-free method to cool electronic equipment. However, the heat transfer coefficient associated with natural convection mode is usually insufficient for electronic cooling and it requires enhancement. Chimneylike flows developed within the cabinets of electronic devices can provide better mass flow and heat transfer rates and can lead to greater cooling efficiency. Constraints in the design of natural convection cooling systems include efficiency of packing, aesthetics, and concerns of material reduction. In this paper, methods based on computational fluid dynamics are used to study the effects of parameters such as (1) vertical alignment of the slots, (2) horizontal alignment of slots, (3) area of slots, (4) differential slot opening, and (5) zonal variation in heat generation on natural convection cooling within such design constraints. Insights thus derived are found useful for designing an energy-efficient and ecofriendly cooling system for electronic devices.

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Measurement and Simulation of a Transonic Innovative Cooling System (ICS) for High-Temperature Transonic Gas Turbine Stages

Volume 3: Turbo Expo 2004 ◽

10.1115/gt2004-53712 ◽

2004 ◽

Cited By ~ 2

Author(s):

E. Go¨ttlich ◽

L. Innocenti ◽

A. Vacca ◽

W. Sanz ◽

J. Woisetschla¨ger ◽

...

Keyword(s):

Temperature Distribution ◽

Gas Turbine ◽

Turbine Blade ◽

Film Cooling ◽

Cooling System ◽

Leading Edge ◽

Numerical Comparison ◽

Blade Surface ◽

Trailing Edge ◽

Advantages And Disadvantages

Gas turbine design technology requires the development of transonic turbine stages capable of carrying high stage load and of handling hot gas temperatures at turbine inlet. A reliable cooling system is necessary to cope with shocks emanating from preceding blade rows and impinging on the blade especially in the leading edge region. In order to fulfill these requirements researchers at Graz University of Technology have been working on an Innovative Cooling System (ICS) since 1995. The ICS is able to cover large areas of the blade surface with an effective cooling film and to reduce the metal temperature without a shower head cooling arrangement at the leading edge and any trailing edge cooling air ejection. In this paper the authors present a numerical comparison of the ICS to a conventional modern film cooling system both implemented in the same industrial transonic gas turbine blade. An experimental determination of the adiabatic film cooling effectiveness distribution around the blades surface was necessary for the ICS because of its uncommon design. The measurements were done on a cylindrical blade in a linear cascade arrangement. An infrared camera system was used to determine the effectiveness of this newly designed cooling system by measuring the temperature distribution on the blade surface. Then a numerical simulation of heat transfer and of internal and external cooling for the turbine blade at test rig conditions was performed. The ICS showed a lower outer wall temperature distribution of the blade compared to a standard film cooling system. The heavily loaded leading edge as well as the trailing edge are well cooled. Further conclusions on the advantages and disadvantages of the ICS are drawn.

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