scholarly journals Modelling fluid and particulate flow through a ventriculoperitoneal shunt in a variable temperature environment

2021 ◽  
Vol 347 ◽  
pp. 00035
Author(s):  
Tshiamo Ramokoka ◽  
Muaaz Bhamjee
Keyword(s):  
Ventriculoperitoneal Shunt ◽  
Volume Flow Rate ◽  
Variable Temperature ◽  
White Blood Cells ◽  
Experimental Results ◽  
Average Error ◽  
Cfd Model ◽  
Shunt System ◽  
Shunt Valve ◽  
Shunt Occlusion

One of the most prevalent causes of failure for a ventriculoperitoneal shunt is blockage, the other being infection. This study looks at the blockage of the shunt valve, and whether the occlusion of a shunt valve is accelerated by the presence of an infection. This study assumes that an infection will raise the number of white blood cells contained in the cerebrospinal fluid to fight it and will thus accelerate shunt occlusion. The experiment simulates a shunt system by suspending a shunt valve in a water bath that has a temperature that varies between 37°C and 41°C. A computational fluid dynamics model of the shunt system is used to gain further insight into the flow behaviour under these conditions. The results of the CFD model were validated using the experimental results. There was an average error of 15% between the readings that were obtained in the experiment and the CFD model. The experimental results showed that there was a decrease in the volume flow rate at the outlet of the shunt system, which was not large enough to point towards any blockage. Both the model predictions and the experimental results show that increased temperature and particulate concentration alone do not result in shunt occlusion, particularly at the shunt valve. This result effectively excluded the shunt valve as a region of shunt occlusion due to infection, as an infection occurs due to the growth of bacteria along the surfaces of the shunt system and this bacterial growth is more likely to occur at the proximal and distal ends of the shunt system.

scholarly journals In situ clearance of a proximal shunt malfunction in a child with hydrocephalus post cerebral arteriovenous malformation rupture noted intraoperatively

2020 ◽  
Vol 11 ◽  
pp. 116
Author(s):  
Zachary Porter ◽  
George Yang ◽  
Shawn Vuong ◽  
Baher Hanna ◽  
Joseph Madsen ◽  
...  
Keyword(s):  
Arteriovenous Malformation ◽  
Ventriculoperitoneal Shunt ◽  
External Ventricular Drain ◽  
Cerebral Arteriovenous Malformation ◽  
Csf Shunt ◽  
Ventricular Catheter ◽  
Csf Flow ◽  
Shunt System ◽  
Shunt Valve

Background: Hydrocephalus shunt malfunctions remain treated with surgical intervention only. Despite efforts at identifying or preventing CSF shunt obstruction, no evidence currently exists to restore CSF flow following proximal occlusion, non-invasively. Case Description: We present direct intraoperative evidence in the case of a 5-year-old male who developed hydrocephalus subsequent to hemorrhagic presentation post cerebral arteriovenous malformation rupture. After weeks of externalized CSF diversion for clearance of CSF red blood cells, he was taken to the operating room for removal of the external ventricular drain and placement of a ventriculoperitoneal shunt for hydrocephalus. At conclusion of placing his ventriculoperitoneal shunt with ReFlow flusher assist device, his shunt valve reservoir was noted to not refill. Following manual depression of the ReFlow flusher, we identified clearance of debris from the obstructed ventricular catheter allowing reestablished CSF flow through the shunt system under live intraoperative ultrasonography. Subsequently, there was return of brisk refill to the shunt valve reservoir. Conclusion: Observations here demonstrate a potentially useful technical strategy toward clearance of proximal shunt obstructions, in situ.

scholarly journals An Indigenous Method of Securing Ventriculoperitoneal Shunt Tube in Peritoneal Cavity

2021 ◽  
Author(s):  
Samir Kumar Kalra ◽  
Krishna Shah ◽  
Sneyhil Tyagi ◽  
Suviraj John ◽  
Rajesh Acharya
Keyword(s):  
Ventriculoperitoneal Shunt ◽  
Operation Time ◽  
Complication Rates ◽  
Effective Technique ◽  
Common Procedure ◽  
Shunt System ◽  
Shunt Tube ◽  
Csf Diversion ◽  
Median Operation Time

Abstract Introduction Ventriculoperitoneal shunt (VPS) is the most common procedure used for cerebrospinal fluid (CSF) diversion in hydrocephalus. Over the years, many technical, procedural, and instrument-related advancements have taken place which have reduced the associated complication rates. Shunt block is a very common complication irrespective of the shunt system used. The abdominal end of the shunt tube gets blocked usually due to plugging of omentum onto the shunt catheter. We describe a technique of catheter fixation and placement under vision coupled with omentopexy done laparoscopically to prevent this complication. Materials and Methods This technique was used in 23 patients (11 female, 12 male; range 16–73 years) afflicted with hydrocephalus from June 2016 and December 2019 after obtaining an informed consent, and the outcomes were noted in terms of shunt patency, complications, if any, and the need for revision. Results The median operation time was 90 minutes (range 35–160 minutes). All shunt catheters were still functional after a mean follow-up of 16.5 months (range 1–34 months) and none required revision. Conclusion Laparoscopic placement of shunt tube along with omental folding is a safe and effective technique for salvaging the abdominal end of VPS and may be helpful in reducing shunt blockage.

