Outlet Device Research Articles

Ventriculosinus shunt: a pilot study to investigate new technology to treat hydrocephalus and mimic physiological principles of cerebrospinal fluid drainage.

Devices draining CSF to the intracranial venous sinus for the treatment of hydrocephalus have been tested in the past, and while clinically effective, have not shown efficacy in the long term. The majority of these devices become obstructed within 3 months due to endothelial overgrowth. In this study, the authors investigated a newly developed ventriculosinus (VS) shunt outlet device with the objective of showing it would remain patent for at least 6 months. Twelve patients in need of shunting for hydrocephalus underwent an operation using the investigational device and were followed for 6 months to record patency of the shunt. In 10 patients, the shunt was patent at 6 months, with the outlet device remaining unobstructed. In the remaining 2 patients, one died just before reaching the 6-month endpoint, and in the other the outlet was misplaced during surgery and therefore ceased to function after 3 months. No occlusion of the internal jugular vein or thrombus formation was noted in any of the 12 cases. These findings indicate that the outlet device can remain patent and has the capability to mimic physiological drainage by diverting CSF to the intracranial sinus. Additional confirmation of its potential as part of a new VS shunt system and ultimately as a viable alternative for ventriculoperitoneal and ventriculoatrial shunting to reduce complication rates requires further clinical trials.

Особенности повышения надежности и эффективности газосепараторов погружных установок электроцентробежных насосов для добычи пластовой жидкости

In oil producing wells with high gas content, an increase in the efficiency of centrifugal pumps is achieved by equipping them with centrifugal gas separators, in which, before entering the pump intake, most of the free gas is taken from the pumped fluid and discharged into the annulus of the well. The efficiency of a centrifugal gas separator significantly depends on the size of the dispersity of the gas-liquid structure of the pumped fluid, on the diameters of gas bubbles, the water cut of the formation fluid, the presence of surfactants, and the pressure at the inlet and outlet of the pump. In the article, based on the analysis of the structural diagrams of the power part of gas separators of various manufacturers, the analysis of the gas-liquid mixture flow features in the separation chamber and the outlet device, recommendations are made for optimizing the separation chamber length and the gas separator head outlet design. Recommendations are proposed for changing the flow path to increase the efficiency of gas separation and reliability of operation. Explanations of the expediency of new design solutions based on empirical formulas and numerical simulations are proposed. It is shown what the information is most important and how it can be obtained in bench tests.

Improving the understanding of on-site stormwater detention performances

ABSTRACT On-site Stormwater Detention has been used around the world to reduce stormwater peak flow at lot scale. However, few studies have evaluated its performance as well as its hydrological and hydraulic parameters on a real scale. To evaluate these variables, two OSDs were monitored in Belo Horizonte/Brazil. Based on the analysis of monitoring data, it was observed that: (i) the OSDs average efficiencies in peak flow damping were higher than 50%; (ii) the storage volume per catchment area was close to 25 L/m2; (iii) the short tubes discharge coefficients were approximately 0.90 and; (iv) the shape of inflow hydrographs were similar to hyetographs. The use of the Unit Hydrograph Modified Rational Method properly represented the rain-runoff transformation. The findings could be used in OSD design to determine the inlet hydrograph, to pre-sizing the storage volume based on contribution area and to use the proper discharge coefficient value for outlet device.

Direct detection of chemical warfare agent simulants in soil by thermal desorption-low temperature plasma-mass spectrometry

