Capillary Tube Research Articles

Usefulness of hot shot intermittent infusion online hemodiafiltration plus far-infrared therapy for dialysis patients with lower extremity arterial disease: a case report

BackgroundLower extremity arterial disease (LEAD) occurs at a high frequency in dialysis patients and is associated with a poor prognosis. In recent years, intermittent infusion online hemodiafiltration (I-OHDF) combined with far-infrared therapy (FIR) has been reported as being useful in dialysis patients with LEAD. However, there are also reports of worsening of the ulcers and gangrene in some cases. Hot shot I-OHDF (HS I-OHDF), which involves intermittent infusion of heated dialysate, is reported as being more effective than conventional I-OHDF for improving the plasma refilling rate (PRR) and peripheral circulation. We report the case of a patient in whom a lower extremity ulcer healed only after we switched from I-OHDF + FIR to HS I-OHDF + FIR, and the usefulness of this treatment.Case presentationThe patient was a 41-year-old male dialysis patient with LEAD who showed worsening of the ulcers in the lower extremity before he was switched from I-OHDF plus FIR to HS I-OHDF plus FIR; we compared the changes in the lower extremity blood flow, PRR, degree of wound healing, and subjective symptoms over time after the switch to HS I-OHDF plus FIR as compared with the values prior to the switching. As compared with the values during I-OHDF plus FIR, the lower extremity blood flow and PRR increased markedly during HS I-OHDF plus FIR. The wounds in the lower extremity improved over time during HS I-OHDF plus FIR and showed complete healing after 6 months; evaluation by visual analog scales (VASs) showed improved scores for all of fatigue, pain, coldness, and insomnia, and the patient reported improved subjective symptoms. The mechanism underlying the effectiveness of HS I-OHDF plus FIR in promoting wound healing is unknown, however, we speculated that the temperature change in the intermittent infusion solution resulted in increased blood flow in the true capillaries (resting vessels) and transfer of the nonthermal effects of FIR to more peripheral vessels.ConclusionsThis case demonstrates that combined use of HS I-OHDF with FIR can enhance the efficacy of FIR in dialysis patients with LEAD by increasing the lower extremity blood flow and PRR, which is useful for wound healing.

Electrically switched asymmetric interfaces for liquid manipulation.

External field driven fluid manipulation, in particular electric field, offers the advantages of real-time control and exceptional flexibility, rendering it highly promising for applications in microfluidic devices, liquid separation and energy catalysis. However, it is still challenging for controlled liquid transport and fine control of droplet splitting. Herein, we demonstrate a strategy to achieve direction-controlled liquid transport and fine droplet splitting on an anisotropic groove-microstructured electrode surface via an electrically switched asymmetric interface. The balance of asymmetric capillary force generated by microstructures and electro-capillary force is critical in determining directional liquid transport and fine droplet splitting. Asymmetric bubbles generated by liquid electrolysis form an asymmetric liquid-gas-solid interface and result in gradient liquid wetting behavior on the two neighboring electrode surfaces. The electric field further enhances the asymmetric wetting of a liquid droplet on the electrode surface, exhibiting electric field direction-dependent motion. Moreover, the groove-microstructured electrode surface can strengthen the liquid droplet anisotropic wetting and correspondingly refine the volume range of the splitting sub-droplet. Even unidirectional/bidirectional liquid droplet transport can be controlled in collaboration with the asymmetric groove-microstructure and electric field. Thus, this work provides a new route for liquid transport and droplet splitting, showing great potential in controllable separation, microreaction and microfluidic devices.

Coarse-Grained MD Simulations of the Capillary Interaction between a Sphere and a Binary Fluid with Truncated Lennard-Jones Potentials.

In atomic force microscopy experiments on fluid samples, a capillary bridge forms between the tip and the fluid, causing an attractive capillary force. Here, we present a computational model of the capillary interaction between a solid sphere and a coarse-grained Lennard-Jones fluid containing 10% antifreeze particles with an enlarged van der Waals radius. The capillary force acting on the sphere is obtained from the displacement of the sphere in a trap potential as the sphere is incrementally approached and then retracted from the fluid. This yields force-distance data similar to that obtained in atomic force microscopy experiments. We use this methodology to study the influence of the cutoff radius of the truncated Lennard-Jones potentials on the capillary force and its temperature dependence. The latter is found to scale with the critical temperature of the system. With the presented approach, the tip-sample interaction can be studied for a wide range of complex fluids, particle shapes, and force-probing schemes.

