Volume Swept Research Articles

Limits of drag augmentation at spacecraft end-of-mission and a mitigation strategy

An increasing number of objects are being launched into low-Earth orbit. Consequently, to avoid the possibility of future in-orbit collisions space object removal techniques are receiving attention. As one of the most developed techniques, drag augmentation is increasingly being considered as an option for end-of-mission removal of objects from low-Earth orbit. This paper highlights a common misconception around drag augmentation: although it can be used to reduce de-orbit time, when used inappropriately it can increase the volume swept by an object and, thus, increase the occurrence risk of collision with another space object. Knowingly ignoring this increased risk of collisions could leave spacecraft operators, and consequently their responsible state party, open to liability risk. By investigating the volume swept and de-orbit lifetime, a strategy of delayed deployment is proposed as a compromise between reducing volume swept and time to de-orbit. However, this increases system complexity and, likely, cost.

OC10.06: Pilot of an obstetrics volume sweep imaging protocol and telemedicine system in Peru

OC10.06: Pilot of an obstetrics volume sweep imaging protocol and telemedicine system in Peru

Volume Sweeping: Learning Photoconsistency for Multi-View Shape Reconstruction

We propose a full study and methodology for multi-view stereo reconstruction with performance capture data. Multi-view 3D reconstruction has largely been studied with general, high resolution and high texture content inputs, where classic low-level feature extraction and matching are generally successful. However in performance capture scenarios, texture content is limited by wider angle shots resulting in smaller subject projection areas, and intrinsically low image content of casual clothing. We present a dedicated pipeline, based on a per-camera depth map sweeping strategy, analyzing in particular how recent deep network advances allow to replace classic multi-view photoconsistency functions with one that is learned. We show that learning based on a volumetric receptive field around a 3D depth candidate improves over using per-view 2D windows, giving the photoconsistency inference more visibility over local 3D correlations in viewpoint color aggregation. Despite being trained on a standard dataset of scanned static objects, the proposed method is shown to generalize and significantly outperform existing approaches on performance capture data, while achieving competitive results on recent benchmarks.

New Ultrasound Telediagnostic System for Low-Resource Areas: Pilot Results From Peru.

Billions of people around the world lack access to diagnostic imaging. To address this issue, we piloted a comprehensive ultrasound telediagnostic system, which uses ultrasound volume sweep imaging (VSI) acquisitions capable of being performed by operators without prior traditional ultrasound training and new telemedicine software capable of sending imaging acquisitions asynchronously over low Internet bandwidth for remote interpretation. The telediagnostic system was tested with obstetric, right upper quadrant abdominal, and thyroid volume sweep imaging protocols in Peru. Scans obtained by operators without prior ultrasound experience were sent for remote interpretation by specialists using the telemedicine platform. Scans obtained allowed visualization of the target region in 96% of cases with diagnostic imaging quality. This telediagnostic system shows promise in improving health care disparities in the developing world.

Self-Lubricating Supramolecular Hydrogel for In-Depth Profile Control in Fractured Reservoirs.

In-depth profile control is a great challenge for high-efficiency oil displacement by water flooding. In this work, a shear-responsive self-lubricating hydrogel FPP-0.5, by combining the thixotropic FT (N-fluorenylmethoxycarbonyl-l-tryptophan) supramolecular network with high-strength PAM–PAANa (PAM: polyacrylamide, PAANa: sodium polyacrylate) polymer network, was synthesized and applied for in-depth profile control in water flooding. The disassembly of the FT supramolecular network induced by shear force, accompanied by the formation of a lubricating layer on the gel surface, gives FPP-0.5 gel self-lubricating function. Meanwhile, the PAM–PAANa polymer network, as a protective scaffold for the FT network, endows FPP-0.5 with high strength, making it difficult to be broken by water flow. Moreover, the shear responsiveness enables FPP-0.5 to adjust its own strength and self-lubricating performance according to the different stages of the profile control process, so as to realize dynamic profile control. From oil displacement results, in comparison to the PAM–PAANa gel, the plugging rate, water flooding volume sweep efficiency, and oil recovery of FPP-0.5 were improved by 83.1, 155.4, and 34.0%, respectively, up to 86.6, 83.5, and 71.3%, indicating its better in-depth profile control ability.

