Reduction In Flow Rate Research Articles

Systematic review and meta-analysis of ketamine-associated uropathy.

This systematic review and meta-analysis focused on the literature regarding ketamine-associated uropathy to summarise its clinical manifestations, the results of urological assessments, and current management. A literature search was conducted using keywords and MeSH terms related to ketamine abuse, urinary tracts, and urological examinations. Databases including Embase, MEDLINE, and the Cochrane Central Register of Controlled Trials were searched up to 26 June 2020. In total, 1365 articles were retrieved; 45 articles (4921 patients) were included in the analysis of patient demographics, clinical manifestations, examination results, and treatments. Frequency was the most common manifestation (pooled prevalence 77.1%, 95% confidence interval [CI]=56.9%-92.2%), followed by urgency (69.9%, 95% CI=48.8%-87.3%) and suprapubic pain (60.4%, 95% CI=35.3%-82.9%). Upper urinary tract involvement was less common; the pooled prevalence of hydronephrosis was 30.2% (95% CI=22.0%-39.2%). Further workup revealed a pooled functional bladder capacity of 95.23 mL (95% CI=63.57-126.88 mL), pooled voided volume of 113.31 mL (95% CI=59.44- 167.19 mL), and pooled maximum urine flow rate of 8.69 mL/s (95% CI=5.54-11.83 mL/s). Cystoscopic examinations and bladder biopsy revealed frequent urothelial denudation, inflammatory changes, and inflammatory cell infiltration. Treatments included oral medications for symptomatic relief, intravesical therapy, and surgery (eg, hydrodistension and bladder reconstruction), but ketamine abstinence was necessary for improvement. Ketamine-associated uropathy frequently involves frequency, urgency, and suprapubic pain; upper urinary tract involvement is less common. Affected patients showed reductions in bladder capacity and urine flow rate. Endoscopic and histological analyses often revealed cystitis. Despite variations in treatment, ketamine abstinence is important for all patients with ketamine-associated uropathy.

Identifying the performance and losses of a scroll compressor with vapour injection and R1234ze(E).

This work investigates a vapour injection scroll compressor integrated in a heat pump using the refrigerant R1234ze(E). The water-to-water heat pump was tested under a wide temperature range at the evaporator and condenser sides. The test results revealed that the performance is significantly reduced for lifts of over 30 K with the coefficient of performance being even below 2 and the maximum 2 nd law efficiency was just 28%. In order to enlighten the reasons behind such significant compressor underperformance, a semi-empirical model has been extended to include vapour injection, and a new improved modelling approach for the suction pressure drop was developed and implemented considering both the turbulent and laminar inlet flow regimes. Once the accuracy of the developed semi-empirical model was verified, the model was then adjusted to account for the R1234ze(E) operation, by fine-tuning its parameters based on the test data. The main loss mechanism identified is the high suction pressure drop, due to the high friction factor, with the inlet refrigerant flow possibly being laminar instead of turbulent. This resulted in a significant reduction of the mass flow rate and volumetric efficiency, while the standard model for suction pressure drop was not able to capture this effect.

Study on the Cavitation Suppression Mechanism of Axial Piston Pump

Gaseous and vaporous cavitation is extremely harmful to axial piston pumps, such as reducing flow rate, increasing flow pulsation, increasing vibration, increasing noise, and shortening life. To suppress the cavitation and improve the performance of axial piston pumps, a mathematical model for suppressing cavitation in the plunger chamber with a constant theoretical flow rate is innovatively established by combining the flow equation of the plunger pump and the pressure drop equation of the plunger chamber. Based on the model, two methods to suppress cavitation in the plunger chamber under the condition of a constant theoretical flow rate are proposed. The first method is to increase the distribution circle radius and correspondingly reduce the rotation speed, and the second method is to increase the plunger chamber radius and correspondingly reduce the rotation speed. To verify the effectiveness of these two methods, the CFD model of the axial piston pump is established, and the correctness of the model is verified by experiments. The results show that the two methods can effectively suppress cavitation in the plunger chamber, improve the actual flow rate, and reduce the flow pulsation under the condition of a constant theoretical flow rate. The research results can provide an important reference for the design and optimization of the plunger pump.

