Currently, biomanufacturing technology and industry are receiving worldwide attention. However, there are still great challenges on bioprocess optimization and scale-up, including: lacing the process detection methods, which makes it difficult to meet the requirement of monitoring of key indicators and parameters; poor understanding of cell metabolism, which arouses problems to rationally achieve process optimization and regulation; the reactor environment is very different across the scales, resulting in low efficiency of stepwise scale-up. Considering the above key issues that need to be resolved, here we summarize the key technological innovations of the whole chain of fermentation process, i.e., real-time detection-dynamic regulation-rational scale-up, through case analysis. In the future, bioprocess design will be guided by a full lifecycle in-silico model integrating cellular physiology (spatiotemporal multiscale metabolic models) and fluid dynamics (CFD models). This will promote computer-aided design and development, accelerate the realization of large-scale intelligent production and serve to open a new era of green biomanufacturing.
Bioreactors ; Computer Simulation ; Fermentation ; Hydrodynamics

Recent improvements have been made to the use of time-resolved, three-dimensional phase-contrast (PC) magnetic resonance imaging (MRI), which is also named four-dimensional (4D) PC-MRI or 4D flow MRI, in the investigation of spatial and temporal variations in hemodynamic features in cardiovascular blood flow. The present article reviews the principle and analytical procedures of 4D PC-MRI. Various fluid dynamic biomarkers for possible clinical usage are also described, including wall shear stress, turbulent kinetic energy, and relative pressure. Lastly, this article provides an overview of the clinical applications of 4D PC-MRI in various cardiovascular regions.
Biomarkers ; Hemodynamics* ; Hydrodynamics ; Magnetic Resonance Imaging*

BACKGROUND: As one of the most frequently occurring accidents in a chemical plant, a fire accident may occur at any place where transfer or handling of combustible materials is routinely performed. METHODS: In particular, a jet fire incident in a chemical plant operated under high pressure may bring severe damage. To review this event numerically, Computational Fluid Dynamics methodology was used to simulate a jet fire at a pipe of a compressor under high pressure. RESULTS: For jet fire simulation, the Kemeleon FireEx Code was used, and results of this simulation showed that a structure and installations located within the shelter of a compressor received serious damage. CONCLUSION: The results confirmed that a jet fire may create a domino effect that could cause an accident aside from the secondary chemical accident.
Chemical Hazard Release ; Fires* ; Hydrodynamics ; Plants

Despite recent development of computational fluid dynamics (CFD) research, analysis of computational fluid dynamics of cerebral vessels has several limitations. Although blood is a non-Newtonian fluid, velocity and pressure fields were computed under the assumptions of incompressible, laminar, steady-state flows and Newtonian fluid dynamics. The pulsatile nature of blood flow is not properly applied in inlet and outlet boundaries. Therefore, we present these technical limitations and discuss the possible solution by comparing the theoretical and computational studies.
Bays ; Cerebral Arteries ; Computer Simulation ; Hydrodynamics*

We investigate the potentials and limitations of computational fluid dynamics (CFD) analysis of patient specific models from 3D angiographies. There are many technical problems in acquisition of proper vascular models, in pre-processing for making 2D surface and 3D volume meshes and also in post-processing steps for display the CFD analysis. We hope that our study could serves as a technical reference to validating other tools and CFD results.
Angiography ; Arteries ; Carotid Arteries ; Hemodynamics ; Humans ; Hydrodynamics

OBJECTIVE: The goal of this study was to compare several parameters, including wall shear stress (WSS) and flow pattern, between unruptured and ruptured anterior communicating artery (ACoA) aneurysms using patient-specific aneurysm geometry.METHODS: In total, 18 unruptured and 24 ruptured aneurysms were analyzed using computational fluid dynamics (CFD) models. Minimal, average, and maximal wall shear stress were calculated based on CFD simulations. Aneurysm height, ostium diameter, aspect ratio, and area of aneurysm were measured. Aneurysms were classified according to flow complexity (simple or complex) and inflow jet (concentrated or diffused). Statistical analyses were performed to ascertain differences between the aneurysm groups.RESULTS: Average wall shear stress of the ruptured group was greater than that of the unruptured group (9.42% for aneurysm and 10.38% for ostium). The average area of ruptured aneurysms was 31.22% larger than unruptured aneurysms. Simple flow was observed in 14 of 18 (78%) unruptured aneurysms, while all ruptured aneurysms had complex flow (p < 0.001). Ruptured aneurysms were more likely to have a concentrated inflow jet (63%), while unruptured aneurysms predominantly had a diffused inflow jet (83%, p=0.004).CONCLUSION: Ruptured aneurysms tended to have a larger geometric size and greater WSS compared to unruptured aneurysms, but the difference was not statistically significant. Flow complexity and inflow jet were significantly different between unruptured and ruptured ACoA aneurysms.
Aneurysm ; Aneurysm, Ruptured ; Arteries ; Hydrodynamics ; Intracranial Aneurysm

