Effects of downcomer-to-riser cross sectional area ratio on operation behaviour of external-loop airlift bioreactors

1996 ◽  
Vol 15 (2) ◽  
pp. 77-85 ◽  
Author(s):  
M. Gavrilescu ◽  
R. Z. Tudose
Keyword(s):  
Area Ratio ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
External Loop ◽  
Airlift Bioreactors

scholarly journals Atrophy patterns in isolated subscapularis lesions

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Gernot Seppel ◽  
Andreas Voss ◽  
Daniel J. H. Henderson ◽  
Simone Waldt ◽  
Bernhard Haller ◽  
...  
Keyword(s):  
Muscle Atrophy ◽  
Area Ratio ◽  
Cross Sectional Area ◽  
Control Group ◽  
Sectional Area ◽  
Cross Sectional ◽  
Subscapularis Muscle ◽  
Mri Scans ◽  
The Mean ◽  
The Cross

Abstract Background While supraspinatus atrophy can be described according to the system of Zanetti or Thomazeau there is still a lack of characterization of isolated subscapularis muscle atrophy. The aim of this study was to describe patterns of muscle atrophy following repair of isolated subscapularis (SSC) tendon. Methods Forty-nine control shoulder MRI scans, without rotator cuff pathology, atrophy or fatty infiltration, were prospectively evaluated and subscapularis diameters as well as cross sectional areas (complete and upper half) were assessed in a standardized oblique sagittal plane. Calculation of the ratio between the upper half of the cross sectional area (CSA) and the total CSA was performed. Eleven MRI scans of patients with subscapularis atrophy following isolated subscapularis tendon tears were analysed and cross sectional area ratio (upper half /total) determined. To guarantee reliable measurement of the CSA and its ratio, bony landmarks were also defined. All parameters were statistically compared for inter-rater reliability, reproducibility and capacity to quantify subscapularis atrophy. Results The mean age in the control group was 49.7 years (± 15.0). The mean cross sectional area (CSA) was 2367.0 mm2 (± 741.4) for the complete subscapularis muscle and 1048.2 mm2 (± 313.3) for the upper half, giving a mean ratio of 0.446 (± 0.046). In the subscapularis repair group the mean age was 56.7 years (± 9.3). With a mean cross sectional area of 1554.7 mm2 (± 419.9) for the complete and of 422.9 mm2 (± 173.6) for the upper half of the subscapularis muscle, giving a mean CSA ratio of 0.269 (± 0.065) which was seen to be significantly lower than that of the control group (p < 0.05). Conclusion Analysis of typical atrophy patterns of the subscapularis muscle demonstrates that the CSA ratio represents a reliable and reproducible assessment tool in quantifying subscapularis atrophy. We propose the classification of subscapularis atrophy as Stage I (mild atrophy) in case of reduction of the cross sectional area ratio < 0.4, Stage II (moderate atrophy) in case of < 0.35 and Stage III (severe atrophy) if < 0.3.

Use of Cardiac Magnetic Resonance Imaging Based Measurements of Inferior Vena Cava Cross-Sectional Area in the Diagnosis of Pericardial Constriction

2015 ◽  
Vol 66 (3) ◽  
pp. 231-237 ◽  
Author(s):  
Kate Hanneman ◽  
Paaladinesh Thavendiranathan ◽  
Elsie T. Nguyen ◽  
Hadas Moshonov ◽  
Rachel Wald ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Cardiac Magnetic Resonance ◽  
Inferior Vena ◽  
Vena Cava ◽  
Area Ratio ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Resonance Imaging ◽  
Cross Sectional ◽  
Aortic Area