Effects of Water–Rock Interaction on the Permeability of the Near-Well Reservoir in an Enhanced Geothermal System

During the operation of an enhanced geothermal system (EGS), the non-equilibrium temperature, pressure, and hydrochemistry caused by fluid injection intensify water–rock interactions, induce the mineral dissolution and precipitation in the reservoir near an injection well (also referred to as the near-well reservoir), and change reservoir permeability, thus affecting continuous and efficient geothermal exploitation. Based on the investigation of the M-1 injection well of the EGS in the Matouying uplift of Hebei Province, China, a THC reactive solute transport model using the TOUGHREACT program was established in this study to explore the mineral dissolution and precipitation laws of the near-well reservoir and their influencing mechanisms on the reservoir porosity and permeability in the long-term fluid injection of this well. As indicated by the results, the dissolution of primary feldspar and chlorite and the precipitation of secondary minerals (mainly dolomite and illite) occurred and water–rock interaction significantly reduced the porosity and permeability of the near-well reservoir in the long-term continuous injection process. Appropriate reduction in the injection flow rate, injection temperature, and the Mg2+ and K+ contents in the injected water can help inhibit the formation of secondary minerals and delay the plugging process of the near-well reservoir.

A Novel Similarity Solution Approach Based Thermal Performance Prediction and Environmental Analysis of Evacuated U-Tube Solar Collector Employing Different Mono/Hybrid Nanofluids

In this article, a novel similarity function-based two-dimensional steady-state model is developed to analyze the thermal performance of an individual evacuated U-tube solar collector (EUTC). Using the developed model, the energy and environment assessments of a EUTC have been carried out employing different water-based mono/hybrid nanofluids as energy exchange fluids (EEF). The influence of nanoparticle volume concentration on energy gain, mass flow rate reduction, and efficacy has been analyzed. The influence of Reynolds number on energy gain is also investigated. The results show that Al2O3+MWCNT (multiwalled carbon nanotube) has high energy gain, whereas MgO has high mass flow reduction compared to water as a base fluid at 2% volume concentration. The efficacy of EUTC has been enhanced using nanoparticles as an additive. Employing Al2O3+MWCNT as EEF, the impact of EEF flow rate, EEF inlet temperature, ambient temperature, and solar intensity on the energy gain and efficacy of EUTC have been analyzed. It is observed that solar intensity and ambient temperature have major and minimum influence on EUTC performance.

Optimization of the Design Configuration and Operation Strategy of Single-Pass Seawater Reverse Osmosis.

The numerical study was conducted to compare process performance depending on the pump type and process configuration. The daily monitoring data of seawater temperature and salinity offshore from Daesan, Republic of Korea was used to reflect the site-specific seawater conditions. An algorithm for reverse osmosis in constant permeate mode was developed to simulate the process in time-variant conditions. Two types of pumps with different maximum leachable efficiencies were employed to organize pump-train configuration: separated feed lines and common pressure center design. The results showed pump type and design configuration did not have a significant effect on process performance. The annual means of specific energy consumption (SEC) for every design configuration were under 2 kWh/m3, except for a worst-case. The worst-case was decided when the pump was operated out of the best operation range. The two operation strategies were evaluated to determine the optimal configuration. The permeate flow rate was reduced to 80% of the designed permeate flow rate with two approaches: feed flow rate reduction in every train and pump shutdown in a specific train. The operation mode with feed flow rate reduction was more efficient than the other. The operating pressure reduction led to a decrease in SEC.

In vitro evaluation of how the presence of the stent retriever and microcatheter influences aspiration parameters in thrombectomy according to their position inside the aspiration catheter.

Several variations of the combined thrombectomy technique for acute ischemic stroke using a stent retriever and aspiration catheter have been described. The aim of our study was to assess how the presence of the microcatheter and stent retriever affect the basic aspiration parameters, namely, flow rate and aspiration force, depending on their position within the aspiration catheter. Two experimental set-ups were designed to assess changes in flow rate and aspiration force according to the position of the stent retriever and microcatheter within the aspiration catheter. The transition of the stent retriever and microcatheter from the distal to proximal position resulted in a progressive increase in the flow rate, but with no impact on aspiration force. Additionally, the size of the stent retriever had no significant effect on flow rate changes and the reduction in flow rate was related to the microcatheter diameter. Negative pressure generated inside the aspiration catheter impacted on its distal segment located beyond the radiopaque marker, thus leading to its partial collapse. As a consequence, the measured aspiration force was lower than the theoretical aspiration force level for all tested aspiration catheters. In our experimental model, the position of the stent retriever and microcatheter within the aspirator catheter affected the flow rate, but not the aspiration force. Negative pressure generated within the aspiration catheter appeared to determine a partial collapse of the distal segment that resulted in a less effective aspiration force than the theoretical aspiration force level.