A novel model for low-permeability reservoir numerical simulation considering dynamic capillary force

ABSTRACT Capillary force is not only affected by water saturation but also affected by fluid flow velocity, which is necessary to modify the prior numerical simulation methods. First, a dynamic capillary force testing device was developed, then, an experimental procedure was adopted to measure the dynamic capillary force curve. Three dynamic capillary force curves were obtained under different displacement velocity conditions. Finally, the dynamic capillary force was introduced into the flow equation of low-permeability reservoir numerical simulation. The oil-phase equation and water-phase equation were discretized in three-dimensional space, and the IMPES method was used to solve the water saturation and pressure difference. The calculation results between the traditional numerical simulation method and the novel method under heterogeneous and inhomogeneous conditions were analyzed. The results reveal that the difference in water cut is mainly reflected in the rapid rise of water cut. In the early stage of rapid increase, the water cut calculated by the new method is slightly higher than traditional method. When the water cut is more than 65%, the water cut calculated by the new method is slightly lower than the traditional method.

Heat transfer and electromagnetic property investigation on the hot air quartz fiber/PTFE capillary/epoxy resin anti/de‐icing composites

AbstractTo achieve the wave‐transparent and anti/de‐icing requirements of electromagnetic functional structural components on the windward surface of the aircraft, the PTFE capillary hot air tubes were pre‐buried inside the quartz fiber cloth and the hot air anti/de‐icing quartz fiber/PTFE capillary/epoxy resin (QF/PTFE/EP) composite components was prepared to that met the wave‐transparent performance. A multi‐field coupled numerical finite element simulation model was established, and the anti/de‐icing performance of the QF/PTFE/EP composite with different built‐in tube diameters were investigated by combining experiments and simulations under different hot air temperatures and pressures. The feasibility of hot air anti/de‐icing was verified through anti/de‐icing experiments and numerical simulation. The electromagnetic transmittance of the prepared hot air anti/de‐icing QF/PTFE/EP composite components was tested to characterize the effect on the stealth performance of the aircraft under the service environment. The experimental results demonstrated that with 5 mm tube pitch and hot air of 60°C ± 1°C, the surface temperature of the component with three tube diameters could reach more than 10°C. Furthermore, the decrease in the transmittance of the hot air anti/de‐icing QF/PTFE/EP composite components caused by different incidence angles and two polarization modes was less than 3%.Highlights The hot air QF/PTFE/EP anti/de‐icing composite components were fabricated. The heat transfer, anti/de‐icing, and electromagnetic transmittance performance of the hot air QF/PTFE/EP anti/de‐icing QF/PTFE/EP components were investigated. The experimental and simulation results verified the hot air anti/de‐icing QF/PTFE/EP components met the requirement of aircraft anti/de‐icing and wave transmission.

Metal-Organic Framework-Derived Ni-Doped Indium Oxide Nanorods for Parts per Billion-Level Nitrogen Dioxide Gas Sensing at High Humidity.

Detecting parts per billion (ppb)-level nitrogen dioxide in high-moisture environments at room temperature without reducing sensing performance is a well-recognized significant challenge for metal oxide-based gas sensors. In this study, metal-organic framework-derived nickel-doped indium oxide (Ni-doped In2O3) mesoporous nanorods were prepared by a solvothermal method combined with the calcination process. The sensors prepared using the obtained Ni-doped In2O3 nanorods showcase an ultrahigh response, low detection limit, and excellent selectivity. Moreover, the abundant active sites triggered by nickel doping and the capillary enhancement effect caused by mesopores endow the sensor with ppb-level (20 ppb) NO2 detection capability in high-moisture environments (95% RH) at room temperature. With the increase in humidity, the carrier concentration of the sensor increases, and the nitric acid generated by nitrogen dioxide dissolved in water can be completely ionized in water and has high conductivity. Therefore, the gas response of the sensors increases with the increase in humidity. This study establishes a promising approach for the development of trace nitrogen dioxide-sensing devices that are resilient in high-humidity environments.

