scholarly journals Device for calibration of low pressure gauges development

2002 ◽  
Vol 2 (4) ◽  
pp. 189-195
Author(s):  
Z.D. Nikitovic
Keyword(s):  
High Vacuum ◽  
Low Pressure ◽  
Calibration Procedure ◽  
Vacuum System ◽  
Molecular Collision ◽  
Gas Discharges ◽  
Dry Air ◽  
Vacuum Region ◽  
Set Up ◽  
Made In

Vacuum system set-up is presented and used for calibration of pressure gauges in the region of rough vacuum, from 103 mbar to 10-1 mbar, with dry air. The capacitance manometer is used for the calibration of piezoresistant manometer, oil, mercury and mercury micrometers U manometers. The applicability of the experimental set-up and obtained results for the low pressure gauges calibration in the medium and high vacuum region is approved. It was shown how calibration of some cheaper pressure gauges might be performed and reliable measurements of the pressure may be made in the region that is of interest for atomic and molecular collision physics and low-pressure gas discharges. It was also shown that mentioned calibration procedure could be used for calibration of different U manometer types in order to renormalize older atomic and molecular collision data.

The design and study of a compact bakeable ultra-high vacuum system for calibrating absolutely low pressure gauges

Vacuum ◽  
1977 ◽  
Vol 27 (9) ◽  
pp. 511-517 ◽  
Author(s):  
K.J. Close ◽  
R.S. Vaughan-Watkins ◽  
J Yarwood
Keyword(s):  
High Vacuum ◽  
Low Pressure ◽  
Ultra High Vacuum ◽  
Vacuum System

Replication of Wet Objects and Cells

1974 ◽  
Vol 32 ◽  
pp. 102-103
Author(s):  
S. Basu ◽  
D. F. Parsons
Keyword(s):  
Water Vapor Pressure ◽  
High Vacuum ◽  
Polystyrene Latex ◽  
Vacuum System ◽  
Saturated Water Vapor ◽  
Replication Method ◽  
New Methods ◽  
Saturated Water ◽  
Water Vapors ◽  
Intermediate Chamber

We are approaching the invasiveness of cancer cells from the studies of their wet surface morphology which should distinguish them from their normal counterparts. In this report attempts have been made to provide physical basis and background work to a wet replication method with a differentially pumped hydration chamber (Fig. 1) (1,2), to apply this knowledge for obtaining replica of some specimens of known features (e.g. polystyrene latex) and finally to realize more specific problems and to improvize new methods and instrumentation for their rectification. In principle, the evaporant molecules penetrate through a pair of apertures (250, 350μ), through water vapors and is, then, deposited on the specimen. An intermediate chamber between the apertures is pumped independently of the high vacuum system. The size of the apertures is sufficiently small so that full saturated water vapor pressure is maintained near the specimen.

Vacuum System to Minimize the Specimen Contamination of High-Performance EM

1977 ◽  
Vol 35 ◽  
pp. 68-69
Author(s):  
N. Yoshimura ◽  
K. Shirota ◽  
T. Etoh
Keyword(s):  
Electron Microscope ◽  
High Speed ◽  
High Performance ◽  
High Vacuum ◽  
Vacuum System ◽  
Pump System ◽  
Pumping System ◽  
Diffusion Pump ◽  
Almost All ◽  
Cascade Type

One of the most important requirements for a high-performance EM, especially an analytical EM using a fine beam probe, is to prevent specimen contamination by providing a clean high vacuum in the vicinity of the specimen. However, in almost all commercial EMs, the pressure in the vicinity of the specimen under observation is usually more than ten times higher than the pressure measured at the punping line. The EM column inevitably requires the use of greased Viton O-rings for fine movement, and specimens and films need to be exchanged frequently and several attachments may also be exchanged. For these reasons, a high speed pumping system, as well as a clean vacuum system, is now required. A newly developed electron microscope, the JEM-100CX features clean high vacuum in the vicinity of the specimen, realized by the use of a CASCADE type diffusion pump system which has been essentially improved over its predeces- sorD employed on the JEM-100C.

A Freeze Shadow Technique for the Preparation of Soft Paint Latexes for Electron Microscopy

1977 ◽  
Vol 35 ◽  
pp. 314-315
Author(s):  
Earl R. Walter ◽  
Glen H. Bryant
Keyword(s):  
Sample Preparation ◽  
High Vacuum ◽  
Vacuum System ◽  
Latex Particles ◽  
New Methods ◽  
Diffusion Pump ◽  
Film Forming ◽  
Routine Basis ◽  
Distribution Studies ◽  
Preparation Techniques

With the development of soft, film forming latexes for use in paints and other coatings applications, it became desirable to develop new methods of sample preparation for latex particle size distribution studies with the electron microscope. Conventional latex sample preparation techniques were inadequate due to the pronounced tendency of these new soft latex particles to distort, flatten and fuse on the substrate when they dried. In order to avoid these complications and obtain electron micrographs of undistorted latex particles of soft resins, a freeze-dry, cold shadowing technique was developed. The method has now been used in our laboratory on a routine basis for several years.The cold shadowing is done in a specially constructed vacuum system, having a conventional mechanical fore pump and oil diffusion pump supplying vacuum. The system incorporates bellows type high vacuum valves to permit a prepump cycle and opening of the shadowing chamber without shutting down the oil diffusion pump. A baffeled sorption trap isolates the shadowing chamber from the pumps.