Evaluation of comprehensive treatment effect of geotechnical and ecological engineering for debris flow: case of Wenchuan County, Sichuan Province

As a crucial link in debris flow disaster control, control engineering can be divided into geotechnical engineering and ecological engineering. Geotechnical engineering is less affected by climate and can play an immediate role in the treatment of debris flow in a short time. Ecological engineering has obvious regulating effect on surface runoff and erosion. Furthermore, there are few discussions on comprehensive treatment effect between geotechnical engineering and ecological engineering for debris flow. Therefore, taking the debris flow gullies with control engineering implemented in Wenchuan area of Sichuan Province as the research object, this paper puts forward an evaluation method of treatment effect comprehensively considering the geotechnical engineering and ecological engineering. It is mainly based on the impact of engineering on the formation conditions of debris flow and the damage of projects. The comprehensive treatment effect of geotechnical and ecological engineering for debris flow is analyzed. The corresponding evaluation indexes are extracted, including 5 first-class evaluation indexes such as landform factor and water source factor, as well as 11 s-class evaluation indexes such as the peak flow reduction rate, the sediment retention ratio and the LAI ratio. The Fuzzy-AHP method is used to establish the evaluation model of treatment effect. The evaluation results are graded. It is considered that the treatment effect of other debris flow gullies is medium or above except that two gullies are poor. The evaluation results are consistent with the actual investigation, which provides a reference for the control of debris flow in this area.

Effect of Dialysate Flow Rate (DFR) Reduction on Adequacy in a Chronic Hemodialysis Unit

Effect of Dialysate Flow Rate (DFR) Reduction on Adequacy in a Chronic Hemodialysis Unit

Estimation of Salivary Flow Rate in Myocardial Infarct Patients and its Association with Type II Diabetes Mellitus

Objective: The aim of our study was to investigate the association between salivary flow rate in diabetes mellitus and the development of coronary artery disease. Methodology: A cross-sectional study was executed in the Cardiology Department of Civil Hospital Karachi. Unstimulated saliva was collected between 9 and 11 a.m. Participants were asked to refrain from eating and drinking for 1 hour before saliva collection. They were then instructed to collect 5 ml of unstimulated saliva in a 15 ml falcon tube for 10 minutes. Finally, the patient’s oral hygiene status was recorded by a dentist. Data was entered in SPSS version 21. Descriptive analysis and significance of relationship was analyzed using chi-square test. Results: Out of 100 myocardial infarct patients between the age range of 30-70 years, 71(71%) were male and 29 (29%) were female. Overall frequency of diabetes mellitus was 55%. Significant relationships were found between occurrence of myocardial infarction in diabetes mellitus, among salivary flow rate reduction and age of the patient, and salivary flow rate reduction and gender of patient Salivary flow reduction below 3mL/10 minute was found in 48 diabetic patients whereas 11 nondiabetic patients had this clinical finding. No significant relationship was found between occurrence of caries and periodontitis with presence of diabetes. Conclusion: Careful monitoring of the oral symptoms related to severity of DM particularly the salivary flow rate can be helpful in early diagnosis of patients at possibility of developing cardiovascular complications. Keywords: Myocardial infarction, unstimulated saliva, Type II DM, Salivary flow rate.

Developing a 3D City Digital Twin: Enhancing Walkability through a Green Pedestrian Network (GPN) in the City of Imola, Italy

Predominantly, dense historical cities face insufficient pedestrian-level greenery in the urban spaces. The lack of greenery impacts the human thermal comfort on the walking paths, which contributes to a considerable reduction in pedestrian flow rate. This study aims at developing a model to assess pedestrian-level thermal comfort in city environments and then evaluate the feasibility of creating a green pedestrian network (GPN). Imola, as a historical city in Italy with a compact urban pattern, is selected as the case study of this paper. To accomplish this, a three-dimensional digital twin at city scale is developed for the recognition of real-time shade patterns and for designing a GPN in this city. The 3D model of the proposed digital twin is developed in the Rhinoceros platform, and the physiological equivalence temperature (PET) is simulated through EnergyPlus, Honeybee, and Ladybug components in grasshopper. This study provides the city with a digital twin that is capable of examining pedestrian-level thermal comfort for designing a GPN based on real-time PET in the compact urban morphology of Imola. The PET model indicates that during the hottest hour of the 25th of June, pedestrians in open spaces can experience 3 °C more than on narrow shaded streets. The results are validated based on in situ datasets that prove the reliability of the developed digital twin for the GPN. It provides urban planners and policy makers with a precise and useful methodology for simulating the effects of pedestrian-level urban greenery on human thermal comfort and also guarantees the functionality of policies in different urban settings.

