Vacuum Line Research Articles

Development of a lab-based In situ XCT oven for vacuum-bag processing of prepreg laminates

Real-time 3D microstructure changes in prepreg laminates during curing was observed using widely available X-ray Computed Tomography (XCT) hardware at high temporal resolution (2 min) and spatial resolution (25 µm voxel size). The methodology was demonstrated in a cylindrical convection oven with an internal diameter of 100 mm, a heating rate of 2°C/min, a maximum operating temperature of 135°C, and an integrated vacuum line. The technique was applied to three representative carbon fibre reinforced epoxy prepreg samples having flat, tapered and corner geometries. The increasingly complex geometries lead to higher void mobility and thickness changes that were captured in 40-50 mm size samples. Image processing of the XCT data was enhanced by the use of deep learning semantic segmentation for feature extraction. Uninterrupted microstructure evolution was visualised in larger samples and more realistic processing conditions than previous lab-based In Situ XCT studies.

The Study Design of a Double-Action Plate Vacuum Pump

Rotary plate vacuum pumps have become widely used as a source of vacuum for milking systems. The main features of a plate vacuum pump include design simplicity, high efficiency, low cost and adaptability to climatic conditions. A plate vacuum pump requires the improvement of specific performance indicators. This refers to the indicator of specific productivity and specific energy intensity. It is possible to improve the vacuum pump by optimizing the design parameters and technological models of operation. The known studies allow the establishment of rational geometric parameters, the number of plates, the ratio of the main dimensions and eccentricity. However, the problem of reducing the degree of uneven air pumping from the vacuum system needs a scientific solution. The use of a vacuum cylinder in a vacuum line of an increased diameter partially solves the problem of vacuum pressure fluctuations. But such a decision requires additional material costs. In addition, the power of a vacuum pump increases to compensate for the pressure losses. In this study, the authors proposed the design of a double-action plate vacuum pump. It was proven that the simultaneous operation of combined rotors with plates shifted by 45° decreased the degree of air pumping by 7.8%. The research results indicated that the productivity of the developed vacuum pump increased by 13.6%. The drive power increased by 12%, and the specific energy intensity was 20% lower than that of vacuum pumps with similar geometric parameters. The relationship between rational kinematic and design parameters of a double-action vacuum pump was established.

Autonomous execution of highly reactive chemical transformations in the Schlenkputer

We design a modular programmable inert-atmosphere Schlenkputer (Schlenk-line computer) for the synthesis and manipulation of highly reactive compounds, including those that are air and moisture sensitive or pyrophoric. Here, to do this, we constructed a programmable Schlenk line using the Chemputer architecture for the inertization of glassware that can achieve a vacuum line pressure of 1.5 × 10−3 mbar, and integrated a range of automated Schlenk glassware for the handling, storage and isolation of reactive compounds at sub-ppm levels of O2 and H2O. This has enabled automation of a range of common organometallic reaction types for the synthesis of four highly reactive compounds: [Cp2TiIII(MeCN)2]+, CeIII{N(SiMe3)2}3, B(C6F5)3 and {DippNacNacMgI}2, which are variously sensitive to temperature, pressure, water and oxygen. Automated crystallization, filtration and sublimation are demonstrated, along with analysis using inline nuclear magnetic resonance or reaction sampling for ultraviolet–visible spectroscopy. Finally, we demonstrate low-temperature reactivity down to −90 °C as well as safe handling and quenching of alkali metal reagents using dynamic feedback from an in situ temperature probe.

Manufacturing Method and Thermal Properties of Open-Cell Type Aluminum Foam by Replication Casting Process

Open-cell type aluminum foam possesses unique structural characteristics comprising numerous interconnected pores within. This intriguing structure facilitates the passage of fluids (gas or liquid) through the interior of the open-cell type aluminum foams, enabling easy transfer to the exterior. The objective of this study is to manufacture open-cell type aluminum foams with varying pore sizes using the replication casting process and to evaluate their thermal properties. The equipment designed for the production of open-cell type aluminum foams consists of a chamber and an inner container. The chamber is connected to a vacuum line and an Ar gas line, with the container positioned inside. The aluminum alloys utilized for the foams were A356 and ADC12, and Na2CO3 served as the space holder. As a result of manufacturing the foams, there was no significant difference of porosity with space holder size and alloy types, the porosity averaged around 62%. To investigate the thermal properties of open-cell type aluminum foams in relation to pore size and alloy types, temperature variations were measured during sample heating via the hot plate method. Consequently, it was confirmed that the thermal properties of the foams were influenced by the structural conditions and alloy types.