Majolica in the Early Colonial Andes: The Role of Panamanian Wares

2001 ◽  
Vol 12 (1) ◽  
pp. 45-58 ◽  
Author(s):  
Ross W. Jamieson
Keyword(s):  
Spanish Colonial ◽  
Important Indicator ◽  
The Andes ◽  
Early Colonial ◽  
The Pacific ◽  
Elite Status ◽  
Set Up ◽  
The City ◽  
Made In

As one of the most common artifact categories found on Spanish colonial sites, the wheel-made, tin-glazed pottery known as majolica is an important chronological and social indicator for archaeologists. Initially imported from Europe, several manufacturing centers for majolica were set up in the New World by the late sixteenth century. The study of colonial majolica in the Viceroyalty of Peru, which encompassed much of South America, has received less attention than ceramic production and trade in the colonial Caribbean and Mesoamerica. Prior to 1650 the Viceroyalty of Peru was supplied with majolica largely produced in the city of Panama Vieja, on the Pacific. Panama Vieja majolica has been recovered from throughout the Andes, as far south as Argentina. Majolica made in Panama Vieja provides an important chronological indicator of early colonial archaeological contexts in the region. The reproduction of Iberian-style majolica for use on elite tables was symbolically important to the imposition of Spanish rule, and thus Panamanian majolicas also provide an important indicator of elite status on Andean colonial sites.

scholarly journals A Selective Solar Absorber for Unconcentrated Solar Thermal Panels

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 900
Author(s):  
Davide De Maio ◽  
Carmine D’Alessandro ◽  
Antonio Caldarelli ◽  
Daniela De Luca ◽  
Emiliano Di Gennaro ◽  
...  
Keyword(s):  
Fossil Fuels ◽  
High Vacuum ◽  
Optimization Procedure ◽  
Energy Transition ◽  
Spectral Emissivity ◽  
Thermal Conversion ◽  
Stagnation Temperature ◽  
Solar Absorber ◽  
Analytical Formulas ◽  
Set Up

A new Selective Solar Absorber, designed to improve the Sun-to-thermal conversion efficiency at mid temperatures in high vacuum flat thermal collectors, is presented. Efficiency has been evaluated by using analytical formulas and a numerical thermal model. Both results have been experimentally validated using a commercial absorber in a custom experimental set-up. The optimization procedure aimed at obtaining Selective Solar Absorber is presented and discussed in the case of a metal dielectric multilayer based on Cr2O3 and Ti. The importance of adopting a real spectral emissivity curve to estimate high thermal efficiency at high temperatures in a selective solar absorber is outlined. Optimized absorber multilayers can be 10% more efficient than the commercial alternative at 250 °C operating temperatures, reaching 400 °C stagnation temperature without Sun concentration confirming that high vacuum flat thermal collectors can give important contribution to the energy transition from fossil fuels to renewable energy for efficient heat production.

scholarly journals Set-up of a high-resolution 300 mK atomic force microscope in an ultra-high vacuum compatible 3He/10 T cryostat

2016 ◽  
Vol 87 (7) ◽  
pp. 073702 ◽  
Author(s):  
H. von Allwörden ◽  
K. Ruschmeier ◽  
A. Köhler ◽  
T. Eelbo ◽  
A. Schwarz ◽  
...  
Keyword(s):  
High Resolution ◽  
Atomic Force Microscope ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Atomic Force ◽  
Set Up

Effect of Nanosized Filler on Matrix Dominated Properties of Fiber Reinforced Epoxy

2011 ◽  
Author(s):  
Yuanxin Zhou ◽  
Shaik Jeelani
Keyword(s):  
Compression Strength ◽  
High Speed ◽  
High Vacuum ◽  
Trapped Air ◽  
Nano Fiber ◽  
Open Hole ◽  
Set Up ◽  
Mechanical Agitator ◽  
Laminar Shear ◽  
Nanosized Filler

In this study, a high-intensity ultrasonic liquid processor was used to obtain a homogeneous molecular mixture of epoxy resin and carbon nano fiber. The carbon nano fibers were infused into the part A of SC-15 (diglycidylether of Bisphenol A) through sonic cavitations and then mixed with part B of SC-15 (cycloaliphatic amine hardener) using a high-speed mechanical agitator. The trapped air and reaction volatiles were removed from the mixture using high vacuum. Nanophased epoxy with 2 wt.% CNF was then utilized in a vacuum assisted resin transfer molding (VARTM) set up with carbon fabric to fabricate laminated composites. The effectiveness of CNF addition on matrix dominated properties of composites has been evaluated by compression, open hole compression and inter-laminar shear. The compression strength, open hole compression strength and ILS were improved by 21%, 23% and 15%, respectively as compared to the neat composite.

Sign in / Sign up

Export Citation Format

Share Document