Peristaltic Pump Research Articles

Development of Copper-based Catalysts for the Preparation of C2+ by Electrochemical Reduction of CO2

Electrocatalytic reduction of carbon dioxide involves the conversion of carbon dioxide (CO2) and water into fuels and other chemicals under mild conditions using electrical energy, thereby simultaneously enabling carbon recycling as well as renewable energy storage. The reaction produces a wide variety of products, of which C2+ products such as ethylene, ethanol and propanol have higher energy density and added value compared to C1+ products such as carbon monoxide and formic acid [1]. Electrochemical reduction of CO2 is carried out using a gas diffusion electrolytic cell, which has many advantages: 1. small size, easy operation, close electrode distance, etc., which can effectively improve the mass transfer efficiency between gas and liquid; 2. the advantage of close electrode distance is low potential and less electrolyte consumption; 3. the reactor is easy to install and dismantle, the reaction system is well-closed and does not leak; the electrolyte is circulated outside the body, and the flow rate is adjusted by a peristaltic pump, which is more convenient and easy to control. At present, a new type of catalyst preparation has been completed and has completed the effect of the test, the catalyst is by the copper iodide (CuI) and 4,4-bipyridine coordination reaction two obtained by the ratio of the amount of different substances of the two mixed as well as the reaction of different time to obtain different coordination form of the catalyst, and the effect of the test, that is, the catalyst mixed with organic solvents are sprayed together with the carbon paper, clamped into the electrolytic cell, the electrolyte is analyzed using various instruments. Various instruments were used to analyze the composition of the electrolyte to derive the percentage of product. Through the test, it was found that the color of the catalyst gradually became darker with the prolongation of the reaction time, and the color of the catalyst gradually became darker with the increase of the proportion of 4,4-bipyridine in the reactants. The catalytic effect of the darker catalysts was significantly better than that of the lighter catalysts, with the percentage of C2+ products such as ethylene and ethanol increasing by 10%-15%.

Lab Experiments for Abrasive Waterjet Perforation and Fracturing in Offshore Unconsolidated Sandstones

Multistage hydraulic fracturing has been proven to be an effective stimulation method to extract more oil from the depleted unconsolidated sandstone reservoirs in Bohai Bay, China. The offshore wellbores in this area were completed with a gravel pack screen that is much too difficult to be mechanically isolated in several stages. Hydra-jet fracturing technology has the advantages of multistage fracturing by one trip, waterjet perforation, and hydraulic isolation. The challenges of hydraulic-jet fracturing in offshore unconsolidated sandstone reservoir can be summarized as follows: the long jet distance, high filtration loss, and large pumping rate. This paper proposes full-scale experiments on the waterjet perforation of unconsolidated sandstone, waterjet penetration of screen liners and casing, and pumping pressure prediction. The results verified that multistage hydra-jet fracturing is a robust technology that can create multiple fractures in offshore unconsolidated sandstone. Lab experiments indicate that the abrasive water jet is capable to perforate the screen-casing in less than one minute with an over 10 mm diameter hole. The water jet perforates a deep and slim hole in unconsolidated sandstone by using less than 20 MPa pumping pressure. Recommended perforating parameters: maintain 7% sand concentration and perforate for 3.0 min. Reduce sand ratio to 5%, maintain 3.0 m3/min flow rate, and continue perforating for 7.0 min. The injection drop of the nozzle accounts for more than 62% of the tubing pump pressure. The recommended nozzle combinations for different fracturing flow rates are 8 × ø6 mm or 6 × ø7 mm for 2.5 m3/min and 3.0 m3/min, and 8 × ø7 mm for 3.5 m3/min and 4.0 m3/min. A one-trip-multistage hydra-jet fracturing process is recommended to be used for horizontal wells in offshore unconsolidated sandstone reservoirs.

The hydrodynamics and kinematics of the appendicularian tail underpin peristaltic pumping.

