Promising Designs of Vacuum System Jet Apparatuses

A novel route to compact, high performance pumping in UHV–XHV vacuum systems

A new steady-state apparatus is designed and constructed for the measurement of thermal conductivity (up to 25 W/mK) on a square specimen (300 mm side) with a heating temperature range from 30 °C to 900 °C. A vacuum container, of which the pressure can reach to 1 Pa, is also built for materials which can be easily oxidized. The structure of the facility is different from that of traditional steady-state devices, especially for the design of heating plate and heat sink. To verify the temperature uniformity of the heating plate, a simulation analysis is carried out in this paper. Besides, the heating system, the heat sink, the measuring system, and the vacuum system are presented in detail. In addition, the thermal conductivities of a heat insulation tile, 304L stainless steel, n-docosane, and erythritol are measured by this apparatus. Finally, an uncertainty analysis is discussed depending on different temperatures and materials.

We report on the trapping of single Rb atoms in tunable arrays of optical tweezers in a cryogenic environment at $\sim 4$ K. We describe the design and construction of the experimental apparatus, based on a custom-made, UHV compatible, closed-cycle cryostat with optical access. We demonstrate the trapping of single atoms in cryogenic arrays of optical tweezers, with lifetimes in excess of $\sim6000$ s, despite the fact that the vacuum system has not been baked out. These results open the way to large arrays of single atoms with extended coherence, for applications in large-scale quantum simulation of many-body systems, and more generally in quantum science and technology.

Upgrading of the equipment for hydro-mechanical processing of raw meats is important both in terms of ensuring the proper profitability of production and in terms of providing consumers with valuable protein meat products of excellent taste. Salting of raw meats, which is related to hydro-mechanical processing, is a complex process embracing mass exchange, transformations of protein and other substances, changes in the water-holding capacity of meat, changes in its microstructure, etc. There are different approaches to the machine and apparatus design and technological modes of hydro-mechanical processing of raw meats. Meat massagers / tumblers used in industry are equipped with devices for cooling and vacuuming the working space. Active research is being conducted to determine the rational duration of work / standstill during processing of raw materials in a drum. For beef, it is recommended to use the mode of alternating 30 min of work with 30 min of standstill for 8-12 h or other modes. The purpose of the article is to present and logically substantiate the results of studies of massaging the processing of meat raw materials in the drum of the massager under different modes of technological processing. Massaging of raw meats was carried out using a laboratory unit for wet salting of meat raw materials (drum massager) Ya5-FMS of our own design. Rheological characteristics were determined using an electromechanical universal testing machine SANS CMT2503. The duration of salting of raw meats depends on their type and quality characteristics, morphological composition, pH, degree of autolysis, mass and shape of meat cuts, quantity, quality and temperature of brine, as well as on the efficiency of the equipment used. Even more effective penetration of curing ingredients is achieved by using a pulsating vacuum, in which the processed meat raw materials are exposed to alternating loads: atmospheric pressure – vacuum. An increase in the intensity of hydro-mechanical processing of raw meats causes corresponding changes in the structure of muscle fibers – their swelling, the occurrence or increase of transverse-slit integrity violations, disruption of membrane structures, loosening and swelling of myofibril proteins. All of the above indicates that the use of pulsating vacuum and drum cooling not only improves, but also significantly accelerates the process of wet salting of raw meats raw materials in the production of ham products. The use of vacuuming in general and pulsating vacuuming in particular contributes to the intensification of the process of wet salting of raw meats. Therefore, the use of massagers with cooling and a pulsating vacuum system is an optimal design solution in terms of product quality and acceptable production profitability for meat processing enterprises.

We describe an experiment in nuclear-isotope mass spectroscopy, suitable for an advanced physics laboratory, which utilizes a relatively inexpensive commercial 60°-dipole residual gas analyzer. Students measure the terrestrial abundance of the isotope Ne22 relative to Ne20 and compare this with recent measurements of this ratio in meteorites. These ratios provide clues to the astrophysical sites, astrophysical processes, and nuclear reactions which formed these isotopes. The mass spectrometer is also used as a residual gas analyzer to examine the gas composition (O2, N2, H2O,…) at various pressures in a typical vacuum system. This gives students insight into the design of vacuum apparatus including the optimal selection of components such as vacuum pumps for particular applications.

Design and Analysis of Experimental Setup for Hydrogen PPM Measurement

Although several research groups have studied the formation of H2 on interstellar dust grains using surface science techniques, few have explored the formation of more complex molecules. A small number of these reactions produce molecules that remain on the surface of interstellar dust grains and, over time, lead to the formation of icy mantles. The most abundant of these species within the ice is H2O and is of particular interest as the observed molecular abundance cannot be accounted for using gas-phase chemistry alone. This article provides a brief introduction to the astronomical implications and motivations behind this research and the requirement for a new dual atomic beam ultrahigh vacuum (UHV) system. Further details of the apparatus design, characterisation, and calibration of the system are provided along with preliminary data from atomic O and O2 beam dosing on bare silica substrate and subsequent temperature programmed desorption measurements. The results obtained in this ongoing research may enable more chemically accurate surface formation mechanisms to be deduced for this and other species before simulating the kinetic data under interstellar conditions.