ВЫБОР ЖИДКОСТНОКОЛЬЦЕВОГО ВАКУУМНОГО НАСОСА ДЛЯ ШАРОВОЙ МЕЛЬНИЦЫ С ВАКУУМНЫМ ОТВОДОМ

The use of powders is of interest in many industries. At the same time, the degree of grinding of materials depends on the intended purpose; in particular, in the production of paints, it is necessary to ensure a certain fineness of grinding of the pigment. The smaller the particles, the higher its hiding power. However, excessively high grinding fineness may reduce the hiding power of the pigment. It is proposed to grind the pigment in a two-section cylindrical-conical ball mill with vacuum removal of particles of a given degree of grinding. The article describes the design of the mill and shows a diagram of the line for vacuum transportation of the crushed pigment. The purpose of the work is to determine the main parameters of the vacuum line of pneumatic transport when grinding solid organic materials using a ball mill with a vacuum outlet. A method for calculating the geometric, kinematic and dynamic parameters of the developed mill and pneumatic transport line is presented. A significant reduction in energy costs for excess grinding is achieved through timely vacuum removal of crushed particles. The vacuum in the system is created and maintained by a liquid ring vacuum pump. Various options for the operation of the developed installation are described: direct grinding; additional grinding and recirculation of additional liquid generated during the operation of the liquid ring vacuum pump, which further reduces energy costs during grinding

Energy loss profile measurements using the ACTAR TPC demonstrator active target

The energy loss profiles of different ion beams (6Li, 27Al and 50Ti) impinging on CF4, isobutane and P10 have been measured with the active target ACTAR TPC demonstrator. The pressure of the gas, monitored during the experiment, has been chosen in order to stop the ions inside the active zone. Starting from the energy loss calculation produced by the SRIM code, the experimental ion tracks have been simulated, taking into account the effect of the thermal diffusion of electrons during their drift towards the pad plane under the effect of a uniform electric field. The uncertainty in the geometry, mainly due to the thickness and deformation of the mylar interface window between the gas volume and the high vacuum line, has been taken into account. A good agreement is obtained between the experimental and simulated energy loss profiles.

RADIOCARBON ANALYSIS AND STATUS REPORT FROM TÜRKIYE: 1MV NATIONAL AMS LABORATORY (TUBITAK-AMS)

ABSTRACTIn autumn of 2016, the National 1MV Accelerator Mass Spectrometry (AMS) Laboratory at The Scientific and Technological Research Council of Türkiye (TÜBİTAK), Marmara Research Center (MRC), Türkiye (Turkey), started to offer radiocarbon (14C) analysis service internationally. In this article, the process from sample acceptance to reporting and the primary procedures implemented and applied for 14C analysis at the TÜBİTAK AMS Radiocarbon Dating Laboratory are described. The service provided by the laboratory includes sample evaluation for 14C analysis, sample preparation, graphite production, AMS measurement, data supervision, calendar date calculations, and consultancy. For commercial testing and analysis, a one-page official report which shows the 14C age and uncertainty is provided for each sample. In addition to a dedicated wet chemistry laboratory to process samples before measurement with AMS, there are two systems for the conversion of CO2 to elemental carbon process; an automated graphitization system (AGE III) and a manual graphitization system based on a glass high vacuum line. A 1MV UAMS NEC Pelletron system installed in the laboratory is used for natural level 14C samples needed to be analyzed for archeological, geological, geographical, and environmental and forensic science applications. In addition to commercial 14C testing and analysis activities, national and international research projects can be developed or contributed to within the scope of project management or partnership.