Pressed Lateral Flow Assay Strips for Flow Delay-Induced Signal Enhancement in Lateral Flow Assay Strips.

This paper proposes that the signal intensity of a lateral flow assay (LFA) strip can be increased by pressing the top of the strip, effectively reducing its flow rate. The reduced flow rate allows more time for antigen–antibody interactions to occur, resulting in increased signal intensity and an improved detection limit. To assess the potential of the pressed LFA (pLFA) strip, C-reactive protein (CRP) diluted in phosphate-buffered saline (PBS) and serum is detected, affording signal enhancement and a lowered limit of detection. Additionally, to show that the signal enhancement by pressure-induced flow delay applies to existing LFA products, commercially available COVID-19 antigen test strips are pressed, and signal enhancement is observed. Lastly, we show that the signal intensity of COVID-19 LFA kits can be increased by approximately two-fold at maximum by applying pressure on top of the manufactured product. This study suggests that pressed LFA strips can be used to reduce the chances of determining ambiguous signals as false-negative results and can potentially improve the detection sensitivity.Graphical abstract Supplementary InformationThe online version contains supplementary material available at 10.1007/s13206-022-00085-w.

Flow rate improvements in additively manufactured flow channels suitable for rocket engine application

This contribution describes the investigation of flow channels which are designed to be directly integrated into an aerospike engine by means of additive manufacturing with laser powder bed fusion (LPBF). During the experimental testing of a previous aerospike engine in 2019, it was observed that high surface roughness of such additively manufactured integrated channels caused a significant reduction in the mass flow rates of the propellants ethanol and liquid oxygen as well as the coolant due to increased pressure drop. In an extensive study within the CFDmikroSAT project, various factors influencing this surface roughness are, therefore, being investigated, which include the geometry of the channels as well as selected manufacturing parameters of the LPBF process, such as layer thickness and component orientation. To further reduce the roughness after manufacturing, suitable post-processing methods are also being investigated for internal cavities, initially analysing the abrasive flow machining process. Within the paper, the overall investigation approach is presented, such as the overview of the considered specimens, and the initial results of a various studies with selected specimens are discussed. These studies consist of the examination of surface roughness reduction, shape accuracy and flow behaviour of post-processed cooling channel specimens. Finally, a brief overview of the already manufactured aerospike demonstrator is presented.

Thermodynamic modeling and multi-objective optimization of a solar-driven multi-generation system producing power and water

The present paper addresses the thermodynamic modeling and multi-objective optimization of a solar-based multi-generation system producing hot water, heating, cooling, hydrogen, and freshwater using a humidification and dehumidification (HDH) unit. Usually, in areas with high radiation intensity, the shortage of drinking water is severe; therefore, using multi-generation systems with solar energy as the prime mover can be a promising option in these areas. The main goals of the current work are multi-aspect assessment and optimization of a solar system to generate potable water and other valuable products. The proposed system is examined using thermodynamic modeling and environmental simulation from different aspects in the present study. The exergy destruction evaluation rate showed that the heliostat had the highest exergy destruction rate, gauged at 1867 kW. Also, in terms of exergy efficiency, the pump and heliostat units had the lowest exergy efficiency, with values of 52.09 % and 65.39 %. Parametric analysis was implemented to find the effect of changing different parameters on the yield of produced fresh water, exergy efficiency, exergy destruction rate, coefficient of performance (COP), sustainability index (SI), and produced hydrogen. Results showed that increasing the compressor pressure ratio from 2 to 6 elicits a reduction in freshwater flow rate and COP. Similarly, increasing the outlet pressure from 70 to 80 bar reduced exergy efficiency and freshwater production. Furthermore, owing to the different effects of the parameters on the studied system, multi-objective optimization was performed using the evolutionary genetic algorithm.

The Investigation of Gas Distribution Asymmetry Effect on Coriolis Flowmeter Accuracy at Multiphase Metering.