For rapid, accurate and real-time detection of trace chemical warfare agents in soil, direct detection of chemical warfare agent simulants in soil by thermal desorption-low temperature plasma ionization-mass spectrometry was developed. Multi-factor analysis of variance was used to quantitatively analyze the factors affecting the ionization efficiency of low temperature plasma based on the emission spectra of the plasma flame. The experimental parameters including the distance between low temperature plasma outlet and thermal desorption device, the flow rate of discharge gas, the temperature of ion source, the thermal desorption temperature and different solvents were optimized. Dimethyl methylphosphonate (DMMP, G-series nerve agent simulant), tributyl phosphate (TBP, V-series nerve agent simulant) and 2-Chloroethyl ethylsulfide (CEES, H-series blister agent simulant) were desorbed and ionized, forming the typical positive ions of [DMMP + H]+, [DMMP-HOCH3+H]+, [TBP + H]+, [TBP-3(C4H8)+H]+ and [CEES-Cl]+, [CEES- C2H4Cl]+. The ions were analyzed using the multiple reaction monitoring (MRM) of triple quadrupole mass spectrometer. Detection limit of the method was 5 pg for DMMP (m/z 125→93, S/N＞3:1), 5 pg for TBP (m/z 267→99, S/N＞3:1) and 5 ng for CEES (m/z 89→61, S/N＞3:1). Trace level of CWA simulants can be directly detected with simple sample pretreatment, suggesting that the thermal desorption-low temperature plasma-mass spectrometry method is useful for quick and direct detection of chemical warfare agents in soil.

Kerr Electro-Optic Sensor for Electric Field in Large-Scale Oil–Pressboard Insulation Structure

The design of the oil–pressboard/paper insulation structure is the key to maintain the safe and reliable operation of power transformers, which mainly relies on simulation and verification test undertaken with simple or equivalent models, falling short of the physical entity verification undertaken in the large-scale structure. Based on the Kerr electro-optic effect and the optical fiber technology, a novel electric field measuring sensor was developed in this paper for the application test in the large-scale oil–pressboard structure. The sensor is contained of collimator, total reflection prism, coupler, and customized optical elements, whose appearance is a miniature capsule-shaped configuration. The key technical performance parameters of sensor were obtained, for instance, and the effect of imported sensor on the electric field under measurement is an average 1.17% reduction in intensity; the sensitivity of designed system is 162.84 V/mm under ac voltage and 40.43 V/mm under dc voltage. Under dc voltage, the measuring accuracy of the designed system is greater than 97.42%, while in the context of ac voltage, it could reach 97.14%. The application test was conducted to capture the dynamic process of the electric field in oil in the large-scale outlet device model, which has three uniformly spaced oil spacings divided by pressboards, under ac voltage, dc voltage, and polarity reversal voltage. The experimental results verify that the developed electric field sensor could be effectively and reliably applied in the large-scale oil–pressboard insulation, and it could be confidently inferred that the larger the scale of insulation structure, the better is the performance of sensor.

Research on the deterioration process of electrical contact structure inside the ±500 kV converter transformer RIP bushings and its prediction strategy

Extra high-voltage converter transformer resin impregnated paper (RIP) bushing is used as the outlet device of the converter transformer, its safe operation is directly related to the reliability of the power system. Under the long-term effects of high current, strong mechanical stress and abrasion, the contact resistance of connection structure inside the bushing is prone to deteriorate. When the local overheating increases to a certain level, the insulation performance of bushing will decline and may lead to penetrating discharge. Therefore, it is vital to develop strategies for predicting the overheating fault of RIP bushings. In this study, firstly, one typical overheating fault of RIP bushing induced by the contact deterioration was diagnosed according to the fretting corrosive model and SF 6 decomposition process. Secondly, using the three-dimensional electromagnetic-thermal-fluid finite element method, the temperature distributions of RIP bushing under the different overheating degrees were simulated. Finally, based on the maintenance experience and simulation results, the diagnosis strategies were proposed. The diagnosis principle and prediction strategies were successfully helped to maintain the faulted RIP bushings and wall bushings before a destructive overheating accident could occur, which provide a basic reference for the fault prediction and improvements of relative standards.

