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2022 ◽  
Vol 3 (1) ◽  
pp. 1-16
Author(s):  
Bradley Feiger ◽  
Erick Lorenzana-Saldivar ◽  
Colin Cooke ◽  
Roarke Horstmeyer ◽  
Muath Bishawi ◽  
...  

Segmentation and reconstruction of arteries is important for a variety of medical and engineering fields, such as surgical planning and physiological modeling. However, manual methods can be laborious and subject to a high degree of human variability. In this work, we developed various convolutional neural network ( CNN ) architectures to segment Stanford type B aortic dissections ( TBADs ), characterized by a tear in the descending aortic wall creating a normal channel of blood flow called a true lumen and a pathologic channel within the wall called a false lumen. We introduced several variations to the two-dimensional ( 2D ) and three-dimensional (3 D ) U-Net, where small stacks of slices were inputted into the networks instead of individual slices or whole geometries. We compared these variations with a variety of CNN segmentation architectures and found that stacking the input data slices in the upward direction with 2D U-Net improved segmentation accuracy, as measured by the Dice similarity coefficient ( DC ) and point-by-point average distance ( AVD ), by more than 15\% . Our optimal architecture produced DC scores of 0.94, 0.88, and 0.90 and AVD values of 0.074, 0.22, and 0.11 in the whole aorta, true lumen, and false lumen, respectively. Altogether, the predicted reconstructions closely matched manual reconstructions.


Metals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1942
Author(s):  
Gerardo Aguilar ◽  
Gildardo Solorio-Diaz ◽  
Alicia Aguilar-Corona ◽  
José Angel Ramos-Banderas ◽  
Constantin A. Hernández ◽  
...  

The use of porous plugs in injecting gas through the bottom of a ladle forms vertical plumes in a very similar way to a truncated cone. The gas plume when exiting the plug has a smaller diameter compared to that formed in the upper zone of the ladle because inertial forces predominate over buoyancy forces in this zone. In addition, the magnitude of the plume velocity is concentrated in an upward direction, which increases the likelihood of low velocity zones forming near the bottom of the ladle, especially in lower corners. In this work, a plug with spiral-shaped channels with different torsion angles is proposed, with the objective that the gas, when passing through them, has a tangential velocity gain or that the velocity magnitude is distributed in the three axes and does not just focus on the upward direction, helping to decrease low velocity zones near the bottom of the ladle for better mixing times. For the experimentation, we worked in a continuous casting ladle water model with two configuration injections, which in previous works were reported as the most efficient in mixing the steel in this ladle. The results obtained using the PIV technique (particle image velocimetry) and conductimetry technique indicate that the plugs with the torsion channels at angles of 60° and 120° improve the mixing times for the two injection configurations.


Author(s):  
Omkar Adhikari

Abstract: By considering the tightening process, the experimental testing will be conducted to explore the mechanism of bolt selfloosening under biaxial loading. The most common mode of failure is overloading: Operating forces of the application produce loads that exceed the clamp load, causing the joint to loosen over time or fail catastrophically. Over torque might cause failure by damaging the threads and deforming the fastener, though this can happen over a very long time. Also, the bolts may fail under fatigue. The components used in the system are bolts, pneumatic cylinder and flow control valve. The pneumatic cylinder is actuated with the help of compressor. The flow of air in the cylinder will be controlled with the help of pneumatic cylinder which will be acted on the bolts in two directions that is from downward & upward direction. This means the load will be tensile and shearing load. The bolts are attached to the plates. Because of actuation of the pneumatic cylinder the bolts will become loose. These bolts will be tested by using biaxial loading. The result & conclusion was drawn after the experimental testing. Keywords: Bi-axial Loading, Fasteners, Bolt Loosening, Residual Torque, Fastener Overloading


Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5266
Author(s):  
Dong-Jin Cheon ◽  
Yong-Chul Kim ◽  
Jong-Ho Lee ◽  
Sung-Won Yoon

Cladding for dome roofs is often made of membrane materials that are light and easy to install. Due to these characteristics, wind damage to dome roof cladding is very common. In particular, open or retractable dome roofs are prone to wind damage because of inadequacies in wind load calculations. In this study, the wind pressure characteristics of a dome with a central opening were investigated. Wind tunnel tests were performed, and the pressure distribution was investigated by analyzing external and internal pressure coefficients. Based on the experimental results, the peak net pressure coefficients for the cladding design of a dome roof with a central opening were proposed. For the external peak pressure coefficients, the values of leeward regions were similar despite height–span ratios and turbulence intensity values. For the internal peak pressure coefficients, negative pressure was dominant, and the coefficients were not significantly affected by changes in height–span ratio. This tendency locally increased the negative peak net pressure, in which the load acts in the upward direction, and relatively significantly increased the positive peak net pressure, in which the load acts in the downward direction.