Highly Sensitive Gas Pressure Sensing with Temperature Monitoring Using a Slightly Tapered Fiber with an Inner Micro-Cavity and a Micro-Channel

A highly sensitive optical fiber gas pressure sensor with temperature monitoring is proposed and demonstrated. It is based on a slightly tapered fiber with an inner micro-cavity forming an in-fiber Mach–Zehnder interferometer (MZI), and a micro-channel is drilled into the lateral wall of the in-fiber micro-cavity using a femtosecond laser to allow gas to flow in. Due to the dependence of the refractive index (RI) of air inside the micro-cavity on its gas pressure and the high RI sensitivity of the MZI, the device is extremely sensitive to gas pressure. To prevent fiber breakage, the MZI is housed in a silicate capillary tube with an air inlet. Multiple modes are excited by slightly tapering the inner micro-cavity, and the resonance dips in the sensor’s transmission spectrum feature different linear gas pressure and temperature responses, so a sensitivity matrix algorithm can be used to achieve simultaneous demodulation of two parameters, thus resolving the temperature crosstalk. As expected, the experimental results demonstrated the reliability of the matrix algorithm, with pressure sensitivity reaching up to ~−12.967 nm/MPa and temperature sensitivity of ~89 pm/°C. The features of robust mechanical strength and high air pressure sensitivity with temperature monitoring imply that the proposed sensor has good practical and application prospects.

Textile fabric's in-plane water permeability determination during wicking

Based on a mathematical formulation of the water flow for different wicking configurations (ascendant-horizontal and descendant), a combined ascendant, horizontal and descendant wicking experimental test was designed to provide detailed measurements of the pertinent wicking performance properties: capillary pressure and in-plane direction permeability. This method was proposed due to capillary flows found in standard vertical wicking tests as well as erroneous assumptions made in other wicking tests. The effective capillary radius was assumed to remain constant as the height of the liquid increases. This assumption would suggest that saturation, capillary pressure, and permeability are also constants. However, experiments show that these properties are only constants in the case of the descendant wicking when liquid front height is varied. The capillary pressure and permeability calculations were made using Darcy’s law and the Lucas-Washburn equation as a function of the saturation level. In the combined wicking test, conducting a horizontal wicking test allows us to calculate the effective capillary radius of a fabric as the saturation rate was found to be constant, which in turn can be used to solve for capillary pressure. That capillary pressure can then be used in a descendant wicking test, where the liquid front flow and the saturation rate remain constant, and Darcy’s law to solve for permeability. A series of experiments was conducted on cotton jersey knitting. The results showed that the ability to wick the water depends on pore size and porosity scales: macro and micropores. The in-plane water permeability was found to be directly related to the saturation rate.

Synthesis and surfactant properties of sulfonate Gemini surfactants

Abstract In this study, a novel high salinity resistant, high temperature tolerant sulfonate Gemini surfactant (CK-3) for enhanced oil recovery was synthesized and is described. The critical micelle concentration (CMC) of CK-3 is 7.3 × 10−5 mol L−1 with a surface tension at CMC, γ CMC , of 30.88 mN m−1, and a pC20 value of 4.80. Moreover, increasing temperature led to delayed micellization, indicating the superior surface activity inherent in Gemini surfactants. When CK-3 was evaluated as an imbibing agent, an interfacial tension of 8.3 × 10−2 mN m−1 was observed between a 0.3 wt% CK-3 solution and crude oil, facilitated by hydrophobic group interactions which allow crude oil detachment. Finally, CK-3 molecules exhibited stable adsorption on rock walls, influencing wetting reversal. Zeta potential measurements exceeding 30 mV indicated stability. In aged capillary tubes, a 0.3 wt% CK-3 solution exhibited a rise height of 2.9 cm. Imbibition experiments on natural core samples showed a water imbibition efficiency of 8.73 %, compared to a significantly improved efficiency of 50.78 % with a 0.3 wt% CK-3 solution. This study also demonstrated the imbibition process and mechanisms of the CK-3, providing novel insights for the efficient development of unconventional oil reservoirs and the enhancement of crude oil recovery rates.