Multiphase flows are encountered in various industries, and the Coriolis flowmeter (CFM) is considered a high potential flowmeter for the metering of these flows. However, the decoupling effect and asymmetrical gas distribution in a CFM might decrease the accuracy of its multiphase flow metering The asymmetry of gas distribution in a CFM and its influence on the metering accuracy have only been qualitatively investigated in a few studies. The present paper quantitatively describes the gas distribution asymmetry in several CFMs under different flow conditions by numerical simulation. The simulation methodology is developed and validated by a results comparison with a conducted experiment and published data for bubbly, stratified and transitional flow regimes. U-shaped and triangle-shaped CFMs of different diameters are investigated at different gas volume fractions and flow rates. It is shown that the increase in the gas volume fraction and the reduction in the mixture flow rate lead to the increase in the gas distribution asymmetry. The strong correlation between the gas distribution asymmetry and the experimentally observed CFM error is demonstrated. The correction of the CFM error is proposed based on this correlation allowing the metering error to be decreased from 34% to 10% for the investigated conditions.

The Optimization of a First-Stage Liquid-Sealing Impeller Structure for a Turbopump Based on Response Surface Methodology

This study investigated the sealing performance of the multistage liquid-sealing impellers of a turbopump. To achieve this purpose, the influence of each structural parameter in the impeller on the pressurization coefficient φ2 and the leakage flow rate Q was analyzed based on response surface methodology, taking the maximum pressurization coefficient φ2 and the minimum leakage flow rate Q as the optimization objectives. We obtained satisfactory ranges for parameters φ2 and Q. A set of parameter combinations was selected as the optimization scheme using the Box–Behnken method for the optimal solution design. The numerical simulation results show that to keep φ2 and Q in the better range, the value ranges of groove width b, groove depth h and groove number z should be (12.8–14 mm), (4.5–5.6 mm) and (23.5–28), respectively. Compared with the original model, the optimized version has an average increase of about 2.5% in pressurization coefficient φ2 at each rotation speed, an average of about 8.2% reduction in the leakage flow rate Q in the leakage state and an average increase in the reverse flow rate Q by about 6.7% in the negative pressure sealing state, indicating better sealing. By comparing pressure data at the experimental monitoring points, the proposed method was verified to have a high degree of confidence.

INOCA affects more than the coronaries

Abstract Background Ischaemia with normal coronary arteries (INOCA) may result in disabling symptoms and has an association with adverse long-term prognosis. The diagnosis of INOCA necessitates invasive coronary angiography to perform a physiological evaluation of microvascular function. The conjunctiva has a readily assessable microvascular network in which physiological parameters can be evaluated. We compared conjunctival haemodynamics in patients with and without coronary microvascular disease (MVD) to assess if systemic microvascular dysfunction was present in this coronary artery disease sub-group. Methods In this study, we recruited patients undergoing invasive coronary angiography for the investigation of angina or angina equivalent symptoms. All patients had physiologically insignificant epicardial disease (FFR≥0.80) and underwent a physiological evaluation of coronary microvascular function. We compared a group with evidence of coronary MVD (IMR≥25 or CFR<2.0); to a group of controls without MVD (IMR<25 and CFR≥2.0). The conjunctival microvasculature was imaged using a previously validated combination of a smartphone and slit-lamp biomicroscope. The conjunctival vasculature was assessed using a semi-automated process of vessel diameter measurement and erythrocyte tracking to obtain haemodynamic parameters of microvascular function. Results A total of 111 patients were included (43 MVD and 68 controls). There were no differences in baseline demographics, co-morbidities, epicardial coronary disease severity or regular pharmacological therapies between the groups. Mean coronary flow reserve (CFR) was lower and mean index of microcirculatory resistance (IMR) higher in the MVD cohort (CFR 2.5±1.3 vs 5.2±2.5, p<0.001 and IMR 28.4±11.8 vs 13.7±5.0, p<0.001). A total of 2295 conjunctival vessels were analysed. The mean number of vessels per patient was 21.0±12.8 (3.2±3.5 arterioles and 14.8±10.8 venules). Significant reductions in axial/cross-sectional velocity, wall shear rate and wall shear stress were observed in the MVD cohort. Table 1 demonstrates a comparison of conjunctival physiological parameters between the groups. The most marked differences were observed in conjunctival arterioles. Due to the heterogenous size distribution of microvessels, arterioles were categorised into 2 diameter sub-groups (10–25 μm and 25–40 μm) for analysis (Table 2). Conclusion The reductions in microvascular blood flow velocity and rate that form the basis for the diagnosis of coronary microvascular dysfunction can be observed non-invasively in the bulbar conjunctiva microcirculation. Conjunctival vascular imaging may have utility as a non-invasive imaging modality to both diagnose microvascular dysfunction and augment conventional cardiovascular risk stratification. Funding Acknowledgement Type of funding sources: Foundation. Main funding source(s): Belfast Trust Heart Trust Fund and Northern Ireland Chest Heart and Stroke