2021 ◽  
Author(s):  
Maryam Habibi ◽  
Mohsen Heidary ◽  
Mohammad Mehdi Tavakol ◽  
Goodarz Ahmadi

Abstract In this study, the dispersion and deposition of particles in the respiratory system attached to a mannequin lying down inside a room were investigated numerically. The respiratory system model was prepared by processing the CT scan images of a volunteer and was attached to a mannequin lying in the middle of a room. The flow field around the mannequin and effects of the thermal plume on the particle aspiration by the mannequin model was simulated using the Ansys-Fluent software. The aspiration efficiency of spherical particles in the airway was studied with the Lagrangian particle trajectory analysis, including the turbulence dispersion effects. For validation of numerical simulations, the aspiration efficiency of the particles obtained from the numerical solution was compared with the case of a standing mannequin. The results are presented for two different modes with upward and downward thermal plumes. For the first mode, due to the strong effect of the thermal plume in the upward direction, the aspiration efficiency of midrange particles increases. However, the aspiration efficiency of large micro-particles decreases for the first mode. For the second mode, with the downward thermal plume, the aspiration efficiency of small micro-particles increases significantly.


2021 ◽  
Vol 6 (2) ◽  
pp. 157-164
Author(s):  
Muhammad Rusdi Adiputra ◽  
Purnama Salura

Mosques as a religious building for the Moslem Community have two orientations and they include the Qibla as the main and direction of the sky as the secondary. Praying is the main element of worship for Moslems and is recommended to be led towards the Qibla or upward direction. The mosque has been discovered not to have a sacred space but Qibla, mihrab, and Qibla marker walls are considered sacred. These sacred orientation signs and markers have been used and developed since the beginning but their existence and understanding have been eroded due to the influence of locals as well as development. Currently, the majority of the mosques in Indonesia have a centralized and strong orientation towards the upper direction when they are expected to have the main orientation in the form of Qibla direction. This study was, therefore, conducted to examine the anatomy of these mosques using semiotic theory by comparing the two mosques with several signs and markers of sacred orientation in the country. The results showed there are new signs and markers but the old ones are still significant in the mosques in the present time.


Minerals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 609
Author(s):  
Wenbao Zheng ◽  
Yiyun Wang

Jiama is a super-large porphyry copper–polymetallic deposit located in the Gangdese metallogenic belt of southern Tibet. The deposit consists of a combination of a polymetallic skarn, Cu–Mo mineralization at the contact between the Jiama Porphyry and hornfels, and distal Au mineralization in fault. The current metal reserves are 7.4 Mt Cu, 0.6 Mt Mo, 1.8 Mt Pb–Zn, 6.65 Moz Au, and 360.32 Moz Ag, with a skarn to porphyry–hornfels host-rock ratio of ~3:1. Based on detailed field and laboratory investigations, this paper indicates that: (i) the skarn and porphyry–hornfels orebodies are almost entirely preserved; (ii) the emplacement age of the Cu-bearing plutonic rocks is earlier than the plutons containing elevated Mo assays; (iii) the permeability of the wall rocks gradually decreases in an upward direction; (iv) the fluid temperature during the precipitation of Cu was higher than that of the Mo mineralization; (v) the lithospheric pressure during the precipitation of Cu and Mo was the same; (vi) the laser Raman spectroscopy shows that the fluid carrying the Cu was rich in magnetite, hematite, and anhydrite, and the fluid carrying Mo was rich in pyrite, CO2, and CH4; and (vii) the SR–XRF mapping shows that the concentration of Cu in the mineralizing fluid was high and that of Mo was low when Cu was deposited. Conversely, the concentration of Cu was relatively low and the concentration of Mo was relatively high during deposition of the Mo. This study also shows that the temporal and spatial separation of Cu and Mo in the porphyry copper–polymetallic deposit at Jiama was associated with the emplacement of the Jiama Porphyry. Transportation of mineralized fluid was controlled by the permeability of the wall rocks, and deposition of the metals related to changes along a redox front and pressure releases during hydrothermal brecciation at the roof of the Jiama Porphyry.


