Feasibility Experiments Research Articles

Measuring droplet fall speed with a high-speed camera: indoor accuracy and potential outdoor applications

Abstract. Acquisition of accurate raindrop fall speed measurements outdoors in natural rain by means of moderate-cost and easy-to-use devices represents a long-standing and challenging issue in the meteorological community. Feasibility experiments were conducted to evaluate the indoor accuracy of fall speed measurements made with a high-speed camera and to evaluate its capability for outdoor applications. An indoor experiment operating in calm conditions showed that the high-speed imaging technique can provide fall speed measurements with a mean error of 4.1–9.7 % compared to Gunn and Kinzer's empirical fall-speed–size relationship for typical sizes of rain and drizzle drops. Results obtained using the same apparatus outside in summer afternoon showers indicated larger positive and negative velocity deviations compared to the indoor measurements. These observed deviations suggest that ambient flow and turbulence play a role in modifying drop fall speeds which can be quantified with future outdoor high-speed camera measurements. Because the fall speed measurements, as presented in this article, are analyzed on the basis of tracking individual, specific raindrops, sampling uncertainties commonly found in the widely adopted optical disdrometers can be significantly mitigated.

Registration of a statistical model to intraoperative ultrasound for scaphoid screw fixation.

Volar percutaneous scaphoid fracture fixation is conventionally performed under fluoroscopy-based guidance, where surgeons need to mentally determine a trajectory for the insertion of the screw and its depth based on a series of 2D projection images. In addition to challenges associated with mapping 2D information to a 3D space, the process involves exposure to ionizing radiation. Three-dimensional ultrasound has been suggested as an alternative imaging tool for this procedure; however, it has not yet been integrated into clinical routine since ultrasound only provides a limited view of the scaphoid and its surrounding anatomy. We propose a registration of a statistical wrist shape+scale+pose model to a preoperative CT and intraoperative ultrasound to derive a patient-specific 3D model for guiding scaphoid fracture fixation. The registered model is then used to determine clinically important intervention parameters, including the screw length and the trajectory of screw insertion in the scaphoid bone. Feasibility experiments are performed using 13 cadaver wrists. In 10 out of 13 cases, the trajectory of screw suggested by the registered model meets all clinically important intervention parameters. Overall, an average 94% of maximum allowable screw length is obtained based on the measurements from gold standard CT. Also, we obtained an average 92% successful volar accessibility, which indicates that the trajectory is not obstructed by the surrounding trapezium bone. These promising results indicate that determining clinically important screw insertion parameters for scaphoid fracture fixation is feasible using 3D ultrasound imaging. This suggests the potential of this technology in replacing fluoroscopic guidance for this procedure in future applications.

A multi-channel fiber optic proximity sensor

In this investigation, we propose an efficient multi-channel optical proximity sensor based on the spectrally-resolved interferometric principle. This sensor consists of a single optical source, a spectrometer and fiber optic components such as an optical circulator, a coarse wavelength division multiplexer (CWDM) and fiber optic probes. A spectrometer is used to detect the spectral interferograms of the measuring probes according to their own spectral bandwidths and the interference signals can be separated by the spectral filtering by a CWDM. The principle of the proposed sensor system was verified with feasibility experiments with the home-built 4 channel sensor system. The measuring range of each channel was 1 mm and the resolution was a few tens of nanometers determined by the deviation of linear motions. The stability of the sensor was less than 30 nm. With the aid of a broadband source and a spectrometer, the measurement channel can be extended further by using a suitable CWDM.

Elimination of the direction ambiguity and the dead zone in spectrally resolved interferometry

We propose a very simple and effective technique to eliminate the direction ambiguity and the dead zone, which limit the measurable range in spectrally resolved interferometry (SRI). By using a dispersive material, the nonlinear spectral phase caused by the dispersion can provide useful information and determine the direction of measuring distances. In addition, the dead zone is removed by two complementary measurement results in dichroic SRI. As the results of feasibility experiments, it was confirmed that the nonlinearity of the spectral phase successfully determined the direction of the measuring distances. Moreover, the final linear distances in the whole measurement range without the dead zone was obtained in dichroic SRI with two LEDs.