Removal of Mn(II) from Acidic Wastewater on the Red Mud– Loess Mixture: Fixed–Bed Column Tests

In this study, the purification effect of red mud–loess mixture (RM–L) as a reactive medium in a permeable reactive barrier (PRB) for groundwater contaminated by acidic wastewater (AW) containing Mn(II) was explored considering removal capacity and pH value, and the safety of Mn(II) on RM–L after purification was evaluated. The breakthrough parameters of the Mn(II) were determined and the purifying performances of RM–L toward AW were evaluated by fixed-bed column tests at various initial concentrations of Mn(II), flow rates, and packing heights. The speciation of Mn(II) loaded on the RM–L was evaluated by the Tessier method. Results show the RM–L with a removal capacity of 17.30 mg·g−1 at 100 mg·L−1 initial concentration, 1 mL·min−1 flow rate and 7 cm packing height. The reduction in initial concentration and flow rate and the increase in packing height improve the total removal percentage of Mn(II) and the removal capacity of the RM–L. Moreover, the RM–L has a long-term effective acid buffer capacity for AW containing Mn(II), ensuring the pH values of effluent could be maintained at a neutral value. Furthermore, the Mn(II) could be loaded on the RM–L after the purification in stable forms that are dominated by the iron-manganese oxidate form.

Simulation and Evaluation of Rainwater Runoff Control, Collection, and Utilization for Sponge City Reconstruction in an Urban Residential Community

Residential areas are important for the underlying surface of a city, and the sponge construction of a residential area is a key topic in sponge city construction. Taking the Zi-Jing community as the research case, the SWMM model was established for simulation, and the rainwater runoff control, collection, and utilization were compared and analyzed before and after the implementation of sponge transformation for the designed rainfall conditions of once in 3, 5, 10, 20, and 50 years. The results showed that the water depth of the four outlet pipes was not a full tube at the first peak time. The full duration time was reduced to 1–5 h at the second peak, and the flow reduction rate at the pipe outlet was between 30% and 100%. The water storage of sub-catchments A1, A3, and A4 increased significantly and continued to increase after the peak rainfall occurred, while that of A2 decreased significantly after the transformation after the transformation. For the whole residential area, the surface runoff decreased by 37–47%, while the surface water storage and infiltration increased by 8–14% and 23–39% respectively after reconstruction. The direct storage volume of rainwater in the four sub-catchment areas was filled at least once above a once in 5 years scenario. The main conclusions were as follows: Sponge transformation in residential areas with 17.46% sunken greenbelt and 40.85% permeable pavement, and the time of the pipe outlet in full status can be shortened by 30–200 min in different rainfall return periods. With the increase in the rainfall return period, the improvement range of the infiltration increased from 23.36% to 39.54%, the improvement range of the storage capacity for rainwater decreased from 14.36% to 8.06%, and the reduction degree of surface runoff increased from 37.73% to 47.43%. The water consumption for flushing is about 30 m3 per day for 1000 people, and the rainwater storage volume of 765 m3 in this study can meet the flushing water demand of 5000 residents in the community for 3–5 days.

Proximal ventricular shunt catheter occlusion model.

Proximal ventricular shunt catheter occlusion remains a problematic cause of shunt malfunction, and there is no consistent in vivo or in vitro model to help clinicians and researchers study this phenomenon. An in vitro model utilizing standard proximal ventricular catheter and biological occluding agents mimicking choroid plexus was designed, constructed, and calibrated to occlude consistently within a specified timeframe. Hydrostatic pressure differential of 100 cmH2O was used as a driving force to generate flow through the catheter. Chalaza and vitelline membranes were harvested from avian eggs and used as occluding agents. Successful occlusion was defined as a greater than 90% reduction in volumetric flow rate through distal outlet. Histological sections of occluded catheters were performed and interpreted by a neuropathologist. Initial trials demonstrated successful standard catheter occlusion within 24h using chalaza, vitelline membrane, and combination treatments. Repeat trials demonstrated consistency in successful occlusion within 5min utilizing only vitelline membrane treatment. Histopathology demonstrated the vitelline membrane to consist of a thin, superficial layer of extraembryonic ectoderm; the chalaza was observed to consist of strands of mucin protein. An in vitro model of proximal ventricular shunt catheter occlusion was developed and calibrated for successful occlusion within 5min. Future studies may utilize this model to rapidly test occlusion-resistant shunt designs and de-obstruction techniques.