Planktonic organisms feed while suspended in water using various hydrodynamic pumping strategies. Appendicularians are a unique group of plankton that use their tail to pump water over mucous mesh filters to concentrate food particles. As ubiquitous and often abundant members of planktonic ecosystems, they play a major role in oceanic food webs. Yet, we lack a complete understanding of the fluid flow that underpins their filtration. Using high-speed, high-resolution video and micro particle image velocimetry, we describe the kinematics and hydrodynamics of the tail in Oikopleura dioica in filtering and free-swimming postures. We show that sinusoidal waves of the tail generate peristaltic pumping within the tail chamber with fluid moving parallel to the tail when filtering. We find that the tail contacts attachment points along the tail chamber during each beat cycle, serving to seal the tail chamber and drive pumping. When we tested how the pump performs across environmentally relevant temperatures, we found that the amplitude of the tail was invariant but tail beat frequency increased threefold across three temperature treatments (5°C, 15°C and 25°C). Investigation into this unique pumping mechanism gives insight into the ecological success of appendicularians and provides inspiration for novel pump designs.

Understanding Prandtl fluid flow in conduits with slip boundary conditions: Implications for engineering and physiology

In this analysis, rotation, magnetic fields, and Hall current effects are considered as they pertain to the flow of a Prandtl fluid via a conduit with slip boundary conditions. Closed-form solutions for velocity and temperature are derived using a long-wavelength approximation and conditions of low Reynolds numbers in the analysis. The results show that the pressure gradient rises for larger values of the first-order slip parameter and the second-order slip parameter but falls for larger values of the Prandtl fluid parameter. Furthermore, in the free, peristaltic, and retrograde pumping regimes, pumping rates increase with an increase in the slip parameters, while pumping rates drop in the back-pumping zone. Although fluid temperature drops with an increase in the Prandtl fluid parameter, it is still affected by the Prandtl fluid parameter and the slip parameters. The ramifications of these findings for developing pumping systems and gastrointestinal health are substantial. They allow the body's fluids to flow smoothly, which improves the efficiency of functions, including oxygen delivery, waste removal, and nutrient delivery.

Investigation of Pressure Variations in Hose Pumps under Different Flow Regimes Using Bidirectional Fluid–Structure Interaction

Hose pumps, renowned for their ability to efficiently transport highly viscous and corrosive fluids, hold an irreplaceable position in numerous engineering domains. With a wide range of fluid types being transported by hose pumps, the study of pressure variations during the conveyance of different fluid states is of paramount importance, as it positively contributes to optimizing hose pump structures, reducing noise, and enhancing hose pump longevity. To investigate pressure variations in hose pumps during the conveyance of varying fluid states, this paper employs a bidirectional fluid–structure coupling method and utilizes commercial finite element software, ANSYS. The research validates the causes of variations in hose pumps during fluid conveyance and examines the overall pressure distribution within the fluid domain of hose pumps conveying different fluid states at varying rotor speeds. The results indicate that when the fluid within the hose pump is in a turbulent state, pressure variations exhibit multiple minor amplitude oscillations, whereas in a laminar state, pressure variations display fewer oscillations but with more significant amplitudes. Moreover, higher rotor speeds exacerbate pressure variations. Recommendations include optimizing the shape of the squeezing roller and enhancing pressure variation control through shell angle optimization.

In vivo structural and functional imaging of human nailbed microvasculature using photoacoustic microscopy.

Monitoring microvascular structure and function is of great significance for the diagnosis of many diseases. In this study, we demonstrate the feasibility of OR-PAM to nailbed microcirculation detection as a new, to the best of our knowledge, application scenario in humans. We propose a dual-wavelength optical-resolution photoacoustic microscopy (OR-PAM) with improved local-flexible coupling to image human nailbed microvasculature. Microchip lasers with 532 nm wavelength are employed as the pump sources. The 558 nm laser is generated from the 532 nm laser through the stimulated Raman scattering effect. The flowing water, circulated by a peristaltic pump, maintains the acoustic coupling between the ultrasonic transducer and the sample. These designs improve the sensitivity, practicality, and stability of the OR-PAM system for human in vivo experiments. The imaging of the mouse ear demonstrates the ability of our system to acquire structural and functional information. Then, the system is applied to image human nailbed microvasculature. The imaging results reveal that the superficial capillaries are arranged in a straight sagittal pattern, approximately parallel to the long axis of the finger. The arterial and venular limbs are distinguished according to their oxygen saturation differences. Additionally, the images successfully discover the capillary loops with single or multiple twists, the oxygen release at the end of the capillary loop, and the changes when the nailbed is abnormal.

