7 research outputs found
Recommended from our members
Performance Characteristics of an Extended Throat Flow Nozzle for the Measurement of High Void Fraction Multi-phase Flows
An extended throat flow nozzle has been examined as a device for the measurement of very high void fraction (a ³ 0.95) multi-phase flows. Due to its greater density and partial contact with the wall, the equilibrium velocity of the liquid phase appreciably lags that of the lighter gas phase. The two phases are strongly coupled resulting in pressure drops across the contraction and in the extended throat that are significantly different than those experienced in single-phase flow. Information about the mass flow rates of the two phases can be extracted from the measured pressure drops. The performance of an extended throat flow nozzle has been evaluated under multi-phase conditions using natural gas and hydrocarbon liquids at 400 and 500 psi. Two hydrocarbon solvents were used as the test liquids, Isopar MÒ (sp = 0.79) and Aromatic 100â (sp = 0.87). These data are compared to prior air-water data at nominally 15 psi. The high and low pressure data were found to be consistent, confirming that the temperature, pressure, and size scaling of the extended throat venturi are correctly represented. This consistency allows different sized devices to be applied under different fluid conditions (temperature, pressure, gas and liquid phase composition, etc) with confidence
Automatic Hip Fracture Identification and Functional Subclassification with Deep Learning
Purpose: Hip fractures are a common cause of morbidity and mortality.
Automatic identification and classification of hip fractures using deep
learning may improve outcomes by reducing diagnostic errors and decreasing time
to operation. Methods: Hip and pelvic radiographs from 1118 studies were
reviewed and 3034 hips were labeled via bounding boxes and classified as
normal, displaced femoral neck fracture, nondisplaced femoral neck fracture,
intertrochanteric fracture, previous ORIF, or previous arthroplasty. A deep
learning-based object detection model was trained to automate the placement of
the bounding boxes. A Densely Connected Convolutional Neural Network (DenseNet)
was trained on a subset of the bounding box images, and its performance
evaluated on a held out test set and by comparison on a 100-image subset to two
groups of human observers: fellowship-trained radiologists and orthopaedists,
and senior residents in emergency medicine, radiology, and orthopaedics.
Results: The binary accuracy for fracture of our model was 93.8% (95% CI,
91.3-95.8%), with sensitivity of 92.7% (95% CI, 88.7-95.6%), and specificity
95.0% (95% CI, 91.5-97.3%). Multiclass classification accuracy was 90.4% (95%
CI, 87.4-92.9%). When compared to human observers, our model achieved at least
expert-level classification under all conditions. Additionally, when the model
was used as an aid, human performance improved, with aided resident performance
approximating unaided fellowship-trained expert performance. Conclusions: Our
deep learning model identified and classified hip fractures with at least
expert-level accuracy, and when used as an aid improved human performance, with
aided resident performance approximating that of unaided fellowship-trained
attendings.Comment: Presented at Orthopaedic Research Society, Austin, TX, Feb 2, 2019,
currently in submission for publicatio
Recommended from our members
Performance Characteristics of an Extended Throat Flow Nozzle for the Measurement of High Void Fraction Multi-Phase Flows
An extended throat flow nozzle has been examined as a device for the measurement of very high void fraction multi-phase flows. Due to its greater density and partial contact with the wall, the equilibrium velocity of the liquid phase appreciably lags that of the lighter gas phase. The two phases are strongly coupled resulting in pressure drops across the contraction and in the extended throat that are significantly different than those experienced in single-phase flow. Information about the mass flow rates of the two phases can be extracted from the measured pressure drops. The performance of an extended throat flow nozzle has been evaluated under multi-phase conditions using natural gas and hydrocarbon liquids at 400 and 500 psi. Two hydrocarbon solvents were used as the test liquids, Isopar M (sp=0.79) and Aromatic 100 (sp=0.87). These data are compared to prior air-water data at nominally 15 psi. The high and low pressure data were found to be consistent, confirming that the temperature, pressure, and size scaling of the extended throat venturi are correctly represented. This consistency allows different sized devices to be applied under different fluid conditions (temperature, pressure, gas and liquid phase composition, etc) with confidence