Numerical Research of Flows into Gullies with Different Outlet Locations

Gullies are sewer inlets placed in pavements usually covered by bar grates. They are the most common linking-element used to drain a wide range of flows from surface runoff into the buried drainage system. Their hydraulic behavior and their overall hydraulic performance is dependent on the flow conditions, the gully dimension, geometry, and location of the outlet device. Herein a numerical research based on Volume Of Fluid ( V O F ) to detect the interface, and on the Shear Stress Transport S S T k - ω turbulence model was conducted to study the importance of the outlet location and characterize flows through them in drainage conditions. Results provided detailed information about flow features, discharge coefficients, and efficiencies for different outlet locations. The authors identified three different regimes, R 1 , R 2 , and R 3 , and concluded that the outlet location influences the velocity field along the gully, the discharge coefficient, and the drainage efficiency. This allows for the estimation of uncertainty and its variation for different outlet positions.

Effects of Insulation Structure on Electric Field Distribution of Valve-Side Outlet Device of Converter Transformer

The valve-side outlet device of the converter transformer is one of the key components of the converter transformer. The insulation structure design is the key technology for the design and manufacture of the outlet device. The insulation structure and electric field distribution of the outlet device have great influence on technical performance and safety. Based on the finite element method and ANSYS simulation software, under the AC and DC electric field distributions of the parts of the straight tube-shaped and allotype-shaped insulation structure were simulated, and the influence of the outlet device’s operation characteristics and safety under AC and DC electric field was analyzed. The result shows that: 1 Under the AC voltage, the electric field distribution of the valve side outlet device depends on the relative permittivity of the material; the DC voltage depends on the resistivity of the material; 2 the insulation structure has a great influence on the electric field distribution of the outlet device.

Influence of Metal Particles on the Electric Field Distribution of Outlet Device in a 500 kV Transformer

Transformer is an important equipment serving in power system. In this paper, the influence of metal particles on the electric field of transformer outlet device is studed via numerical simulation. The results reveal that the metal particles can increase the maximum field strength between the oil gap of the outlet device and the maximum field strength increases with the increase of the particle radius. The local field strength greater than the allowable oil gap may cause local micro-discharge. Metal particles in the alternating current field oscillation and discharge may be the bubble can make the electric field distortion, accelerate the process of insulation cracking and may further lead to insulation breakdown. By altering the oil gap width of outlet device, its insulation endurance can be improved under the influence of metallic particles.

Тепловой расчет выпускного устройства воды для полипропиленовых труб холодного водоснабжения в зимних условиях Крайнего Севера

Тепловой расчет выпускного устройства воды для полипропиленовых труб холодного водоснабжения в зимних условиях Крайнего Севера

A pillar-based microfilter for isolation of white blood cells on elastomeric substrate.

Our goal is to design, fabricate, and characterize a pillar-based microfluidic device for size-based separation of human blood cells on an elastomeric substrate with application in the low-cost rapid prototyping of lab-chip devices. The single inlet single outlet device is using parallel U-shape arrays of pillars with cutoff size of 5.5 μm for trapping white blood cells (WBCs) in a pillar chamber with internal dead-volume of less than 1.0 μl. The microstructures are designed to limit the elastomeric deformation against fluid pressures. Numerical analysis showed that at maximum pressure loss of 15 kPa which is lower than the device conformal bonding strength, the pillar elastomeric deformation is less than 5% for flow rates of up to 1.0 ml min(-1). Molding technique was employed for device prototyping using polyurethane methacrylate (PUMA) resin and polydimethylsiloxane (PDMS) mold. Characterization of the dual-layer device with beads and blood samples is performed. Tests with blood injection showed that ∼18%-25% of WBCs are trapped and ∼84%-89% of red blood cells (RBCs) are passed at flow rates of 15-50 μl min(-1) with a slight decrease of WBCs trap and improve of the RBCs pass at higher flow rates. Similar results were obtained by separation of mixed microspheres of different size injected at flow rates of up to 400 μl min(-1). Tests with blood samples stained by fluorescent gel demonstrated that the WBCs are accumulated in the arrays of pillars that later end up to blockage of the device. Filtration results of using elastomeric substrate present a good consistency with the trend of separation efficiencies of the similar silicon-based filters.