Significance of heat transfer on the peristaltic pump of blood fluid under the inclined magnetic field

Context/PurposeA wide range of scientific research on this subject has been presented recently due to the fundamental importance of the peristalsis phenomenon in various biological systems like the movement of chyme in the gastrointestinal tract, lungs devices, blood circulation in vessels, and heart pumping. The transfer of sanitary materials, the construction of roller pumps, and many other industrial processes all benefit from the innovative function that peristaltic pumping performs. Magnetohydrodynamics is currently used to pump fluids for both pulsating along with non-pulsating continuous flows in various microchannel designs. It is also highly useful for flow control. In the current study, it is examined how an inclined magnetic field and a heat source/sink affect the peristaltic blood flow in an inclined asymmetric channel with thermal radiation. Mathematical analysis was done after the magnetic field was in alignment. The wave velocity is used in a reference system that simulates a wave to look at the flow. MethodsFirst, a model of the physical issue is created; then, an analytical solution is produced using small Reynolds number as well as a long wavelength preconception. ResultsThere are expressions for velocity, temperature, gradients in pressure, and heat transfer coefficient. Additionally, the frictional force and pressure rise's numerical findings were established. InterpretationNumerical findings are visually described for a range of physical parameter values. ConclusionThe behavior of many interest parameters is displayed graphically. Furthermore, it is anticipated that the results of this research will produce equally trustworthy theoretical predictions of a variety of potential mechanical fluid flow parameters for peristaltic blood transportation.

Pump, Vacuum, Infusion and Intraocular Pressure Control in Vitrectomy Devices

In vitrectomy devices pump, vacuum, intraocular pressure control and infusion systems must be in a delicate balance for optimal surgical results. In parallel with the advances in technology, there have been significant developments in pump and infusion systems in devices. The devices with only peristaltic or venturi pumps in conventional devices have been replaced by hybrid systems where both pumps are in the same device and can be easily switched between pumps during surgery. Likewise, gravity-dependent infusion systems have been replaced by automated systems that allow more controlled operation. These developments have allowed faster, safer and more comfortable surgery. In terms of finding the device that surgeons can work comfortably with, it is important to know the advantages and disadvantages of each vitrectomy device and to have information about these systems, which we will describe in our review.

PROCESSING OF WELLHEAD CHRISTMAS TREES PIPE HEADER

In this study, the components of the tubing head of the Wellhead Christmas tree are classified. Information on how to install the tubing head to the Christmas tree (oil and gas) is also provided. The tested tubing head ensures the passage of liquid or gas into the spaces between the tubes. They have to control the pressure and conduct the necessary well studies. The tubing header seals and hangs the riser columns, which is especially effective when inserting concentric or parallel columns into the well. As a result of the conducted studies, the tubing head fully controls the flow of the technological liquid. Tubing headers to perform these processes should be manufactured according to the working pressure requirements between 14 and 105 MPa. Using a tubing head, you can connect different numbers of pipelines, as well as control the distribution of the medium flow in the circular zone of the valve. Of the cost-effective methods we have mentioned one is connected to the upper flange of the pipeline column header with a lower mounting fixing component. The design of the tubing head is completed by threaded holes in the body through which you can quickly replace the side valves in the head tube. The tubing head is designed to stop one or more rows of riser (pump and compressor) tubes and is used to perform technological operations during the development, operation and repair of wells. The top of the tubing at the wellhead is screwed into the tubing cap of the Christmas tree (oil and gas). Once installed at the wellhead, the Christmas tree (oil and gas) tubing header is compressed to the allowable pressure for pressure testing the production casing. Tubing head design and strength characteristics are shown in this figure: a) working pressure (7, 14.21, 35, 70 and 105 MPa), b) numbers of pipes lowered into the well (one and two concentric rows of pipes), c) constructions of locking devices (valves and taps) dimensions of the flow section along the trunk (50... 150 mm) and side branches (50... 100 mm). The tubing head holds and takes over the pressure generated between the tubes and can be prohibitive, which is quite dangerous for people's lives and health. Keywords: Christmas tree (oil and gas), tubing header, pressure, flow, wellhead, test, well.

