Bayesian estimate of system availability for consecutive k-out-of-n:F system

In the efficient design and functionality of complex systems, redundancy problems in systems play a key role. The consecutive-k-out-of-n:F structure, which has broad application in street light arrangements, vacuum systems in an accelerator, sliding window detection, relay stations for a communication system. Availability is one of the significant measures for a maintained device because availability accounts for the repair capability. A very significant feature is the steady-state availability of a repairable device. For the repairable consecutive k-out-of-n:F system with independent and identically distributed components, the Bayesian point estimate (B.P.E) of steady-state availability under squared error loss function (SELF) and confidence interval are obtained.

Study on the Calculation Method for Pumping Process in as Vacuum System

The calculation methods for vacuum system pumping were usually based on some simple theoretical models, the corresponding results had significant deviations from actual situations. In this study, medium and low vacuum systems (including vacuum chambers, pipes and pumps) were taken as research objects. With a measured vacuum system, and relationship between pump’s suction flowrate and inlet pressure, a new calculation method for vacuum pumping time was proposed, in which laminar or turbulent model was selected according to the pipeline’s flow state. New and traditional laminar method were used to calculate the pumping process of the measured system, which found that in the middle and high pressure stage, the pipeline flow was in turbulent state and the resistance was non-negligible. If the influence of turbulence was ignored, the calculated pressure drop would be faster than actual situation. The calculation result was verified by actual measurement result, indicating that new method is practical for vacuum pumping time calculation.

Transportation of Sulfuric Acid with Vacuum Unit

In the chemical industry, for example, in the production of sulfuric acid and the movement of sulfur recovered in refineries, the temperature of liquid substances can vary widely. The study of the effect of aggressive liquid temperature and concentration on the productivity and energy efficiency of vacuum systems for transporting liquids has been carried out. The performance (dry air pumping rate) and the consumed power of the vacuum pump ZhVN-12N depending on the pressure in the working chamber are considered. The correction coefficients of productivity for pumping out humid air have been determined for different temperatures. The performance indicators of a vacuum system for transporting liquids based on ZhVN-12N have been investigated. It was found that an increase in the temperature of the pumped humid air increases the average productivity of the vacuum system for transporting liquids, reducing its energy consumption. It is shown that an increase in the sulfuric acid solution concentration results in a decrease in productivity and an increase in the energy consumption of the vacuum system, while the efficiency decreases slightly.

Influence of Voltage Sags on the Continuity of the Operation and Lifespan of Single-Phase Industrial Robots

Due to the increase in the number of automated processes that employ industrial robots (especially in industrial and laboratory environments, including vacuum systems), and the resulting increase in the number of unresolved service requests, the purpose of the authors’ research was to confirm the occurrence of disturbances in the form of voltage sags that are not recorded by automation systems and which lead to the destruction of robots or their equipment in areas defined by the characteristics of ITIC/SEMI F47 and CBEMA as being free from such disturbances. The article also describes the environmental classification of robots by their process functionalities/features, and recommends equipment that is able to compensate for these disturbances. Such a classification approach can be an excellent tool for building an exploitation culture and assist the conscious selection of electrical equipment in robotised systems susceptible to disturbances (e.g., robots in load-lock in vacuum environment).

Use of vacuum systems for early implant-associated infection after decompression and stabilization surgery for lumbar spinal stenosis

Objective. To analyze the results of treatment of patients with implant-associated surgical site infection after decompression and stabilization surgery performed for lumbar spinal stenosis.Material and Methods. Results of treatment of 43 patients with early (up to 90 days after the operation) suppuration of the surgical wound after decompression and stabilization operations for lumbar spinal stenosis were analyzed.Results. A total of 4033 operations for lumbar spinal stenosis with implantation of stabilization systems were performed from 2015 to 2019. There were 43 (1.06 %) cases of early suppuration of the surgical wound with the installed instrumentation. Out of them seven (16.27 %) cases were superficial and 36 (83.78 %) – deep. In all cases, the wound revision, surgical debridement and installation of a vacuum assisted closure (VAC-dressing) were performed. The treatment of superficial suppuration was accompanied by a single installation of a VAC-dressing before wound closure, and in deep suppuration from 2 to 8 (on average 4.10 ± 1.73) VAC-dressings were changed. Wound healing was achieved in all patients within 14–55 (average 29.10 ± 10.06) days. Timely diagnosis of the complication and application of negative pressure therapy allowed arresting the inflammatory process and preserving the implants in all patients with a follow-up period of 12 months.Conclusion. In the case of development of early suppuration of the surgical wound, the patient needs an urgent sanitizing operation. Negative pressure treatment with VAC-dressings is an effective and safe way to relieve this complication. This method combined with etiotropic antibiotic therapy makes it possible to quickly cleanse and heal the wound while preserving the implanted instrumentation.

The photon beamline vacuum system of the European XFEL

The photon beamline vacuum system of the European X-ray Free-Electron Laser Facility (European XFEL) is described. The ultra-large, in total more than 3 km-long, fan-like vacuum system, consisting of three photon beamlines is an essential part of the photon beam transport. It is located between the accelerator vacuum system and the scientific instruments. The main focus of the design was on the efficiency, reliability and robustness of the entire system to ensure the retention of beam properties and the operation of the X-ray optics and X-ray photon diagnostics components. Installation started in late 2014, the first of the three beamline vacuum systems was commissioned in spring 2017, and the last one was operational in mid-2018. The present state and experience from the first years of operation are outlined.

The importance of lunar dust mitigation during future human led lunar missions

<p>With the Artemis mission set to launch in 2024, returning humans to the lunar surface for the first time in over half a century, it is imperative to ensure human health and safety on a variety of fronts. Lunar dust exposure is one of many areas of concern regarding astronaut health and safety. During the Apollo missions it was reported that lunar dust was a nuisance and induced allergic-like symptoms upon exposure. In addition, it was also reported that instruments became coated with dust that was difficult to remove, and that the dust adhered to everything and tore through space suit fabric. Numerous inhalation studies have determined that lunar dust is more toxic than analogous terrestrial materials but less so than silica dust. Apollo dust mitigation systems were successful on some missions but failed on others. As humans are to stay on the lunar surface for extended periods relative to the Apollo missions, it is vital to fabricate instruments that would address the lunar dust problem with greater reliability. There must be multiple steps to remove all lunar dust, including the ultra-fine <10 µm fraction which was the most difficult dust size to remove. There must be multiple steps regarding lunar dust removal including a chamber to remove dust and de-suit, and a vacuum with high level HEPA filtration to remove dust. The first chamber would be to filter out any dust that comes into the module from the outside. Once all the air is clear, then the next step would be to remove any remaining dust on the suits using a hand-held vacuum with a HEPA H14 filter which only allows up to a maximum 0.005% of particles 100 nm in size to pass through the filter. Then, it would be safe to de-suit. It would be wise to have a second chamber between the first chamber and the command center of the lunar module that would vacuum any remaining dust before opening to the main command chamber. Ultra-high quality HEPA filters of both the chamber and hand-held vacuum systems should be replaced frequently to maintain optimal dust mitigation. Investing time and resources into lunar dust mitigation should be a top priority for the upcoming Artemis mission to avoid the issues encountered on the Apollo missions.</p>