Endothelial Beta 1 Integrins are Necessary for Microvascular Function and Glucose Uptake.

Microvascular insulin delivery to myocytes is rate limiting for the onset of insulin-stimulated muscle glucose uptake. The structural integrity of capillaries of the microvasculature is regulated, in part, by a family of transmembrane adhesion receptors known as integrins, which are composed of an α and β subunit. The integrin β1 (itgb1) subunit is highly expressed in endothelial cells (EC). EC itgb1 is necessary for the formation of capillary networks during embryonic during development and its knockdown blunts the reactive hyperemia that manifests during ischemia reperfusion. We investigated the contribution of EC itgb1 in microcirculatory function and glucose uptake with emphasis in skeletal muscle. We hypothesized that loss of EC itgb1 would impair microvascular hemodynamics and glucose uptake during insulin stimulation, creating 'delivery'-mediated insulin resistance. An itgβ1 knockdown mouse model was developed to avoid lethality of embryonic gene knockout and the deteriorating health resulting from early post-natal inducible gene deletion. Mice with (itgb1fl/flSCLcre) and without (itgb1fl/fl) tamoxifen inducible stem cell leukemia cre recombinase (SLCcre) expression at 10 days post cre induction had comparable exercise tolerance and pulmonary and cardiac functions. Using robust in vivo experimental platforms (i.e., intravital microscopy and hyperinsulinemic-euglycemic clamp), we show that itgb1fl/flSCLcre mice compared to itgb1fl/fl littermates have, i) deficits in capillary flow rate, flow heterogeneity, and capillary density; ii) impaired insulin-stimulated glucose uptake despite sufficient transcapillary insulin efflux; and iii) reduced insulin-stimulated glucose uptake due to perfusion-limited glucose delivery. Thus, EC itgb1 is necessary for microcirculatory function and to meet the metabolic challenge of insulin stimulation.

Capillary flow velocity-based length identification of PCR and RPA products on paper microfluidic chips.

This work demonstrates a novel, non-fluorescence approach to the length identification of polymerase chain reaction (PCR) and recombinase polymerase amplification (RPA) products, utilizing capillary flow velocities on paper microfluidic chips. It required only a blank paper chip, aminated microspheres, and a smartphone, with a rapid assay time and under ambient lighting. A smartphone evaluated the initial capillary flow velocities on the paper chips for the PCR and RPA products from various bacterial samples, where the pre-loaded aminated microspheres differentiated their flow velocities. Flow velocities were analyzed at different time frames and compared with the instantaneous flow velocities and interfacial tension (γLV) data. Subsequent error analysis justified the use of the initial time frames. A robust linear relationship could be established between the initial flow velocities against the square root of the product lengths, with R2 values of 0.981 for PCR and 0.993 for RPA. The assay seemed not to have a significant dependency on the cycle numbers and initial target concentrations. This novel method can be potentially used with various paper microfluidic methods of nucleic acid amplification tests towards rapid and handheld assays.

Enhancement of critical current density using micro-porous structure in a low-temperature water electrolysis

The critical current density (CCD), which limits the hydrogen production rate was measured by forming micro-porous structures on the cathode electrode in a low-temperature water electrolysis. Several micro-porous structures were formed by the electrodeposition method varying the current density during the deposition. A maximum 54% enhancement of the CCD was recorded compared to the plain surface. With the micro-porous structures, the superior capillary wicking effect allowed the electrolyte to penetrate the structure, resulting in the increased number of hydrogen nucleation sites. The increased hydrogen nucleation sites led to the decreased hydrogen bubble size and increased departed bubble density, which delayed formation of the hydrogen film leading to the CCD. The surface morphology revealed that the multiple pore layers with the interconnected pores exhibited superior capillary wicking effect compared to the open type single pore layer. It is expected that the results of present work stimulate further research regarding electrode surface design in the low-temperature water electrolysis.

MiR-497-5p Ameliorates Deep Venous Thrombosis by Facilitating Endothelial Progenitor Cell Migration and Angiogenesis by Regulating LITAF.