A Low-Cost Programmable Reversing Flow Column Apparatus for Investigating Mixing Zones.

This note describes the development and testing of a novel, programmable reversing flow 1D (R1D) experimental column apparatus designed to investigate reaction, sorption, and transport of solutes in aquifers within dynamic reversing flow zones where waters with different chemistries mix. The motivation for constructing this apparatus was to understand the roles of mixing and reaction on arsenic discharging through a tidally fluctuating riverbank. The apparatus can simulate complex transient flux schedules similar to natural flow regimes The apparatus uses an Arduino microcontroller to control flux magnitude through two peristaltic pumps. Solenoid valves control flow direction from two separate reservoirs. In-line probes continually measure effluent electrical conductance, pH, oxidation-reduction potential, and temperature. To understand how sensitive physical solute transport is to deviations from the real hydrograph of the tidally fluctuating river, two experiments were performed using: (1) a simpler constant magnitude, reversing flux direction schedule (RCF); and (2) a more environmentally relevant variable magnitude, reversing flux direction schedule (RVF). Wherein, flux magnitude was ramped up and down according to a sine wave. Modeled breakthrough curves of chloride yielded nearly identical dispersivities under both flow regimes. For the RVF experiment, Peclet numbers captured the transition between diffusion and dispersion dominated transport in the intertidal interval. Therefore, the apparatus accurately simulated conservative, environmentally relevant mixing under transient, variable flux flow regimes. Accurately generating variable flux reversing flow regimes is important to simulate the interaction between flow velocity and chemical reactions where Brownian diffusion of solutes to solid-phase reaction sites is kinetically limited.

Chicken plastination: its role in teaching avian anatomy

This paper describes the preparation of six plastinated chicken dissections for Veterinary Anatomy teaching at the University of Pretoria, South Africa. Specimens were fixed in 10% formalin for seven to ten days, depending on the size of the specimen. Room temperature acetone baths were used for dehydration over a period of six weeks. Impregnation in S10 took place over a period of three weeks at -16 °C. The specimens were cured with S6. A peristaltic pump was used during preparation to ensure the intestines were rinsed properly, and the chemicals penetrated the whole specimen. In the curing phase, a compressor was used to inflate the duodenum and small intestines to show the digestive and reproductive tracts. The plastinated specimens were then labelled. Three chicken hearts in different stages of dissection (one intact, one from the ventrum/cranial, one from the dorsum/caudal aspect) were prepared. A muscle dissection was carried out on a whole chicken with its intestines intact. It was found to be preferable to carry out the dissection while the specimen was stored in the acetone bath. When the dissection was complete, the body wall of the chicken was cut through with an oscillating saw before impregnation in S10. Another adult chicken was used for the skeleton. All the muscle was removed, and the skeleton placed in formalin for fixation. After a week, the skeleton was placed in acetone for dehydration. The aim with this skeleton was to show how the ligaments maintain skeletal integrity. The ovary and reproductive tract were also dissected. The plastinated specimens are now available to the students in the anatomical museum. Now students, at their own pace, may study and learn the anatomy of the chicken more intensely.