2021 ◽  
pp. 61-63
Author(s):  
Bharath. V ◽  
Hemanth Kumar ◽  
Ashwanth Narayan ◽  
Venkatachalam .K ◽  
Ashwin. VY ◽  
...  

The Inter-Pedicular and Inter-Pars distance was measured in a plain AP radiography (X-Ray) of 150 and 75 CT images normal patients between 18- 47 years of age. The aim of the study is to measure the normal Inter-Pedicular and Inter-Pars distance. We found that by studying the anatomical relationship between the inner or medial Pedicular border and the Pars outer or lateral border, gives the Orthopaedic Surgeon a reproducible and consistent guide towards exacting a pedicular screw placing. We found that both X-Ray and CT images shows steady increase in the Ipr and Ipd from L1 to L5, there is a minimal difference from L1-L2 and marked difference seen from L3 to L5, and showing the differences in distances are more in the males, compared to females. The Means of all the groups compared also proves that there is steady raise in the diameter of the IPR and IPD from L1 to L5, where there is dramatical and signicant change in the upward direction, noted from L3 to L5. The mean difference is almost constant from L1to L2. So this study, did essentially to help, establish that, the inner medial border of pedicle, is in near relationship to, the outer lateral border of the Pars-Interarticularis, which helps in establishing the latero-medial entry point for the pedicular screw insertion in the lumbar spine.


Medicina ◽  
2021 ◽  
Vol 57 (3) ◽  
pp. 207
Author(s):  
Gina Nam ◽  
Sa Ra Lee ◽  
Sung Hoon Kim ◽  
Hee Dong Chae

Uterine incarceration is rare, but it can cause serious complications, in which the uterus is trapped in the pelvic cavity behind the sacral promontory. Fibroid uterus can cause urinary frequency and retention, which can result from compression of the urinary bladder with an enlarged fibroid uterus and the compression of the bladder neck or urethra, respectively. To our knowledge, there is no report on prolonged complete urinary obstruction because of an incarcerated uterus in nonpregnant women to date. A 51-year-old woman was referred for uterine myomas. She could not void for 30 months after she received an intradetrusor injection of botulinum toxin for urinary frequency management at the urology department of another hospital. She underwent clean intermittent catheterization for 30 months. She was referred to the gynecologic department for the evaluation of uterine myoma found on using abdominopelvic computed tomography. On physical examination, the uterine cervix was extremely displaced in the upward direction and was not exposed on speculum examination. Sonography and magnetic resonance imaging revealed that the urethra and the bladder neck were compressed by an extremely retroflexed fibroid uterus. Manual reduction of the incarcerated uterus failed; hence, we performed robot-assisted laparoscopic total hysterectomy with left salpingo-oophorectomy. She immediately urinated immediately after the operation and had normal urination at 1- and 48-month follow-up visits. Uterine incarceration by a fibroid uterus can cause complete urinary obstruction, as in this case. Uterine incarceration should be considered in women with urinary frequency or retention to avoid prolonged, serious complications.


Author(s):  
Wan Mohd Fariz Bin Wan Azman ◽  
Rosnah Binti Shamsudin ◽  
Mohd Zuhair Bin Mohd Nor ◽  
Azman Bin Hamzah

Starch is one of the food sources that can be extracted from cereals, roots, tubers and stem. Sago palm (metroxylon spp.) is one example of the starch source. The efficiency of the starch extraction process depends on the mechanical properties of process material. This study was conducted to determine the angle of repose between grated sago and kinetic friction of the contact surface between process material and machine. The angle of repose (θ) of grated sago was determined by using a cone shape hopper attached to an adjustable height bar. The cone was filled with a 100g sample of grated sago and slowly adjusted to an upward direction to release the grated sago and will form a conical shape. The cone shape base diameter and height were measured. Next, a square block of debarked sago trunk (8cm × 8cm × 8cm) was placed on a stainless steel plate and attached to a rope at middle connected to force gauges. The pulling speed was at 1.27 mm/min and the result of total pulling load (F) was recorded. The process was repeated for materials with different moisture content (MC) of 60%, 50%, 40%, and 30%. Based on the experimental results, the angle of repose (AoR= 47.000±0.31) and coefficient of kinetic friction (μ k) 0.88±0.005 at MC= 60% showed decrease in value (AoR= 43.610±0.34; μ k = 0.83±0.002) when the MC decrease by 30% (P<0.01).


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