Miniature Probe Research Articles

Velocity–pressure correlation measurement based on planar PIV and miniature static pressure probes

This study aimed to measure pressure-related turbulence statistics such as the velocity–pressure or the pressure–strain correlations. To do so, the pressure field evaluation based on the velocity data measured by particle image velocimetry (PIV) was combined with direct single-point-measurement by miniature static pressure probes (SP-probe). The instantaneous pressure field was derived from the measurement results by PIV, and the pressure fluctuations associated with the large-scale vortex motion were extracted using the instantaneous pressure directly measured by the SP-probe as a reference signal. The measurement was taken in a turbulent near wake of a circular cylinder. After the validity of the instantaneous pressure evaluated from the PIV data was addressed, the velocity–pressure correlation and the pressure–strain correlation were investigated.

Rapid ratiometric biomarker detection with topically applied SERS nanoparticles.

Multiplexed surface-enhanced Raman scattering (SERS) nanoparticles (NPs) offer the potential for rapid molecular phenotyping of tissues, thereby enabling accurate disease detection as well as patient stratification to guide personalized therapies or to monitor treatment outcomes. The clinical success of molecular diagnostics based on SERS NPs would be facilitated by the ability to accurately identify tissue biomarkers under time-constrained staining and detection conditions with a portable device. In vitro, ex vivo and in vivo experiments were performed to optimize the technology and protocols for the rapid detection (0.1-s integration time) of multiple cell-surface biomarkers with a miniature fiber-optic spectral-detection probe following a brief (5 min) topical application of SERS NPs on tissues. Furthermore, we demonstrate that the simultaneous detection and ratiometric quantification of targeted and nontargeted NPs allows for an unambiguous assessment of molecular expression that is insensitive to nonspecific variations in NP concentrations.

Laser-generated ultrasound with optical fibres using functionalised carbon nanotube composite coatings

Optical ultrasound transducers were created by coating optical fibres with a composite of carbon nanotubes (CNTs) and polydimethylsiloxane (PDMS). Dissolution of CNTs in PDMS to create the composite was facilitated by functionalisation with oleylamine. Composite surfaces were applied to optical fibres using dip coating. Under pulsed laser excitation, ultrasound pressures of 3.6 MPa and 4.5 MPa at the coated end faces were achieved with optical fibre core diameters of 105 and 200 μm, respectively. The results indicate that CNT-PDMS composite coatings on optical fibres could be viable alternatives to electrical ultrasound transducers in miniature ultrasound imaging probes.

Leaf litter water content and soil surface CO2 fluxes in a deciduous forest

This study has examined the ability of a commercial, miniature soil moisture probe to measure water content within the leaf litter layer found on the floor below a deciduous forest site in Oak Ridge, eastern Tennessee. With its small size and high moisture sensitivity, this probe provides a potential opportunity for monitoring the water content beneath complex vegetation systems within the soil–air interface normally characterized by a large spatial variability and small magnitude of energy, water and carbon fluxes. With its low-cost and low-power, many of these probes can be easily deployed at a much lower cost than the single traditional soil moisture probe that is usually used for monitoring local-site soil moisture and is unsuitable for litter wetness. Miniature probe measurements of litter moisture were compared with gravimetric measurements from litter sample baskets positioned across the forest floor and the change in the magnitude of the probe output correlated linearly to the water content of the litter. Gravimetric measurements of the litter water content ranged from 1 to 3 g (H2O) g−1 (litter dry weight), and hourly values varied with precipitation, radiation, and wind speed. Measurements of the litter and soil water content were incorporated into empirical models adopted from the literature for estimating the litter and soil components of the CO2 flux. The comparison between the modeled and the measured hourly CO2 flux on the forest floor produced root means square differences (RMSD) of about 1.11 and 1.32 umol m−2 s−1 for estimates with and without litter layer, respectively, and about 25% of the forest floor CO2 flux was due to direct contributions from the litter layer. The results of the study indicate that the probes performed well in a complex forest environment and can be used to help evaluate the water, energy and CO2 fluxes on the soil surface inside a variety of vegetation stands.

Management of small-bowel polyps at double-balloon enteroscopy.