Lung Ultrasound Volume Sweep Imaging for Pneumonia Detection in Rural Areas: Piloting Training in Rural Peru.

Objective:Pneumonia is the leading cause of pediatric mortality worldwide among children 0–5 years old. Lung ultrasound can be used to diagnose pneumonia in rural areas as it is a portable and relatively economic imaging modality with ~95% sensitivity and specificity for pneumonia in children. Lack of trained sonographers is the current limiting factor to its deployment in rural areas. In this study, we piloted training of a volume sweep imaging (VSI) ultrasound protocol for pneumonia detection in Peru with rural health workers. VSI may be taught to individuals with limited medical/ultrasound experience as it requires minimal anatomical knowledge and technical skill. In VSI, the target organ is imaged with a series of sweeps and arcs of the ultrasound probe in relation to external body landmarks.Methods:Rural health workers in Peru were trained on a VSI ultrasound protocol for pneumonia detection. Subjects were given a brief didactic session followed by hands-on practice with the protocol. Each attempt was timed and mistakes were recorded. Participants performed the protocol until they demonstrated two mistake-free attempts.Results:It took participants a median number of three attempts (range 1–6) to perform the VSI protocol correctly. Time to mastery took 51.4 ± 17.7 min. There were no significant differences among doctors, nurses, and technicians in total training time (P = 0.43) or number of attempts to success (P = 0.72). Trainee age was not found to be significantly correlated with training time (P = 0.50) or number of attempts to success (P = 0.40).Conclusion:Rural health workers learned a VSI protocol for pneumonia detection with relative ease in a short amount of time. Future studies should investigate the clinical efficacy of this VSI protocol for pneumonia detection.Key Message:A volume sweep imaging (VSI) protocol for pneumonia detection can be taught with minimal difficulty to rural health workers without prior ultrasound experience. No difference was found in training performance related to education level or age. VSI involves no significant knowledge of anatomy or technical skill.

Shear rate and direct numerical calculation of the Metzner-Otto constant for a pitched blade turbine

Metzner-Otto's concept regarding the existence of an average shear rate (γ˙av) around the impeller was numerically undertaken for shear-thinning fluids. This study focuses on investigating the region around the pitched blade turbine (PB4) which could be considered as the region where Metzner-Otto's constant can be extracted directly from non-Newtonian simulations as Ks=γ˙av/N (where N is the impeller speed). For this purpose, ten succeedingly increasing volumes enclosing the impeller were defined in the mesh with the objective of studing γ˙av in these zones. Results show that γ˙av in the volume swept by the blades for the PB4 is similar with that reported for the Rushton turbine. However, the region where Ks can be computed for the PB4 extends approximately up to 1.22 impeller radii and 2.5 impeller blade heights. The Metzner-Otto's constant in this region (Ks = 8.86) was found to be in good agreement with our experimental (Ks = 8.53) result and with reported data (Ks = 8.58).

Enantioselective analysis of pheniramine in rat using large volume sample stacking or cation-selective exhaustive injection and sweeping coupled with cyclodextrin modified electrokinetic chromatography

