Dry Vacuum Research Articles

Beyond Molecular Design: Cocrystallization in Hydrogen‐Bonded Organic Frameworks for Energy‐Conserving Dehydration and Real‐Time Luminescent Humidity Detection

ABSTRACTLuminescent probes attract increasing attentions for the unique superiorities like visually real‐time detecting. However, for optical humidity sensing, it is still quite challenging to attain facile dehydration/activation in sensing materials, due to the high polarity of water molecules, which limits their applications in real‐time detection and energy‐conserving applications. Here, we report two fluorescent hydrogen‐bonded organic frameworks (HOFs), HPISF‐H2O and TPISF. HPISF‐H2O achieves water absorption in low humidity, but needs an energy‐intensive step (heating to ∼92°C in air) to dehydrate. Conversely, despite only a hydroxyl group being replaced, TPISF cannot bind to H2O at all. In other words, real‐time detection is not readily achieved through straightforward molecular design. Therefore, we propose a cocrystallization strategy to adjust their water‐binding capacity. As a result, the HOF cocrystals are adjusted to have both good H2O absorptivity and very gentle desorbing operation without heating (dry gas blowing or vacuuming). Benefiting from this strategy, appreciable advantages for an effective humidity sensor are realized, including real‐time detection (second‐scale response/recovery) and distinguishing fluorescence variation. Efficient sensing across a broad relative humidity (RH) range (10.0%–80.0%) was further achieved. Moreover, the mechanistic insight of fluorescent sensing was ascertained through detailed analyses of structural transformation, spectroscopic data, and theoretical approach.

Design of toothed belt driven screw vacuum pumps

Abstract Most screw vacuum pumps use oil-lubricated gears for timing of the rotors. An alternative is a toothed belt to drive and synchronise the screw rotors. In combination with grease-lubricated bearings this drive concept allows the design of completely oil-free pumps. However, belts are less accurate in terms of timing, hence the design of efficient pumps is challenging. In this paper, the development of a new series of belt driven dry screw vacuum pumps is discussed. It covers the overall pump concept including cooling system, material selection and noise damping. Particular attention is paid to the design of the screw rotors with respect to the properties of the belt drive. It is shown that the disadvantage of the inaccurate timing and the need for wide rotor to rotor clearance can be overcome with a high number of wraps. Furthermore, it gives insight to applications and practical field experience.

Research on the influence of gas types on the pumping performance of dry Roots vacuum pump

With the advancement of technology, dry vacuum pumps are widely used in aerospace, semiconductor, chemical and pharmaceutical and scientific equipment due to their clean and oil-free advantages. Usually the pumped medium contains different types of gases, dry Roots vacuum pumps are prone to unstable performance, which can adversely affect process efficiency. To investigate the influence of gas types on the pumping performance of Roots vacuum pump, experimental research was conducted on self-designed dry vacuum pump theoretical verification platform and test pump. The gas mixture of 70 % nitrogen and 30 % helium was tested using 2-lobe, 3-lobe and 5-lobe Roots while numerical simulations were conducted on air, nitrogen, helium and hydrogen. The experimental results indicate that the gas type affects the pumping speed of the Roots pump. In addition, the numerical simulation results show that hydrogen has the greatest influence on the pumping performance of the Roots; the pumping speed shows ‘W’ type fluctuation in one cycle when the 3-lobe Roots pumps hydrogen. The pumping speed of the 5-lobe Roots is most affected by changes in gas types. This study is of guiding significance for the application and design of dry Roots vacuum pumps in different process environments.

Cold Spray Deposition of MoS2- and WS2-Based Solid Lubricant Coatings

The cold spray deposition technique has been used to produce a new class of solid lubricant coatings using powder feedstocks of the metal disulfides WS2 or MoS2, either pure or mixed with Cu and Ni metal powders. Friction and cycle lives were obtained using ball-on-flat reciprocating tribometry of coated 304 SS flats in dry nitrogen and vacuum at higher Hertzian contact stresses (Smax = 1386 MPa (201 ksi)). The measured friction and thickness of the coatings were much lower than for previous studies (COF = 0.03 ± 0.01 and ≤1 µm, respectively), which is due to their high metal disulfide:metal ratios. Cu-containing metal sulfide coatings exhibited somewhat higher cycle lifetimes than the pure metal sulfide coatings, even though the Cu content was only ~1 wt%. Profiling of wear tracks for coatings tested to 3000 cycles (i.e., pre-failure) yielded specific wear rates in the range 3–7 × 10−6 mm3N−1m−1, similar to other solid lubricant coatings. When compared to other coating techniques, the cold spray method represents a niche that has heretofore been vacant. In particular, it will be useful in many precision ball-bearing applications that require higher throughput and lower costs than sputter-deposited MoS2-based coatings.

