Connecting Tube Research Articles

Achromobacter species (sp.) outbreak caused by hospital equipment containing contaminated water: risk factors for infection

Nosocomial outbreaks of urinary tract infections caused by Achromobacter spp. have been rare in recent decades. To identify the origin of an Achromobacter sp. outbreak, conduct multi-modal infection control measures, and finally to stop the outbreak. To this end, an epidemiological outbreak investigation and risk factor analysis were performed. Achromobacter sp. was detected in 22 patients in our urology wards and six environmental cultures of specimens obtained from the operating rooms. Strains isolated were submitted for antimicrobial susceptibility testing. An on-site epidemiological investigation, evaluation of patient medical records, and environmental sampling were performed to identify the source of the outbreak, and implementation of infection control intervention. A case-control study was performed to analyse the potential risk factors. Environmental sampling showed that the source of the infection for 22 patients was an ISA-IIIA-type medical pressurizer containing contaminated water. A case-control analysis showed that the risk factors for infection were: diagnosis of kidney/ureteral stones, surgery, placement of a double-J stent, and history of hospitalization in the past three months. It was concluded that the outbreak occurred in patients who underwent internal lithotripsy and double-J stent placement, due to contact transmission with the contaminated sensor and connecting tubes of the ISA-IIIA-type medical pressurizer.

Breaking the symmetry of cell contractility drives tubulogenesis via CXCL1 polarization

The intricate interplay between biomechanical and biochemical pathways in modulating morphogenesis is an interesting research topic. How biomechanical force regulates epithelial cell tubulogenesis remains poorly understood. Here, we established a model of tubulogenesis by culturing renal proximal tubular epithelial cells on a collagen gel while manipulating contractile force. Epithelial cells were dynamically self-organized into tubule-like structures by augmentation of cell protrusions and cell-cell association. Reduction and asymmetric distribution of phosphorylated myosin light chain 2, the actomyosin contractility, in cells grown on soft matrix preceded tube connection. Notably, reducing matrix stiffness via sonication of collagen fibrils and inhibiting actomyosin contractility with blebbistatin promoted tubulogenesis, whereas inhibition of cytoskeleton polymerization suppressed it. CXC chemokine ligand 1 (CXCL1) expression was transcriptionally upregulated in cells undergoing tubulogenesis. Additionally, inhibiting actomyosin contractility facilitated CXCL1 polarization and cell protrusions preceding tube formation. Conversely, inhibiting the CXCL1-CXC receptor 1 pathway hindered cell protrusions and tubulogenesis. Mechanical property asymmetry with cell-collagen fibril interaction patterns at cell protrusions and along the tube structure supported the association of anisotropic contraction with tube formation. Furthermore, suppressing the mechanosensing machinery of integrin subunit beta 1 reduced CXCL1 expression, collagen remodeling, and impaired tubulogenesis. In summary, symmetry breaking of cell contractility on a soft collagen gel promotes CXCL1 polarization at cell protrusions which in turn facilitates cell-cell association and thus tubule connection.

