scholarly journals The Need of Slanted Side Holes for Venous Cannulae

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Joong Yull Park
Keyword(s):  
Numerical Modeling ◽  
Shear Rate ◽  
Blood Vessel ◽  
Penetration Depth ◽  
Flow Rate ◽  
Analysis Study ◽  
Side Hole ◽  
Good Flow

Well-designed cannulae must allow good flow rate and minimize nonphysiologic load. Venous cannulae generally have side holes to prevent the rupture of blood vessel during perfusion. Optimizing side hole angle will yield more efficient and safe venous cannulae. A numerical modeling was used to study the effect of the angle (0°–45°) and number (0–12) of side holes on the performance of cannulae. By only slanting the side holes, it increases the flow rate up to 6% (in our models). In addition, it was found that increasing the number of side holes reduces the shear rate up to 12% (in our models). A new parameter called “penetration depth” was introduced to describe the interfering effect of stream jets from side holes, and the result showed that the 45°-slanted side holes caused minimum interfering for the flow in cannula. Our quantitative hemodynamic analysis study provides important guidelines for venous cannulae design.

scholarly journals Development of Rotational Intraperitoneal Pressurized Aerosol Chemotherapy to Enhance Drug Delivery into the Peritoneum

2021 ◽  
Author(s):  
Soo Jin Park ◽  
Eun Ji Lee ◽  
Hee Su Lee ◽  
Junsik Kim ◽  
Sunwoo Park ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Methylene Blue ◽  
Penetration Depth ◽  
Flow Rate ◽  
Tissue Concentration ◽  
Palliative Therapy ◽  
Drug Distribution ◽  
Pharmacokinetic Properties ◽  
Blue Solution ◽  
Restricted Use

Abstract Background Pressurized intraperitoneal aerosol chemotherapy (PIPAC) has been introduced as palliative therapy for treating peritoneal metastasis (PM) of solid tumors. However, restricted use in the limited countries and the uneven distribution and penetration in various regions of the peritoneal cavity ac as disadvantages of PIPAC. Thus, the KOrean Rotational Intraperitoneal pressurized Aerosol chemotherapy (KORIA) trial group developed rotational intraperitoneal pressurized aerosol chemotherapy (RIPAC) for enhancing drug delivery into the peritoneum to treat PM, and evaluated the drug distribution, tissue concentrations, penetration depth, pharmacokinetic properties, and toxicities after RIPAC with doxorubicin in pigs. Methods For delivering doxorubicin as aerosols, we used our prototype for PIPAC, which sprayed about 30-µm sized droplets through the nozzle. The mean diameter of the sprayed region was 18.5 cm, and the penetration depth ranged from 360 to 520 µm, comparable to the microinjection pump (Capnopen®; Capnomed, Villingendorf, Germany). For RIPAC, a conical pendulum motion device was added to PIPAC for rotating the nozzle. RIPAC and PIPAC were conducted using 150 ml of 1% methylene blue to evaluate drug distribution and 3.5 mg of doxorubicin in 50 ml of 0.9% NaCl to evaluate tissue concentration and penetration depth, pharmacokinetic properties, and toxicities. All agents were sprayed as aerosols via the nozzle with a velocity of 5 km/h at a flow rate of 30 ml/min under a pressure of 7 bars, and capnoperitoneum of 12 mmHg was maintained for 30 minutes. As a control, we conducted early postoperative intraperitoneal chemotherapy (EPIC) using 1% methylene blue solution with an infusion flow rate of 100 ml/min for 30 minutes and the drainage of 1 L every 10 minutes. Results RIPAC showed a wider distribution and stronger intensity than EPIC and PIPAC. Moreover, the tissue concentration and penetration depth of doxorubicin were higher in RIPAC than in PIPAC. In RIPAC, the pharmacokinetic properties reflected hemodynamic changes during capnoperitoneum, and there were no renal and hepatic toxicities related to RIPAC using doxorubicin. Conclusions RIPAC may have the potential to enhance drug delivery into the peritoneum compared to PIPAC.

scholarly journals Rheological characteristics of polyethylene-nanotube composites by capillary rheometry

2020 ◽  
Author(s):  
S Al-Baghdadi ◽  
A Al-Amiery
Keyword(s):  
Shear Rate ◽  
Flow Rate ◽  
Applied Load ◽  
Critical Parameter ◽  
Raw Materials ◽  
Rheological Characteristics ◽  
Capillary Rheometry ◽  
Solid Load ◽  
Nanotube Composites ◽  
Newtonian Behavior