Advancements in oxidative chemical vapor deposition (oCVD) with liquid oxidant: A true dry vacuum manufacturing approach for optoelectronic devices

Advancements in oxidative chemical vapor deposition (oCVD) with liquid oxidant: A true dry vacuum manufacturing approach for optoelectronic devices

Development of a Real-Time Anomaly Detection System for Dry Vacuum Pumps Using Low-Cost IoT Devices and Machine Learning

Development of a Real-Time Anomaly Detection System for Dry Vacuum Pumps Using Low-Cost IoT Devices and Machine Learning

Ultrasound-Assisted Extraction- and Liquid Chromatography-Based Method Development and Validation for Obtaining and Qualitative Determination of Apple Pomace Three Triterpene Acids using Analytical Quality by Design

Background: Apple pomace has garnered significant attention within the life sciences domain due to its underutilized status as a waste material from apple processing. It represents a cost-effective and abundant source of triterpene acids due to its multifunctional clinical, nutritional, and pharmaceutical benefits. Purpose: The present study aimed to develop and validate a new, selective, effective, robust and reproducible laboratory methodology based on extraction, purification and analytical procedures to obtain and determining three major triterpene acids – Ursolic acid (UA), Oleanolic acid (OA) and Betulinic acid (BA) into the dry extracted product from apple pomace. Method: A new, cost-efficient, rapid, selective and high-yield two-stage ultrasound-assisted extraction procedure was developed and the effect of critical parameters: ultrasonic power, extraction time, solvent volume, temperature, and the amount of raw material on the extraction process were investigated. The dry column vacuum chromatography technique was used for purification to remove unwanted non-polar and polar impurities from the target bioactive compounds; A new, effective, specific, sensitive, and rapid HPLC analytical procedure was developed using analytical quality by design (AQbD) approach and validated according to ICH guidelines. Conclusion: The method has a good accuracy (the mean recovery >95 %) and linearity (R2>0.999). The limit of quantitation (LOQ) is 0.0001 mg/mL for UA, 0.00005 mg/mL for OA and 0.000025 mg/mL for BA. The validation results confirm that the method is specific, precise and robust. The purity of the extracted and purified target product from apple pomace is not less than 93 %. The developed laboratory methodology is capable of being considered for industrial purposes and through the appropriate technology transfer process can be successfully transferred to the industrial scale.

Overview of Dry Sealed Vacuum Pump

Overview of Dry Sealed Vacuum Pump

Model EV-X, Dry Vacuum Pump for Middle Harsh Process

Model EV-X, Dry Vacuum Pump for Middle Harsh Process

Dry Vacuum Pump for General Industry Model SST/SSX

Dry Vacuum Pump for General Industry Model SST/SSX

Smart Vacuum Cleaning Robot

In today's fast-paced world, the demand for efficient and convenient household technologies continues to surge. Among these, smart vacuum cleaning robots have emerged as indispensable tools, promising automated cleaning solutions that integrate seamlessly into modern lifestyles. This abstract presents a comprehensive overview of a cutting-edge smart vacuum cleaning robot embedded system, featuring five key components for enhanced functionality. The system is anchored by an Arduino Nano-based model, leveraging the versatility and reliability of Arduino technology to orchestrate the robot's operations. Through a Bluetooth-operated interface facilitated by a dedicated mobile application, users can effortlessly control the robot's movements and cleaning schedules, offering unparalleled convenience and flexibility. Equipped with a dry vacuum cleaning system optimized for dust collection, the robot ensures thorough cleaning performance while minimizing maintenance hassles. Additionally, an ultrasonic sensor serves as a robust obstacle detector, enabling the robot to navigate intelligently and avoid collisions with furniture and other obstructions. Crucially, the entire system operates on a battery-powered module, granting the freedom to traverse various spaces without constraints imposed by traditional power sources. By synergizing these components, the proposed smart vacuum cleaning robot embedded system epitomizes the convergence of innovation and practicality, poised to revolutionize the landscape of home cleaning automation.

SF1: A Standardised Fraction of Clinacanthus nutans That Inhibits the Stemness Properties of Cancer Stem-Like Cells Derived from Cervical Cancer