Function of the Speech Recognition of the Smartphone to Automatically Operate a Portable Sample Pretreatment Microfluidic System.

We proposed a portable sample pretreatment microsystem, which can be automatically operated through speech recognition in a smartphone app. The proposed sample pretreatment microsystem consists of a microfluidic chip, an air router, pressure and vacuum lines with air pump motors, six 3-way solenoid valves, and a microcontroller with a Bluetooth module. The command of a human voice conducted the whole process of DNA extraction from pathogenic bacterial samples. Thus, manual interference during the DNA extraction is eliminated, preventing any potential infection from human touch. The palm-sized sample pretreatment microsystem can be run by a portable battery or a conventional smartphone charger. Genomic DNA ofSalmonella typhimuriumwas purified on a chip in less than 1 min with an extraction efficiency of 70 ± 5%.

Effect of deaeration on processability of poorly flowing powders by roller compaction

Roller compaction (RC) is a common granulation process for manufacturing solid dosage forms. However, its applicability to the growing number of powders with very low bulk densities and high cohesiveness can be limited due to poor powder feeding. Although deaeration with a vacuum in the feeding line is an effective approach to enhance the powder feeding performance, a systematic assessment of its effects on RC process is lacking. In this work, we have examined the effect of vacuum on the processability of RC using an extremely poorly flowing powder, colloidal silica, and two grades of microcrystalline cellulose (MCC). A processable range is defined by roll speed and screw speed that attain stable feeding under the roller-gap controlled mode. A 0.35 barg vacuum level was sufficient to make the colloidal silica processable and a higher vacuum level solved the subfeeding issue and significantly expanded the RC operation range. In contrast, deaeration slightly narrowed the processable range for MCC PH105 and PH101, while only minimally affects the relationship between roll speed and screw speed. The effects of vacuum on the processability of these materials qualitatively correlated with the sensitivity of their bulk densities to pressure. A better understood effects of material properties (bulk density), process parameters (roller gap), and deaeration (vacuum level) on RC processability of powders help to determine an appropriate use of a vacuum line to improve the RC process.

A spectroscopic method for monitoring photochemical reactions in the gas phase

We have developed an infrared spectroscopic method for monitoring photochemical reactions in the gas phase. This method is based on the major components such as repetitive scan FT-IR spectrometer, multi-pass long-path gas cell, and Nd:YAG laser (ns). The FT-IR spectrometer was used as it is. The gas cell was further modified for the photolysis of the precursor. The vacuum line was designed and constructed solely in our laboratory. We make optical arrangements for both separation of fourth-harmonics (266 nm) from the fundamental (1064 nm) of Nd:YAG laser as well as to guide the UV light to the gas cell housed in the sample compartment of FT-IR. A special arrangement was done in order to get a multi-pass of UV light across the gas cell so that photolysis efficiency will increase significantly. We estimate the photolysis efficiency based on laser power, optical path-length of the laser light, vapor pressure of the precursor, and its absorption cross-section. Furthermore, we have done quantitative analysis for the precursor and photo-products using infrared absorbance and optical path length. This method is tested and validated by monitoring the photodegradation pathways of halobenzenes in the UV light.•Repetitive scan FT-IR spectrometer coupled with a multi-pass long-path gas cell and Nd:YAG laser.•Estimate photolysis efficiency of precursor and concentration of photoproducts.•Monitoring gaseous phase photochemical reactions up-to 100 of ms with spectral resolution 2 cm−1 is possible with this system.

Ten ultrasound endometrial issues

Abnormal uterine bleeding is probably the most frequent gynecological issue that leads women to a consult with a subsequent ultrasound. Transvaginal ultrasonographic evaluation represents the most sensitive method of endometrial evaluation, being more adequate than the transabdominal approach, especially when differentiating the benign lesions from the malignant ones. Transvaginal ultrasound is extremely useful in measurement, morphology and vascularization examination of the uterine cavity, especially the endometrium. We present 10 endometrial issues in which transvaginal ultrasound has proven its utility in the paraclinical evaluation of the patient: endometrial cycle phase, endometrial thickness, endomyometrial junction, endometrial vacuum line, cystic endometrium, endometrial vascularization, endometrial polyp, intracavitary development of leiomyomas, thick endometrium and endometrial cancer.