Abstract The viscosity and flow rate as rheological characteristics are fundamental in evaluating the nanofillers in processing the polyethylene-nanotube (PE-NT) composite in injecting molding. The purpose of this investigation is to study the rheological conduct of PE-NT composite plastic feedstock through capillary rheometry. For the purpose of obtaining a flawless component, the feedstock is used as a critical parameter, and care must be taken while introducing the raw materials with high solid load and hence perfect flowability. The shear rate viscosity of different feedstocks at an NT ratio extending at 0–3 wt.% has been determined at L/D equal to 10 die and a load extending at 40.0–80.0 KGF at temperatures 140.0, 150.0 and 160.0°C. The three specimens’ viscosity was measured in order to exhibit that the corresponding flow conduct factor varies from 0.40 to 0.70, demonstrating the non-Newtonian behavior of the specimens. The three specimens’ activation energies at the studied temperature degrees were evaluated and turned out to be 36.5–69.88 kJ/mol according to the applied load.

scholarly journals Fines mobility and distribution in streaming fibre networks: experimental evidence and numerical modeling

Cellulose ◽  
2020 ◽  
Vol 27 (16) ◽  
pp. 9663-9682
Author(s):  
Jakob D. Redlinger-Pohn ◽  
Melanie Mayr ◽  
Gregor Schaub ◽  
David Gruber ◽  
Stefan Radl
Keyword(s):  
Numerical Modeling ◽  
Flow Rate ◽  
Removal Rate ◽  
Small Particles ◽  
Classical View ◽  
Fibre Network ◽  
Fibre Suspensions ◽  
Fibre Suspension ◽  
Network Strength

AbstractThe motion of flocculated fibres in a streaming suspension is governed by the balance of the network strength and hydrodynamic forces. With increasing flow rate through a channel, (1) the network initially occupying all space, (2) is then compressed to the centre, and (3) ultimately dispersed. This classical view neglects fibres-fines: we find that the distribution of these small particles differs in streaming suspensions. While it is known that fibre-fines can escape the fibre network, we find that the distribution of fibre-fines is non-homogenous in the network during compression: fibre-fines can be caged and retarded in the streaming fibre network. Hence, the amount of fibre-fines is reduced outside of a fibre network and enriched at the network’s interface. Aiming on selectively removing fibre-fines from a streaming network by suction, we identify a reduction of the fines removal rate. That documents a hindered mobility of fibre-fines when moving through the network of fibres. Additionally, we found evidence, that the mobility of fibre-fines is dependent on the fibre-fines quality, and is higher for fibrillar fines. Consequently, we suggest that the quality of fibre-fines removed from the suspension can be controlled with the flow regime in the channel. Finally, we present a phenomenological model to compute the length dependent fibre distribution in an arbitary geometry. For a fibre suspension channel flow we are able to predict a length-dependent fibre segregation near the channel’s centre. The erosion of a plug of long fibres was however underestimated by our model. Interestingly, our model with parameters fitted to streaming fibre suspension qualitatively agreed with the motion of micro-fibrillated cellulose. This gives hope that devices for handling flocculated fibre suspensions can be designed in the future with greater confidence.

The Effect of Nozzle Diameter, Lance Height and Flow Rate on Penetration Depth in a Top-blown Water Model

2006 ◽  
Vol 77 (2) ◽  
pp. 82-90 ◽  
Author(s):  
Annie Nordquist ◽  
Nitesh Kumbhat ◽  
Lage Jonsson ◽  
Pär Jönsson
Keyword(s):  
Penetration Depth ◽  
Flow Rate ◽  
Nozzle Diameter ◽  
Water Model ◽  
Lance Height

scholarly journals Investigation of Ultrasound-Measured Flow Velocity, Flow Rate and Wall Shear Rate in Radial and Ulnar Arteries Using Simulation

2017 ◽  
Vol 43 (5) ◽  
pp. 981-992
Author(s):  
Xiaowei Zhou ◽  
Chunming Xia ◽  
Gandy Stephen ◽  
Faisel Khan ◽  
George A. Corner ◽  
...  
Keyword(s):  
Shear Rate ◽  
Flow Velocity ◽  
Flow Rate ◽  
Wall Shear Rate ◽  
Velocity Flow ◽  
Measured Flow ◽  
Wall Shear

Numerical Investigation for the Effect of Blood Flow Rate and Asymmetric Bifurcation Angle on the Anterior Circulation Aneurysm Formation

2011 ◽  
Author(s):  
Soyoon Kim ◽  
Kyoungchul Ro ◽  
Hong Sun Ryou
Keyword(s):  
High Pressure ◽  
Blood Flow ◽  
Blood Vessel ◽  
Flow Rate ◽  
Rate Ratio ◽  
Arterial Wall ◽  
Blood Flow Rate ◽  
Flow Rate Ratio ◽  
Anterior Circulation ◽  
Bifurcation Angle

