Diverter Valve Research Articles

Effect of the solids inventory and fluidization gas velocity on the hydrodynamics of a circulating fluidized bed

The hydrodynamics behavior of a bench-scale circulating fluidized bed (CFB) system has been analyzed in terms of the axial pressure profile and solids circulation rate. Experimental runs were carried out at room conditions using beds of quartz sand and air as the fluid phase in order to know the effect of the overall solids inventory and the superficial gas velocity used in the riser. Static pressure signals obtained from the gas-particle flow were registered at several positions along the CFB loop and the solids circulation rate was measured by using a diverter valve installed at the standpipe section. A statistical analysis applied on the experimental data show that the solids inventory and the superficial gas velocity in the range here studied lead to significant changes on the hydrodynamics of the circulating fluidized bed system.Keywords: Circulating fluidized bed riser, gas-particle hydrodynamics, static pressure signals, solids circulation rate.

Automatically Monitoring, Controlling, and Reporting Status/Data for Multiple Product Life Test Stands

This paper describes an industry laboratory implementation of local and remote automation monitoring and control of several product testing stands for status, safety, and an efficient use of resources, as well as the purpose and inter-relationship between the tests, product reliability estimations, customer applications, and possible solutions to test specification issues. Like an airport departure/arrival board, the summary statuses of several life stands are reported on a monitor using a mobile application interface. Detailed data analysis reports and emergency shutdown statuses are emailed to authorized-interested parties. The life stands include submersion tanks and flow rigs at different fluid temperatures (steady-state, slow cycling, thermal shock). To reduce equipment costs and lab space requirements, some life test stands are combined to share heating/cooling transfer fluids and pumping resources that are automatically controlled to direct different fluid temperature ranges through different flow paths. A heater/chilling system cycles between −80 °C and +140 °C with automated diverter valves to route −80 °C to +85 °C fluid through a set of products; when the fluid temperature is increased to > +85 °C, diverter valves route the > +85 °C fluid through a different set of products that are tested only between fluid temperatures of +85 °C to +140 °C.

Theoretical Modeling, Design and Simulation of an Innovative Diverting Valve Based on Coanda Effect

The present work is focused on the study of an innovative fluidic device. It consists of a two-ways diverter valve able to elaborate an inlet water flow and divert it through one of the two outlets without moving parts but as a result of a fluctuation of pressure induced by two actuation ports, or channels. Such apparatus is named Attachment Bi-Stable Diverter (ABD) and is able to work with the effect of the fluid adhesion to a convex wall adjacent to it, this phenomenon is known as Coanda Effect; it generates the force responsible for the fluid attachment and the consequent deviation. The main purpose of this work is to develop a knowhow for the design and development of such particular device. A mathematical model for the ABD has been developed and used to find the relationships between the geometrical parameters and the operative conditions. A configuration has been designed, simulated with a computational fluid dynamics approach. A prototype has been printed with and additive manufacturing printer and tested in laboratory to check the effective working point of the device.

Design and simulation for driving system and steering system of hydraulic chassis of rice transplanter

A new hydraulic chassis of rice transplanter is designed based on the paddy machinery operation requirements. Driving system adopts single pump four-motor scheme, and the anti-slide valve group is used to prevent the slippage of the shunt-wound hydraulic motors. Hydraulic steering system adopts single-way stable diverter valve for ensuring its response in time. Then, hydraulic system and components parameters are designed and calculated. The driving resistance and average slip rate are measured in paddy field. The experimental data verifies the correctness of theoretical calculation. The designed hydraulic driving system and steering system are simulated in AMESim. The simulated data, including pressure, flow, and torque, basically conform to the design requirement. The results verify the feasibility and reliability of chassis hydraulic scheme. The proposed design scheme may be extended to other vehicles for improving chassis performance.