Cancer stem cells (CSCs) are a small population of tumour cells that are responsible for tumour initiation, metastases, recurrence, and resistance to conventional therapy. Hence, targeting CSCs is crucial in the fight against cancer. SF1, a standardised fraction from Clinacanthus nutans leaf extract, has been reported to exhibit potent and selective antineoplastic effects against cervical cancer cells. In this study, the potential of SF1 to inhibit the stemness of cervical cancer stem-like cells has been evaluated. SF1 extraction was carried out using the dry column vacuum chromatography technique. SiHa cell lines were cultured as spheres in CSC-conditioned medium (cervospheres), and the IC50 of SF1 against cervospheres was determined using the OZBlue Cell Viability Kit. The effects of SF1 on the cervosphere’s stemness markers, including CD49f, CK17, SOX2, OCT4, and NANOG, were assessed using a flow cytometry assay. Self-renewal inhibition and anti-tumorigenesis effects of SF1 in cervospheres were evaluated using a sphere formation assay and a xenograft mouse model. The present study shows that SF1 treatment at an IC50 of 17.07 µg/mL inhibited the proliferation, self-renewal, and tumorigenic capacity of SiHa cervospheres in vitro and in vivo. A decrease in the expressions of CK17, SOX2, CD49f, and OCT4 in cervical CSCs indicated that SF1’s inhibitory effects were also associated with the suppression of stemness markers. These results suggest that SF1 possesses an antitumor effect against cervical CSCs and may be regarded as a promising approach to the development of targeted anticancer agents for cervical cancer.

Noise analysis of dry scroll vacuum pump based on experiment and CFD

The scroll vacuum pump is a dry vacuum pump with a wide range of applications. The radiated noise of a multi-stage scroll vacuum pump under different suction pressures is tested. The discharge velocity field is measured by the PIV technique. When the suction pressure changes from 101 kPa to 5 Pa, the average sound pressure level of the scroll pump decreases from 80.37 dB to 58.13 dB, which is reduced by 22.24 dB. The maximum and minimum sound power levels are 97 dB and 74.76 dB, respectively. The spectrum characteristics and the distribution law of radiated noise are analyzed. The measured noises at the rear of all operating conditions are the smallest, followed by the positions above the front part, and the next is the directly above position. Aeroacoustics is the main noise source in the scroll pump. Based on the CFD method, the simulation calculation is carried out at different suction pressures and the maximum simulation error is −5.7%. The location and formation mechanism of the aeroacoustics source are analyzed. In different working processes, the main excitation sources of aeroacoustics are different. The results are helpful to the noise source identification and aeroacoustics improvement of the scroll vacuum pump.

Influence of moisture on the ferroelectric properties of sputtered hafnium oxide thin films

While the influence of various fabrication parameters during deposition on the ferroelectricity of hafnium oxide has been extensively studied, the effect of different atmospheres on the actual switching process has not yet been investigated. In this work, we characterized the ferroelectric properties of undoped hafnium oxide prepared by reactive sputtering under three different atmospheres: dry oxygen/nitrogen, wet nitrogen, and vacuum conditions. We found a significant correlation between dry and wet atmospheres and resulting polarization. Specifically, we observed a direct effect on ferroelectric switching when the film was exposed to dry atmospheres and vacuum, resulting in a higher electric field necessary to initialize the wake-up effect due to an initial imprint effect. Increasing the amount of wet nitrogen during switching decreased the imprint and lowered the necessary voltage required for the wake up. We present a simple model that explains and discusses the incorporation of moisture and its resulting consequences on the ferroelectric properties of hafnium oxide. Additionally, kinetic Monte Carlo simulations showed that the addition of protons to the oxide thin film leads to a lowering of the potential and to a redistribution of protons and oxygen vacancies, which reduces the initial imprint.

Impact of fractional distillation on physicochemical and biological properties of oregano essential oil of Lippia graveolens H.B.K. grown wild in Mexico

The aim of this work was to evaluate the impact of fractional distillation on the physicochemical and biological properties of oregano essential oil obtained from Lippia graveolens H.B.K. Dry vacuum fractional distillation allowed the division of oregano essential oil into two distinct fractions. The first fraction was rich in ρ-cymene (45.32%) and γ-terpinene (19.14%), while the second fraction had enrichments on the phenolic thymol and carvacrol components (47.63% and 35.56%, respectively), reaching up to 83% of the total chemical composition. In addition, it was shown that fractionation influenced the biological properties of the essential oil. The fraction enriched on thymol and carvacrol showed a higher antioxidant activity than the complete oregano essential oil and the terpenic fraction, as measured by the DPPH method. Moreover, the phenolic fraction produced a concentration-dependent viability decrease on HeLa, Hep2 and A-549 cancer cell lines. The cytotoxic activity of the phenolic fraction was higher compared to that of complete oregano essential oil as well as that of the terpenic fraction. It can be concluded that dry vacuum fractional distillation is an effective separation method that could be used to rectify and improve the quality of oregano essential oils, making them more attractive in the market. As another benefit, the fractions generated could be used for different purposes. In practice, the terpenic fraction, for example, could be used in flavouring and fragrance industries. Regarding the phenolic fraction, new and deeper studies are needed to establish its potential use in food safety and pharmaceutical industries.