Humans ; Diverticulum, Colon ; Fecal Impaction ; Hydrodynamics

OBJECTIVE: In order to study the mechanism of the aqueous humor circulation and its relationship to the glaucoma macroscopically with engineering methods. METHODS: A dynamistic model was presented, which can be used to simulate the situation and the treatment of the primary open angle glaucoma (POAG). The frame of the model was built based on the ophthalmically accepted feedback mechanism between the aqueous humor circulation and the intraocular pressure (IOP). The transfer functions and the parameters were educed from the analysis of physiological theories, the basic elements of hydrodynamics, and the clinical parameters. The relation between the parameters of the system and the episode mechanism of POAG was discussed. A digital method was used to simulate the Challenge test and some medicines' treatment of POAG, and the results were consistent with clinical observations. RESULTS: The results of simulation illuminate that the model can simulate the mechanism of the aqueous humor circulation and the curative mechanism of some medicines under the physiological condition and the pathological condition of the POAG. CONCLUSION: A few parameters which can hardly be captured with clinical method could be obtained from the model. These parameters can be helpful for the diagnosis and prediction of the curative effect.
Aqueous Humor* ; Diagnosis ; Glaucoma ; Glaucoma, Open-Angle* ; Hydrodynamics ; Intraocular Pressure

The clinical significance of cystic fluid motion in syringomyelia is uncertain. Because of its sensitivity to fluid motion, MR imaging was used to investigate fluid dynamics in syringomyelia by various tecniques. SPAMM (Spatial Modulation of Magnetization) MRI is one of these techniques which shows the fluid motion of syrinx in syringomyelia. After taking preimaging pulse sequence, the MR images show periodic bands due to the magnetic modulation. Motion between the time of banding and image formation is directly demonstrated as a corresponding displacement of the bands. The authors evaluated 7 patients of syringomyelia due to various causes with SPAMM MRI technique and compared preoperative SPAMM MRI findings and clinical results, postoperative size of syrinx. Among 4 patients of syringomyelia with Arnold-Chiari malformation, 3 patients showed band shift representing fluid motion of syrinx on SPAMM MRI. Clinical results of these patients were good and the size of postoperative syrinx decreased. Three patients of posttraumatic or postmeningitic syringomyelia who did not show band shift on SPAMM MRI had poor clinical courses and the sizes of postoperative syrinx remained unchanged. These results indicate that SPAMM MRI may be useful in dete rmining the type of treatment and predicting clinical results in syringomyelia.
Arnold-Chiari Malformation ; Humans ; Hydrodynamics ; Magnetic Resonance Imaging* ; Prognosis* ; Syringomyelia*

OBJECTIVES: The objective of this study was to investigate the effect of chain installation condition on stress distribution that could eventually cause disastrous failure from sudden deformation and geometric rupture. METHODS: Fractographic method used for the failed chain indicates that over-stress was considered as the root cause of failure. 3D modeling and finite element analysis for the chain, used in a crane hook, were performed with a three-dimensional interactive application program, CATIA, commercial finite element analysis and computational fluid dynamic software, ANSYS. RESULTS: The results showed that the state of stress was changed depending on the initial position of the chain that was installed in the hook. Especially, the magnitude of the stress was strongly affected by the bending forces, which are 2.5 times greater (under the simulation condition currently investigated) than that from the plain tensile load. Also, it was noted that the change of load state is strongly related to the failure of parts. The chain can hold an ultimate load of about 8 tons with only the tensile load acting on it. CONCLUSION: The conclusions of this research clearly showed that a reduction of the loss from similar incidents can be achieved when an operator properly handles the installation of the chain.
Accidents, Occupational ; Aluminum Hydroxide ; Carbonates ; Finite Element Analysis ; Hydrodynamics