On-column capillary suppressor for open tubular ion chromatography

BackgroundSuppressors with different dead volumes are required to match different suppressed ion chromatography systems. Especially for suppressed open tubular ion chromatography (SOTIC), the dead volume is a critical parameter. Both connection tubes between open tubular (OT) columns and suppressors and the dead volumes of the suppressors should be as short/small as possible to minimize peak dispersion. Suppressors with different dead volumes are required to match the various suppressed ion chromatography systems that operate at low flow rates 20–200 nL/min. ResultsWe describe three designs of on-column capillary suppressors for SOTIC: (A) on-column electrodialytic suppressor prepared by making small cracks on the cycloolefin polymer (COP) capillary at targeted locations, (B) on-column electrodialytic suppressor built on a polyether ether ketone (PEEK) capillary by removing the wall materials at target locations, (C) on-column chemical suppressor based on a single cut on a PEEK capillary at a targeted location a single cut on a PEEK capillary at a targeted location. The on-column electrodialytic suppressors work in two different modes with suppression voltage applied in co-current and counter-current direction to the eluent flow. Because of very narrow column inner diameter (i.d.), up to several hundred volts were required to suppress the hydroxide eluent, but it was found the there was a >90% loss of analytes in the suppressor accompanied with a high noise level after on-column electrodialytic suppression. Theoretical analysis reveals that high suppression voltage significantly affects the retention of specific analytes by electromigration. Further analysis indicated that the electrodialytic on-column suppressor in co-current mode would behave totally different from traditional suppressors. The on-column chemical suppression, with minimum dead volume of 0.27 nL, provides fairly well suppression of low hydroxide eluent without analyte loss in the suppressor. In design C, an efficiency of 47000 ± 1800 plates/m for Cl−, corresponding to a peak volume of 17.9 ± 0.7 nL, was obtained when separating five anion mixture (0.5 mM each) in the 25 μm i.d. AS18 latex coated PEEK OT column with an injection of 7.3 nL. Theoretical calculation revealed that a column efficiency loss of ≤3% would result in a cylindrical chemical suppression channel and thus it is taken as the acceptable dispersion contribution originating from the on-column chemical suppressor. SignificanceDifferent on-column suppressors have been designed on OT columns with i.d.s less than 30 μm. Two electrodialytic on-column suppressor designs with eluent flow parallel to the direction of electric field were proposed and tested. The eluent flow rate, analytes’ retention behavior, resistance of suppression channel, current-voltage relationship, and working principles in both co-current and counter-current were experimentally investigated and comprehensively discussed. It was found that although the on-column electrodialytic suppressions (Design A and B) are not feasible in practice, the electrodialytic on-column suppressor on co-current mode has a potential of being used as an enriching capillary column for analyte ions. Design C provides fairly well chemical suppression. Theoretical calculation indicates that the loss of column efficiency can be controlled within 3%.

New insights into the mechanism of load transfer in steel-encased CFST connections

Extensive numerical studies and analysis are presented to gain insights into the mechanism of load transfer in T- and K-type concrete-filled steel tube (CFST) connections. The new mechanism of load transfer investigated in this paper manifests that the shear load is transferred non-uniformly in the CFST column. Using validated finite element (FE) models, contact pressure stresses of the concrete-tube and angle-concrete interfaces are investigated to examine the interfacial interaction between each component. It indicates that the friction resistances between three components occur almost throughout the loading process, which is non-uniformly distributed along the column length. In addition, stress in each component is evaluated to determine the region of non-uniform load transfer in the column. For T-type connection, non-uniform load transfer shall only be considered for concrete-tube interface. For K-type connection, non-uniform load transfer should be considered for both concrete-tube and angle-concrete interfaces. Non-uniform load transfer mainly occurs in the connecting region and one time diameter of column above the connecting region for theses connections. Finally, the uneven transferred load of each component for the connections is analysed, whilst different force allocation schemes are compared. Based on the shear stresses at the tube-concrete and concrete-angle interfaces, non-uniform load transfer factor of each interface is calculated to quantitatively evaluate the non-uniformity of load transfer for the T- and K-type CFST connections.

Pain scores reduction with the use of ultrasound-guided paracervical nerve block in patients with cervical cancer undergoing intracavitary brachytherapy: A randomized controlled trial.

To determine the safety and effectiveness of ultrasound-guided paracervical nerve blocks for the painless treatment of patients with cervical cancer post-implantation. Single-center randomized controlled trial. Fourth Hospital of Hebei Medical University (July 2023 to October 2023). ChiCTR2300071580 [https://clin.larvol.com/trial-detail/ChiCTR2300071580]. Eighty patients with cervical cancer underwent post-implantation treatment. Patients receiving and not receiving paracervical nerve blocks (Groups T and C, respectively) were randomly allocated. Primary measures included visual analog scale (VAS) scores and patient body movement scores at various stages, including vaginal speculum placement (T1), applicator/needle insertion (T2), treatment administration following connection of the treatment tube (T3), needle withdrawal and hemostasis (T4), and willingness to receive further treatment. The secondary observation indices in this study included the operation time, incidence of hypoxemia, occurrence of nausea and vomiting, adverse events related to the circulatory system, patient satisfaction score, operator satisfaction score, and operation duration required by patients with an Alderte score of ≥ 9. Forty patients each were randomly allocated into Groups T and C. The VAS scores did not differ significantly between the two groups at T1. However, at T3 and T4, the VAS scores of Group T was significantly lower than that of Group C. No significant difference was observed in the body movement scores between the two groups at T1 and T3. However, the body movement score of Group T was significantly lower than that of Group C (P < 0.001) at T2 and T4. Group T showed higher postoperative satisfaction and willingness to receive further treatment compared to that of Group C. Ultrasound-guided paracervical nerve block effectively reduced the pain scores in patients with cervical cancer undergoing post-implantation treatment and enhanced their inclination to undergo further treatment.

