PTFE Tube Research Articles

Detection of High-Temperature Gas Leaks in Pipelines Using Schlieren Visualization

This paper investigates the application of Schlieren flow visualization for detecting leaks in pipelines carrying high-temperature fluids. Two experimental setups were constructed: one with a 25 mm PTFE tube featuring a 2 mm diameter perforation, and another with a 100 mm diameter pipe insulated with an aluminum jacket and featuring a 12 mm leak gap. A single-mirror-off-axis Schlieren system, employing a 150 mm diameter parabolic mirror, was used to visualize the leaks. The temperature of the leaking air varied between 20 and 100 °C, while the ambient temperature was maintained at 14 °C. To quantify the leaks, the coefficient of variation for pixel intensity within the leak region was calculated. Results showed that for the PTFE tube, leaks became detectable when the temperature difference exceeded 34 °C, with the coefficient of variation surpassing 0.1. However, in the insulated pipe, detecting clear leak patterns was challenging. This research demonstrates the potential of Schlieren visualization as a valuable tool in enhancing pipeline leak detection.

Mass transfer phenomena of partially miscible liquids under liquid-liquid slug flow in a circular microchannel

Microreactors have been demonstrated to become an effective tool for increasing mass and heat transfer in heterogeneous chemical processes that are unachievable in batch or continuous stirred tank reactors. The key to superior performance is the availability of a large specific surface area (A/V) in the microsystem for mass and heat transfer between phases. Among the flow patterns generated in the two-phase liquid-liquid flow, slug is an ideal flow with a high stability characteristic, regular velocity, and uniform dimension throughout a microchannel system. The flow behavior gives slugs great potential to increase mass and heat transfer between phases, so optimizing the utilization of microreactors in many chemical process applications needs an in-depth understanding of the liquid-liquid hydrodynamic. Therefore, the current work aims to determine the mass transfer coefficient under liquid-liquid slug flow and the influence of slug dimensions, channel material, volumetric flow rate, and the flow rate ratio of the organic-aqueous phase on the mass transfer coefficient. The experiments were performed in 1 mm (ID) circular PTFE and silicone tubes, with a 30–40 ml/hour flow rate, and sodium hydroxide concentrations of 0.1, 0.13, and 0.15 M were used. The results exhibit that the most prominent overall mass transfer coefficient was 0.121/s, attained at 0.15 M sodium hydroxide concentration, with 40 ml/hour total discharge within the silicone channel. Microchannels generated smaller slug sizes at a higher aqueous phase flow rate than the organic phase. The smaller size provided a large specific surface area (A/V) for enhancing the mass transfer coefficient.

Nanomaterials as a Service (NaaS) concept: on-demand protocols for volume synthesis of nanomaterials.

Establishing scalable nanomaterials synthesis protocols remains a bottleneck towards their commercialisation and, thus, a topic of intense research and development. Herein, we present an automated machine-learning microfluidic platform capable of synthesising optically active nanomaterials from target spectra originating from prior experience, theorised or published. Implementing unsupervised Bayesian optimisation with Gaussian processes reduces the optimisation time and the need for prior knowledge to initiate the process. Using PTFE tubing and connectors enables facile change in reactor design. Ultimately, the platform substitutes the labour-intensive trial-and-error synthesis and provides a pathway to standardisation and volume synthesis, slowing down the translation and commercialisation of high-quality nanomaterials. As a proof-of-concept, Ag nanoplates and Prussian-blue nanoparticle protocols were optimised and validated for volume production.

Microfluidic technology for macro systems: Removal of textile dyes from wastewater in a microreactor

Wastewater from textile industry contains considerable amount of dissolved dye that can trigger environmental issues if is not treated properly. Numerous methods have been developed to degrade recalcitrant pollutants safely and utterly. Among them, enzymatic treatment of wastewater is gaining attention due to the enzyme’s specificity, easier manipulation, and generation of less toxic by-products. Still, the cost of enzymatic systems is the main limitation keeping the biocatalysts at lab-scale. Alternative solution for reducing the cost of enzymatic reaction systems is the use of microfluidic systems, which contribute to better mixing, process intensification and cleaner production. In this study, implementation of horseradish peroxidase for removal of the textile dye Acid Violet 109 is performed in a microfluidic reactor. The microreactor consists of three plunger pump units, two mixers and PTFE tube. The process parameters: residence time, dye, hydrogen peroxide, enzyme activity, the reactors’ diameter and length were optimized. Under the optimal process conditions: 30 mg/L dye concentration, 0.8 U/mL horseradish peroxidase activity, 0.1 mM hydrogen peroxide, 0.25 mm reactor’s diameter, 97,3 % removal was achieved at residence time of 6 min. The results from this study show that enzymatic microfluidic reactors are a convenient technology for dye removal.