Electric explosion of flat copper conductors in asymmetric and symmetric configurations in the current skinning mode

Plasma formation on the surface of conductors as a result of a skin explosion is one of the key issues of the efficiency of energy transportation along the vacuum lines of terawatt-level pulsed generators. Experimental studies of plasma formation on the surface of flat conductors were carried out on the MIG generator (current level ~ 2.5 MA, rise time ~ 100 ns). The magnitude of the magnetic field induction exceeded the values required for the explosion of the conductor surface facing the magnetic field in an asymmetric configuration or both surfaces of the conductor in a symmetric configuration. It was shown that in both configurations, a plasma channel is formed on the surface of a copper foil with a thickness of 100 microns along its longitudinal axis. Experimental data on the dynamics of plasma formation at the edges of a flat conductor have been obtained. A magnetohydrodynamic simulation of an explosion in strong magnetic fields of flat conductors whose width is much greater than their thickness showed that: the expansion of the plasma along the width of the conductor is suppressed, and the plasma expands mainly along its thickness. The simulation results are in good agreement with the experimental once.

Detection of human coronavirus RNA in surgical smoke generated by surgical devices

BackgroundGaseous by-products generated by surgical devices – collectively referred to as ‘surgical smoke’ – present the hazard of transmitting infective viruses from patients to surgical teams. However, insufficient evidence exists to evaluate and mitigate the risks of SARS-CoV-2 transmission via surgical smoke.AimTo demonstrate the existence and infectivity of human coronavirus RNA in surgical smoke using a model experiment and to evaluate the possibility of lowering transmission risk by filtration through a surgical mask.MethodsPelleted HeLa-ACE2-TMPRSS2 cells infected with human coronavirus were incised by electric scalpel and ultrasonic scalpel, separately. A vacuum system was used to obtain surgical smoke in the form of hydrosol. Reverse transcription–quantitative polymerase chain reaction was used to analyse samples for the presence of viral RNA, and infectivity was determined through plaque assay. Furthermore, a surgical mask was placed centrally in the vacuum line to evaluate its ability to filter viral RNA present in the surgical smoke.FindingsIn this model, 1/106 to 1/105 of the viral RNA contained in the incision target was detected in the collected surgical smoke. The virus present in the smoke was unable to induce plaque formation in cultured cells. In addition, filtration of surgical smoke through a surgical mask effectively reduced the amount of viral RNA by at least 99.80%.ConclusionThis study demonstrated that surgical smoke may carry human coronavirus, though viral infectivity was considerably reduced. In clinical settings, surgical mask filtration should provide sufficient additional protection against potential coronavirus, including SARS-CoV-2, infection facilitated by surgical smoke.

Manipulating Chemicals at Small‐ and Semimicro‐Scale in Inert Atmosphere

AbstractThe rational use of chemicals requires that their properties be compatible with the planned application. These properties are modified by the interactions to which the chemical substance is subjected, among which particularly relevant are those with the components of the lab atmosphere, collectively labelled air sensitivity. The air sensitivity of chemicals is remarkably amplified in the presently common small‐ and semimicro‐scale samples and operations, due to the increased surface‐to‐mass ratio with respect to the time‐honoured multigram scale. In this note we present ergonomy‐aware procedures implemented in small‐ and semimicro‐scale laboratory operations, which enable to work easily in an inert atmosphere without the need for awkward or expensive apparatuses such as glove box or vacuum line.