The dual outlet device – Key to size-selective flotation

This paper discusses a new method to control particle size distribution in a flotation cell. As known from the literature, fine and coarse particles have different flotation rate constants, hydrodynamic behavior and require different reagent regimes. The device discussed allows separate processing of finer and coarser slurry by the extraction of a third stream, carrying finer slurry, from the flotation cell. By separate treatment of fine and coarse slurry operational conditions, flotation recovery for both can be optimized more efficiently. This dual outlet device (DOD) can be installed in a traditional flotation cell without a need for equipment replacement. Pilot plant tests were conducted in a single 5 m 3 Outotec flotation cell and the results show that the DOD can extract a fine slurry from the flotation cell and that the DOD product represents 5–15% of the volume flow rate of the feed. In this paper, the first pilot scale tests of the DOD in a single flotation cell are discussed. The aim is to introduce the method and investigate the effect of different DOD configurations on the extracted DOD product. For more strict evaluation of the influence of the DOD on flotation recovery and froth stability (pilot) plant scale tests for a bank of cells and for the entire circuit will be conducted.

Can Wound Desiccation Be Averted During Cardiac Surgery? An Experimental Study

During cardiac surgery the wound is exposed to desiccation, especially as a result of operating room ventilation and the insufflation of dry carbon dioxide (CO(2)) for de-airing. We compared the gas humidity and desiccation rates in an in vitro model of a cardiothoracic wound during these conditions and during insufflation of humidified CO(2). To assess the influence of flow velocity, CO(2) was insufflated at 10 L/min via two devices, a standard open-ended tube and a low-velocity gas diffuser. The treatment arms were compared with a control without insufflation. When insufflated via the open-ended tube the humidity in the model was almost equal to the control, both with dry and humidified CO(2). However, the total desiccation rate was more rapid than the control (P < 0.001), especially in the area exposed to the gas jet where the desiccation rate was three times more rapid (P < 0.001). With the gas diffuser, dry CO(2) caused almost zero humidity and a desiccation rate that was almost equal to the control. Humidified CO(2) increased humidity in comparison with the control (P < 0.001) and decreased the desiccation rate by >90% (P < 0.001). Humidified CO(2) may be used to avert desiccation of the cardiothoracic wound. The humidified gas is effective only when delivered via a low-velocity outlet device.

The efficiency function of detention reservoirs in urban drainage systems

Detention reservoirs in urban drainage systems are provided for reducing the peak flows downstream of the reservoir. The flow reduction is due to the storage volume of the reservoir in which the incoming flow is temporarily stored. The relationship between the peak reduction ratio (the peak outflow discharge to the peak inflow discharge) and the relative storage ratio (maximum volume stored in the reservoir to the volume of the inflow hydrograph) is evaluated in this study. This relationship, named the efficiency function, is derived by a numerical solution of the dimensionless routing equation. Using the three‐parameter gamma distribution to represent the inflow to the reservoir, the efficiency functions can be expressed by simple linear equations. Each equation depends on a single parameter whose value is determined by the reservoir configuration (depth‐storage relationship) and the type of the outlet device (e.g., spillway or culvert). The implementation of the efficiency function is most suitable for the preliminary design stage where a large number of alternative designs can be easily tested without performing the conventional routing procedure.

A simplified cannulation procedure for pharmacokinetic experiments in rats

A convenient, simplified method for cannulating theJugular vein of rats is described. The technique has been developed for use in pharmacokinetic experiments. The construction of the cannula has been simplified compared with previously described methods. In addition, a small and simple outlet device for the cannula is described which allows the connection of tubing for sampling at short time intervals or for short-term infusions (several hours). In order to reduce stress on the animal, the tubing can be disconnected during sampling at long time intervals, allowing free movement of the animal with only a very small external outlet device.

Self‐tuning control of chip level in a Kamyr digester

AbstractA study is presented of the application of a self‐tuning regulator to the control of the level of wood chips in a Kamyr digester, used in the production of wood pulp. Following an initial phase of experiments and model structure selection, two control schemes were studied, using respectively the blow flow and the outlet device speed as manipulated variables. The approach finally adopted uses the outlet device as the primary control. The control has been in operation for several months and has provided significantly improved control and a high degree of operator acceptance.