Detection of Microbubbles Using the Hough Transform

2013 ◽  
Vol 378 ◽  
pp. 478-482
Author(s):  
Yoshihiro Mitani ◽  
Toshitaka Oki
Keyword(s):  
Image Processing ◽  
Error Rate ◽  
Hough Transform ◽  
Detection Method ◽  
Experimental Results ◽  
Average Error ◽  
Image Processing Techniques ◽  
Average Error Rate ◽  
Processing Techniques

The microbubble has been widely used and shown to be effective in various fields. Therefore, there is an importance of measuring accurately its size by image processing techniques. In this paper, we propose a detection method of microbubbles by the approach based on the Hough transform. Experimental results show only 4.49% of the average error rate of the undetected microbubbles and incorrectly detected ones. This low percentage of the error rate shows the effectiveness of the proposed method.

scholarly journals Subgaleal Migration of the Distal Catheter of a Ventriculoperitoneal Shunt

2009 ◽  
Vol 52 (2) ◽  
pp. 77-79 ◽  
Author(s):  
Fatih Serhat Erol ◽  
Bekir Akgun
Keyword(s):  
Ventriculoperitoneal Shunt ◽  
Ventricular Catheter ◽  
Peritoneal Catheter ◽  
Shunt Valve ◽  
Distal Catheter ◽  
X Ray ◽  
Proximal Migration ◽  
Shunt Dysfunction ◽  
Valve Placement ◽  
The Brain

Proximal migration of the distal end of a ventriculoperitoneal shunt has been observed much more rarely than other numerous shunt-related complications. Subgaleal migration of the peritoneal end is one of the samples. In the preset report we have discussed a case of subgaleal migration of the peritoneal end detected as a result of the examinations performed for shunt dysfunction. There was ventricular dilatation on CT scan of the brain. X-ray examinations confirmed proper ventricular catheter and shunt valve placement but a complete migration of distal (peritoneal) catheter into the subgaleal space. Then the patient’s shunt was revised. When our case and the literature were examined, we observed that this complication was frequently encountered during the first postoperative months, in the pediatric ages and in patients with advanced hydrocephalus. Besides, we have detected that the peritoneal catheters had tendency to migration into the subgaleal tissues similar to pre-insertion forms of the preoperatively original packages.

Experimentally Validated Computational Fluid Dynamics Model for Data Center With Active Tiles

2018 ◽  
Vol 140 (1) ◽  
Author(s):  
Jayati Athavale ◽  
Yogendra Joshi ◽  
Minami Yoda
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Flow Rate ◽  
Data Center ◽  
Hot Spot ◽  
Volume Flow Rate ◽  
Optimal Number ◽  
Inlet Temperature ◽  
Cfd Model ◽  
Level Model

Abstract This paper presents an experimentally validated room-level computational fluid dynamics (CFD) model for raised-floor data center configurations employing active tiles. Active tiles are perforated floor tiles with integrated fans, which increase the local volume flow rate by redistributing the cold air supplied by the computer room air conditioning (CRAC) unit to the under-floor plenum. The numerical model of the data center room consists of one cold aisle with 12 racks arranged on both sides and three CRAC units sited around the periphery of the room. The commercial CFD software package futurefacilities6sigmadcx is used to develop the model for three configurations: (a) an aisle populated with ten (i.e., all) passive tiles; (b) a single active tile and nine passive tiles in the cold aisle; and (c) an aisle populated with all active tiles. The predictions from the CFD model are found to be in good agreement with the experimental data, with an average discrepancy between the measured and computed values for total flow rate and rack inlet temperature less than 4% and 1.7 °C, respectively. The validated models were then used to simulate steady-state and transient scenarios following cooling failure. This physics-based and experimentally validated room-level model can be used for temperature and flow distributions prediction and identifying optimal number and locations of active tiles for hot spot mitigation in data centers.

scholarly journals Mobile Robot Wall-Following Control Using Fuzzy Logic Controller with Improved Differential Search and Reinforcement Learning

Mathematics ◽  
2020 ◽  
Vol 8 (8) ◽  
pp. 1254 ◽  
Author(s):  
Cheng-Hung Chen ◽  
Shiou-Yun Jeng ◽  
Cheng-Jian Lin
Keyword(s):  
Fuzzy Logic ◽  
Reinforcement Learning ◽  
Mobile Robot ◽  
Fuzzy Logic Controller ◽  
Search Algorithm ◽  
Experimental Results ◽  
Average Error ◽  
Stopover Site ◽  
Accumulated Reward ◽  
Wall Following