Purpose To evaluate the value of cardiac magnetic resonance imaging (MRI)–based measurements of inferior vena cava (IVC) cross-sectional area in the diagnosis of pericardial constriction. Methods Patients who had undergone cardiac MRI for evaluation of clinically suspected pericardial constriction were identified retrospectively. The diagnosis of pericardial constriction was established by clinical history, echocardiography, cardiac catheterization, intraoperative findings, and/or histopathology. Cross-sectional areas of the suprahepatic IVC and descending aorta were measured on a single axial steady-state free-precession (SSFP) image at the level of the esophageal hiatus in end-systole. Logistic regression and receiver-operating curve (ROC) analyses were performed. Results Thirty-six patients were included; 50% (n = 18) had pericardial constriction. Mean age was 53.9 ± 15.3 years, and 72% (n = 26) were male. IVC area, ratio of IVC to aortic area, pericardial thickness, and presence of respirophasic septal shift were all significantly different between patients with constriction and those without ( P < .001 for all). IVC to aortic area ratio had the highest odds ratio for the prediction of constriction (1070, 95% confidence interval [8.0-143051], P = .005). ROC analysis illustrated that IVC to aortic area ratio discriminated between those with and without constriction with an area under the curve of 0.96 (95% confidence interval [0.91-1.00]). Conclusions In patients referred for cardiac MRI assessment of suspected pericardial constriction, measurement of suprahepatic IVC cross-sectional area may be useful in confirming the diagnosis of constriction when used in combination with other imaging findings, including pericardial thickness and respirophasic septal shift.

Assessment of sand stabilization potential of a plant-derived biomass

2016 ◽  
Vol 23 (2) ◽  
pp. 227-236 ◽  
Author(s):  
Dunja Perić ◽  
Paul A. Bartley ◽  
Lawrence Davis ◽  
Ali Ulvi Uzer ◽  
Cahit Gürer
Keyword(s):  
Area Ratio ◽  
Cross Sectional Area ◽  
Experimental Program ◽  
Early Age ◽  
Shear Stresses ◽  
Sectional Area ◽  
Cross Sectional ◽  
Near Surface ◽  
Total Cross Sectional Area ◽  
Dry Sand

AbstractLignin is a coproduct of biofuel and paper industries, which exhibits binding qualities when mixed with water. Lignin is an ideal candidate for a sustainable stabilization of unpaved roads. To this end, an experimental program was devised and carried out to quantify effects of lignin on compaction and early age shear strength behaviors of sand. Samples were prepared by mixing a particular type of coproduct called calcium lignosulfonate (CaL) with sand and water. Based on the extensive analyses of six series of strength tests, it was found that a normalized cohesion increased with an increasing normalized areas ratio. Normalizations were carried out by dividing the cohesion and area ratio by gravimetric CaL content whereby the area ratio was obtained by dividing the portion of the cross-sectional area occupied with lignosulfonate-water (CaL-W) paste by the total cross-sectional area. While the increase in the normalized cohesion eventually leveled out, the cohesion peaked at 6% of CaL. Thus, sand-CaL-water (S-CaL-W) mixes sustained larger shear stresses than dry sand for a range of normal stresses below the limiting normal stress. Consequently, the early age behavior indicates that adding CaL-W to sand is clearly beneficial in the near-surface applications in dry sand.

scholarly journals Numerical Investigation of a two-inlet PVT air collector

2019 ◽  
Vol 136 ◽  
pp. 05014
Author(s):  
Zhangyang Kang ◽  
Zhaoyang Lu ◽  
Xin Deng ◽  
Qiongqiong Yao
Keyword(s):  
Heat Transfer ◽  
Single Channel ◽  
Numerical Study ◽  
Convection Heat Transfer ◽  
Thermal Characteristics ◽  
Area Ratio ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Maximum Heat

A numerical study of heat and mass transfer characteristics of a two-inlet PV/T air collector is performed. The influence of thermal characteristics and efficiency is investigated as the area ratios of inlet and outlet of the single channel with two inlets are changed. The design of the two-inlet PV/T air collector can avoid the poor heat transfer conditions of the single inlet PV/T air collector and improve the total photo-thermal efficiency. When the inlet/outlet cross-sectional area ratio is reduced, the inlet air from the second inlet enhances the convection heat transfer in the second duct and the temperature distribution is more uniform. As the cross-sectional area of the second inlet increase, the maximum heat exchange amount of the two-inlet PV/T air collector occurs between the inlet and outlet cross-sectional area ratio L=0.645 and L=0.562.

