Stainless Steel Capillary Research Articles

Sensitive Monitoring of the Minimum Inhibitor Concentration under Real Inorganic Scaling Scenarios.

Flow assurance is a long-term challenge for oil and gas exploration as it plays a key role in designing safe and efficient operation techniques to ensure the uninterrupted transport of reservoir fluids. In this regard, the sensitive monitoring of the scale formation process is important by providing an accurate assessment of the minimum inhibitor concentration (MIC) of antiscale products. The optimum dosage of antiscale inputs is of pivotal relevance as their application at concentrations both lower and higher than MIC can imply pipeline blockages, critically hindering the entire supply chain of oil-related inputs and products to society. Using a simple and low-cost impedimetric platform, we here address the monitoring of the scale formation on stainless-steel capillaries from its early stages under real topside (ambient pressure and 60 °C) and subsea (1000 psi and 80 °C) sceneries of the oil industry. The method could continuously gauge the scale formation with a sensitivity higher than the conventional approach, i.e., the tube blocking test (TBT), which proved to be mandatory for avoiding misleading inferences on the MIC. In fact, whereas our sensor could entail accurate MICs, as confirmed by scanning electron microscopy, TBT suffered from negative deviations, with the predicted MICs being lower than the real values. Importantly, the impedance measurements were performed through a hand-held, user-friendly workstation. In this way, our method is envisioned to deliver an attractive and readily deployable platform to combat the scale formation issues because it can continuously monitor the salt precipitation from its early stages and yield the accurate determination of MIC.

Visualized investigation of a nitrogen pulsating heat pipe

This paper presents the results of a visualization study of a cryogenic pulsating heat pipe (PHP). The impact of radiation heat leakage was reduced by minimizing optical windows. Visual images of the adiabatic section of a 2-turn PHP with nitrogen as working fluid were obtained at a filling ratio of 50 % and an inclination angle of 90°. The lengths of the evaporator, adiabatic section, and condenser were 50 mm, 100 mm, and 50 mm, respectively. The adiabatic section was made of quartz, whereas the evaporator and condenser were made of stainless-steel capillaries soldered onto copper plates. The flow channel of PHP was 1 mm. The fluid characteristics of the PHP under quasi-steady state conditions at different heat inputs were captured using a high-speed camera. Based on the experimental results, the evolution of flow patterns and fluid motion characteristics, and the coupling relationship between flow and heat transfer were illustrated and discussed.

Development of a test setup for hydrodynamic characterization of hydrocephalus shunts

Abstract Implantation of a shunt system is the most common neurosurgical procedure for the treatment of hydrocephalus. Hydrodynamic parameters of hydrocephalus shunt systems are valuable variables to address patients' needs. In this report, we present a test setup to evaluate hydrodynamic parameters of hydrocephalus shunt systems. The test setup was validated using a stainless steel capillary and compared with the analytical solution according to Bernoulli's equation. It was demonstrated that the experimental setup is able to model the pressure in a physiologically relevant range. The measured and averaged flow resistance was 2.96 mmHg/(ml min-1). According to the analytical solution of Bernoulli's equation, the flow resistance is 2.86 mmHg/(ml min-1). Therefore, the measured flow resistance is 3.5% higher than the analytical solution. Moreover, the nonlinear characteristic of the pressure drop at the inlet and outlet of the capillary plays a minor role compared to the friction of the tube flow. As a result, the increase in flow rate with increasing pressure load can be well approximated by a linear function for the low flow rates measured here. The experimental setup presented will be used in the future to characterize commercially available shunt systems under various hydrodynamic conditions.

Electrospinning spinneret: A bridge between the visible world and the invisible nanostructures

Electrospinning spinneret: A bridge between the visible world and the invisible nanostructures

Research on high-frequency induction cladding manufacturing technology by embedding stainless steel capillary tube in shaftclass parts

Research on high-frequency induction cladding manufacturing technology by embedding stainless steel capillary tube in shaftclass parts

Mitigating paraffin wax deposition by dispersants and crystal modifiers in flow testing