Numerical Prediction of Refrigerant Oil Two-Phase Flow from Scroll Compressor Discharge to the Suction Side via Back Pressure Chamber

Oil lubricates the contact between the orbiting and stationary scroll in the refrigerant scroll compressor, while the sealing between the scrolls is achieved through the refrigerant vapour pressure in the sealed back pressure chamber. The back pressure should be adjusted using the refrigerant oil two-phase flow from the oil separator at the compressor discharge to the back pressure chamber and the refrigerant oil flow from the back pressure chamber to the compressor suction side. Both of the flows are conducted through connecting tubes with corresponding high-pressure and low-pressure nozzles with small diameters. Models for predicting the refrigerant oil critical and subcritical flows through the nozzles were developed and applied in enable the prediction of the back pressure. The models are original, because the slip between the oil and the refrigerant as well as the refrigerant solubility in the oil are taken into account. The critical flow model is validated against the experimental data that are available in the literature. The back pressure is predicted by equating the mass flow rates of refrigerant and oil two-phase mixtures through the high- and low-pressure nozzles. The results show that the critical flow takes place through the high-pressure nozzle, while the subcritical flow through the low-pressure nozzle can also exist in cases with a small pressure difference between the back pressure chamber and the compressor suction side. The refrigerant solubility in the oil has a small influence on the critical and subcritical refrigerant oil mixture mass flow rates, while the influence on the back pressure is more pronounced.

Study on seismic behavior of prefabricated shear walls with steel double tube connections

The joints are crucial for influencing the overall mechanical performance of precast shear wall constructions under seismic actions. The existing joint connections are complex and not efficient enough. To maximize the potential of prefabricated structures, this study proposed innovative prefabricated shear walls with steel double tube connections. Two pseudo-static tests were conducted to investigate the influence of axial compression ratio on the seismic behavior of the innovative shear walls. The failure modes were all bending failures, and it had been discovered that increasing the axial compression ratio can improve the carrying capacity and energy dissipation capacity. Seven models with different axial pressure ratios were established to conduct nonlinear finite element analysis. The result showed that as the axial compression ratios raised, the carrying capacity and stiffness of the models increased, but the decreasing trend of force–displacement curves were also more distinct. Therefore the recommended axial pressure ratio of the models did not exceed 0.4. Finally, the calculation method of the loading capacity of novel shear walls was proposed, which provided the basis for the design of innovative shear walls.

Design and fabrication of microfluidic devices: a cost-effective approach for high throughput production

Microdevices have been recognized as a potential platform for performing numerous biomedical analysis and diagnostic applications. However, promising and viable techniques for a cost-effective and high throughput production of microfluidic devices still remain as a challenge. This paper addresses this problem with an alternative solution for the fabrication of microfluidic devices in a simple and efficient manner. We utilized laser-assisted engraving technique to fabricate a master mold on an acrylic sheet of different thicknesses from 4 to 20mm. Low cost indigenously developed CO2 (10.6μm wavelength) laser engraving device was used for the experiments. The effect of various laser parameters such as power and speed of operation on the height of engraved structures was studied in detail. Optimal engraving results were obtained with a laser speed of 200–250mm s−1 with a spacing interval of 0.002mm at a laser power of 10–12W. Master mold of microdevice with a channel width of 100μm were produced using this technique. The replica transfer was performed by a simple imprinting method using a benchtop universal testing machine that can provide a maximum compressive load upto 1kN. The replicas were successfully generated on various thin film substrates including polymers, plastics, Whatman filter paper, teflon, vinyl sheets, copper, and aluminum sheets. The effect of load applied on the depth of the microfluidic channel was studied for the substrates such as teflon and Whatman filter paper. A load of 1kN can generate a depth of a few hundred micrometers on various substrates mentioned above. The replicas were also transferred to thermoformable PETG (polyethylene terephthalate glycol) sheets under load with an elevated temperature. The channel-imprinted PETG substrates were later sandwiched between two acrylic sheets with adhesive-coated polymer sheets and screws at the corners. Soft lithographic techniques were also performed to replicate the channel on a poly dimethyl siloxane substrate which was later bonded to a glass plate using an oxygen plasma cleaner device. Fluidic flow testing was conducted by pumping dye-mixed deionized (DI) water through the channels using a syringe pump and connecting tubes at a constant flow rate of 5ml min−1. The outcomes of this study provide an alternative solution for a simple and low-cost method for microdevice fabrication at a large scale.