For the aim of simultaneously performing the enantioseparation and determination of the trace enantiomers in plasma samples, enantioseparation by HPLC using five kinds of chiral stationary phases were initially investigated. But unfortunately, enantioseparation could not be detected in reversed mobile phase mode with all the five columns. For this reason, two simple, economical and highly efficient online preconcentration methods, large volume sample stacking and sweeping (LVSS-sweeping) and cation-selective exhaustive injection and sweeping (CSEI-sweeping) both followed by the cyclodextrin modified electrokinetic chromatography (CDEKC) were examined in the present work. Parameters affecting the enantioseparation and enhancement efficiency of these two injection modes were monitored in detail, and migration order of the two enantiomers was identified by circular dichroism (CD) and HPLC. Upon optimization, two enantiomers were best separated with the improvement of sensitivity reaching 160-fold and 4000-fold respectively for LVSS-sweeping and CSEI-sweeping comparing with the normal CDEKC separation. Then the optimal condition of CSEI-sweeping-CDEKC was validated and showed high sensitivity (10 ng/mL for lower limit of quantification, LLOQ), satisfactory accuracy (96.8–111.6%) and precision (relative standard deviation, RSD within 9.4%). This demonstrated it to be a suitable strategy for the rapid enantioselective determination and quantitative analysis of pheniramine enantiomers in plasma samples. Therefore, the method was further applied in the enantiomeric analysis of pheniramine in rat pharmacokinetics and plasma protein binding investigations. Stereoselectivity in pharmacokinetics as well as plasma protein binding were observed, suggesting that the stereoselective protein binding might be responsible for the stereoselectivity in pharmacokinetics.

Screening the second-trimester fetal heart in women with an increased body mass index using three-dimensional volume sweep.

To determine the percentage of fetal cardiac anatomy as detailed in the International Society of Ultrasound in Obstetrics and Gynecology Practice Guidelines on sonographic screening examination of the fetal heart, which can be visualised in women with a body mass index (BMI) >30 kg/m2 using three-dimensional (3D) volume sweeps. 3D volumes of the fetal heart were taken prospectively in 40 fetuses during routine second-trimester fetal anatomy scan. Scans and 3D volume sweeps were performed by two experienced sonographers and two experienced raters interpreted the 3D data. 3D volume acquisitions and post-processing analysis were performed according to the techniques described by Weissmann-Brenner et al. The two raters were able to detect an average of 12.9 and 14.1 of the 16 parameters in the 40 patients. Agreement between raters for the 16 parameters had an average of 80%. Five parameters (stomach, situs, heart occupies a third of thoracic area, majority of heart in the left chest and cardiac axis) were detected by both raters on all patients. The range of agreement was between 40% and 100%. The three-vessel view and bifurcation had agreement <60%. Consistent identification of all views of the fetal heart was not achieved using the simple method described in women with a BMI > 30 kg/m2.

Time Interval Ray Tracing for Motion Blur.

We introduce a new motion blur computation method for ray tracing that provides an analytical approximation of motion blurred visibility per ray. Rather than relying on timestamped rays and Monte Carlo sampling to resolve the motion blur, we associate a time interval with rays and directly evaluate when and where each ray intersects with animated object faces. Based on our simplifications, the volume swept by each animated face is represented using a triangulation of the surface of this volume. Thus, we can resolve motion blur through ray intersections with stationary triangles, and we can use any standard ray tracing acceleration structure without modifications to account for the time dimension. Rays are intersected with these triangles to analytically determine the time interval and positions of the intersections with the moving objects. Furthermore, we explain an adaptive strategy to efficiently shade the intersection intervals. As a result, we can produce noise-free motion blur for both primary and secondary rays. We also provide a general framework for emulating various camera shutter mechanisms and an artistic modification that amplifies the visibility of moving objects for emphasizing the motion in videos or static images.

A direct calculation method of the Metzner-Otto constant by using computational fluid dynamics

The best-known paper on non-Newtonian fluids in mixing systems is the Metzner and Otto’s work. A central idea of their contribution is based on the assumption that in laminar flow there exists an average shear rate (γ̇av) around the impeller (whose exact location and geometric shape is not clearly specified), and that it is proportional to the impeller speed (N), i.e., γ̇av=KsN, where Ks is the Metzner-Otto constant. In this work, an in-depth investigation of this assumption is carried out by using computational fluid dynamics (CFD) to calculate the three-dimensional flow induced by a Rushton turbine (RT). It was found that the volume swept by the blades is the region where Ks may be computed explicitly as Ks=γ̇av/N directly from non-Newtonian flow simulations. The obtained Ks values in this region were found in good agreement with reported data. Furthermore, power number measurements and data from literature were used to validate the simulations. The CFD method developed in this study can be used to readily and reliably evaluate Ks of industrial mixing impellers without resorting to power data of Newtonian fluids.