In this study, a fuzzy logic controller with the reinforcement improved differential search algorithm (FLC_R-IDS) is proposed for solving a mobile robot wall-following control problem. This study uses the reward and punishment mechanisms of reinforcement learning to train the mobile robot wall-following control. The proposed improved differential search algorithm uses parameter adaptation to adjust the control parameters. To improve the exploration of the algorithm, a change in the number of superorganisms is required as it involves a stopover site. This study uses reinforcement learning to guide the behavior of the robot. When the mobile robot satisfies three reward conditions, it gets reward +1. The accumulated reward value is used to evaluate the controller and to replace the next controller training. Experimental results show that, compared with the traditional differential search algorithm and the chaos differential search algorithm, the average error value of the proposed FLC_R-IDS in the three experimental environments is reduced by 12.44%, 22.54% and 25.98%, respectively. Final, the experimental results also show that the real mobile robot using the proposed method can effectively implement the wall-following control.

New Correlation for Two-Phase Flow in 90 Degree Horizontal Elbows

2010 ◽  
Author(s):  
Florencio Sanchez-Silva ◽  
Ignacio Carvajal-Mariscal ◽  
Rene Tolentino-Eslava
Keyword(s):  
Pressure Drop ◽  
Two Phase Flow ◽  
Experimental Results ◽  
Galvanized Steel ◽  
Average Error ◽  
Phase Flow ◽  
Volumetric Fraction ◽  
Dean Number ◽  
Two Phase ◽  
Flow Pressure

The comparison of experimental data and results obtained from four global models — homogeneous, Dukler, Martinelli and Chisholm, used to evaluate the two-phase flow pressure drop in circular 90° horizontal elbows — is presented in this paper. An experimental investigation was carried out using three galvanized steel 90° horizontal elbows (E1, E2, E3) with internal diameters of 26.5, 41.2 and 52.5 mm, and curvature radii of 194.0, 264.0 and 326.6 mm, respectively. According to the experimental results, the model proposed by Chisholm best fitted them, presenting for each elbow an average error of E1 = 18.27%, E2 = 28.40% and E3 = 42.10%. Based on experimental results two correlations were developed. The first one is the classical Chisholm model modified to obtain better results in a wider range of conditions; it was adjusted by a dimensionless relationship which is a function of the homogeneous volumetric fraction and the Dean number. As a result, the predictions using modified Chisholm model were improved presenting an average error of 8.66%. The second developed correlation is based on the entire two-phase mass flow taken as liquid and adjusted by the homogeneous volumetric fraction ratio. The results show that this last correlation is easier and accurate than the adjusted Chisholm model, presenting an average error of 7.75%. Therefore, this correlation is recommended for two-phase pressure drop evaluation in horizontal elbows.

Evaluation of Ventriculoperitoneal Shunt Valve Effectiveness in Adults Using Intracranial Pressure Monitoring

Neurosurgery ◽  
1999 ◽  
Vol 45 (3) ◽  
pp. 730-731
Author(s):  
Panayiotis Varelas ◽  
Romergryko G. Geocadin ◽  
Alexander Y. Razumovsky ◽  
Maureen O'Brien ◽  
Daniel F. Hanley ◽  
...  
Keyword(s):  
Intracranial Pressure ◽  
Ventriculoperitoneal Shunt ◽  
Intracranial Pressure Monitoring ◽  
Pressure Monitoring ◽  
Shunt Valve

scholarly journals Experimental Analysis and Simulation of Novel Technical Textile Reinforced Composite of Banana Fibre

Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1134 ◽  
Author(s):  
Mario Monzón ◽  
Rubén Paz ◽  
Martí Verdaguer ◽  
Luis Suárez ◽  
Pere Badalló ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Predictive Modelling ◽  
Experimental Results ◽  
Average Error ◽  
Acceptable Error ◽  
Simulation Based ◽  
Banana Fibre ◽  
The One ◽  
Textile Reinforced Composite ◽  
Definition Of

The use of natural fibres allows reducing environmental impact, due to their natural renewable origin and the lower energy needed for their production and processing. This work presents the mechanical characterization of a newly developed technical textile, with banana fibre treated by enzymes, comparing experimental results with numerical simulation based on the definition of the unit cell at micromechanical level. The experimental test shows that the composite with the fabric of banana fibre presents worse mechanical behaviour than the one with commercial flax fibre. The presence of wool, necessary for producing the yarn, reduces the mechanical properties of the banana textile. The numerical simulation had an acceptable error compared with the experimental results, with a global average error of 9%, showing that the predictive modelling based on the multiscale method is suitable for the design process of this kind of composite.

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