Syringe-based microextraction for the removal of vanadium from different water and food samples using newly synthesized imino diacetate functionalized polystyrene as a new adsorbent: A multivariate approach

In this work, a new imino diacetate functionalized polystyrene (PS-Plina-ida) was synthesized and used as adsorbent for the removal of vanadium. The long narrow column solid phase microextraction connected to the portable syringe (LCSPME-PSS) system consists of a microextraction column filled with a solid phase material, a syringe, and a connecting tube. The microextraction column is made of a long and narrow glass column filled with a solid phase material (PS-Plina-ida) that selectively binds the target analyte. The syringe is used to aspirate the sample into the microextraction column and to elute the extracted analyte into the syringe for analysis. SEM, 1HNMR, DSC, and FTIR techniques were used to characterization of PS-Plina-ida. The key variables such as pH, amount of PS-Plina-ida, the concentration of vanadium, and adsorption cycle (min) of the proposed method were studied by using RSM of the design of the experiment under the desired condition. The experimental data was checked by using various isothermal models to check their adsorption behavior. Kinetic and thermodynamic studies were also carried out. When the analytical competence was tested, a linear response with (r) 0.989 for ranges of 0.50 and 10 mg/L was observed. A low limit of detection (30 ng/L) and a high enhancement factor (100) were obtained. Different real samples (water and digested food) were used to evaluate the practical application of the reported method.

Design, manufacture, and experiments of lightweight CFRP hydraulic cylinder tube without metal liner

AbstractHydraulic cylinders are widely used in aircraft rudder surface control, landing gear retraction, flaps and speed brakes retraction, ground steering driving, and engine thrust reverser control. The huge weight of hydraulic cylinders severely limits the aircraft's potential for increased range, maneuverability, energy efficiency, and carrying capacity. To achieve the maximum weight reduction, the carbon fiber reinforced polymer (CFRP) hydraulic tube without a metal liner is designed in this paper. In response to the lack of a parameter calculation method for CFRP hydraulic tubes, the accurate calculation method is developed through mechanical modeling and analysis of parameter influence law. For the structure design challenges of connection, sealing, and friction of CFRP hydraulic tube without metal liner, we have proposed and verified the wave contour inlaid structure, three leak‐proof solutions of the connection interface, the leak‐proof structure of the wound CFRP body and the seal friction pair. For the difficulties of multi‐material and high‐precision molding, a new process of split manufacturing‐combined molding is developed to achieve high‐precision and low‐cost manufacturing. Finally, the prototype is manufactured and tested by the presented method, and its weight reduction ratio is 56.64% compared with the original metal hydraulic tube. This study has further matured the application of CFRP hydraulic tubes without metal liners and has great lightweight benefits in aircraft.Highlights CFRP hydraulic tube without metal liner is designed to reduce weight. An accurate calculation method of CFRP parameters is developed. Connection structure, leak‐proof structure, and seal friction pair are designed. The high‐precision and low‐cost molding process is innovatively proposed.