Deep vein thrombosis (DVT) is a clinical manifestation of venous thromboembolism and a major global burden of cardiovascular disease. In recent years, the crucial role of microRNAs (miRNAs) in cardiovascular disease has been confirmed. Here, we aimed to investigate the specific effect of miR-497-5p on DVT. The endothelial progenitor cells (EPCs) were obtained from the bone marrow of newborn rats and transfected with miR-497-5p mimics or/and pcDNA3.1/lipopolysaccharide-induced TNF factor (LITAF). The proliferation and migration abilities of EPCs were detected using CCK-8 assay and transwell assay, respectively. Angiogenesis was evaluated using tube formation assay. The interaction of miR-497-5p and LITAF was confirmed by luciferase reporter experiment. DVT rat model in vivo was established by inferior vena cava (IVC) ligation in Sprague-Dawley rats. Histological analysis of IVC tissue was conducted by hematoxylin-eosin staining. We found that enhancing miR-497-5p expression facilitated the abilities of proliferation and migration of EPCs. Additionally, overexpression of miR-497-5p increased the capacity of EPCs to form capillary tubes on Matrigel. LITAF was found to be targeted by miR-497-5p and negatively regulated by miR-497-5p. Overexpression of LITAF counteracted the miR-497-5p overexpression's effect on the proliferation, migration, and angiogenesis abilities of EPCs. Moreover, the injection of agomir-miR-497-5p alleviated thrombus formation, reduced thrombus weight, and reduced the serum level of D-dimer in DVT rat model by reducing LITAF expression. This study suggests that miR-497-5p alleviates DVT by facilitating EPCs proliferation, migration, and angiogenesis by targeting LITAF.

Effect of surface roughness on the liquid bridge between two rigid spheres

We aimed to investigate the impact of surface roughness on liquid bridges between spherical particles. Sandblasting was used to control the particle size and produce glass beads and plates with different surface roughness. First, by measuring the advancing and receding contact angles of droplets on different rough surfaces, we analyzed the effects of surface roughness on wettability and hysteresis. Next, we used a custom-made liquid-bridge stretching device to measure the capillary forces of the liquid bridges between spherical particles with different surface roughness values. A charge-coupled device camera acquisition system was set up to capture the morphological changes of the liquid bridge during stretching, and Image View software was used to extract the morphological parameters of the liquid bridge. Theoretically, we reasonably simplified and solved the differential equations for the liquid bridge morphology and used the Young–Laplace equation to calculate the theoretical capillary force of the liquid bridge, providing an in-depth analysis of the influence of surface roughness on the capillary force. Finally, we studied the impact of surface roughness on the volume ratio of the liquid bridge during static stretching and the residual liquid remaining after the liquid bridge breaks. Experimental results indicated that, as the surface roughness increased, the hydrophobicity and wettability hysteresis of the solid surface also increased. The increased hydrophobicity of the surface reduces the solid-liquid contact area of the liquid bridges between the particles, making it easier to form “columnar” or “convex” liquid bridges. Additionally, the enhanced wettability hysteresis causes the solid-liquid contact boundary to lag during the stretching of the liquid bridge, resulting in a decrease in the solid-liquid contact angle. These factors directly alter the geometric shape of liquid bridges during static stretching, thereby affecting capillary forces. Meanwhile, the increase in surface roughness weakens the effect of gravity on the morphology of the liquid bridge, resulting in less liquid mass remaining on the lower sphere after the liquid bridge breaks as the surface becomes rougher.

Discrepancy in oil displacement mechanisms at equivalent interfacial tensions: Differentiating contributions from surfactant and nanoparticles on interfacial activities