Erosive wear reduction for safe and reliable pneumatic conveying systems: review and future directions

Pneumatic Conveying System (PCS) is widely used to transport powdered and granular materials. If the conveyed material is hard and abrasive, it leads to erosion of bends and other surfaces, like diverter valves, which enforce a directional change and make the transport operations unsafe and unreliable. Researchers have attempted a variety of solutions to reduce the severity of erosion in such cases. New materials have been used, different bend geometries have been investigated, and flow improvements have also been tried out. This paper investigates and reviews various solutions to reduce the magnitude of erosion of bends resulting in enhanced life of the components. It also highlights the future directions that could mitigate the problem of erosive wear.

A UHPLC-MS/MS method for profiling multifunctional steroids in human hair.

It is important to profile steroids in many physiological and pathological processes. Recently, hair has been used for the long-term measurement of endogenous steroid hormones. Analyzing hair has advantages of being noninvasive and time sequential compared with other bio-specimens. Liquid chromatography-mass spectrometry (LC-MS) techniques have been widely used over the past decades; however, it is challenging to profile estrogens in hair by LC-MS, and more comprehensive steroid profiling is required. In this paper, an ultra high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was developed to simultaneously profile 28 multifunctional steroids, including corticosteroids (n=6), estrogens (n=13), androgens (n=5) and progestogens (n=4), in human scalp hair in a single run. To optimize the sample preparation procedure, we evaluated extraction time, post-incubation purification and hair fragment length; 30mg hair samples were washed with hexane, cut into 5mm pieces and incubated in methanol for 18h at 25°C. Methanol extraction derivatized using Girard P and dansyl chloride reagent was analyzed within 25min using an automated injection program combined with a diverter valve switch and step analysis (AIDSA). The method was well validated in terms of linearity, limit of detection (LOD), limit of quantification (LOQ), precision, accuracy, matrix effect and recovery, and was successfully applied to a steroid profile from male and female hairs. Significant differences were observed between genders. In addition, steroids showed a declining trend from the proximal to more distal hair segments; thus, care should be taken when obtaining hair samples for analysis to account for this difference in steroid levels along the length of hair. Graphical Abstract The workflow of the estabished UHPLC-MS/MS method.

Methylmalonic aciduria combined with hydrocephalus treated with ventriculoperitoneal shunt

Objective To summarize the experience of the ventriculoperitoneal shunt in treating children with methylmalonic aciduria combined with hydrocephalus, and to assess the clinical value. Methods From September 2012 to May 2016, a total of 12 patients with methylmalonic aciduria combined with hydrocephalus in Peking University First Hospital were enrolled, including 7 boys and 5 girls.All the 12 patients underwent ventriculoperitoneal shunt.Drug the-rapy was performed after surgery.The clinical manifestations and imaging findings were used as the basis for adjusting the pressure of the diverter valve appropriately.The clinical condition of patients were evaluated retrospectively.The patients′ clinical symptoms, signs, imaging materials, surgical complications and postoperative prognosis were analyzed. Results All the cases were followed up for 3 to 36 months, no death case and no serious postoperative complications of hydrocephalus occurred.Clinical symptoms of intracranial hypertension were relieved or disappeared.The head circumference progressive enlargement stopped.The anterior fontanelle tension decreased significantly. Setting-sun sign of eyes disappeared.One out of 4 cases with convulsion and epilepsy was relieved after the operation.Seven cases of poor vision or vision loss, postoperative visual acuity were improved though not recover to normal eyesight.One case of the children with hearing loss, postoperative hearing recovered.During the follow-up period, the head CT showed that the ventricle was narrowed significantly, interstitial brain edema improved obviously. Conclusion Ventriculoperitoneal shunt is a effective method for treating children with methylmalonic aciduria combined with hydrocephalus, which is beneficial for patients with these diseases. Key words: Methylmalonic aciduria; Hydrocephalus; Ventriculoperitoneal shunt

Transient Ion-Pair Separations for Electrospray Mass Spectrometry.