Most of aneurysms in the cranial cavity occur at the bifurcation of anterior circulation system. A cerebral aneurysm is easily ruptured, and it is fatal for most patients. Generally it is known that aneurysm occurs when arterial wall is deformed by high pressure or high wall shear stress (WSS). A blood flow pattern and the geometry and the blood vessel are important factors for aneurysm formation and the location. The transient interaction between blood flow and the arterial wall affects for simulating deformation of the blood vessel. Thus, numerical analysis is performed for various bifurcation angles and flow rate ratio in bifurcation artery with different diameters to predict the location of aneurysm by hemodynamic characteristics of blood flow. A bifurcation angle between the internal carotid artery and the anterior cerebral artery (ACA) increased, a region of high pressure moved to the bifurcated artery with larger bifurcation angle when ratio of blood flow rate is constant case. When the ratio of blood flow increased, the region of high wall shear stress moved to the side of large flow rate ratio. Our results showed that the high WSS or high pressure region occur at the location of aneurysm as mentioned in the clinical research. Thus, this indicates that the geometry of blood vessel and blood flow rate affect the location of the anterior circulation aneurysm.

Modification of lymph by lymph nodes. III. Effect of increased lymph hydrostatic pressure

1985 ◽  
Vol 249 (4) ◽  
pp. H777-H782 ◽  
Author(s):  
T. H. Adair ◽  
A. C. Guyton
Keyword(s):  
Steady State ◽  
Hydrostatic Pressure ◽  
Blood Vessel ◽  
Lymph Nodes ◽  
Flow Rate ◽  
Protein Concentration ◽  
Lymph Flow ◽  
Blood Capillary ◽  
Fluid Exchange ◽  
Very High

Previous studies have shown that lymph nodes function as fluid exchange chambers in which the protein concentration of lymph is changed in the direction required to establish equilibrium of the Starling forces acting across the nodal blood-lymph barrier. We examined the effect of increased lymph hydrostatic pressure on efferent lymph by use of an isolated dog popliteal node preparation in which lymph having a protein concentration averaging 27.6 +/- 1.2% (SD) of that of plasma was infused into the node at a flow rate averaging 45.6 +/- 0.2 (SD) microliter/min. We compared steady-state values of prenodal and postnodal lymph flow and protein concentration following step increases in efferent lymph pressure from 0 to over 15 mmHg. Increasing efferent lymph pressure to values less than about 8 mmHg caused the efferent lymph protein concentration to increase; however, further increases in lymph pressure caused the lymph protein concentration to decrease to values approaching those attained at very low lymph pressures. We suggest that the failure of high lymph pressure to increase lymph protein concentration might be caused by blood vessel collapse within the node, a condition believed to increase nodal blood capillary pressure and to decrease blood-lymph barrier filtration coefficient. An important finding was that increasing efferent lymph pressure caused significant amounts of lymph proteins to be lost during nodal transit. Therefore, it appears that increasing efferent lymph pressure to very high values has little effect on lymph protein concentration but has great effect on postnodal lymph protein flux.

Application of Taguchi Methods and ANOVA in Optimization of Process Parameters for Surface Roughness of Fused Silica in the Magnetorheological Finishing Processes

2013 ◽  
Vol 662 ◽  
pp. 449-452 ◽  
Author(s):  
Wei Ran Duan ◽  
Yi Fan Dai ◽  
Yong Shu ◽  
Ian Sherrington
Keyword(s):  
Surface Roughness ◽  
Penetration Depth ◽  
Flow Rate ◽  
Design Method ◽  
Processing Parameters ◽  
High Energy ◽  
Fused Silica ◽  
Taguchi Methods ◽  
Magnetorheological Finishing ◽  
Rotating Speed

Surface roughness plays an important role on optical performances for optics in high-energy laser systems. In this study, optical surface of fused silica were polished by the Magnetorheological Finishing (MRF) processes. The polishing factors in term of Magnetorheological fluid (MR fluid) flow rate, polishing wheel rotational speed, electromagnet current, and polishing ribbon penetration depth, were carried out using an self-developed MRF machine to determine optimum conditions for surface roughness. The settings of the MRF processing parameters were determined by using Taguchi’s experimental design method. Taguchi’s orthogonal array, signal-to-noise (S/N) ratio and analysis of variance (ANOVA) were employed to investigate the optimal processing parameters. The experimental results indicate that surface with smaller roughness could be machined under the conditions with slower rotating speed and higher flow rate and current, and nearly independent of penetration depth.

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