Obstruction-type Chip Breakers for Controllable Chips and Improved Cooling/Lubrication During Drilling – A Feasibility Study

During drilling, long stringy chips resulting from ductile plastic deformation of engineering materials cause severe chip clogging within the narrow helical flutes and edge chipping, leading to premature tool wear and breakage, poor tool life, poor hole quality and the productivity. Cutting fluid cannot efficiently access to the cutting edge that plays a vital role for improving machining performance. To address the localized heat and chip control issues during drilling, research was previously performed using conventional flood cooling, modified tool geometry, tool coating materials, and internal coolant via through hole(s). This works focuses on design and insertion of some obstruction-type chip breakers such as ribs and pins on the drill flutes and their influence on chip formation behavior. For feasibility experiments, small round pins made of stainless steel at a diameter of about 0.8-0.85mm diameter are prepared and attached on the electro-discharge machined (EDM) blind holes on twisted drill flutes. By varying spindle speed and feed rate, drilling experiments are performed on two engineering materials including Al6061 and Inconel 625 superalloys at four cutting conditions. Most chips are found to be broken and some split into two fractions due to the pins. Force and power values with pin-inserted drill bits were found to be reduced from 5-9%. This finding indicates that there is a good potential to implement such obstruction-type chip-breakers on the drill flutes for obtaining controllable chip while also improving coolant flow at the cutting edge through the tiny tool-chip interface.

Differential Die-Away Analysis for detection of 235U in metallic matrix

Differential Die-Away Analysis is a powerful tool for detecting small quantity of fissile material even if it is shielded or placed in non-fissile matrix. The technique can be used to monitor and characterize fissile content for nuclear waste assay. In this paper, we have discussed the application of differential die away technique for detection of small quantity of fissile material in nuclear waste assay. Feasibility experiments to optimize various parameters have been carried out for detection of 235U in metallic matrix and reported in this paper. A minimum quantity of 1g of 235U in 150kg of metallic matrix has been detected in the experimental configuration being reported.

Dichroic spectrally-resolved interferometry to overcome the measuring range limit

In this investigation, a simple method to eliminate the dead zone without the minimum measurable distance and extend the measurable range of spectrally resolved interferometry (SRI) twice based on the bandwidth separation by a dichroic beam splitter (DBS) is proposed. The main advantage of this dichroic SRI is that it can be simply implemented with a dichroic beam splitter and another reference mirror from the typical SRI. Feasibility experiments were performed to verify the principle of the dichroic SRI and the result confirmed the effectiveness of this method as the extended measuring range. Some practical error sources are considered and the alternative solutions are also discussed.

Bone enhancement in ultrasound using local spectrum variations for guiding percutaneous scaphoid fracture fixation procedures.

The scaphoid bone is the most frequently fractured bone in the wrist. When fracture fixation is indicated, a screw is inserted into the bone either in an open surgical procedure or percutaneously under fluoroscopic guidance. Due to the complex geometry of the wrist, fracture fixation is a challenging task. Fluoroscopic guidance exposes both the patient and the physician to ionizing radiation. Ultrasound-based guidance has been suggested as a real-time, radiation-free alternative. The main challenge of using ultrasound is the difficulty in interpreting the images due to the low contrast and noisy nature of the data. We propose a bone enhancement method that exploits local spectrum features of the ultrasound image. These features are utilized to design a set of quadrature band-pass filters and subsequently estimate the local phase symmetry, where high symmetry is expected at the bone locations. We incorporate the shadow information below the bone surfaces to further enhance the bone responses. The extracted bone surfaces are then used to register a statistical wrist model to ultrasound volumes, allowing the localization and interpretation of the scaphoid bone in the volumes. Feasibility experiments were performed using phantom and in vivo data. For phantoms, we obtain a surface distance error 1.08 mm and an angular deviation from the main axis of the scaphoid bone smaller than 5°, which are better compared to previously presented approaches. The results are promising for further development of a surgical guidance system to enable accurate anatomy localization for guiding percutaneous scaphoid fracture fixations.

Transapical sutureless aortic valve implantation under magnetic resonance imaging guidance: Acute and short-term results