We report a novel ion-pair chromatography (IPC) approach for liquid chromatography electrospray ionization mass spectrometry (LC-ESI-MS), where the eluent does not contain any ion-pairing reagent (IPR). The IPR is injected on the column, much like the sample, and moves down the column. Significant amounts of a high retention factor IPR is injected, resulting in a transient but reproducible regional coating that progresses along the column. The sample is injected after a brief interval. The sample components interact with the IPR coated region during their passage; the chosen eluent gradient elutes the analytes of interest into the mass spectrometer before the IPR. Following analyte elution, the gradient is steeply raised, the IPR is washed out, and the effluent is sent to waste via a diverter valve until it is fully removed. As the nature of the analyte retention continuously changes along the column and with time, we call this transient ion-pair separation (TIPS). As the IPR never enters the MS, TIPS addresses two major drawbacks of IPC for ESI-MS: it avoids both ion suppression and ion source contamination. The potential of the generic approach for other modes of separation is discussed. An illustrative separation of two small inorganic ions, iodate and nitrate, is demonstrated on a reverse phase column by a transient prior injection of hexadecyltrimethylammonium chloride as IPR.

Determination of oxadixyl in wines by liquid chromatography- tandem mass spectrometry: single-laboratory and interlaboratory validation study.

A direct injection LC/MS/MS method for the determination of the pesticide oxadixyl in wines was developed and validated. A sample divert valve was used to deliver the fraction that contained oxadixyl to the mass spectrometer's electrospray ionization source. Oxadixyl was monitored and quantitated using two transitions in multiple reaction monitoring mode. The method demonstrated recoveries of 99.2 ± 2.0 and 96.7± 5.2% for red and white wines, respectively, a linearity range of 2-20 μg/L, LOD at 0.7 μg/L, LOQ of 2.0 μg/L, and precision values of 8.2% (RSDr) and 6.2% (RSDR). Direct injection of the wine onto a C18 ultra-performance LC column allowed automation and high throughput screening. Benefits of this approach includeminimal sample preparation, short (3 min) run times, and the use of matrix-matched calibration standards, which minimize the matrix effect due to interferences from wine phenolics, sugars, and various other components. The method's performance characteristics were not statistically different for white and red wines. An additional interlaboratory validation study involved 12 laboratories and demonstrated gooddata agreement with HorRat values ranging from 0.23 to 0.52.

Optical‐Mechanical System for On‐Combine Segregation of Wheat by Grain Protein Concentration

Grain segregation by grain protein concentration (GPC) may help growers maximize revenues in markets that offer protein premiums. Our objective was to develop an on‐combine system for automatically segregating wheat (Triticum aestivum L.) by GPC during harvest. A multispectral optical sensor scans the grain as it is conveyed by the combine’s grain bin‐filling auger. Light from the optical probe is transmitted through a fiber optic cable to a spectrometer, which determines the spectral characteristics of the grain. This information is processed by the instrument control software that is programmed to calculate GPC from a chemometric model. The continuous GPC output is simultaneously fed to a binary computer algorithm for triggering a logic circuit and operating a mechanical diverter valve that diverts the grain into either one of two bins. Field tests of the system were conducted during harvest of hard red spring wheat using a Case IH 1470 combine modified with front and rear bins. Front and rear bins were compared in terms of the mean and frequency distribution of the optically sensed GPC. In addition, the grain in each bin was manually sampled and tested in the laboratory for GPC. Results showed that it is possible to use the GPC measured by an optical sensor to effectively control a mechanical diverter valve for routing the grain into one of two bins on a combine. An advantage of this approach is that prior knowledge of harvesting zones is not required.

Oil emulsion separation with fluidic oscillator generated microbubbles

Surfactants stabilise oil droplets in water, forming a dispersed oil–water emulsion. Treatment of oily effluents is a serious challenge owing to the high stability and colloidal nature of the oil droplets. In many applications, microbubbles are employed for separation purposes due to their buoyancy and increased surface area to volume ratio. This property has been exploited in the water treatment industry for separation in a process known as dissolved air flotation (DAF). Though practically efficient, the process is energy intensive operating at >5 bars and consequently consuming ∼90% of the total energy required in water purification plants. In this study microbubbles were produced by fluidic oscillation via a no-moving part diverter valve to cut down the energy consumption considerably. Microbubbles are applied for the separation of emulsified oil in a process known as microflotation. The mean bubble size generated by fluidic oscillation from the 50μm pore diffuser was ∼100μm, otherwise coarse bubbles were produced under steady flow. The effect of surfactant concentration on oil droplet size was investigated. It was found that oil droplet size varied inversely proportional to surfactant concentration. In addition, it was found that the oil removal efficiency also depends on the surfactant concentration. The maximum oil removal efficiency by Microflotation was found to be 91% under lowest surfactant concentration tested (0.3wt%) whilst at highest surfactant concentration used (10wt%); lowest recovery efficiency (19.4%) was recorded.