New tele-diagnostic model using volume sweep imaging for rural areas.

Advances in information and communications technologies provide a new opportunity to improve the access to healthcare in remote rural areas (RA) where there is a lack of infrastructure and medical experts. This paper implements a new model for tele-ultrasound (US) based on volumetric sweep imaging protocols specially designed for the acquisition of US. Non-physician health personnel from the RA are trained on the use of these protocols in a few days. The operator utilizes the medical box (MB), a specially designed telecommunication system, to guide, compress, encrypt and transmit the US sweeps through the cloud to the radiologist who performs the diagnosis remotely. The report is automatically sent back to the MB. The system was able to send US volumetric images with poor connectivity conditions in 6 minutes on average. These results of implementing this tele-ultrasound model in RAs are encouraging and support future validations.

Free flowing and cohesive powders agitation in a cylindrical convective blender- kinetics experiments and Markov chain modelling

An original methodology for studying powder flow in a cylindrical convective blender has been developed. A free-flowing and a cohesive powder were studied, at a fixed stirring speed, in rolling regime. For both powders, three apparent flow mechanisms were evidenced: convection in the volume swept by the blades, diffusion/shearing between the agitated zone and the stagnant one, as well as in the stagnant zone itself, and avalanches at the powder bed surface between agitated and stagnant zones. After defining six zones in the blender, tracing experiments were carried out by placing appropriate tracers in different starting zones and sampling the whole bed at different stirring times, which lead to mixing kinetics of the powders into themselves. A Markov chains model of the blender allowed the quantification of the three mechanisms respective magnitude by fitting the experimental data. This simple model has a good agreement with the free-flowing powder data, but is not able to represent well the observations for the cohesive powder. Bed consolidation should probably be taken into account for this kind of powders and thus a linear Markov model is not sufficient.

Assessment of the effective viscous dissipation for deagglomeration processes induced by a high shear impeller in a stirred tank

A ring-style high shear impeller Hockmeyer® type (HockD-2R) of practical importance (Hockmeyer® Equipment Corp. D-Blade), commonly used in the paint and coatings industry to rapidly break lumps of powdery material in a liquid was investigated, and its performance compared against the classical Rushton turbine (RT). A numerical and experimental study in an unbaffled tank, operating in the laminar to transitional flow regime (50⩽Re⩽125) was carried out. Simulations were conducted using commercial Computational Fluid Dynamics (CFD) solver ANSYS Fluent 14.5. Local hydrodynamics (velocity vectors and viscous dissipation), averaged viscous dissipation values and pumping capacities, obtained from simulations, were firstly used to compare the impeller’s performance. After that, experiments were performed to investigate the influence of the viscous dissipation on the amount of fines generation from mineral powders. It was found that the volume swept by the blades is the region of maximum effective viscous dissipation, considering its effects on breakage of particle agglomerates. Further experiments were conducted to investigate the influence of the power input on the powder dispersion efficiency. At the same power draw and higher speeds, the HockD-2R was found to be more efficient than the RT for fine aggregates production.

空間掃引を用いたロボット教示のためのAugmented Reality利用

Nowadays industrial robots are used widely in factories. A robot programming method in which everyone can easily teach robots ”good” motions is demanded. For this purpose, our group proposed a robot programming method that uses manual volume sweeping by operators and automatic motion planning to generate motion plans with short cycle times. A swept volume is the space through which robots have passed without collision. Therefore, it is movable space of robots. In this paper, we proposed using augmented reality in this programming method by volume sweeping. We constructed a system in which an operator can perceive obtained swept volumes and generated paths by augmented reality. Teaching experiments were performed to evaluate the performance of this system. As a result, it was showed that non-skilled operators can make robots move in shorter time than teaching/playback by direct teaching.