Functional molecules such as dispersants and crystal modifiers can be effective in mitigating wax deposition from crude oils and gas condensates. Both chemicals reduce the average wax particle size to sub-micron and change the crystal morphology. Water has a further significant effect on size reduction in dispersants. This work focuses on the effectiveness of these two additives in flow condition in a stainless-steel capillary tube. Unlike conventional flow loop systems, a simple open flow system is used to ensure constant wax content to avoid large fluid volume handling. Capillary tubes of 1- and 2-ft long are used to investigate effectiveness of dispersants and crystal modifiers in the laminar flow regime for a light shale oil with saturate content of 80 wt%. The effect of flow rate, concentration of the chemical additives (dispersant, crystal modifier), tube length, and brine on wax deposition are studied.An optimum concentration of chemical additives is found in flow tests, above which the effectiveness of additive decreases. Without aqueous phase, the crystal modifier is more effective than the dispersant. However, with 4% volume brine (of 5 wt% NaCl), the dispersant becomes more effective than the crystal modifier. Both additives are more effective at a higher flow rate; the influence of flow rate is more pronounced in the crystal modifier system than the dispersant. Wettability alteration to hydrophilic state is induced by adsorption of the dispersant backbone chains onto the stainless-steel (and wax molecules). Our results reveal that water improves dispersant effectiveness even in small amounts. A major observation in this work is pronounced pressure fluctuations in dispersants which relate to adhesion.

Research on Measurement Principle and Key Measuring Devices of Pressure Change Rate for Electronically Controlled Pneumatic Brake of Commercial Vehicle Based on Poiseuille's Law.

For intelligence brakes in the electronic pneumatic brake system of commercial vehicles, the pressure change rate is used as the key control parameter and evaluation index. This can improve the brake safety, stability, and ride comfort of the vehicle. The real-time detection of the brake pressure change rate for commercial vehicles is the premise for realizing the accurate control of brake pressure change rate. Based on Poiseuille’s law, an efficient measurement method of brake pressure change rate is proposed for commercial vehicles, and a new measuring device with an isothermal container and laminar flow resistance tube as the core components is designed. Through thermal insulation performance tests, flow resistance tests and measurement accuracy tests, combined with simulations, the effects of structural parameters and copper wire filling density on the performance of the isothermal container are analyzed, and these key parameters are optimized to improve the thermal insulation performance. A tubular laminar flow resistance tube composed of 304 stainless steel capillaries in parallel is designed. The influence mechanism of core parameters such as the number, radius, and length of laminar flow channels on its performance is studied, and the optimal parameter array is selected to optimize its performance. The experimental platform for measuring brake pressure change rate is constructed. By comparing the measurement curve of brake pressure change rate under simulation and experiment, the correctness and effectiveness of the pressure change rate measurement principle and the key components for electronically controlled pneumatic brakes of commercial vehicles are verified to meet engineering requirements.

Ppb-level gas detection using on-beam quartz-enhanced photoacoustic spectroscopy based on a 28 kHz tuning fork

In this paper, an on-beam quartz-enhanced photoacoustic spectroscopy (QEPAS) sensor based on a custom quartz tuning fork (QTF) acting as a photoacoustic transducer, was realized and tested. The QTF is characterized by a resonance frequency of 28 kHz, ~15% lower than that of a commercially available 32.7 kHz standard QTF. One-dimensional acoustic micro resonator (AmR) was designed and optimized by using stainless-steel capillaries. The 28 kHz QTF and AmRs are assembled in on-beam QEPAS configuration. The AmR geometrical parameters have been optimized in terms of length and internal diameter. The laser beam focus position and the AmR coupling distance were also adjusted to maximize the coupling efficiency. For comparison, QEPAS on-beam configurations based on a standard QTF and on the 28 kHz QTF were compared in terms of H2O and CO2 detection sensitivity. In order to better characterize the performance of the system, H2O, C2H2 and CO2 were detected for a long time and the long-term stability was analyzed by an Allan variance analysis. With the integration time of 1 s, the detection limits for H2O, C2H2 and CO2 are 1.2 ppm, 28.8 ppb and 2.4 ppm, respectively. The detection limits for H2O, C2H2 and CO2 can be further improved to 325 ppb, 10.3 ppb and 318 ppb by increasing the integration time to 521 s, 183 s and 116 s

Sulfolane as a novel stationary phase for analytical separations by gas chromatography

Sulfolane is explored as a novel stationary phase for use in analytical separations by capillary column gas chromatography with flame ionization detection (GC-FID). Stainless steel capillaries were found to provide a good substrate for coating and retaining a sulfolane phase, whereas fused silica tubing did not perform well for this. In general, the phase was found to be stable for several hours of use when using elevated carrier gas pressures (90 psi) and a small restriction (25 μm I.D. tubing) at the outlet. This normally provided good performance at temperatures up to about 200 °C with very little background interference in the FID. Given its separation properties, a short 2 m × 100 μm I.D. column was found to be preferable for most separations in this study. Measurements indicated the coating procedure yielded a sulfolane film near 4 μm thick on this column, which produced 4400 plates for benzene with a sample capacity near 30 μg. The sulfolane phase yielded good retention and peak shape for many analytes including alkanes, aromatics, alcohols, bases, sulfides, phosphites, thiols, and others. Compared to longer conventional GC columns, the relatively short sulfolane column was found to offer improved selectivity in the separation of unsaturated, aromatic, and alkane test analytes. As such the method was successfully applied to the analysis of aromatics in gasoline headspace. Results suggest that sulfolane could be a potentially useful stationary phase to further explore in GC separations.