Direct pharmacokinetic analysis of puqietinone by in vivo microdialysis sampling and turbulent-flow chromatography coupled with liquid chromatography–mass spectrometry

Sample pretreatment is a key step in bioanalytical process because of possible interference and matrix effects in mass spectrometry analysis. In this work, a novel strategy towards high speed and sensitivity was developed combining in vivo microdialysis (MD) sampling, turbulent-flow chromatography (TFC), and liquid chromatography–mass spectrometry (LC–MS). The procedures of cleanup, preconcentration, and separation were completed on-line in one step within 10min. During the MD optimization procedure, 1% hydroxypropyl-β-cyclodextrin (HP-β-CD) was used to improve the relative recovery of the analyte. Untreated MD samples were directly injected, and a TFC precolumn was flushed for 1min with aqueous phase of 4mL/min flow rate to desalt and concentrate biosamples. The retained analytes were then back-flushed by a switching valve onto a fast LC column (4.6mm×50mm, 1.8μm) for separation. Another diverter valve was employed to prevent the HP-β-CD that interferes with the ESI process from entering the MS. Puqietinone, a lipophilic alkaloid from Fritillaria puqiensis, was used as a case for validation. Results showed that the limit of quantification for puqietinone was 0.10ng/mL, and good linearity (R2=0.9993) was maintained over the range of 1.02–200.02ng/mL. Accuracy and precision were satisfactory within the range of the standard curve. This approach was able to effectively eliminate the influences of matrix effect and carry-over as the injection volume increased up to 20μL. The developed method was successfully applied to pharmacokinetic study of puqietinone after intravenous administration to rat. Results demonstrate the potential of using MD with TFC-LC/MS for in vivo monitoring experiments.

Analysis of iodinated haloacetic acids in drinking water by reversed-phase liquid chromatography/electrospray ionization/tandem mass spectrometry with large volume direct aqueous injection

A large volume direct aqueous injection method was developed for the analysis of iodinated haloacetic acids in drinking water by using reversed-phase liquid chromatography/electrospray ionization/tandem mass spectrometry in the negative ion mode. Both the external and internal standard calibration methods were studied for the analysis of monoiodoacetic acid, chloroiodoacetic acid, bromoiodoacetic acid, and diiodoacetic acid in drinking water. The use of a divert valve technique for the mobile phase solvent delay, along with isotopically labeled analogs used as internal standards, effectively reduced and compensated for the ionization suppression typically caused by coexisting common inorganic anions. Under the optimized method conditions, the mean absolute and relative recoveries resulting from the replicate fortified deionized water and chlorinated drinking water analyses were 83–107% with a relative standard deviation of 0.7–11.7% and 84–111% with a relative standard deviation of 0.8–12.1%, respectively. The method detection limits resulting from the external and internal standard calibrations, based on seven fortified deionized water replicates, were 0.7–2.3ng/L and 0.5–1.9ng/L, respectively.