Foam-in-Vein: Characterisation of Blood Displacement Efficacy of Liquid Sclerosing Foams.

Sclerotherapy is among the least invasive and most commonly utilised treatment options for varicose veins. Nonetheless, it does not cure varicosities permanently and recurrence rates are of up to 64%. Although sclerosing foams have been extensively characterised with respect to their bench-top properties, such as bubble size distribution and half-life, little is known about their flow behaviour within the venous environment during treatment. Additionally, current methods of foam characterisation do not recapitulate the end-point administration conditions, hindering optimisation of therapeutic efficacy. Here, a therapeutically relevant apparatus has been used to obtain a clinically relevant rheological model of sclerosing foams. This model was then correlated with a therapeutically applicable parameter-i.e., the capability of foams to displace blood within a vein. A pipe viscometry apparatus was employed to obtain a rheological model of 1% polidocanol foams across shear rates of 6 s-1 to 400 s-1. Two different foam formulation techniques (double syringe system and Tessari) and three liquid-to-gas ratios (1:3, 1:4 and 1:5) were investigated. A power-law model was employed on the rheological data to obtain the apparent viscosity of foams. In a separate experiment, a finite volume of foam was injected into a PTFE tube to displace a blood surrogate solution (0.2% w/v carboxymethyl cellulose). The displaced blood surrogate was collected, weighed, and correlated with foam's apparent viscosity. Results showed a decreasing displacement efficacy with foam dryness and injection flowrate. Furthermore, an asymptotic model was formulated that may be used to predict the extent of blood displacement for a given foam formulation and volume. The developed model could guide clinicians in their selection of a foam formulation that exhibits the greatest blood displacement efficacy.

Optical collection of extracellular vesicles in a culture medium enhanced by interactions with gold nanoparticles.

Extracellular vesicles (EVs) exist in biological fluids such as blood, urine, and cerebrospinal fluid and are promising cancer biomarkers. Attempts to isolate and analyze trace EVs, however, have been a challenge for researchers studying their functions and secretion mechanisms, which has stymied the options for diagnostic application. This study demonstrated a collection of EVs that was enhanced by gold nanoparticles (AuNPs) via the use of optical force. The collection system consists of an inverted microscope equipped with a CCD camera, a square capillary connected with a PTFE tube, and an Nd:YAG laser that generates optical force. The laser beam was focused on a capillary wall in which a cell culture medium containing EVs flowed continuously. Control of the surface charges on both the capillary wall and the AuNPs achieved the collection and retention of EVs on the capillary wall. The positively charged capillary wall retained EVs even after the laser irradiation was halted due to the negative charges inherent on the surface of EVs. Conversely, positively charged AuNPs had a strong electrostatic interaction with EVs and enhanced the optical force acting on them, which made collecting them a much more efficient process.

Programmable Millifluidic Platform Integrating Automatic Electromembrane Extraction Cleanup and In-Line Electrochemical Detection: A Proof of Concept.

A fully automatic millifluidic sensing platform coupling in-line nonsupported microelectromembrane extraction (μ-EME) with electrochemical detection (ECD) is herein proposed for the first time. Exploiting the features of the second generation of flow analysis, termed sequential injection (SI), the smart integration of SI and μ-EME-ECD enables (i) the repeatable formation of microvolumes of phases for the extraction step in a membrane-less (nonsupported) arrangement, (ii) diverting the acceptor plug to the ECD sensing device, (iii) in-line pH adjustment before the detection step, and (iv) washing of the platform for efficient removal of remnants of wetting film solvent, all entirely unsupervised. The real-life applicability of the miniaturized sensing system is studied for in-line sample cleanup and ECD of diclofenac as a model analyte after μ-EME of urine as a complex biological sample. A comprehensive study of the merits and the limitations of μ-EME solvents on ECD is presented. Under the optimal experimental conditions using 14 μL of unprocessed urine as the donor, 14 μL of 1-nonanol as the organic phase, and 14 μL of 25 mM NaOH as the acceptor in a 2.4 mm ID PTFE tubing, an extraction voltage of 250 V, and an extraction time of 10 min, an absolute (mass) extraction recovery of 48% of diclofenac in urine is obtained. The proposed flow-through system is proven to efficiently remove the interfering effect of predominantly occurring organic species in human urine on ECD with RSD% less than 8.6%.