An Automated System for MeasuringIn SituK–Ar Ages

A completely automated system for measuringin situK–Ar ages using laser ablation for argon extraction and potassium measurement, and mass spectrometry for argon determination is described. The system consists of a laser system, an optical spectrometer, a vacuum line, a noble gas mass spectrometer and control software. The automated prototype was designed with ease of use in mind, specifically planned for dating many samples at low cost and reasonable precision. This instrumentation can perform one hundred K–Ar analyses every 24 h with the current setup, including blanks, reference materials and unknowns. Measurement results for the reference materials HDB‐1 biotite, GL‐O glauconite, LP‐6 biotite, Mica‐Mg phlogopite, Alder Creek sanidine and two tektites (moldavite and indochinite) are presented. It is shown that very different sample matrices require specific calibrations. Uncomplicated sample preparation, fast analytical times and uncertainties typically below 5% (1 standard deviation), depending on the age and potassium content, are the hallmarks of the system, which is suitable for many exploratory geology applications (e.g. geological mapping, mineral provenance and dating of drill cores).

A SIMPLE CO2 EXTRACTION METHOD FOR RADIOCARBON ANALYSES OF DISSOLVED INORGANIC CARBON IN WATER SAMPLES WITHOUT A CARRIER GAS

ABSTRACTWe developed a simple and cost-effective method for extracting carbon from dissolved inorganic carbon (DIC) in water samples without a carrier gas. This method only slightly modifies the existing vacuum line for CO2 purification in radiocarbon research laboratories by connecting several reservoirs and traps. The procedure consists of repeated cycles of CO2 extraction from water into the headspace of the reaction container, expansion of the extracted gas into the vacuum line, and cryogenic trapping of CO2. High CO2 yield (∼98%) was obtained from a variety of water samples with a wide range of DIC concentrations (0.4–100 mmol·L−1, in the case of 1.2 mgC). The δ13C fractionation depended on the CO2 yield, while the 14C concentration was constant within the error range, regardless of the CO2 yield. The average δ13C discrepancy between the results of this method and direct analyses made using the GC-IRMS was 0.02 ± 0.06‰. The standard deviations (1σ) in fraction of modern carbon (F14C) ranged from 0.0002 to 0.0004 for waters below 0.01 of F14C, and below 0.8% of F14C values for waters above 0.1. We conclude that this method is useful for effectively extracting CO2 from DIC in water and yields accurate 14C data.

The Effect of Urine Collection with a Novel External Catheter Device on Common Urine Chemistry and Urinalysis Results.

Urine collection from incontinent individuals can be challenging. Various methods have been devised to collect the sample without catheterization. Recently the PureWick external catheter was developed to draw the sample gently away from external female genitalia. While the primary purpose of the device is to prevent moisture and maintain skin integrity, the urine that is collected may be sent for laboratory analysis. We sought to validate the use of this collection method for common urine chemistry assays and urinalysis. Twenty pools of residual urine samples were separated into "control" and "PureWick" treated samples. The control samples were maintained at room temperature while 15 mL of urine was added to the PureWick device which was connected to a vacuum line through a collection canister. The urine collected in the canister and the controls samples were all subject to urine chemistry strip, microscopic, and automated urine chemistry analysis. Results were compared between pairs of treated and control samples. No clear affect was noted on urine strip semi-quantitative or automated chemistry analysis from the PureWick collection. There was a statistically significant decrease in microscopic measurements of white blood cells and crystals in the PureWick urine samples. This study supports the use of the PureWick external catheter for collection of samples for most urinalysis and urine chemistry tests.

Engineering design of a Permeator Against Vacuum mock-up with niobium membrane

Permeator Against Vacuum (PAV) is one of the technologies proposed for the Tritium Extraction and Removal System (TERS) of the Water-Cooled Lithium Lead Breeding Blanket (WCLL BB). The paper presents the activity aimed at the engineering design of a PAV mock-up with a niobium membrane, in order to later assemble and qualify it. Experience gained in the engineering design of the mock-up, the heating system, the instrumentation, and the vacuum line is illustrated. This experience will be useful for the preliminary design, the manufacturing and the operation of the PAV with niobium membrane for DEMO. Niobium was selected as membrane material of this mock-up because of its high permeability and for its lower cost compared to vanadium, the other candidate material for membranes. Besides, niobium has a lower tendency to oxidation than vanadium. Oxidation would reduce the hydrogen isotopes permeation flux. In this paper, the solution adopted to manufacture the PAV mock-up, a complex component with niobium and P22 parts, is illustrated. The Nb/P22 welding issues are also presented, in particular related to the compatibility of the welded joints with LiPb. In the chosen design, the LiPb flows with two passages in 16 (8 + 8) niobium “U” shaped pipes installed in a vacuum chamber and welded to a P22 plate. The U-pipes configuration was selected to minimize the welding area, the volume of the component and the membrane thickness while trying to preserve the highest possible extraction efficiency.