Collision of water drops with a thin cylinder

The collision of water drops with a thin cylinder is studied. The droplet flight trajectory and the cylinder axis are mutually perpendicular. In the experiments, the drop diameter is 3 mm, and the diameter of horizontal stainless-steel cylinders is 0.4 and 0.8 mm. The drops are formed by a liquid slowly pumped through a vertical stainless-steel capillary with an outer diameter of 0.8 mm, from which droplets are periodically separated under the action of gravity. The droplet velocity before collision is defined by the distance between the capillary cut and the target (cylinder); in experiments, this distance is approximately 5, 10, and 20 mm. The drop velocities before the impact are estimated in the range of 0.2–0.5 m/s. The collision process is monitored by high-speed video recording methods with a frame rate of 240 and 960 Hz. The test liquids are water. Experiments and numerical simulation show that, depending on the drop impact height (droplets velocity) different scenarios of a drop collision with a thin cylinder are possible: a short-term recoil of a drop from an obstacle, a drop flowing around a cylindrical obstacle while maintaining the continuity of the drop, the breakup of a drop into two secondary drops, one of which can continue flight and the other one is captured by the cylinder, or both secondary droplets continue to fly, and the drop can be also captured by the cylinder, until the impact of the next drop(s) forces the accumulated drop to detach from the cylinder. Numerical modeling satisfactorily reproduces the phenomena observed in the experiment.

Residual solvent analysis with hyper-fast gas chromatography-mass spectrometry and a liquid carbon dioxide cryofocusing in less than 90 s

A new hyper-fast gas chromatography method with less than 90 s runtime including the column cool down was developed for the analysis of four gases and 16 residual solvents, combining a CO2 cryofocusing with a flow-field thermal gradient gas chromatograph (FF-TG-GC) and ToF-MS. The extremely low analysis time can be achieved by combining the new FF-TG-GC and a very short Rxi-624 Sil MS separation column with a small inner diameter and small film thickness (2.05 m × 0.1 mm × 1.0 µm).The column is inserted into a low thermal mass, resistively heated stainless steel capillary. This enables fast temperature programs with heating rates up to 3000 °C/min and a column cool down within a few seconds. In addition to temporal temperature gradients, the FF-TG-GC can generate a spatial temperature gradient that leads to an improved peak shape. Further, an external liquid CO2 cryo-trap was designed in order to reduce the injection bandwidths of analytes and to take full advantage of the resolving power of the separation column. No modifications are required to the FF-TG-GC for the use of the cryogenic trap, as the cooled spot is heated by the resistively heated stainless steel capillary during the temperature program. With cryofocusing, analyzed residual solvents are baseline separated. R2 values over 0.99 for calibration curves and low relative standard deviations (mainly < 3%) for repeatability tests were obtained.

Simple method for constructing and repairing tissue microarrays using simple equipment.

ObjectiveMany methods for tissue microarray (TMA) construction were described in previous reports. Because TMA-based methods are expensive and complicated, their widespread application may be restricted. This study aimed to develop a simple method for TMA construction.MethodsHigh-density TMAs were constructed using simple equipment, and hematoxylin and eosin and immunohistochemical staining were performed to analyze the effect on the TMA block.ResultsA recipient block with 162 holes of 0.9 mm in diameter was prepared using a mini-drill and plastic mold. Tissue cores of 1.0 mm in diameter were obtained from multiple donor blocks with stainless-steel capillary tubes driven by the mini-drill. Under the fixation and guidance of the plastic mold, tissue cores could be easily injected into the holes in the recipient block by inserting a stainless-steel wire into the stainless-steel tube with the tissue core and then pressing using the stainless-steel wire.ConclusionA high-density TMA block with 162 1.0-mm cores was created. This new modified technique could be a good alternative in many laboratories.