Small bowel tumors (SBTs) are uncommon, insidious in presentation, and frequently represent a diagnostic challenge. The advent of video capsule endoscopy (VCE) and double-balloon endoscopy (DBE) is a significant breakthrough for visual diagnosis of SBTs throughout the small bowel. Contrast-enhanced computed tomography (CECT) and fluoroscopic enteroclysis had significantly lower diagnostic yields of tumors that were 10 mm or smaller in diameter, but VCE and DBE had high diagnostic yields regardless of tumor size. Regarding SBTs larger than 10 mm in diameter, CECT had a significantly lower diagnostic yield of epithelial tumors compared to subepithelial tumors, whereas fluoroscopic enteroclysis and DBE had high diagnostic yields regardless of the tumor type. VCE had a slightly lower diagnostic yield of subepithelial tumors (78%) compared to epithelial tumors. Therefore, a combined examination method by using CECT and VCE is useful for screening of SBTs. In case suspicious of stenosis, patency capsule should be performed to confirm passage before VCE. DBE is useful for further precise examination including biopsy and ultrasonography by using miniature probe, and enteroscopic treatment. After medical, enteroscopic, and surgical treatment, VCE is helpful for follow-up. DBE is safe and useful in resecting the SBTs deep within the small bowel without laparotomy. Indications of enteroscopic resection may be benign tumors regardless of epithelial or subepithelial type, localizing in the mucosal or submucosal layer, which are symptomatic at present or possibly symptomatic or transforming in the future. Malignant tumors localized in the mucosal layer may be indications although detecting at an early stage is challenging. In this review article, we describe management of SBTs/polyps by various modalities.

Miniature forward‐imaging B‐scan optical coherence tomography probe to guide real‐time laser ablation

Investigations have shown that pulsed lasers tuned to 6.1 µm in wavelength are capable of ablating ocular and neural tissue with minimal collateral damage. This study investigated whether a miniature B-scan forward-imaging optical coherence tomography (OCT) probe can be combined with the laser to provide real-time visual feedback during laser incisions. A miniature 25-gauge B-scan forward-imaging OCT probe was developed and combined with a 250 µm hollow-glass waveguide to permit delivery of 6.1 µm laser energy. A gelatin mixture and both porcine corneal and retinal tissues were simultaneously imaged and lased (6.1 µm, 10 Hz, 0.4-0.7 mJ) through air. The ablation studies were observed and recorded in real time. The crater dimensions were measured using OCT imaging software (Bioptigen, Durham, NC). Histological analysis was performed on the ocular tissues. The combined miniature forward-imaging OCT and mid-infrared laser-delivery probe successfully imaged real-time tissue ablation in gelatin, corneal tissue, and retinal tissue. Application of a constant number of 60 pulses at 0.5 mJ/pulse to the gelatin resulted in a mean crater depth of 123 ± 15 µm. For the corneal tissue, there was a significant correlation between the number of pulses used and depth of the lased hole (Pearson correlation coefficient = 0.82; P = 0.0002). Histological analysis of the cornea and retina tissues showed discrete holes with minimal thermal damage. A combined miniature OCT and laser-delivery probe can monitor real-time tissue laser ablation. With additional testing and improvements, this novel instrument has the future possibility of effectively guiding surgeries by simultaneously imaging and ablating tissue.

Corrigendum to “Integrated miniature fluorescent probe to leverage the sensing potential of ZnO quantum dots for the detection of copper (II) ions” [Talanta 116 (2013) 514–519

Quantum dots are fluorescent semiconductor nanoparticles that can be utilised for sensing applications. This paper evaluates the ability to leverage their analytical potential using an integrated fluorescent sensing probe that is portable, cost effective and simple to handle. ZnO quantum dots were prepared using the simple sol-gel hydrolysis method at ambient conditions and found to be significantly and specifically quenched by copper (II) ions. This ZnO quantum dots system has been incorporated into an in-house developed miniature fluorescent probe for the detection of copper (II) ions in aqueous medium. The probe was developed using a low power handheld black light as excitation source and three photo-detectors as sensor. The sensing chamber placed between the light source and detectors was made of 4-sided clear quartz windows. The chamber was housed within a dark compartment to avoid stray light interference. The probe was operated using a microcontroller (Arduino Uno Revision 3) that has been programmed with the analytical response and the working algorithm of the electronics. The probe was sourced with a 12V rechargeable battery pack and the analytical readouts were given directly using a LCD display panel. Analytical optimisations of the ZnO quantum dots system and the probe have been performed and further described. The probe was found to have a linear response range up to 0.45mM (R(2)=0.9930) towards copper (II) ion with a limit of detection of 7.68×10(-7)M. The probe has high repeatable and reliable performance.