Investigation of dissipative heat transfer and peristaltic pumping on MHD Casson fluid flow in an inclined channel filled with porous medium

A theoretical investigation is performed for free convective peristaltic pumping of a Casson fluid through an inclined porous wavy channel. The flow is subjected to uniform magnetic field in the transverse direction. In addition, the energy equation contains porous and viscous dissipation effects. The governing flow problem is modeled for Casson fluid with the help of conservation laws of mass, momentum, and energy under the long wavelength assumption. Using a regular perturbation method, we obtained the analytical expressions for the axial velocity, temperature, pressure rise per one wavelength, and heat transfer rate. The consequences of various effects on the flow quantities are demonstrated in the form of graphical representations and discussed in detail. The findings reveal that the rise in the thermal Grashof number and permeability parameter leads to an increment in the velocity and thermal fields. The heat transfer rate strengthened when the Casson parameter and magnetic parameter were increased. The pressure rise exhibits an enhancing trend for the Brinkmann number and permeability parameter. Further, we observed a decreasing behavior on streamlines for increasing magnetic field strength. Moreover, the obtained findings are applicable to a variety of fields in the bioengineering and medical sciences, such as targeted drug delivery, heart-lung machines, MRI, cancer therapy, power conversion devices, and micromanufacturing processes.

Control of magnetic dissipation and radiation on an unsteady stagnation point nanofluid flow: A numerical approach

This study investigates two-dimensional time-dependent stagnation point nanofluid flow over a permeable stretching or sinking sheet. The electrically conducting fluid allows for the interaction of a transverse magnetic field along with magnetic dissipation and thermal radiation to enrich the flow phenomena. The use of nanofluids is becoming increasingly important in a variety of industrial applications, as well as in engineering and biomedicine. The process of peristaltic pumping, the flow of blood in the artery, the drug delivery process, and besides that, the cooling of electronic devices for the better shape of the product at the final stage of production, the use of nanofluid, are all important. The transformed dimensionless governing equations are obtained by the implementation of various transformation rules, and the model is designed by using different thermophysical properties such as viscosity, conductivity, etc. Finally, the numerical technique RK-fourth-order method is deployed to solve the set of equations and the iteration process is continued up to the desired accuracy of 10[Formula: see text]. The validation of the current result is shown with the earlier investigation in particular cases, and further, the behavior of the physical parameters is presented through graphs. It is observed that the particle concentration has a greater impact in enhancing the velocity distribution for the variation of suction/injection. The behavior of the magnetic parameter vis-à-vis the unsteadiness parameter and the thermal buoyancy presents their greater contribution in enhancing the magnitude of nanofluid velocity.

A 3D-printed phantom for quality-controlled reproducibility measurements of arterial spin labeled perfusion.

To develop a portable MR perfusion phantom for quality-controlled assessment and reproducibility of arterial spin labeled (ASL) perfusion measurement. A 3D-printed perfusion phantom was developed that mimics the branching of arterial vessels, capillaries, and a chamber containing cellulose sponge representing tissue characteristics. A peristaltic pump circulated distilled water through the phantom, and was first evaluated at 300, 400, and 500 mL/min. Longitudinal reproducibility of perfusion was performed using 2D pseudo-continuous ASL at 20 post-label delays (PLDs, ranging between 0.2 and 7.8 s at 0.4-s intervals) over a period of 16 weeks, with three repetitions each week. Multi-PLD data were fitted into a general kinetic model for perfusion quantification (f) and arterial transit time (ATT). Intraclass correlation coefficient was used to assess intersession reproducibility. MR perfusion signals acquired in the 3D-printed perfusion phantom agreed well with the experimental conditions, with progressively increasing signal intensities and decreasing ATT for pump flow rates from 300 to 500 mL/min. The perfusion signal at 400 mL/min and the general kinetic model-derived f and ATT maps were similar across all PLDs for both intrasession and intersession reproducibility. Across all 48 experimental time points, the average f was 75.55 ± 3.83 × 10-3 mL/mL/s, the corresponding ATT was 2.10 ± 0.20 s, and the T1 was 1.84 ± 0.102 s. Intraclass correlation coefficient was 0.92 (95% confidence interval 0.83-0.97) for f, 0.96 (0.91-0.99) for ATT, and 0.94 (0.88-0.98) for T1 , demonstrating excellent reproducibility. A simple, portable 3D-printed perfusion phantom with excellent reproducibility of 2D pseudo-continuous ASL measurements was demonstrated that can serve for quality-controlled and reliable measurements of ASL perfusion.