Optimization of accurate controlled formation of Au MNPs via non-thermal microplasma continuous glow discharge within aqueous electrochemical (GDE) method

In this work, micro plasma-induced non-equilibrium liquid chemistry was utilized to synthesize and controlled formation of gold metallic nanoparticles (Au MNPs) by governing the concentration of (HAuCl4). These new approaches based on both plasma and liquid electrolytes contain charged species, and the interactions between the two phases represent a unique combination of physics, chemistry, and materials science. Continuous and stable DC glow discharge was done in home–made cavity to synthesize the definite sizes of (Au MNPs) by means of (3 kV) discharge voltage and (2 mA) discharge current for a period of (7 min) in aqueous solution of HAuCl4 with four different concentrations of about 1 mM, 5 mM, 10 mM and 20 mM at room temperature. The atmospheric pressure plasma discharge between stainless steel capillary tube cathode electrode over the (HAuCl4) solution and platinum plate as an anode dipped in solution for rapid formation of colloidal Au MNPs. Morphology aspects of the synthesized Au MNPs layer were studied by examining the (FE-SEM), HR-TEM images and X-ray difraction (XRD) pattern. Optical features of (Au MNPs) were considered via a UV–Vis beam spectrophotometer. These measurements showed that Au MNPs were organized by governing the concentration of HAuCl4, and uniform Au MNPs with specific exclusive sizes were acquired. Grain size, specific surface area and optical stability of Au MNPs strongly be affected by the HAuCl4 concentrations.

Development of a Pressure Stable Inline Droplet Generator with Live Droplet Size Measurement

For the research on droplet deformation and breakup in scaled high-pressure homogenizing units, a pressure stable inline droplet generator was developed. It consists of an optically accessible flow channel with a combination of stainless steel and glass capillaries and a 3D printed orifice. The droplet size is determined online by live image analysis. The influence of the orifice diameter, the mass flow of the continuous phase and the mass flow of the disperse phase on the droplet diameter were investigated. Furthermore, the droplet detachment mechanisms were identified. Droplet diameters with a small diameter fluctuation between 175 µm and 500 µm could be realized, which allows a precise adjustment of the capillary (Ca) and Weber (We) Number in the subsequent scaled high pressure homogenizer disruption unit. The determined influence of geometry and process parameters on the resulting droplet size and droplet detachment mechanism agreed well with the literature on microfluidics. Furthermore, droplet trajectories in an exemplary scaled high-pressure homogenizer disruption unit are presented which show that the droplets can be reinjected on a trajectory close to the center axis or close to the wall, which should result in different stresses on the droplets.

Flexible Coaxial Ribbon Cable for High-Density Superconducting Microwave Device Arrays

Superconducting electronics often require high-density microwave interconnects capable of transporting signals between temperature stages with minimal loss, cross talk, and heat conduction. We report the design and fabrication of superconducting 53 wt% Nb-47 wt% Ti (Nb47Ti) FLexible coAXial ribbon cables (FLAX). The ten traces each consist of a 0.076 mm O.D. NbTi inner conductor insulated with PFA (0.28 mm O.D.) and sheathed in a shared 0.025 mm thick Nb47Ti outer conductor. The cable is terminated with G3PO coaxial push-on connectors via stainless steel capillary tubing (1.6 mm O.D., 0.13 mm thick) soldered to a coplanar wave guide transition board. The 30 cm long cable has 1 dB of loss at 8 GHz with -60 dB nearest-neighbor forward cross talk. The loss is 0.5 dB more than commercially available superconducting coax likely due to impedance mismatches caused by manufacturing imperfections in the cable. The reported cross talk is 30 dB lower than previously developed laminated NbTi-onKapton microstrip cables. We estimate the heat load from 1 K to 90 mK to be 20 nW per trace, approximately half the computed load from the smallest commercially available superconducting coax from CryoCoax

Fabrication of zeolite coatings onto stainless-steel capillary tubes for supercritical hydrocarbon cracking

In tubular reactors, the pressure drop can be decreased, and the heat transfer can be enhanced by coating the catalyst on its inner-wall when compared with the performance of fixed-bed types. This study focused on preparing catalyst coatings in capillary tubes for hydrocarbon cracking. The effect of pretreatment processes on the physicochemical properties of the catalyst was studied, and the influence was negligible. In addition, the preparation process was optimized by adjusting the coating method, binder types and contents. The coating prepared using 10 wt% organic binder with an interval coating method showed optimal adhesion. The mass loss was 3.92% after thermal shock and ultrasonic oscillation treatment. During n-dodecane cracking, the gas production rate (GPR) without coating was 8.27%, while that were 31.62% and 65.42% with ZSM-5 and MFI coatings, respectively. Above all, the coatings inhibited coke formation so that the reaction could be continuously performed at 600 °C.