Optimization of solid-phase extraction and liquid chromatography–tandem mass spectrometry for the determination of domoic acid in seawater, phytoplankton, and mammalian fluids and tissues

We previously reported a solid-phase extraction (SPE) method for determination of the neurotoxin domoic acid (DA) in both seawater and phytoplankton by liquid chromatography–tandem mass spectrometry (LC–MS/MS) with the purpose of sample desalting without DA pre-concentration. In the present study, we optimized the SPE procedure with seawater and phytoplankton samples directly acidified with aqueous formic acid without addition of organic solvents, which allowed sample desalting and also 20-fold pre-concentration of DA in seawater and phytoplankton samples. In order to reduce MS contamination, a diverter valve was installed between LC and MS to send the LC eluant to waste, except for the 6-min elution window bracketing the DA retention time, which was sent to the MS. Reduction of the MS turbo gas temperature also helped to maintain the long-term stability of MS signal. Recoveries exceeded 90% for the DA-negative seawater and the DA-positive cultured phytoplankton samples spiked with DA. The SPE method for DA extraction and sample clean-up in seawater was extended to mammalian fluids and tissues with modification in order to accommodate the fluid samples with limited available volumes and the tissue extracts in aqueous methanol. Recoveries of DA from DA-exposed laboratory mammalian samples (amniotic fluid, cerebrospinal fluid, plasma, placenta, and brain) were above 85%. Recoveries of DA from samples (urine, feces, intestinal contents, and gastric contents) collected from field stranded marine mammals showed large variations and were affected by the sample status. The optimized SPE–LC–MS method allows determination of DA at trace levels (low pg mL −1) in seawater with/without the presence of phytoplankton. The application of SPE clean-up to mammalian fluids and tissue extracts greatly reduced the LC column degradation and MS contamination, which allowed routine screening of marine mammalian samples for confirmation of DA exposure and determination of fluid and tissue DA concentrations in experimental laboratory animals.

Bistable diverter valve in microfluidics

Bistable diverter valves are useful for a large number of no-moving-part flow control applications, and there is a considerable interest in using them also in microfluidics, especially for handling small pressure-driven flows. However, with decreasing Reynolds number, the Coanda effect—on which the flow diverting effect depends—becomes less effective. Authors performed a study, involving flow visualisation, PIV experiments, measurements of the flow rates, and numerical flowfield computations, aimed at clarifying behaviour of a typical fluidic valve at low Reynolds numbers. A typical fluidic valve originally developed for high Re operation was demonstrated to be useful, though with progressively limited efficiency, down to surprisingly low Re values as small as Re = 800. Also observed was a previously not reported discontinuation in the otherwise monotonic decrease in performance at Re between 1,500 and 2,000.

A rapid and quantitative LC-MS/MS method to profile sphingolipids

Sphingolipids comprise a highly diverse and complex class of molecules that serve not only as structural components of membranes but also as signaling molecules. To understand the differential role of sphingolipids in a regulatory network, it is important to use specific and quantitative methods. We developed a novel LC-MS/MS method for the rapid, simultaneous quantification of sphingolipid metabolites, including sphingosine, sphinganine, phyto-sphingosine, di- and trimethyl-sphingosine, sphingosylphosphorylcholine, hexosylceramide, lactosylceramide, ceramide-1-phosphate, and dihydroceramide-1-phosphate. Appropriate internal standards (ISs) were added prior to lipid extraction. In contrast to most published methods based on reversed phase chromatography, we used hydrophilic interaction liquid chromatography and achieved good peak shapes, a short analysis time of 4.5 min, and, most importantly, coelution of analytes and their respective ISs. To avoid an overestimation of species concentrations, peak areas were corrected regarding isotopic overlap where necessary. Quantification was achieved by standard addition of naturally occurring sphingolipid species to the sample matrix. The method showed excellent precision, accuracy, detection limits, and robustness. As an example, sphingolipid species were quantified in fibroblasts treated with myriocin or sphingosine-kinase inhibitor. In summary, this method represents a valuable tool to evaluate the role of sphingolipids in the regulation of cell functions.

New Procedure for the Determination of 3-Nitrotyrosine in Plasma by GC–ECD

A method suitable for the determination of 3-nitrotyrosine, a well known marker of nitro-oxidative stress, in plasma by GC–ECD has been investigated. After deproteinisation, SPE and LC separation, 3-nitrotyrosine was derivatised by a single-step procedure to the corresponding N-heptafluorobutyryl heptafluorobutyl ester and analysed. The precision and reliability of the procedure were assured by using 4-nitrophenylalanine as internal standard and a diverter valve to protect the detector. The method was applied to the analysis of volunteers’ plasma samples.