A100Simulating to manage post thyroidectomy haematoma safely: Improving fidelity whilst reducing cost

Simulation training sessions were designed at the University Hospital of Wales in order to implement the new national guidelines for the management of suspected haematoma following thyroid surgery [1]. Opportunities included on site portable training with a part task trainer and high-fidelity scenarios simulating patient deterioration following thyroid surgery in an immersive environment. Our initial design for the high-fidelity set-up included a simulated neck haematoma achieved by using a second generation supraglottic airway device (SAD) with an inflatable cuff placed in the manikin’s neck with the laryngeal opening outwards and tubing inside the chest. The opening was filled with red jelly, covered by simulated strap muscles (made from simulated small bowel with interrupted sutures) and simulated neck skin (which presented a sutured incision complete with steri-strips). Ongoing bleeding was simulated by injecting liquid jelly through the SAD’s gastric port via a long connecting tube in the manikin’s thorax. This simulation training increased confidence and familiarity with the steps required to manage post thyroid surgery haematomas in 100% (15/15) of candidates, with 73% grading the mannikin ≥4/5 for realism. However, it was costly to provide and time-consuming to set up. It was decided to try to make the set-up cheaper and easier to reproduce without impairing quality. Equipment costs were reviewed and alternative options identified. Expensive components included the SAD and bowel material, which were replaced with a cheaper SAD and a disposable tourniquet fashioned as shown in Making the simulation larynx and strap muscles. A step by step guide The cost of disposable props used in each session was reduced from £133.04 to £8.52 with the new equipment. The designers also felt it was significantly more robust and easier to reproduce. This approach could also be easily adapted for mobile part-task training, improving multi-disciplinary access to training. Feedback showed 47% of candidates felt the new set-up to be better, and 47% reported non-inferiority. Changing to new equipment resulted in a design that was significantly cheaper, easier to source and set-up, while being at least as realistic and offering training opportunities outside the high-fidelity environment. Authors confirm that all relevant ethical standards for research conduct and dissemination have been met. The submitting author confirms that relevant ethical approval was granted, if applicable.

Pneumatic Microballoons for Active Control of the Vibration-Induced Flow.

Vibration-induced flow (VIF), in which a mean flow is induced around a microstructure by applying periodic vibrations, is increasingly used as an active flow-control technique at the microscale. In this study, we have developed a microdevice that actively controls the VIF patterns using elastic membrane protrusions (microballoons) actuated by pneumatic pressure. This device enables on-demand spatial and temporal fluid manipulation using a single device that cannot be achieved using a conventional fixed-structure arrangement. We successfully demonstrated that the device achieved displacements of up to 38 µm using the device within a pressure range of 0 to 30 kPa, indicating the suitability of the device for microfluidic applications. Using this active microballoon array, we demonstrated that the device can actively manipulate the flow field and induce swirling flows. Furthermore, we achieved selective actuation of the microballoon using this system. By applying air pressure from a multi-input channel system through a connection tube, the microballoons corresponding to each air channel can be selectively actuated. This enabled precise control of the flow field and periodic switching of the flow patterns using a single chip. In summary, the proposed microdevice provides active control of VIF patterns and has potential applications in advanced microfluidics, such as fluid mixing and particle manipulation.

Use of a portable negative pressure wound therapy device on a hard-to-heal wound with exposed bone: a case study.

This case study examines the effectiveness of using negative pressure wound therapy (NPWT) in the management of a hard-to-heal (chronic) wound with exposed ankle bone to reduce associated wound exudate and promote production of granulation tissue. A 60-year-old male patient who was able to attend wound follow-up diligently twice weekly for eight weeks, and weekly thereafter, was selected from a private hospital to take part. During each dressing change, the wound was cleansed with superoxidised cleansing solution, and minimal sharp debridement was performed. In the authors' opinion, the NPWT device used in this study is light and convenient for use in the community or home care setting. The NPWT wound dressing was connected to the NPWT machine via a connecting tube and the device then switched on using the default setting of a negative pressure of 125mmHg. Following the application of the NPWT device, the exposed ankle bone was successfully covered with healthy granulation tissue and healed within 20 weeks with minimal exudate formation in the wound. In the authors' opinion, NPWT is able to promote progress to wound healing; to minimise unnecessary dressing changes and, based on feedback from the patient, is comfortable to wear and when in use.