High performance liquid-solid tubular triboelectric nanogenerator for scavenging water wave energy

The exploitation of clean and renewable wave energy has attracted fully concern in the world wide. In this work, a high-output array of liquid-solid tubular triboelectric nanogenerator (LST-TENG) based on the contact electrification between PTFE and water was proposed. The low-frequency wave motion was simulated to systematically analyze the impacts of several factors on the electrical performance of LST-TENG to provide guidance for the fabrication of the PTFE tube and the electrode arrangement for the achievement of high wave energy transition. An increase in the length/diameter of the tube, distance and width of the electrodes made a positive impact on the output performance of LST-TENG unit. A typical LST-TENG here should be an optimum water-to-cylinder volume ratio, as well it is better to wrap electrodes from the end, especially for short electrodes. Moreover, the influences of the motion characteristics including the angle, frequency and amplitude of oscillation was also considered. To achieve high peak output, we compared the output performance of series-wound and parallel LST-TENG arrays to find that parallel connection showed linear rise with the number of units is a feasible approach to get peak output voltage exceed 500 V, which extended the potential application of the LST-TENG arrays. At the optimal operating condition, the power density achieved 228 mW/m3. This study provided the assessment of the power quality of LST-TENG and considering the diverse motion of the TENG units integrated into the blocks, which is expected to be the reference for the optimization of LST-TENG in the future.

Design and Evaluation of a Robotic Forceps With Flexible Wrist Joint Made of PEEK Plastic

This letter presents the design and evaluation of a robotic forceps in which the wrist joint is made of polyetheretherketone (PEEK) plastic. Due to the structural improvement of enclosing a flexible backbone of PTFE tube inside the wrist joint, the developed forceps simultaneously fulfills the requirements of small diameter, bending dexterity, sufficient axial stiffness, and even the control rigidity. The proposed robotic forceps employs pneumatic drive with wire actuation mechanism. For accurate motion control and external force estimation, we developed a novel inverse dynamics model considering the coupled dynamic effect between the wrist joint and the gripper motions. The position control accuracy of the wrist joint bending angle is at the level of 1 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^\circ$</tex-math></inline-formula> and is not affected by the simultaneous open–close motion of the gripper. The translation and grasping forces are beyond 4.5 N, enabling powerful tasks in laparoscopic surgery. Furthermore, the robotic forceps is capable of multi-DOF external force estimation. The estimation accuracy of the translation force is about 0.2 N, and the estimation accuracy of grasping force remains within 0.2 N regardless of the bending angle of the wrist joint. The performance evaluation results demonstrate that the developed forceps is eligible to be used in robotic-assisted laparoscopic surgery.

Experimental study of rheological behavior of foam flow in capillary tubes

• Rheological behavior of the pre-generated foam was studied in capillary tubes • Tube materials were: PTFE and FEP (hydrophobic) and glass tubes (hydrophilic) • Foam behaves as shear-thinning fluid in all capillary tubes • Transition foam quality in tubes depends on the material type and tube diameter • Foam's apparent viscosity is higher in hydrophobic tubes than in hydrophilic tube due to wall-slip velocity • Wall-slip velocity depends on the tube material type and diameter • Foam texture in tubes is highly dependent on foam quality and flow rate Studies of foam flow in highly permeable porous media are still limited due to foam's complex behavior and discrepancies in foam research. Specifically, it is still unclear how foam flows in capillary tubes and what the effects of material and tube diameter are. We have investigated the rheology of pre-generated foam in capillary tubes. Experiments were carried out using two types of capillary tubes: hydrophobic (PTFE – polytetrafluoroethylene; FEP – fluorinated ethylene propylene) and hydrophilic (GT – glass tubes). The foam was previously formed in the sand-pack by co-injecting a surfactant solution and nitrogen gas. We investigated the effect of material and tube size on foam rheology versus gas fraction (for a fixed flow rate) and flow rate (for a fixed gas fraction). A three-parameter Herschel-Bulkley model was used to describe foam rheology in capillary tubes. Pictures of foam flow in GT and FEP tubes were taken to determine the mean bubble area using image analysis. We estimated wall-slip velocity in capillary tubes and compared the results with the bulk-foam rheology using an analytical expression of the Herschel-Bulkley model for volumetric flow through the circular tubes. We observed shear-thinning behavior in all capillary tubes (FEP, PTFE, GT), and the Herschel-Bulkley model successfully fitted its behavior. The foam in PTFE tubes behaved as a yield-stress fluid, while yield stress was not observed in GT and FEP tubes. We also found that transition foam quality depends on the material type and tube diameter. The results show that foam's apparent viscosity is higher in hydrophobic tubes (FEP and PTFE tubes) than in hydrophilic glass tubes. This was explained by the wall-slip velocity being higher in glass tubes than in FEP and PTFE tubes because of the difference in surface roughness. The corrected flow rate without wall slip matches the flow rate calculated using the measured bulk foam viscosity better. Therefore we conclude that considering wall-slip velocity is important when studying foam flow in porous media.