Photon-Counting Detector CT for Femoral Stent Imaging in an Extracorporeally Perfused Human Cadaveric Model.

This study aims to compare the performance of first-generation dual-source photon-counting detector computed tomography (PCD-CT) to third-generation dual-source energy-integrating detector (EID-CT) regarding stent imaging in the femoral arterial runoff. Continuous extracorporeal perfusion was established in 1 human cadaver using an inguinal and infragenicular access and peristaltic pump. Seven peripheral stents were implanted into both superior femoral arteries by means of percutaneous angioplasty. Radiation dose-equivalent CT angiographies (high-/medium-/low-dose: 10/5/3 mGy) with constant tube voltage of 120 kVp, matching iterative reconstruction algorithm levels, and convolution kernels were used both with PCD-CT and EID-CT. In-stent lumen visibility, luminal and in-stent attenuation as well as contrast-to-noise ratio (CNR) were assessed via region of interest and diameter measurements. Results were compared using analyses of variance and regression analyses. Maximum in-stent lumen visibility achieved with PCD-CT was 94.48% ± 2.62%. The PCD-CT protocol with the lowest lumen visibility (BV40: 78.93% ± 4.67%) performed equal to the EID-CT protocol with the best lumen visibility (BV59: 79.49% ± 2.64%, P > 0.999). Photon-counting detector CT yielded superior CNR compared with EID-CT regardless of kernel and dose level ( P < 0.001). Maximum CNR was 48.8 ± 17.4 in PCD-CT versus 31.28 ± 5.7 in EID-CT (both BV40, high-dose). The theoretical dose reduction potential of PCD-CT over EID-CT was established at 88% (BV40), 83% (BV48/49), and 73% (BV59/60), respectively. In-stent attenuation was not significantly different from luminal attenuation outside stents in any protocol. With superior lumen visibility and CNR, PCD-CT allowed for noticeable dose reduction over EID-CT while maintaining image quality in a continuously perfused human cadaveric model.

Smart Manufacturing Implementation of a Continuous Downstream Precipitation and Filtration Process for Antibody Purification

Abstract Recently, continuous bioprocessing has gained momentum in biomanufacturing and can alleviate many of the hurdles faced in batch or semi-batch operations. Moreover, the parallel development of smart manufacturing (SM) allows the rapid small-scale prototyping and large-scale implementation of continuous bioprocesses. With this background, this paper presents the laboratory-scale implementation of a continuous precipitation-filtration process that can ultimately be used for therapeutic protein capture purification. The experimental setup includes four static mixers, four peristaltic pumps, one hollow fiber dewatering filtration module, and multiple pressure sensors and weigh scales. The system also includes an in-line advanced microscopic particle imaging probe that provides real-time images and derived metrics of the precipitate particle morphologies and a fiber optic 880 nm optical absorbance probe. A polyclonal human serum antibody mixture (hIgG) (10 g/L) was used as a stand-in for a monoclonal antibody therapeutic along with 7 % w/v polyethylene glycol (PEG, volume exclusion agent) and 10 mM zinc chloride (cross-linking agent) as the precipitants to demonstrate the principles of operation and control of a precipitation-based process using SM technology. An integrated input/output (I/O) system was used to acquire pressure, flow rate, and weigh scale data and also to communicate with the pumps to change flow rates in real-time. Edge computers communicate with the I/O system and the imaging probe and host the software layer. The software layer enables real-time data acquisition, data-driven and first-principles model predictions, closed-loop control of precipitate particle morphology using pump flow rate of PEG, and cloud communications with the Clean Energy Smart Manufacturing Innovation Institute Smart Manufacturing Innovation Platform. The paper presents the initial results obtained with this integrated system, demonstrating the potential of SM strategies to enhance the production of life-saving biopharmaceutical products.