Discrepancies in oil displacement mechanisms at equivalent interfacial tensions were principally explored in the current study, with a novel emphasis on distinguishing the contributions of surfactants and nanoparticles in interfacial activities. The hypothesis was that if both chemicals exhibit similar interfacial activities, the oil displacement outcomes at the capillary scale should be consistent. Otherwise, differences would indicate distinct interfacial behaviors. Fluid displacement experiments were conducted using a two-dimensional micromodel, where nanofluids and surfactant solutions were tested at equivalent interfacial tensions. In the high interfacial tension pair (20 mN/m), the surfactant solution displaced oil more efficiently and rapidly than nanofluids, achieving greater ultimate oil recovery. This difference was attributed to the effective reinforcement of capillary forces in the surfactant system, which drove the displacement process. In contrast, the nanofluids did not achieve the same level of performance due to their limited ability to modify interfacial forces. This finding highlighted the two chemicals’ fundamentally different interfacial activities and oil displacement mechanisms. Furthermore, in the lowest interfacial tensions pair, where the surfactant achieved 6.5 mN/m and the nanofluids 15.6 mN/m, both systems unexpectedly displayed similar oil displacement efficiencies and fingering-like behaviors. This similarity, however, arose from distinct underlying mechanisms: capillary instability drove fingering in the surfactant system, while expansive layer flow induced fingering-like in the nanofluids. These findings challenge the assumption that reducing interfacial tension with nanoparticles is the primary mechanism in enhanced oil recovery (EOR). The study highlighted the need for a more refined understanding of the action of nanoparticle interfacial activities within EOR processes. To further validate these insights, future research should scale up fluid displacement studies to Darcy’s scale using core-flooding tests, enabling a more comprehensive examination of complex two-phase flow dynamics.

Threshold of Saturation Degree of Unsaturated Sand to Cause Liquefaction Considering the Sample Volumetric Strain: Modelization and Experimental Laboratory Investigation

ABSTRACT This paper aims to determine a non-liquefiable domain corresponding to the threshold of saturation degree where liquefaction does not occur under cyclic loading. To determine this threshold, sample volumetric strain at liquefaction state of unsaturated soil was modeled considering the suction. In low saturation degree zones, capillary suction is taken into account. In a high saturation degree zone, spherical suction caused by surface tension of air bubbles is considered by using its microscopic analysis and its equivalent size. Finally, three series of experimental tests have been made to give the data and verify the presented model.

Smart Green Cotton Textiles with Hierarchically Responsive Conductive Network for Personal Healthcare and Thermal Management.

Whereas cotton as an abundant natural cellulose has been widely used for sustainable and skin-friendly textiles and clothes, developing cotton fabrics with smart functions that could respond to various stimuli is still eagerly desired while remaining a great challenge. Herein, smart multiresponsive cotton fabric with hierarchically copper nanowire interwoven MXene conductive networks that are seamlessly assembled along a 3D woven fabric template for efficient personal healthcare and thermal comfort regulation is successfully developed. The robust hierarchically interwoven conductive network was "glued" and protected by organic conductive polymer poly(3,4-ethylenedioxythiophene) along a 3D interconnected fabric template to enhance interfacial adherent and environmental stability. Benefiting from the robust multiresponsive hierarchically interwoven conductive network, smart cotton fabric exhibits real-time response to various external stimuli (light/electrical/heat/temperature/stress), and the details of human activities can be accurately recognized and monitored. Furthermore, the porous structure of 3D smart fabric induced strong capillary force and confinement to phase change materials PEG, which exhibits a wide range of phase transition temperatures for efficient thermal comfort regulation. After further encapsulation with transparent fluorosilicone resin, the smart cotton fabric exhibits excellent self-cleaning performance with water/oil repellent. The smart multiresponsive cotton fabrics hold great promise in next-generation wearable systems for efficient personal healthcare and thermal management.

Antioxidant Sulfide‐Linked Polymer Membrane with Inherent Microporosity Enables Fuel Cells to Achieve Outstanding Power Density and Durability Over a Wide Temperature Range

AbstractConventional phosphoric acid (PA) doped polybenzimidazole are regarded as the most promising materials for high‐temperature proton exchange membrane fuel cells (HT‐PEMFCs). Yet, their practical application has been hindered by their high production cost, poor oxidation stability, and loss of PA at low temperatures. Here, a polymer of intrinsic microporosity containing “sulfide‐linkage” radical‐sacrificial‐agent is designed with good solubility and high PA retention, which enables it to operate for long periods at 80–180 °C. Specifically, the “sulfide‐linkage” radical‐sacrificial‐agent enabled PSBI‐IM to be durable for 100 h with mass retention still higher than 90%, and the capillary effect of the micropores enabled PSBI‐IM/PA to retain more than 60% of PA under high humidity. After rational optimization, the cell assembled with PSBI‐IM/PA achieved a power density of 1.62 W cm−2 with a specific power of 2.7 W mg−1 and an operating time of more than 500 h (0.2/0.4 A cm−2@160 °C). In addition, the voltage drop is only 5% even after 40 h of accelerated stress testing at 0.4 A cm−2@ 80 °C. Therefore, the PSBI‐IM/PA can be stabilized over a wide temperature range from 80 to 160 °C, providing a new material for the HT‐PEMFCs with flexible operational temperature.