Continuous Segmented-Flow Synthesis of Ag and Au Nanoparticles Using a Low Cost Microfluidic PTFE Tubing Reactor.

We present in here a simple and low cost continuous segmented-flow process for the synthesis of Ag and Au spherical-shaped nanoparticles. Different residence times (RT) were used to perform the nanoparticle synthesis, observing that at low RT, the Ag nanoparticles production, which uses a fast reduction reaction with NaBH4, is improved due to an enhancement in the mixing of the reactants. However, the flow conditions have an opposite effect in the case of Au nanoparticles synthesis. Indeed, since the chemical reduction process (Turkevich method) exhibit a much slower kinetics, high RT (low flowrates) improve the synthesis yield and the quality of the nanoparticles. The Ag and Au nanoparticles were characterized by UV-Vis spectrophotometry (UV-Vis) and Transmission Electron Microscopy (TEM). The Ag spherical-shaped nanoparticles presented a LSPR at 400 nm (size ≈ 4 nm), while the synthesized Au nanoparticles exhibit LSPR and sizes in the range 520 - 550 nm and 14 - 17 nm, respectively.

First visualisation of bacterial biofilms in 3D porous media with neutron microtomography without contrast agent.

Characterising bacterial biofilm growth in porous media is important for developing reliable numerical models of biofouling in industrial biofilters. One of the promising imaging methods to do that has been a recent successful application of X-ray microtomography. However, this technique requires a contrast agent (1-chloronaphtalene, for example) to distinguish biofilm from the liquid phase, which raises concern about biofilm disruption and impaired image interpretation. To overcome these drawbacks, we tested a new approach based on neutron tomography (NT), which does not need a contrast agent, by imaging two types of porous media (polytetrafluoroethylene - PTFE - and clay beads of various diameters) in glass or PTFE tubes in which bacterial biofilms were grown for 7 days and by comparing these images with the ones obtained with X-ray microtomography. NT images showed that the biofilm formed preferentially around the beads and at bead/bead interface. Visual comparison of both imaging techniques showed consistent biofilm spatial distributions and that the contrasting agent did not significantly disrupt the biofilm. NT images, on the other hand, were still too noisy to allow quantitative measurements. Therefore, X-ray microtomography (provided it uses non-disruptive contrast agents) seems to provide more reliable microstructural descriptors.

Regenerating Critical Size Rat Segmental Bone Defects with a Self-Healing Hybrid Nanocomposite Hydrogel: Effect of Bone Condition and BMP-2 Incorporation.

The aim of the current study is to assess the biological performance of self-healing hydrogels based on calcium phosphate (CaP) nanoparticles and bisphosphonate (BP) conjugated hyaluronan (HA) in a critical size segmental femoral bone defect model in rats. Additionally, these hydrogels are loaded with bone morphogenetic protein 2 (BMP-2) and their performance is compared in healthy and osteoporotic bone conditions. Treatment groups comprise internal plate fixation and placement of a PTFE tube containing hydrogel (HABP -CaP) or hydrogel loaded with BMP-2 in two dosages (HABP -CaP-lowBMP2 or HABP -CaP-highBMP2). Twelve weeks after bone defect surgery, bone formation is analyzed by X-ray examination, micro-CT analysis, and histomorphometry. The data show that critical size, segmental femoral bone defects cannot be healed with HABP -CaP gel alone. Loading of the HABP -CaP gel with low dose BMP-2 significantly improve bone formation and resulted in defect bridging in 100% of the defects. Alternatively, high dose BMP-2 loading of the HABP -CaP gel does not improve bone formation within the defect area, but leads to excessive bone formation outside the defect area. Bone defect healing is not affected by osteoporotic bone conditions.