Super-hydrophobic graphene-based high elastic sponge with superior photothermal effect for efficient cleaning of oil contamination

Oil spills are frequent and often accompanied by chemically corrosive and complex operating environments, so there is an urgent need for new absorbent materials that can absorb oil efficiently and with stable performance. Herein, we reported a reduced graphene oxide coated melamine sponge (F-rGO@MF) modified by silane grafting, which had excellent superhydrophobic/superoleophilic surface properties (WCA up to 157.7°), high absorption capacity (58.7–147.8 g/g) for a variety of oils, and could perform multiple absorption cycles. The separation efficiency of the oil/water mixture was as high as 99.32%, and the separation efficiency could still reach 97.48% after 80 separation cycles. The absorbent could also separate oil and water continuously by peristaltic pump. Besides, F-rGO@MF still retained floating and chemical stability under strong corrosive environment. More importantly, due to the photothermal property of rGO, the surface temperature of F-rGO@MF could rapidly rise to 101 °C under 1.0 kw/m2 light intensity for 225 s, which was contribute to the viscosity reduction of crude oil and absorbed 14.75 g of crude oil in 7 min, providing the possibility of absorbing high viscosity oil spills.

Microfluidic Device Integrated With PDMS Microchannel and Unmodified ITO Glass Electrodes for Highly Sensitive, Specific, and Point-of-Care Detection of Copper and Mercury.

This work delves upon developing a two-layer plasma-bonded microfluidic device with a microchannel layer and electrodes for electroanalytical detection of heavy metal ions. The three-electrode system was realized on an ITO-glass slide by suitably etching the ITO layer with the help of CO2 laser. The microchannel layer was fabricated using a PDMS soft-lithography method wherein the mold created by maskless lithography. The optimized dimensions opted to develop a microfluidic device with length of 20 mm, width of 0.5 mm and gap of 1 mm. The device, with bare unmodified ITO electrodes, was tested to detect Cu and Hg by a portable potentiostat connected with a smartphone. The analytes were introduced in the microfluidic device with a peristaltic pump at an optimal flow rate of [Formula: see text]/min. The device exhibited sensitive electro-catalytic sensing of both the metals by achieving an oxidation peak at -0.4 V and 0.1 V for Cu and Hg respectively. Furthermore, square wave voltammetry (SWV) approach was used to analyze the scan rate effect and concentration effect. The device also used to simultaneously detect both the analytes. During simultaneous sensing of Hg and Cu, the linear range was observed between [Formula: see text] to [Formula: see text], the limit of detection (LOD) was found to be [Formula: see text] and [Formula: see text] for Cu and Hg respectively. Further, no interference with other co-existing metal ions was found manifesting the specificity of the device to Cu and Hg. Finally, the device was successfully tested with real samples like tap water, lake water, and serum with remarkable recovery percentages. Such portable devices pave way for detecting various heavy metal ions in a point-of-care environment. The developed device can also be used for detection of other heavy metals like cadmium, lead, zinc etc., by modifying the working electrode with the various nanocomposites.

Numerical Analysis of a Novel Rotating Piston Blood Pump Based on CFD

Currently, centrifugal and roller pumps are primarily used as ECMO blood pumps, but their high pressure or high shear force may lead to complications such as hemolysis and platelet activation. Thus, a new blood pump structure was designed by improving the rotating piston pump and applying it to the blood pump. The blood pump flow field was simulated using CFD simulation software to ensure that this pump can produce pulsatile blood flow and guarantee good distribution of flow velocity, pressure, and shear stress in the blood pump. The hemolysis value of the pump was calculated using the Lagrangian particle tracking method. The research results demonstrate that this pump has excellent hemodynamic performance and that most of the shear stresses are less than 100 Pa, as well as a small hemolysis index. Furthermore, the pump combines the advantages of pulsatile and non-pulsatile pumps. This newly developed pump is expected to provide a new direction for ECMO blood pump development and provides important evidence for further optimization and performance evaluation of rotating piston blood pumps.