High-Speed Design with Separated Tapering for Reducing Cogging Torque and Torque Ripple of a 3 kW Dry Vacuum Pump Motor for the ETCH Process

This paper proposes a design method to reduce cogging torque and torque ripple in the concentrated winding of IPMSMs (Interior Permanent Magnet Synchronous Motors) used in motors for the semiconductor ETCH process. IPMSMs can utilize reluctance torque through the difference in inductance between the d axis and q axis, but they are at a disadvantage in terms of reducing cogging torque while tapering the rotor and stator to reduce torque ripple. In addition, the existing single tapering can push the permanent magnets into the rotor. If the rotor’s permanent magnets are embedded, the magnetic reluctance will increase, and the overall performance of the motor will decrease. However, an optimum design method was derived in which the magnets do not move during rotor tapering. This geometric design is an optimum design method that reduces cogging torque and torque ripple. This paper compares and analyzes four models, the concentrated winding model, distributed winding model, conventional tapering model, and separated tapering model, using 2D and 3D finite element analysis (FEA).

Research on pumping laws of different-shaped Roots rotors for multi-stage vacuum pump design

Multi-stage Roots dry vacuum pumps are widely used in the semiconductor industry, metallurgy, pharmaceuticals, solar photovoltaic, thin film equipment, and other such fields. There are many combinations of rotors from the inlet to the exhaust of the multi-stage Roots vacuum pump. Depending on the application process of the multi-stage Roots vacuum pump, different rotation and self-combination designs are required. Currently, the pumping characteristics of different rotor types of the multi-stage Roots dry vacuum pump are not clear, and the combined design of the multi-stage pump rotor cannot be supported. In order to realize the applicability analysis of different rotors in different pressure ranges, a vacuum pump test platform and an adjustable rotor Roots experimental pump were designed. The pumping performance and power consumption of two-lobe Roots rotors, three-lobe Roots rotors and five-lobe Roots rotors in different pressure ranges were tested in experiments, and the internal flow conditions of multi-stage pump exhaust stages were numerically simulated. The results demonstrate that considering the ultimate performance and power consumption, the two-lobe Roots rotors and the three-lobe Roots rotors are more suitable for the exhaust pressure range of 1–10,000 Pa. With the increase of the exhaust pressure, the pumping performance of the three-lobe Roots rotors begins to gradually improve, and the pumping performance has obvious advantages. When the exhaust pressure exceeds 50,000 Pa, the advantages of the five-lobe Roots rotors gradually become obvious. The five-lobe Roots rotors can better handle the process of direct exhaust to atmosphere. The research methods and conclusions adopted in this paper can provide a reference for the design of the rotor combination scheme of the multi-stage Roots dry vacuum pump.

Study the Effect of Operating Temperature on Performance in Dry Scroll Vacuum Pump

The dry scroll vacuum pump is a kind of variable capacity dry vacuum pump that is applied in chemical, pharmaceutical, semiconductor, and scientific instruments. Analyzing the thermodynamic characteristics of the scroll vacuum pump and studying the impact of operating temperature on its consistent performance are necessary for the design and application of the cooling system of the scroll vacuum pump. Based on the dynamics mesh method, the computational fluid dynamics (CFD) simulation model of a multi-stage dry scroll vacuum pump is established in this study. Under the suction pressure of 1000 Pa, the simulation calculation is carried out at different operating temperatures of fixed scrolls (25 °C, 45 °C, and 65 °C). The results show that the pumping speed, the gas compression power, and the energy efficiency ratio are significantly affected by different temperatures. The operating temperature of the pump has been reduced from 65 °C to 25 °C, the pumping speed is increased by approximately 5.97%, the gas compression power is increased by approximately 4.32%, and the energy efficiency ratio is increased by approximately 1.745%. This research provides a transient simulation method using dynamic mesh technology for the study of the dry scroll vacuum pump, and the results can provide a theoretical basis for the design and application of the cooling system of the dry scroll vacuum pump.

Report on Topical Meeting of Division of Vacuum Technologies, “The Latest Trend of Dry Vacuum Pumps”

Report on Topical Meeting of Division of Vacuum Technologies, “The Latest Trend of Dry Vacuum Pumps”

Development of Improved DNA Collection and Extraction Methods for Handled Documents

Handwritten documents may contain probative DNA, but most crime laboratories do not process this evidence. DNA recovery should not impair other evidence processing such as latent prints or indented writing. In this study, single fingermarks on paper were sampled with flocked swabs, cutting, and dry vacuuming. In addition, two extraction methods were compared for the sample type. DNA yields were low across all methods; however, this work confirms the ability to recover DNA from paper and the usefulness of the vacuum sampling method combined with the Chelex-Tween method. Stability of touch DNA deposits were compared over an 11-month period to better understand degradation that may occur over time. No significant difference in DNA recovery was observed, suggesting DNA deposits on paper are stable over an 11-month span.