Continuous Preparation of Precious Metal Nanoparticles from Plant Biomass and CFD Simulation

Precious metal nanomaterials have broad application prospects in many fields. However, most of the existing synthesis processes of precious metal nanomaterials are carried out in a batch reactor. Recently, the technology of batch preparation of noble metal nanoparticles by chemical method has become mature, but with the increase of reactor volume, the problems of heat and mass transfer of the system are prominent. In this paper, the technology of reducing plant biomass with green characteristics to prepare precious metal nanoparticles was introduced into the continuous operation of micro channel reactor and reactor to investigate the influence of reactor structure parameters and reaction conditions on the formation and particle size distribution of precious metal nanoparticles, and combined with computational fluid dynamics (CFD) simulation technology to explore its influence mechanism. In this paper, it is found that the AgNPs (4.7 ± 1.9 nm) prepared by ETFE tube has a larger average particle size and a wider particle size distribution than the AgNPs (4.24 ± 0.9 nm) prepared by PTFE tube.

Towards a Wristed Percutaneous Robot With Variable Stiffness for Pericardiocentesis

Pericardiocentesis is the drainage of excessive fluid in the pericardium surrounding the heart under ultrasound guidance. The percutaneous procedure comes with the risk of cardiac perforation since the needle is inserted towards the beating heart. This letter presents a novel percutaneous robot that features a flexible wrist made of shape memory alloy (SMA) spring which can vary its stiffness through temperature variation. The SMA spring can be heated and thus stiffened to allow insertion. At lower temperature, it behaves like a spring backbone that allows the needle to be bent away from the heart and thus minimizing the chance of cardiac perforation. A heating tube made of nichrome wire and PTFE tube was developed to be the heat source for the SMA spring. The robot has an outer diameter of 4 mm, similar to the dilator used in pericardiocentesis, and a lumen to pass a guidewire through. A stiffness model and kinematics model were developed and verified through experiments. The surface temperature of the SMA-based wrist was evaluated to be less than the tissue necrosis temperature. Lastly, we demonstrated that the robot could be inserted into gelatin phantoms of different stiffnesses and produce a wristed motion under ultrasound guidance.

Graphite-polystyrene composite with enhanced electrochemical and electroanalytical performance

A new composite electrode (G-PSE) was developed from graphite powder and expanded polystyrene (EPS, Styrofoam) by simply dissolving the foam in chloroform, incorporating the graphite particles under mixing and volatilizing the solvent at 80 °C. The resulting rigid black composite can be softened with acetone and so it can easily be molded to any shape, e.g., into a PTFE tube with an electric contact, to build the electrode. A 75% graphite content (w/w) was found appropriate for preparing the G-PSE with a working potential similar to that of carbon paste electrodes, superior mechanical stability and a much faster response to ferrocyanide, close to reversible and similar to that of the much more expensive glassy carbon electrode. Applications of the G-PSE to dipyrone and paracetamol quantification in pharmaceutical formulations were demonstrated. The results accomplished by flow injection analysis with amperometric detection at the G-PSE were successfully validated against standards methods.

Inhomogeneous generation of hydroxyl radicals in hydrogen peroxide solution induced by ultraviolet irradiation and in a Fenton reaction system

The density of hydroxyl radical (•OH) generation by degeneration of hydrogen peroxide (H2O2) during UVB irradiation and in a Fenton reaction system was estimated. The purpose of this study was to evaluate whether these reaction systems generate spatially uniform or inhomogeneous •OH from H2O2 in the reaction mixture. A series of 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) solutions of several concentrations (0.13‒1661 mM) were prepared. For UVB irradiation, 1 μl of 98 mM, 980 mM, or 9.8 M H2O2 solution was added to a 100-μl aliquot of DMPO solution, and the reaction mixture was irradiated with UVB. For the Fenton reaction, 1 μl of 98 mM H2O2 and 1 μl of 100 mM FeSO4 were added to a 100-μl aliquot of DMPO solution. After UVB irradiation or adding FeSO4, the entire volume of the reaction mixture was drawn into PTFE tubing and measured by X-band EPR. The DMPO-OH concentration in the reaction mixture was plotted versus the molecular density of DMPO, and the density of •OH generation was estimated from an inflection point on the plotted profile. The local densities of the UV-induced •OH in the H2O2 water solutions depended on the concentration of H2O2 in the solution, and were likely localized. The energy absorption process of photons was suspected to occur in a step-wise manner in a limited volume. •OH generation in the Fenton reaction system was expected to be uniformly distributed, but inhomogeneous •OH generation was observed at the molecular level.