J0530202 乱流促進デバイスを用いた航空エンジン用低圧タービン翼の高負荷化に関する研究([J053-02]流体機械の研究開発におけるEFD/CFD(2),流体工学部門)

In order to improve the efficiency of high-lift low pressure turbines, this paper investigates two types of airfoils which have two-dimensional contouring with a small step or dimples on the suction surface to suppress the separation bubble that causes large aerodynamic loss, especially in the case of high stage loading. A linear cascade test facility is employed to investigate the aerodynamic performance of the two-dimensional contoured airfoil by use of miniature Pitot probes and RANS simulations are carried out to investigate the three types of dimple layouts. The Reynolds number based on the chord length was varied in the range of 40,000 to 170,000 to simulate a typical flight condition. It is found that the proposed methods are capable of reducing the profile loss, resulting in an improvement of cascade performance.

Measurements of Turbulence in a Liquid-Metal Two-Phase Flow by Using a Miniature Electro-Magnetic Probe

A nitrogen gas-lead bismuth two-phase flow was experimentally studied as a two-phase flow with large liquid-to-gas density ratio. Experiments were performed to understand turbulent structure in a liquid-metal two-phase flow by using a miniature electro-magnetic probe. Radial profiles of axial liquid velocity and turbulence intensity were measured by using the electro-magnetic probe. Turbulence is induced mainly by rising bubbles in the liquid-metal. Measurement results show that the turbulence intensity at the tube center was proportional to the void fraction to the power of 0.8 for higher void fraction at the present experimental conditions.

A Miniature Four-Hole Probe for Measurement of Three-Dimensional Flow with Large Gradients

A miniature four-hole probe with a sensing area of 1.284 mm2to minimise the measurement errors due to the large pressure and velocity gradients that occur in highly three-dimensional turbomachinery flows is designed, fabricated, calibrated, and validated. The probe has good spatial resolution in two directions, thus minimising spatial and flow gradient errors. The probe is calibrated in an open jet calibration tunnel at a velocity of 50 m/s in yaw and pitch angles range of ±40 degrees with an interval of 5 degrees. The calibration coefficients are defined, determined, and presented. Sensitivity coefficients are also calculated and presented. A lookup table method is used to determine the four unknown quantities, namely, total and static pressures and flow angles. The maximum absolute errors in yaw and pitch angles are 2.4 and 1.3 deg., respectively. The maximum absolute errors in total, static, and dynamic pressures are 3.4, 3.9, and 4.9% of the dynamic pressures, respectively. Measurements made with this probe, a conventional five-hole probe and a miniature Pitot probe across a calibration section, demonstrated that the errors due to gradient and surface proximity for this probe are considerably reduced compared to the five-hole probe.

An attempt to measure fluctuating local pressure in free turbulent flow in water

We developed a technique for the measurement of fluctuating hydraulic-pressure at an arbitrary point in turbulent flow. A pressure-measuring system was composed of a miniature static-pressure probe (SP-probe), a strain-gagetype pressure transducer, and a tube connecting them. A model equation of dynamic response of the pressuremeasuring system was introduced, and a calibration technique for determining parameters in the model equation was developed. Effects of the size of the SP-probe, length of the tube, and sensitivity of the pressure sensor were systematically investigated using several SP-probes, tubes, and pressure transducers with di fferent sizes, lengths, and sensitivities, and fluctuating hydraulic-pressure measurement was performed in a wake of a circular cylinder.

Heat transfer and shear stress in a gas-liquid flow in an inclined flat channel

Results of experimental investigation of a bubbly gas-liquid flow in an inclined flat channel are presented. Themeasurements were carried out in the range of superficial liquid velocities of 0.3–1.1 m/s and with different values of the volumetric gas flow rate ratio. The hydrodynamic structure wasmeasured bymeans of an electrochemical method using miniature shear stress probes. Values of average shear stress and heat transfer coefficient for different orientation of the channel were found. It is shown that in a bubbly gas-liquid flow the shear stress and heat transfer depend substantially on the channel inclination angle.

POSITIONAL ERROR COMPENSATION AND SLL CONTROL OF MINIATURE DEEP SPACE PROBE BASED ANTENNA ARRAYS

As the boundary of the universe which is explored by human expanded, antenna used in deep space exploration (DSE) could become too large to carry and deploy, miniature deep space probe based antenna arrays (MDSPBAA) provide a novel solution for the problem. This kind of antenna array may lower the difficulty of sending antenna to the area where is tend to be detected and may also monitor cost effectively in the work of deep space detect. However, turbulence and positional errors provide a challenging operational environment when it comes to the implementation of these systems. Turbulence will deteriorate SLL badly. In some cases, the level could be changed by almost 10 dB. Therefore, a SLL control algorithm is presented, which could well compensate the SLL which is caused by positional error.