Evaluation of sound localization and speech recognition with a sound enhancing connection tube for non-linear earplugs

Noise-induced hearing-loss (NIHL) can occur when an individual is exposed to high-intensity acoustic stimuli. To prevent NIHL, individuals may use non-linear-earplugs (NLEPs) that provide some attenuation, substantially within the frequency range of 1–4 kHz. Wearing NLEPs can reduce speech recognition as well as sound localization. As weapon noise is mostly present in the 1–4 kHz range and is therefore partly attenuated by NLEPs, there is a downside to the reduced ability of a soldier using them to localize the source of enemy gunfire. A perforated sound-enhancing connection tube (SECT) was designed to connect to NLEPs for improving the user’s ability to localize sound and speech recognition in noise while retaining the NLEPs's noise attenuation benefits of protecting one's hearing. A previous experiment examined the effect of the SECT with NLEPs on the Head Related Transfer Function (HRTF) of a head-and-torso-simulator (HATS) (manikin). The obtained HRTF demonstrated a 3–10 dB difference in the 1–4 kHz frequency range relative to the HRTF with the NLEPs alone, implying that sound stimuli in that frequency range might be more audible to the user. The presented work will demonstrate the speech recognition in noise and sound localization of participants when using the SECT with NLEPs.

Bolted end-plate tube connections subject to tension and bending

A large amount of research has been undertaken on tubular bolted end-plate connections loaded in axial tension, and considerably less on such connections in flexure. This paper studies the combined effects of these two loads and presents the first laboratory tests on these connections under combined tension and flexure. Using validated finite element models, a parametric study with 360 numerical models is performed on these connections under axial and eccentric tension loads. After screening this database of experimental tests and numerical results to isolate only connection failure modes, current design methods for predicting the connection capacity under eccentric tension are evaluated and revised. In addition, based on interaction curves, a novel approach is proposed to design these splices under combined loads. For all methods, the use of the plate ultimate and yield stress was compared for the end-plate material strength parameter. Lastly, a reliability analysis is performed for the application of the recommended design methods to Canadian practice.

Enhancing Patient Autonomy in Home Hemodialysis: Innovations in 3D Printed Aids for Independent Tubing Connection

Home Hemodialysis(HD) is an advantageous alternative to in-center treatments, offering greater convenience, flexibility, and improved quality of life [1]. The rising prevalence of end-stage renal disease (ESRD) globally has increased the demand for accessible renal replacement therapies [2]. Factors such as an aging population, higher rates of chronic conditions, improved survival rates for chronic kidney disease patients, and increased healthcare access contribute to the growing burden on healthcare systems [3]. Home HD has gained prominence by enabling patients to receive treatment at home, providing control over their healthcare management [1]. It offers flexibility in scheduling, reduces travel time and costs, and creates a relaxed environment that positively impacts the patient experience [4]. Improved clinical outcomes, including better blood pressure control and enhanced quality of life, have been associated with home HD. However, challenges persist during the inlet/ outlet preparation and tubing connection phase, involving awkward elbow and wrist maneuvers, which can cause joint stress and discomfort [5]. Limited mobility or dexterity can further complicate the task, leading to potential complications. Addressing these challenges and promoting patient autonomy in tubing connection are crucial for improved treatment experiences and outcomes. Innovative solutions are being developed to facilitate independent tubing connection in home HD, empowering patients and reducing complications. Evaluations of the aids have shown promising results, enhancing patient outcomes and satisfaction [6].

Testing and analytical modeling the lateral behavior of precast columns with a novel column-to-column connection

A novel connection system is proposed for the rapid construction of reinforced concrete structures in seismic regions, called precast core steel tube reinforced concrete (PCSTRC) column. The system incorporates a core steel tube connection that utilizes the mortise-tendon mechanism, along with a rebar sleeve connection for longitudinal reinforcement, enabling column-to-column assembly. Six full-scale precast and cast-in-situ columns, with varying axial loads and detailing, were fabricated and subjected to quasi-static tests to investigate their seismic performance. The deformation characteristics and force-transferring mechanism of the precast columns were analyzed. The results indicate that the mechanical properties and hysteretic characteristics of the proposed PCSTRC column resemble those of the cast-in-situ specimen. An analytical model was developed for the PCSTRC column. The results of the analytical model for the PCSTRC column are basically consistent with the experimental results, considering both the load-carrying capacity and displacement composition in the total lateral response of the specimens. The model effectively captures the effect of different design parameters. It has been demonstrated that the proposed analytical model can accurately analyze and estimate the lateral behavior of the PCSTRC column.