Determination of oxymatrine and its metabolite matrine in rat blood and dermal microdialysates by high throughput liquid chromatography/tandem mass spectrometry

Oxymatrine (OMT) and matrine (MT) are the major quinolizidine alkaloids found in certain Sophora plants, which have been extensively used in China for the treatment of viral hepatitis, cancer, cardiac diseases and skin diseases (such as atopic dermatitis and eczema). A precise, sensitive and high throughput LC–MS/MS was developed to determine OMT and its metabolite MT in rat blood and dermis collected using microdialysis technique. Microdialysis probes were inserted into the jugular vein/right atrium and dermis of Wistar rats, and 3% OMT gel (1 g) was administered via topical application. The samples were collected and then injected into the LC–MS/MS system after adding the internal standard (codeine, CDN). Chromatographic separation was achieved in a run time of 2 min on a reversed phase short-column (50 mm × 2.1 mm, 3.5 μm). The mobile phase for column separation was methanol–ammonium formate (pH 5.0; 25 mM) (70:30, v/v) with a flow rate of 0.3 mL/min. A diverter valve was installed post-LC column for desalting. Detection of analytes and IS was done by tandem mass spectrometry, operating in positive ion and multiple reaction monitoring (MRM) acquisition mode. The protonated precursor to product ion transitions monitored for OMT, MT and IS was m/ z 265.0 → 247.3, 249.1 → 148.3 and 300.0 → 215.2, respectively. The lower limit of quantification (LLOQ) for OMT and MT was 0.5 ng/mL. The calibration curves were linear over the range of 0.5–1000 ng/mL for OMT and MT with a coefficient of determination >0.999. This selective and sensitive method is useful for the determination of OMT and MT and in the pharmacokinetic studies of these compounds. The blood and dermal concentration–time profile of OMT and its metabolite MT suggest that the limiting factor for dermal metabolism is the low capacity of enzymes in the skin rather than the quantity of penetrated OMT.

Multiclass analysis of illicit drugs in plasma and oral fluids by LC-MS/MS

An analytical procedure for the simultaneous determination in human plasma and oral fluids of several illicit drugs belonging to different chemical and toxicological classes is presented. Amphetamine, methamphetamine, morphine, 6-monoacetylmorphine, methylenedioxyamphetamine, methylenedioxyethylamphetamine, methylenedioxymethamphetamine, cocaine, benzoylecgonine, tetrahydrocannabinol, carboxytetrahydrocannabinol, ketamine, and phencyclidine have been quantified in real samples using a very rapid sample treatment, basically a protein precipitation. The quantitative analysis was performed by liquid chromatography-tandem mass spectrometry and has been fully validated. All the analytes were detected in positive ionization mode using a TurboIonSpray source, except carboxytetrahydrocannabinol, which was detected in negative ionization mode. The use of a diverter valve between the column and the mass spectrometer allows the preservation of the ion source performances for high-throughput analysis.

Thermal Load Control Methods for the HTTR-IS Nuclear Hydrogen Production System

One of the key technology requirements to achieve the non-nuclear-grade hydrogen plants coupled to the HTTR is the development of control methods mitigating the effect of IS process-abnormal thermal load transients on the reactor operation. This study focused on developing the control methods for the thermal mitigation system in the HTTR-IS system. The control methods are developed to stabilize the steam generator helium gas outlet temperature increase against the high-temperature helium gas inflow. The key parameters and equipment are determined and the control operations are simulated. The simulation results show that the steam generator water temperature can be effectively decreased by interfacing the actuation of the air cooler inlet shut-off valve with the actuation of the diverter valve. Furthermore, the air cooler outlet shut-off valve is activated as the pressure difference approaches zero between the steam generator bottom and the down comer from the air cooler to the steam generator. It is demonstrated that the control methods developed enable the continuation of the nuclear reactor normal operation under IS process abnormal conditions and without operator intervention.