Effect of Weld Defects on Tensile Properties of Lightweight Materials and Correlations With Phased Array Ultrasonic Nondestructive Evaluation

2014 ◽  
Author(s):  
Mohammad W. Dewan ◽  
M. A. Wahab ◽  
Ayman M. Okeil
Keyword(s):  
Tensile Strength ◽  
Aluminum Alloy ◽  
Tensile Properties ◽  
Phased Array ◽  
Critical Value ◽  
Area Ratio ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Strength And Toughness

Fusion welding of Aluminum and its alloys is a great challenge for the structural integrity of lightweight material structures. One of the major shortcomings of Aluminum alloy welding is the inherent existence of defects in the welded area. In the current study, tests have been conducted on tungsten inert gas (TIG) welded AA6061-T651 aluminum alloy to determine the effects of defect sizes and its distribution on fracture strength. The information will be used to establish weld acceptance/rejection criteria. After welding, all specimens were non-destructively inspected with phased array ultrasonic and measured the projected area of the defects. Tensile testing was performed on inspected specimens containing different weld defects: such as, porosity, lack of fusion, and incomplete penetration. Tensile tested samples were cut along the cross section and inspected with Optical Microscope (OM) to measure actual defect sizes. Tensile properties were correlated with phased array ultrasonic testing (PAUT) results and through microscopic evaluations. Generally, good agreement was found between PAUT and microscopic defect sizing. The tensile strength and toughness decreased with the increase of defect sizes. Small voids (area ratio <0.04) does not have significant effect on the reduction of tensile strength and toughness values. Once defective “area ratio (cross sectional area of the defect) / (total specimen cross sectional area)” reached a certain critical value (say, 0.05), both strength and toughness values decline sharply. After that critical value both the tensile strength and toughness values decreases linearly with the increase of defect area ratio.

scholarly journals Disc measurement and nucleus calibration in a smoothened lumbar model increases the accuracy and efficiency of in-silico study

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Jingchi Li ◽  
Chen Xu ◽  
Xiaoyu Zhang ◽  
Zhipeng Xi ◽  
Shenglu Sun ◽  
...  
Keyword(s):  
In Silico ◽  
Area Ratio ◽  
Cross Sectional Area ◽  
Computational Time ◽  
Sectional Area ◽  
Imaging Data ◽  
Cross Sectional ◽  
Fea Model ◽  
In Silico Study ◽  
Nucleus Position

Abstract Backgrounds Finite element analysis (FEA) is an important tool during the spinal biomechanical study. Irregular surfaces in FEA models directly reconstructed based on imaging data may increase the computational burden and decrease the computational credibility. Definitions of the relative nucleus position and its cross-sectional area ratio do not conform to a uniform standard in FEA. Methods To increase the accuracy and efficiency of FEA, nucleus position and cross-sectional area ratio were measured from imaging data. A FEA model with smoothened surfaces was constructed using measured values. Nucleus position was calibrated by estimating the differences in the range of motion (RoM) between the FEA model and that of an in-vitro study. Then, the differences were re-estimated by comparing the RoM, the intradiscal pressure, the facet contact force, and the disc compression to validate the measured and calibrated indicators. The computational time in different models was also recorded to evaluate the efficiency. Results Computational results indicated that 99% of accuracy was attained when measured and calibrated indicators were set in the FEA model, with a model validation of greater than 90% attained under almost all of the loading conditions. Computational time decreased by around 70% in the fitted model with smoothened surfaces compared with that of the reconstructed model. Conclusions The computational accuracy and efficiency of in-silico study can be improved in the lumbar FEA model constructed using smoothened surfaces with measured and calibrated relative nucleus position and its cross-sectional area ratio.

Sign in / Sign up

Export Citation Format

Share Document