How Influential Is the Duration of Contrast Material Bolus Injection in Perfusion CT? Evaluation in a Swine Model

Purpose To analyze the effect of the duration of contrast material bolus injection on perfusion values in a swine model by using the maximum slope method. Materials and Methods This study was approved by the institutional animal care committee. Twenty pigs (weight range, 63–77 kg) underwent dynamic volume computed tomography (CT) of the kidneys during suspended respiration. Before the CT examination, a miniature cuff-shaped ultrasonographic flow probe encircling the right renal artery was surgically implanted in each pig to obtain true perfusion values. Two sequential perfusion CT series were performed in 30 seconds, each comprising 30 volumes with identical parameters (100 kV, 200 mAs, 0.5 sec rotation time). The duration of contrast material bolus (0.5 mL/kg of body weight) was 3.8 seconds in the first series (short bolus series) and 11.5 seconds in the second series (long bolus series), and the injection flow rate was adapted accordingly. In each pig, cortical kidney volume was determined by using the volume with the highest cortical enhancement. CT perfusion values were calculated for both series by using the maximum slope method and were statistically compared and correlated with the true perfusion values from the flow probe by using linear regression analysis. Results Mean true perfusion and CT perfusion values (in minutes−1) for the short bolus series were 1.95 and 2.03, respectively (P = .22), and for the long bolus series, they were 2.02 and 1.92, respectively (P = .12). CT perfusion showed very good correlation with true perfusion in both the short (slope, 1.01; 95% confidence interval: 0.91, 1.11) and long (slope, 0.92; 95% confidence interval: 0.78, 1.04) series. On the basis of the regression analysis, CT perfusion values in the short bolus series were overestimated by 1% and those in the long bolus series were underestimated by 8%. Conclusion Duration of contrast material bolus injection does not influence CT perfusion values substantially. The longer, clinically preferred intravenous injection scheme is sufficiently accurate for CT perfusion. © RSNA, 2013

How Influential Is the Duration of Contrast Material Bolus Injection in Perfusion CT? Evaluation in a Swine Model

To analyze the effect of the duration of contrast material bolus injection on perfusion values in a swine model by using the maximum slope method. This study was approved by the institutional animal care committee. Twenty pigs (weight range, 63-77 kg) underwent dynamic volume computed tomography (CT) of the kidneys during suspended respiration. Before the CT examination, a miniature cuff-shaped ultrasonographic flow probe encircling the right renal artery was surgically implanted in each pig to obtain true perfusion values. Two sequential perfusion CT series were performed in 30 seconds, each comprising 30 volumes with identical parameters (100 kV, 200 mAs, 0.5 sec rotation time). The duration of contrast material bolus (0.5 mL/kg of body weight) was 3.8 seconds in the first series (short bolus series) and 11.5 seconds in the second series (long bolus series), and the injection flow rate was adapted accordingly. In each pig, cortical kidney volume was determined by using the volume with the highest cortical enhancement. CT perfusion values were calculated for both series by using the maximum slope method and were statistically compared and correlated with the true perfusion values from the flow probe by using linear regression analysis. Mean true perfusion and CT perfusion values (in minutes(-1)) for the short bolus series were 1.95 and 2.03, respectively (P = .22), and for the long bolus series, they were 2.02 and 1.92, respectively (P = .12). CT perfusion showed very good correlation with true perfusion in both the short (slope, 1.01; 95% confidence interval: 0.91, 1.11) and long (slope, 0.92; 95% confidence interval: 0.78, 1.04) series. On the basis of the regression analysis, CT perfusion values in the short bolus series were overestimated by 1% and those in the long bolus series were underestimated by 8%. Duration of contrast material bolus injection does not influence CT perfusion values substantially. The longer, clinically preferred intravenous injection scheme is sufficiently accurate for CT perfusion.