Despite the increasing success and applicability of transcatheter aortic valve replacement, 2 critical issues remain: the durability of the valves, and the ideal imaging to aid implantation. This study was designed to investigate the transapical implantation of a device of known durability using real-time magnetic resonance imaging (MRI) guidance. A sutureless aortic valve was used that employs a self-expanding nitinol stent and is amenable to transapical delivery. MRI (1.5-T) was used to identify the anatomic landmarks in 60-kg Yucatan swine. Prostheses were loaded into an MRI-compatible delivery device with an active guidewire to enhance visualization. A series of acute feasibility experiments were conducted (n = 10). Additional animals (n = 6) were allowed to survive and had follow-up MRI scans and echocardiography at 90 days postoperatively. Postmortem gross examination was performed. The valve was MRI compatible and created no significant MRI artifacts. The 3 commissural struts were visible on short-axis view; therefore, coronary ostia obstruction was easily avoided. The average implantation time was 65 seconds. Final results demonstrated stability of the implants with preservation of myocardial perfusion and function over 90 days: the ejection fraction was 48% ± 15%; the peak gradient was 17.3 ± 11.3 mm Hg; the mean gradient was 9.8 ± 7.2 mm Hg. Mild aortic regurgitation was seen in 4 cases, trace in 1 case, and a severe central jet in 1 case. Prosthesis positioning was evaluated during gross examination. We demonstrated that a sutureless aortic valve can be safely and expeditiously implanted through a transapical approach under real-time MRI guidance. Postimplantation results showed a well-functioning prosthesis, with minimal regurgitation, and stability over time.

Quadrature birdcage coil with distributed capacitors for 7.0 T magnetic resonance data acquisition of small animals

ABSTRACTHigh static magnetic field magnetic resonance imaging (MRI) is commonly used for preclinical studies in rodents. In this context, minimization of coil losses is mandatory to scan samples that are small compared to the radiofrequency wavelength in the medium. In this study we construct a radiofrequency (RF) birdcage probe with distributed capacitors, operating in quadrature, tailored for 7.0T 1H MRI of small animals. The design eliminates the need for extra electrical components on the probe structure and affords a high SNR, a uniform field (homogeneity of 93% in the axial plain of the phantom) and a coil sensitivity of 9.8 . Feasibility experiments of mouse imaging are conducted and the competitive capability of a 7.0 T human system equipped with the proposed coil is demonstrated in both body and brain preclinical imaging. © 2015 Wiley Periodicals, Inc. Concepts Magn Reson Part B (Magn Reson Engineering) 44B: 83–88, 2015

Heavy metal removal in groundwater originating from acid mine drainage using dead Bacillus drentensis sp. immobilized in polysulfone polymer

Batch, column, and pilot scale feasibility experiments for a bio-sorption process using a bio-carrier (beads) with dead Bacillus drentensis sp. in polysulfone polymer were performed to remove heavy metals in groundwater originating from an acid mine drainage (AMD). For batch experiments, various amounts of bio-carrier each containing a different amount of dead biomass were added in artificial solution, of which the initial heavy metal concentration and pH were about 10 mg/L and 3, respectively. The heavy metal removal efficiencies of the bio-carrier under various conditions were calculated and more than 92% of initial Pb and Cu were found to have been removed from the solution when using 2 g of bio-carriers containing 5% biomass. For a continuous experiment with a column packed with bio-carriers (1 m in length and 0.02 m in diameter), more than 98% of Pb removal efficiency was maintained for 36 pore volumes and 1.553 g of Pb per g of bio-carrier was removed. For the pilot scale feasibility test, a total of 80 tons of groundwater (lower than pH of 4) were successfully treated for 40 working days and the removal efficiencies of Cu, Cd, Zn, and Fe were maintained above 93%, demonstrating that one kg of bio-carrier can clean up at least 1098 L of groundwater in the field.

Application Research on Reflective Insulation Coating Composite Insulation Wall

Kind of self-insulation walls which combined silt sintered porous brick with reflective insulation coating to local conditions are introduced in this paper. It not only can reach the effect of composite insulation, but also can eliminate fire safety hidden danger of the self-insulation wall. Exterior wall of the summer and winter thermal performance were analyzed, Through its feasibility experiments and is worth a certain region to promote.

Formability Evaluation of Microchannels of Aluminum Bipolar Plate Stamped Under Pulsating Load

The weight of a bipolar plate is one of the most crucial properties from the viewpoint of improving the power density of a proton-exchange membrane fuel cell (PEMFC) stack. Aluminum alloys have good material characteristics such as low electrical resistivity, high thermal conductivity, and low density. Furthermore, they are less expensive and easily machinable compared to graphite when used for fabricating bipolar plates. In this study, the use of AA5052 for fabricating a bipolar plate was investigated. The results of the feasibility experiments conducted to develop fuel cells with AA5052 bipolar plates having multiple microchannels were presented. The formability of microchannels under various types of pulsating loads was estimated for different punch loads and die radii using 0.3 mm thick AA5052 sheets. For a 0.1 mm die radius, the optimum formability was obtained for five cycles of sine wave dynamic loading with a maximum load of 90 kN. The experimental results demonstrated the feasibility of the proposed technique for fabricating bipolar plates.