Real-time monitoring for the CFRP/aluminium-alloy bonding structure during curing process using encapsulated fiber Bragg grating sensor

In order to get better bonding effect of CFRP/aluminum alloy materials, it is necessary to monitor the curing process of the structure. A real-time monitoring system for the curing process of CFRP/aluminium alloys based on optical fiber sensor was constructed, which can monitor the reaction information of different stages in the adhesive layer. First, a kind of encapsulated temperature sensor based on stainless steel capillary is designed and the bare grating, encapsulated sensor and thermocouple are embedded in the adhesive layer respectively. Then, the bonding structure was prepared by the vacuum bag pressing technology, and the structure was cured by holding in an oven at 80 °C for 140 min. The results show that the polymerization occurred inside the adhesive layer which releases a lot of heat. With the help of three-dimensional transient heat transfer control theory, flakiness theory model and condensation reaction model, the change of temperature and strain in the process of temperature rise of layer is well explained. The residual strain can also be obtained by the monitoring system. The study provides theoretical guidance for the following optimization of bonding technology and on-line monitoring of curing process and the service stage of aeronautical composite structures.

Highly Sensitive Photoacoustic Microcavity Gas Sensor for Leak Detection.

A highly sensitive photoacoustic (PA) microcavity gas sensor for leak detection is proposed. The miniature and low-cost gas sensor mainly consisted of a micro-electro-mechanical system (MEMS) microphone and a stainless-steel capillary with two small holes opened on the side wall. Different from traditional PA sensors, the designed low-power sensor had no gas valves and pumps. Gas could diffuse into the stainless-steel PA microcavity from two holes. The volume of the cavity in the sensor was only 7.9 μL. We use a 1650.96 nm distributed feedback (DFB) laser and the second-harmonic wavelength modulation spectroscopy (2f-WMS) method to measure PA signals. The measurement result of diffused methane (CH4) gas shows a response time of 5.8 s and a recovery time of 5.2 s. The detection limit was achieved at 1.7 ppm with a 1-s lock-in integral time. In addition, the calculated normalized noise equivalent absorption (NNEA) coefficient was 1.2 × 10−8 W·cm−1·Hz−1/2. The designed PA microcavity sensor can be used for the early warning of gas leakage.

Fabrication of nanocomposites by electric explosion of stainless steel capillaries filled with carbon nanotubes

Conventional electric explosion of wires (EEW) method can produce carbon nanotubes (CNTs) based nanocomposite with little impact on the CNTs, but complicated due to the liquid operations. A novel EEW method with micro-tubular metallic material filled with CNTs water solution was proposed to fabricate the CNT-based composite. The fabrication process of the products could be extremely fast comparing to the conventional EEW in the CNTs’ aqueous solution, and the composites are directly deposited on the substrates without further separation and purification procedures. Microscopic morphology analysis of the as-prepared deposited film samples reveals that the nanocomposites consisting of metallic nanoparticles and the CNTs were obtained. The compounds with Fe-C bonds existed in the CNT-based nanocomposites generated in the explosive products. Beyond the demonstrated CNTs and steel, this method can be a general framework for the deposition of metallic nanoparticles and liquid-soluble one-dimensional nanomaterials.

Ordinary microfluidic electrodes combined with bulk nanoprobe produce multidimensional electric double-layer capacitances towards metal ion recognition

While multidimensional sensors are powerful platforms towards multitarget analyses, the successive synthesis/fabrication of multiple probes and measurements to each one of these units still damage the device miniaturization, scalability, cost, consumption of samples, operational simplicity, precision, and analysis time. Herein, we describe an electrochemical sensing array that affords the discrimination of metal ions from a single ready-to-use probe and experiment. The sensing probe consisted of commercial stainless-steel capillaries, which defined a microfluidic circuit and acted as electric double-layer parallel capacitors into devices prototyped by a fast, cleanroom-free, and green technique. The probes assured differential responses due to heterogeneous interactions with samples and multichannel capacitance outputs. In addition, we address an effective strategy to further improve the repeatability and recognition ability of the sensor by using oxidized multi-walled carbon nanotubes as a single bulk probe. The nanotubes provided differential electrostatic adsorptions of ions, then increasing the variance of the capacitance responses. The approach was successfully applied in the identification of samples of mineral water, lake, and petroleum according to the presence of metal ions. Using supervised machine learning tasks, the sensor assured reproducible, sensitive, and accurate classification of dozens of lake samples spiked with multiple heavy metals in accordance with their safe limits. Remarkably, simultaneous quantification of the individual concentration of these ions was also possible from universal impedimetric assays by treating the data through multi-output regression. The sensor will be of significance for advanced discriminations from a single ordinary probe and measurement in a direct mode using scalable chips.