A coupled displacement-pressure model for elastic waves induce fluid flow in mature sandstone reservoirs

Elastic (seismic) wave stimulation is considered one of the unconventional enhanced oil recovery (EOR) methods. Increasing water quantity in the high permeability layer of a mature oil reservoir is highly challenging and can significantly decrease the ultimate recovery due to the reservoir heterogeneity. Using seismic waves can be considered low-cost, environmentally friendly, and illuminates the entire reservoir size compared to conventional EOR methods. A numerical model is developed by extending the Quintal approach for seismic attenuation due to wave-induced fluid flow (WIFF) to incorporate capillary pressure in partially saturated porous media and shift undrained boundary conditions to exclude external flow stress for drained boundary conditions. Therefore, the fluid distribution due to the capillary effect makes the developed finite element method (FEM) u-p model more widely applicable for oil recovery in mature reservoirs. A two-layer partially saturated media was subjected to compressive seismic stress at low frequency (3 Hz). The results indicated that the vertical displacement gradients of the bottom and upper layers decline with excitation time for both fully and partially saturated media. On the other hand, partially saturated pore pressure gradients of both the upper and bottom layers have higher amplitudes with excitation time than fully saturated pore pressure gradients due to the influence of capillar pressure. The cumulative crossflow oil volume for 180 days of continuous stimulation was 1176 bbl, 1032 bbl, and 648 bbl in low permeability layers: 200 md, 100 md, and 50 md, respectively. Therefore, the developed model has the potential for field-scale EOR applications. The study also suggests coupling elastic EOR with CO2 flooding to recover more oil due to increasing fluid mobility and relative permeability to oil in low-permeability reservoirs or tight formations.

Distance-based analytical device integrated with carbon nanomaterials for sarcosine quantification in human samples.

Astraightforward distance-based paper analytical device (dPAD) was developedfor monitoring sarcosine levels in human samples for the rapid diagnosis and prognosis of prostate cancer and related symptoms. This assay eliminates the need for the expensive horseradish peroxidase (HRP) enzyme by utilizing carbon nanodots (CDs) as a peroxidase-like nanozyme. The proposed dPAD sensor consists of a sample zone pre-deposited with sarcosine oxidase (SOx) and CDs, and a detection zone containing 3,3',5,5'-tetramethylbenzidine (TMB). When a solution containing sarcosine is added to the sample zone, hydroxyl radicals (•OH) are produced through SOx oxidation and subsequent peroxidase catalysis by the CDs. The formed •OH radicals immediately flow to the detection zone via capillary force, where they oxidize TMB, resulting in a visible colour change from colourless to blue. Sarcosine quantification is effortlessly accomplished by measuring the distance of the blue colour in the detection zone. The developed dPAD offers a linear working range between 12.5 and 35.0nmol L-1 (R2 = 0.9959) and a detection limit (LOD) of 10.0nmol L-1. This covers the clinical range for urinary sarcosine determination, thereby suggesting no additional sample preparation or dilution is needed. The sensor shows high precision with the highest relative standard deviation (RSD) of 4.58% and demonstrates excellent selectivity with no observed interferences. Furthermore, recovery studies in human control urine samples ranged from 98.67 to 101.50%, with the highest RSD of 2.03%. Correspondingly, our dPAD method showed a great match with the performance of a commercial ELISA method for detecting sarcosine in human control serum. The sensor is more cost-effective, user-friendly, and accessible than previous methods. Overall, the proposed method represents a promising analytical tool for sarcosine quantification. The concept is also applicable for broader analytical applications in detecting other biomolecules.