Subject-specific real-time respiratory liver motion compensation method for ultrasound-MRI/CT fusion imaging.

Ultrasound-MRI/CT fusion imaging is widely used in minimal invasive surgeries, such as liver biopsy and tumor ablation. However, respiration-induced quasi-periodic liver motion and deformation cause unacceptable misalignment of the fusion images (i.e., fusion error). A subject-specific liver motion model based on skin-mounted position sensor and corresponding ultrasound liver image sequence was developed to compensate for liver motion. External surrogate respiratory motion signal is used to predict internal liver motion. An electromagnetic position sensor fixed on abdominal skin is introduced to track the respiratory motion, and 2D ultrasound images are used to track the liver motion synchronously. Based on these measurements, a subject-specific model describing the relationship of respiratory skin motion and internal liver motion is built and applied in real time (ultrasound-MRI/CT fusion imaging system) to predict and to compensate for the liver motion due to respiratory movement. Feasibility experiments and clinical trials were carried out on a phantom and eight volunteers. Qualitative and quantitative analyses and visual inspections performed by experienced clinicians show that the proposed model could effectively compensate for the liver motion, and the ratio of motion-compensated fusion error to the original varied from 10 % (0.96/9.40 mm) to 28 % (2.90/10.22 mm). An online liver motion modeling and compensation method was developed that provides surgeons with stable and accurate multimodality fusion images in real time.

Bioremoval of heavy metals from recycling industry electronic waste by a consortium of moderate thermophiles: process development and optimization

Abstract The aim of the current work is to develop an environmentally friendly process for the removal of heavy metals (Cu, Zn, Ni, Cd, Al, Cr, Pb) from recycling industry electronic waste with a consortium of Sulfobacillus thermosulfidooxidans and Thermoplasma acidophilum . The performances of commercial S 0 powder and biogenic S 0 sludge as substrates for the bio-removal of heavy metals were compared. Empirical models for the bioleaching process based on a statistical analysis were developed to evaluate the individual and combined effects of critical variables including S 0 dosage, particle size, pulp density and bacterial feed formulation (inoculum size and inoculation style) in shaken flasks while specifying the effective variable ranges. Upscale feasibility experiments in a stirred tank reactor demonstrated a maximum metal bio-removal efficiency (92%) at a 1% dosage of biogenic S 0 sludge and 2% dosage of commercial S 0 powder (82%), given a 15% pulp density and 150 μm particle size with an intermittent low-concentration addition of inoculum (1ｘ10 6 cells/mL). Biogenic S 0 sludge showed a higher degree of S 0 oxidation (95%) in a shorter time period (12 days) compared to commercial S 0 powder (82% in 24 days), thereby reducing the process cost. Risk assessments of discarded electronic wastes before and after bioremediation by the toxicity characteristic leaching procedure (TCLP), waste extraction test (WET), synthetic precipitation test (SPLP) and total threshold limit concentration (TTLC) indicated that the leaching/toxicity of bio-remediated residue was well within the regulatory limits.

Retrospective analysis of clinical data associated with patients enrolled in a molecular diagnostic feasibility study highlights the potential utility for rapid detection of bloodstream infection

BackgroundMeasurement of pathogen DNA polymerase activity by enzymatic template generation and amplification (ETGA) has shown promise in detecting pathogens in bloodstream infection (BSI). We perform an in-depth analysis of patients with clinical BSI enrolled in ETGA feasibility experiments. MethodsIn addition to hospital blood cultures, 1 study aerobic culture bottle was drawn from patients with suspected BSI. The study bottle was split into 2 bottles and was additionally subjected to ETGA analysis. Enzymatic template generation and amplification sensitivity/specificity for BSI detection was determined against the Centers for Disease Control BSI definition. When split cultures were both positive, time course analysis was performed to determine time to detection. The records of patients with BSI were reviewed for presence of systemic inflammatory response syndrome, antibiotic timing and appropriateness, and organism identification. ResultsOf 307 enrollees, 38 met the Centers for Disease Control BSI definition. Seventy-four percent met systemic inflammatory response syndrome criteria on admission. Antibiotic coverage was adequate in 76% of patients. Antibiotics were more often delayed in afebrile patients (odds ratio, 5).Twenty-seven of the split study culture bottles were positive in at least 1 sample, and ETGA detected microbes within all samples (sensitivity/specificity, 70.3%/99.3%). Of these, 22 were culture positive in both split study bottles and underwent ETGA time course analysis. Enzymatic template generation and amplification detected microbes within these 3-fold faster than culture. ConclusionsPatients with BSI often have diagnostic and treatment delays. Enzymatic template generation and amplification provides clinically meaningful data more rapidly than cultures. Future development should focus on real-time application of assays that detect microbes at the molecular level.