A miniature ultrasound probe is useful in reducing rebleeding after endoscopic cyanoacrylate injection for hemorrhagic gastric varices

Objective. To better assess the usefulness of miniature ultrasound probe (MUP) sonography in the evaluation of the adequacy of gastric variceal injection with cyanoacrylate to decrease the risk of post injection rebleeding. Material and methods. Sixty-nine patients with bleeding gastric varices were included in this study. Endoscopic cyanoacrylate injection was performed in the acute phase for variceal hemostasis. After injection, patients (n = 34) included in the MUP group prospectively received endoscopic ultrasonography (EUS) with MUP during each scheduled endoscopic follow-up session. Patients (n = 35) in the control group who were included historically were followed up with the same interval with endoscopy only. Results. Four (11.4%) patients in the control group received reinjection, and there were 10 episodes of rebleeding in 7 (20.0%) patients. Nine (26.5%) patients received reinjection due to inadequate obturation as judged by EUS. There were six episodes of rebleeding in three (8.8%) patients in the MUP group. The free-of-rebleeding rate for the MUP group was significantly higher than that for the control group (p < 0.05). The cumulative survival for the MUP group was slightly better than that for the control group but was not statistically significant. The patients' compliance in both groups was similar. The endosonographers considered the performance of MUP sonography to be convenient. Conclusions. MUP sonography is useful for the evaluation of the adequacy of tissue adhesive obturation of gastric varices that may reduce the probability of rebleeding.

Integrated miniature fluorescent probe to leverage the sensing potential of ZnO quantum dots for the detection of copper (II) ions

Quantum dots are fluorescent semiconductor nanoparticles that can be utilised for sensing applications. This paper evaluates the ability to leverage their analytical potential using an integrated fluorescent sensing probe that is portable, cost effective and simple to handle. ZnO quantum dots were prepared using the simple sol–gel hydrolysis method at ambient conditions and found to be significantly and specifically quenched by copper (II) ions. This ZnO quantum dots system has been incorporated into an in-house developed miniature fluorescent probe for the detection of copper (II) ions in aqueous medium. The probe was developed using a low power handheld black light as excitation source and three photo-detectors as sensor. The sensing chamber placed between the light source and detectors was made of 4-sided clear quartz windows. The chamber was housed within a dark compartment to avoid stray light interference. The probe was operated using a microcontroller (Arduino Uno Revision 3) that has been programmed with the analytical response and the working algorithm of the electronics. The probe was sourced with a 12V rechargeable battery pack and the analytical readouts were given directly using a LCD display panel. Analytical optimisations of the ZnO quantum dots system and the probe have been performed and further described. The probe was found to have a linear response range up to 0.45mM (R2=0.9930) towards copper (II) ion with a limit of detection of 7.68×10−7M. The probe has high repeatable and reliable performance.

Miniature real-time intraoperative forward-imaging optical coherence tomography probe

Optical coherence tomography (OCT) has a tremendous global impact upon the ability to diagnose, treat, and monitor eye diseases. A miniature 25-gauge forward-imaging OCT probe with a disposable tip was developed for real-time intraoperative ocular imaging of posterior pole and peripheral structures to improve vitreoretinal surgery. The scanning range was 2 mm when the probe tip was held 3-4 mm from the tissue surface. The axial resolution was 4-6 µm and the lateral resolution was 25-35 µm. The probe was used to image cellophane tape and multiple ocular structures.

Design and evaluation of a miniature probe integrating diffuse optical tomography and electroencephalographic source localization

We present a dual-modality three-dimensional imaging approach that integrates diffuse optical tomography (DOT) and electroencephalographic source localization (ESL). This dual-modal DOT/ESL approach is evaluated using solid tissue-like phantoms where targets having both optical and electrical contrasts relative to the background phantom are included. The results obtained from extensive phantom experiments show that this dual-modal approach is suitable for imaging seizure focus in the study of epilepsy.

Passive control of unsteady-wing tip vortex via a slender half-delta wing in both reverse and regular configurations

The passive control of the tip vortex generated by an oscillating NACA 0012 wing via a tip-mounted half-delta wing, in both regular and reverse configurations, was investigated experimentally at Re = 2.45 × 105. Velocity and vorticity measurements, performed using a miniature triple hot-wire probe, show that vortex breakdown occurred when the regular half-delta wing (HDW) was mounted, but not for the reverse half-delta wing (RHDW) configuration. The HDW vortex breakdown led to a rapidly diffused tip vortex, suggesting an enhanced wake-vortex decay. For the RHDW wing configuration, the tip vortex remained concentrated but had a smaller size and also a weaker strength and rotation compared to the oscillating baseline wing. In addition, the vortex center of the oscillating RHDW wing-generated tip vortex was also found to be greatly displaced, especially in the transverse direction, which could translate into an increased blade-vortex-impingement miss distance and, as a result, an alleviated blade-vortex interaction.