EP04.05: Screening the second trimester fetal heart in women with an increased body mass index using three dimensional volume sweep

EP04.05: Screening the second trimester fetal heart in women with an increased body mass index using three dimensional volume sweep

A Preliminary In-situ TEM Study of Martensite/Austenite Interface Migration in an Fe-20Ni-5.4Mn Alloy

We report an in-situ TEM investigation of a reverse martensite transformation in an Fe–Ni–Mn alloy at temperature ranging from 400°C to 600°C. Two modes, normal and ledge motions, have been observed during retreating migration of the broad interfaces (∼habit plane) between austenite and martensite. A large number of dislocations nearly perpendicular to the interface were observed in the volume swept by a fast normal motion of the interface, while few dislocations are left behind in the fresh austenite transformed by a ledge motion. During the ledge motion, concurrent displacement of the interfacial dislocations along both ledge riser and terrace plane is evidently detected. The normal displacement component for the dislocations in the broad interface is small and this is associated with a slow normal motion of the interface.

Feasibility of three-dimensional reconstruction and automated measurement of fetal long bones using 5D Long Bone.

ObjectiveTo evaluate the feasibility of five-dimensional Long Bone (5D LB), a new technique that automatically archives, reconstructs images, and measures lengths of fetal long bones, to assess whether the direction of volume sweep influences fetal long bone measurements in three-dimensional (3D) ultrasound and 5D LB, and to compare measurements of fetal long bone lengths obtained with 5D LB and those obtained with conventional two-dimensional (2D) and manual 3D techniques.MethodsThis prospective study included 39 singleton pregnancies at 26+0 to 32+0 weeks of gestation. Multiple pregnancies, fetuses with multiple congenital anomalies, and mothers with underlying medical diseases were excluded. Fetal long bones of the lower extremities-the femur, tibia, and fibula were measured by 2D and 3D ultrasound, and 5D LB, by an expert and non-expert examiner. First, we analyzed the 3D ultrasound and 5D LB data according to 2 different sweeping angles. We analyzed intra- and inter-observer variability and agreement between ultrasound techniques. Paired t-test, interclass correlation coefficient, and Bland-Altman plot and Passing-Bablok regression were used for statistical analysis.ResultsThere was no statistical difference between long bone measurements analyzed according to 2 different volume-sweeping angles by 3D ultrasound and 5D LB. Intra- and inter-observer variability were not significantly different among all 3 ultrasound techniques. Comparing 2D ultrasound and 5D LB, the interclass correlation coefficient for femur, tibia, and fibula was 0.91, 0.92, and 0.89, respectively.Conclusion5D LB is reproducible and comparable with conventional 2D and 3D ultrasound techniques for fetal long bone measurement.

Volume sweep imaging: open-source technology for pediatric global health collaboration.

Volume sweep imaging: open-source technology for pediatric global health collaboration.

Predicting the Method of Oil Recovery in the Gas-assisted Gravity Drainage Process

Gas-assisted gravity drainage (GAGD), solving the problem of low volume sweep coefficient for continuous gas injection (CGI) or water-alternating-gas injection (WAG) and increasing the ultimate recovery to a great extent, is a latest method for enhancing oil recovery. However, no effective predicting methods of oil recovery for GAGD exists. The oil recovery is determined by a set of parameters, such as heterogeneity of the formation, wettability, oil and gas density, oil and gas viscosity, viscous force, capillary force, gravity, gas injection rate, and other controllable parameters. Based on the research of producing mechanism of GAGD and dimensional analysis method, the authors analyzed four dimensionless varies, capillary number, bond number, gravity number, and gravity drainage number, and evaluated its influence on oil recovery. Considering the effect of wettability, viscosity ratio, and the difference between oil density and gas density, gravity number and gravity drainage number are modified. Relationship of gravity drainage number with recovery is re-established by experiments and case data. Finally a new predicting method of oil recovery for GAGD is set up. Application shows that this method is far more suitable for GAGD and its predictive result is more reasonable.