Creep Age Formability of Friction Stir Welded 2A12 Aluminum Alloy Structures

To establish the efficacy of creep age forming of the integrally friction stir welded panels, feasibility experiments were first conducted on friction stir welded rib-web panels of 2A12 aluminum alloys by using a designed air-loading age forming setup, and then related forming characteristics were investigated by using a mechanical-loading setup on the samples with and without friction stir welding joints. Results show that good age-formability can be observed from friction stir welded rib-web parts after creep age forming. The surface springback of the integral parts decreases with increasing the aging time and temperature. For 2A12 aluminum alloy, under an aging temperature of 190°C, a relatively better forming effect and strength can be reached at an aging time of about 8h. Compared with the non-welded structures, the introduction of friction stir welding will inhibit forming rate and will shorten the time of creep age forming.

Fabrication and analysis of PMMA, ABS, PS, and PC superhydrophobic surfaces using the spray method

In this study, superhydrophobic surfaces were fabricated using a facile spraying technique with poly(methyl methacrylate) (PMMA), acrylonitrile butadiene styrene (ABS), polystyrene (PS) and polycarbonate (PC). Also, the surface energy was qualitatively analyzed via the water contact angle with respect to the spraying time and the sprayed position. Firstly, PMMA, ABS, PS and PC were dissolved by using solvents such as methyl chloride, methanol, THF (tetrahydrofuran), and methanol, respectively. After that, the dissolved polymer was sprayed onto a thin film of the same polymer for various spraying times. Nozzle size, pressure and spraying distance were fixed as 0.2 mm, 0.1 bar, and 100 mm, respectively, after several feasibility experiments. For the sprayed surfaces, the topology was analyzed with scanning electron microscopy (SEM) and confocal microscopy, and the surface energy was qualitatively analyzed using the water-contactangle measurement. According to a quantitative analysis using the roughness factor and he Wenzel equation, all specimens could be assumed to be in a Wenzel state. To convert the Wenzel state into a Cassie-Baxster state by decreasing the surface energy of polymer-sprayed specimen, we treated the polymer-sprayed surfaces by using trichloro (1H, 1H, 2H, 2H-perfluorooctyl) silane. Consequently, non-sticky superhydrophobic surfaces having water contact angles greater than 155° and water sliding angles lower than 8° were fabricated. The water contact angle and the water sliding angle were measured by using a contact-angle-measuring device. In addition, a brief qualitative analysis of the effect of surface topology on the water sliding angle was conducted for the polymer-sprayed specimens.

Effect of stamping load variation on deformation behaviour of stainless steel thin plate with microchannel

A thin plate like a bipolar plate for a proton exchange membrane fuel cell is one of the core parts for improving the power density in a fuel cell. Stainless steel has excellent characteristics in terms of electrical resistivity, density, and thermal conductivity. Furthermore, stainless steel, instead of graphite, is used as a bipolar plate because it is cheaper and easier to machine. Therefore, in this study, a stainless steel alloy is selected as the ideal material for a bipolar plate. In this article, the results of feasibility experiments are presented; these experiments are performed with the aim of developing fuel cells using stainless steel bipolar plates with multiple channels. In this investigation, a dynamic load was applied, and the formability of microchannels was estimated with different punch pressures and die roundness, using a thin sheet metal of SUS304 with thicknesses of 0.3 and 0.1 mm. In the case of the die roundness of 0.1 mm, the formability is optimized with a sine wave dynamic load that has 90 kN of maximum pressure and five cycles of punch movement. The experimental results demonstrate the feasibility of the proposed manufacturing technique for fabricating bipolar plates.

Using virtual reality and 3D industrial numerical models for immersive interactive checklists

At the different stages of the PLM, companies develop numerous checklist-based procedures involving prototype inspection and testing. Besides, techniques from CAD, 3D imaging, animation and virtual reality now form a mature set of tools for industrial applications. The work presented in this article develops a unique framework for immersive checklist-based project reviews that applies to all steps of the PLM. It combines immersive navigation in the checklist, virtual experiments when needed and multimedia update of the checklist. It provides a generic tool, independent of the considered checklist, relies on the integration of various VR tools and concepts, in a modular way, and uses an original gesture recognition. Feasibility experiments are presented, validating the benefits of the approach.