Thermally induced long-term behavior of energy piles under vertical-horizontal combined mechanical loads

At present, energy piles have been gradually applied to support the foundation of bridge abutments, high-rise buildings, earth retaining structures, seafront structures, or buildings located on the sloping ground [1, 2, 3]. During the long-term service, energy piles are subjected to vertical-horizontal combined mechanical loads while under thermal cycles. Nevertheless, most of the research presented in the literature focused on the effects of thermal cycles on the axial mechanical responses of energy piles [4, 5, 6]. Studies evaluating the effects of thermal cycles on the long-term behavior of energy piles under vertical-horizontal combined mechanical loads are scarce.&#x0D; To this end, this study presents an experimental method based on a small-scale pile model installed in saturated kaolin clay to study the long-term thermomechanical performance of energy piles under thermal cycles and inclined mechanical loads. As shown in Figure 1, the experimental setup consists of a cylindrical steel soil tank, a temperature control system, and a data acquisition system. The soil tank has a diameter of 548 mm and a height of 980 mm. A two-layer geotextile filter and an insulation PVC material covered the internal and external surfaces, respectively. The model pile is made of an aluminum tube with a length of 600 mm, an outer diameter of 20 mm, and an inner diameter of 18 mm. The outer surface of the pile was coated with sand to maximize the roughness.&#x0D; During the tests, the model pile was placed at the center of the soil tank. The distance between the pile tip and the bottom of the soil tank was 340 mm, which equals 17 D (i.e., the outer diameter of the pile), and the distance between the outer surface of the pile and the inner wall of the soil tank was 264 mm, corresponding 13.2 D. The above values are all greater than 10 D and the influence of boundary effect on the test results can be considered to be insignificant [7]. Besides, the particle-size scaling effect can be negligible because the ratio of the pile diameter to the mean particle size of the kaolin clay is larger than the threshold value of 40 suggested by Fioravante [8].&#x0D; The testing protocole can be divided into four steps. (i) First, a sand layer of 40 mm was placed on the bottom of the soil tank to ensure that water could flow from the bottom to the top more quickly. Then the kaolin clay with an optimum water content of 29% was compacted by 50 mm thick layers until the soil tank was full of kaolin clay with a maximum dry density of 1450 kg/m3. (ii) Second, a water reservoir was used to inject de-aired water from the bottom of the soil tank for two months. (iii) Third, the vertical mechanical load of 100 N, corresponding to 20% of the pile resistance, was applied to the pile head for two days, and the settlement of the pile head was observed to be stable. Then, three levels of horizontal loading of 35, 71, and 109 N were selected to apply to the pile head and maintained for one month at each level to consolidate the soil before the coming of thermal cycles. (iv) At each horizontal load level, fifteen thermal cycles with an amplitude of ±4.5 ℃ were applied to the pile by the temperature-controlled bath and a peristaltic pump. Each thermal cycle was completed within 24 hours, which consisted of a heating duration of 3 hours, a cooling duration of 3 hours, and a recovery duration of 18 hours for active heating to return to the initial temperature.&#x0D; The results show that irreversible settlement and horizontal displacement of the pile head are induced by the thermal cycles. The effect of thermal cycles on the mechanical response of the model energy pile is more pronounced in the horizontal direction compared to the axial direction. The most significant increment of irreversible pile head settlement and horizontal displacement is caused by the first heating-cooling cycle; then, as the number of thermal cycles increases, the subsequent increments decrease and tend to stabilize. Furthermore, the finite element method was employed to simulate the model test and compare experimental and numerical results to discuss the mechanisms at the origin of the irreversible displacement to gain further insight into the experimental data. The results highlight the critical role of inclined mechanical loads in the pile-soil interaction subjected to long-term thermomechanical loading.