Customized hybrid and NIR-light triggered thermoresponsive drug delivery microparticles synthetized by photopolymerization in a one-step flow focusing continuous microreactor

Photopolymerization is a selective technique that takes advantage of light-sensitive molecules to initiate and propagate monomeric structures to render covalently bonded macromolecular materials structures known as polymers. Herein, we present a novel one-step microfluidic synthesis of customized hybrid-thermoresponsive Poly(N-isopropylacrylamide) (PNIPAm) based microparticles (MPs) containing plasmonic hollow gold nanoparticles (HGNPs) and bupivacaine (BVP) used as a model drug. Those hybrid microparticles were prepared using a flow-focusing microreactor coupled to a UV LED device built with a simple outer PTFE tubing and an inner flexible capillary. Different tubing characteristics and flow rate ratios were altered in order to control the size of the resulting microparticles. In addition, components such as monomer, crosslinker and photoinitiator concentrations, as well as LED intensity and irradiation time were tuned to obtain different MPs and their characteristics and polymerization rates were compared by Gel Permeation Chromatography (GPC). Thermoresponsive properties were analyzed and the presence of HGNPs was confirmed in light-activated triggered drug release applications. Bupivacaine loading and release studies were evaluated with the resulting hollow and solid microparticles (which were obtained depending on the polymerization rate used) and their temperature responsiveness was assessed using a NIR laser when HGNPs were present in the constructs. Finally, cytotoxicity studies, cell-cycle arrest and apoptotic induction were carried out to certify their suitability for further biomedical applications to be used as triggerable drug depots.

Leiomyosarcoma of the Vena Cava. A Case Report of Resection of the Infrarenal Cava with Auto-transplantation of Both Kidneys

Introduction: Leiomyosarcoma of the IVC is a rare but potentially fatal condition where a complete R0 resection is the only potential cure. Since the first case of a leiomyosarcoma described back in 1871 there have been approximately 470 cases reported in the literature with varying techniques used to manage the cava and so a consensus on best surgical management has never been reached[1].We present a rare case of a Leiomyosarcoma of section II of the inferior vena cava with auto transplantation of both kidneys. Methods: Intra-operatively there was a very large bilobed leiomyosarcoma originating from the IVC at the level of the renal veins and growing around the porta hepatitis and below the liver. the liver was fully mobilised to allow exposure of the cava and facilitate tumour resection. In order to preserve both kidneys they were resected and auto transplanted into the pelvis at the end of the procedure. The tumour was resected with approximately 10cm of IVC and replaced with a PTFE tube graft. Results: Postoperative course was stormy complicated by perinephric haematomas, chest sepsis and delayed graft function. She spent 11 days in ICU (9 on CRRT) and was discharged home on day 27 with a creatinine of 61 Pathology was confirmed as a grade 3 leiomyosarcoma arising from the wall of the inferior vena cava. It wasn't possible to assess excision margins due to the fragmented specimen however sampled blood vessels and small amount of adherent liver parenchyma were clear of infiltration. Conclusion: Tumours involving the inferior vena cava remain a rare pathology with radical resection as the only option for improving long term survival. Resection of the cava can be achieved with or without replacement depending on collateral venous drainage and the location of the renal veins in relation to the resected segment. This case demonstrates a new surgical option for achieving R0 resection margins and avoiding renal dysfunction with autologous bilateral renal transplants. Disclosure: Nothing to disclose

Investigation on planar microwave sensors with enhanced sensitivity from microfluidic integration

In this paper, microwave planar sensors are discussed for liquid characterization, mainly for microfluidic application. Three common sensors are implemented in complementary split ring resonator, extended gap split ring resonator, and conventional circular split ring resonator resonating at 1.7, 1.9, and 3.6 GHz, respectively. The sensitivity of material on top of the resonator is analyzed, and is modified with respect to the volume of material under test for more comprehensive evaluation of sensor’s performance. The circular resonator is found to be the optimum in terms of sample volume and offers up to 50 % higher sensitivity for permittivity range from 1 to 30. This sensor is further developed by embedding the material under test inside its substrate and the sensitivity is also enhanced on average by ∼ 45 % for bulk material sensing of the same permittivity range. In experimental verification of the embedding concept, a water sample concentrated with 10%–50% methanol is placed above/inside substrate and remarkable improvement of 360 % in sensitivity is observed for the latter when PTFE tubes are installed. Finally, microfluidic channels are uniquely implemented inside the substrate of circular split ring resonator and distinct signatures are detected, which proved the concept of sensitivity enhancement in resonators while minimizing the sample volume.