Methane generation from low-maturity coals and shale source rocks at low temperatures (80–120 °C) over 14–38 months

This study contributes long-term (14 to 38 months) experimental evidence for geocatalytically mediated methanogenesis in immature to early mature shale and coal source rocks at temperatures from 80 to 120 °C. Borosilicate glass tubes with pre-outgassed coal and shale source rock chips and water were sealed under vacuum, sterilized, heated isothermally, and finally opened in connection with a vacuum line where headspace gases methane (CH4) and carbon dioxide (CO2) were collected. The possibility of admitting pre-existing CH4 from closed pores into product gases during heating experiments was evaluated by comparative ball milling of original and heated rock chips, followed by quantitation of released gases with a novel closed-circuit laser-based SARAD RTM2200 gas detector system with sub-µmol sensitivity. The yields of produced CH4 from individual source rocks were corrected by subtracting the amounts of pre-existing CH4 from formerly closed pores in original source rocks that had leaked during long-term heating. Different shales and coals express contrasting propensities to geocatalytically generate CH4 and CO2, with CH4 yields ranging from 0.1 to 5.5 µmol g−1 total organic carbon (TOC). CH4 yields from two petrographically different samples of Springfield Coal with comparable thermal maturity suggest that liptinite expresses a far higher propensity for methanogenesis, but liberates less CO2 than vitrinite. Shale from the Second White Specks Formation generated approximately 10 times more CH4 than New Albany Shale per g of TOC, further suggesting complex controls on CH4 generation during catalytic methanogenesis. Higher temperature can enhance the activities of catalytic methanogenesis. The extrapolation of laboratory-based reaction rates to natural conditions in organic-rich buried sediments suggests that geocatalytic methanogenesis can be fast enough in some source rocks to generate economically sizeable gas plays from immature to early mature source rocks over geologic time.

A sealed-tube method for offline δ13 C analysis of CO2 via a Gas Bench II continuous-flow isotope ratio mass spectrometer.

The isotopic measurement of environmental sample CO2 via isotope ratio mass spectrometry (IRMS) can present many analytical challenges. In many offline applications, exceedingly few samples can be prepared per day. In such applications, long-term storage (months) of sample CO2 is desirable, in order to accumulate enough samples to warrant a day of isotopic measurements. Conversely, traditional sample tube cracker systems for dual-inlet IRMS offer a capacity for only 6-8 tubes and thus limit throughput. Here we present a simple method to alleviate these concerns using a Gas Bench II gas handling device coupled with continuous-flow IRMS. Sample preparation entails the cryogenic purification and quantification of CO2 on a vacuum line. Sample CO2 splits are expanded from a known volume to several sample ports and allowed to isotopically equilibrate (homogenize). Equilibrated CO2 splits are frozen into 3 mm outer diameter Pyrex break-seals and sealed under vacuum with a torch to a length of 5.5 cm. Sample break-seals are scored, placed into 12 mL Labco Exetainer® vials, purged with ultrahigh-purity helium, cracked inside the capped helium-flushed vials and subsequently measured via a Gas Bench equipped IRMS instrument using a CTC Analytics PAL autosampler. Our δ13 C results from NIST and internal isotopic standards, measured over a time period of several years, indicate that the sealed-tube method produces accurate δ13 C values to a precision of ±0.1‰ for samples containing 10-35 μgC. The tube cracking technique within Exetainer vials has been optimized over a period of 10 years, resulting in decreased sample failure rates from 5-10% to <1%. This technique offers an alternative method for δ13 C analyses of CO2 where offline isolation and long-term storage are desired. The method features a much higher sample throughput than traditional dual-inlet IRMS cracker setups at similar precision (±0.1‰).