Cryogenic temperature deformation behavior and shape memory mechanism of NiTiFe alloy

The excellent shape memory properties of NiTiFe alloys make them a popular choice for tube connection components and actuators in the aerospace industry. However, in order to obtain these properties, the alloy must undergo pre-deformation at specific cryogenic temperatures to induce the martensitic phase transformation. Despite their widespread use, the deformation behavior and shape memory mechanism of NiTiFe alloys at cryogenic temperatures remain unclear. To address this, we conducted a study investigating the deformation behavior and shape memory mechanism of Ni47Ti50Fe3 alloy at temperatures ranging from −190 °C to 150 °C using tensile tests, free recovery tests, and EBSD analysis. Our findings suggest that the deformation behavior of NiTiFe alloy can be classified into four classes corresponding to different deformation mechanisms. At temperatures above the Md (−15 to −30 °C), dislocation slip and {114}B2 deformation twinning occur without reversible strain. However, reversible and irreversible strains occur simultaneously at temperatures between −50 to −90 °C. At temperatures ranging from −110 to −150 °C, the reorientation/detwinning of the R-phase, stress-induced martensitic phase transformation, and yield stage of martensite occur in sequence. When the deformation temperature is within the range of −165–190 °C, the reorientation/detwinning of martensite occurs during the stress platform stage, and irreversible strain occurs during the yield stage of martensite. The best shape memory effect of the NiTiFe alloy is observed at deformation temperatures near Mf (−180 °C). Moreover, the reverse phase transformation temperatures increase with the increasing deformation amounts, even without plastic deformation. The temperature-dependent deformation map of NiTiFe alloy was obtained based on the tests conducted in this study, from which the influence of deformation temperatures on the different critical stresses and the deformation mechanism under different temperature conditions can be determined.

Multi‐objective design optimization of microreactor arrays for distributed renewable energy conversion: A case study

AbstractRenewable energy accommodation entails extensive use of modular devices, whose performance degrades remarkably from the lab scale to the industrial scale. This work presents a multi‐objective design optimization approach for modular devices scale‐up as exemplified by hierarchical numbering‐up of reverse water‐gas shift microreactors. The optimization objectives cover a wide span of competing system performance metrics, including the reaction performance, energy efficiency, space occupation, environmental impact, and costs. The decision variables involve the hierarchical geometry, branching, and inter‐stack connection schemes of the microreactor stacks. The obtained Pareto‐optimal designs suggest that multiple short stacks with small intra‐stack distribution channels and large inter‐stack connection tubes can well balance cost and performance. Meanwhile, single‐stack structures with large distribution channels are more suitable for portable applications. The methodology not only can be extended to the numbering‐up of various types of microreactors but also has essential guidance for the integration design of other modular devices.

Transient simulation of SO2 absorption into water in a bubbling reactor

A bubbling reactor is an important type of gas scrubber to reduce SO2 emissions in maritime shipping. Both experiments and simulations were conducted to study the relationship between the periodic gas bubbling process and SO2 concentration at the outlet of the reactor, and the entrainment of liquid droplets on SO2 absorption. The accuracy of the model was verified by comparing the bubble size, the depth of bubbles injected into the water, and the SO2 concentration obtained in both experiments and simulations. The gas bubbling process is accompanied by bubble formation, rise, and collapse. The gas bubbling period is affected by the disturbance of the liquid level. The period of the SO2 concentration at the outlet of the gas bubbling reactor is smaller than that at the gas jar outlet which acts as the gas buffering region. The amounts of water carried out of the bubbling reactor by the gas bubbling process increase with the gas flow rates. The droplets and liquid film in the gas jar and the connecting tube play an important role in the absorption of SO2. This study encourages more research to reduce the fluctuation of SO2 concentration and consider droplet entrainment in the design of bubbling reactors.