Piezometric pressure measurements for water flow in a pipe with electrified inner surface

A novel approach to pipe flow improvement is presented on the basis of positive electric voltages applied to the pipe. The flow improvement is measured by piezometry. A common problem, connected with all forms of transport of fluids in pipes, is loss of pressure due to the friction, i.e. piezometric pressure loss. If the friction depends upon the fluid and surface interaction, which is of electric origin, then the question is whether it is possible to decrease the friction at the pipe wall by controlling the electric potential between the fluid and the pipe wall. A verification study is carried out in a 13.1 m slanting epoxy-coated pipe made of black steel, through which water flows. The measured piezometric pressure drop over the pipe under no-applied-voltage conditions is 357 mm of water. The results show a decrease in the piezometric pressure loss over the pipe when electric voltages of 0.6–1.6 V are applied between the pipe and a counterelectrode made of stainless steel (with positive end on the pipe). Maximum reduction is 7 mm of water at an applied voltage of 1.0 V (0.379 V vs. Ag|AgCl|KCl_sat reference electrode for the pipe at the pipe inlet). As a positive voltage applied to the pipe polarizes its coated inner surface contacting water, the results indicate that the observed pressure loss reduction effect is related to changes in the properties of interfacial water layer between the coated inner surface and the bulk water. Published in Russian in Elektrokhimiya, 2006, Vol. 42, No. 12, pp. 1478–1483. Based on the report delivered at the 8th International Frumkin Symposium “Kinetics of the Electrode Processes,” October 18–22, 2005, Moscow. The text was submitted by the authors in English.     

Flow pattern maps for particle-fluid mixture transport in a horizontal pipe - application of a three-layer model

A modified three-layer model was applied to model particle-fluid mixture flow in a horizontal pipe, the viscoelastic properties of carrier polymer solution were taken into consideration, and the Deborah number was used to calculate solid-fluid friction factor. An energy equation was applied to determine temperature distribution of carrier fluid along a horizontal pipe to accurately represent the rheological properties of carrier fluid. During the transport process, particles quickly settle out of carrier fluid and accumulate on pipe bottom forming a particle bed, so a particle bed load flow is observed. The transport mechanisms of particles in moving particle bed are govern by fluidization, which causes the height of this layer to be small and equal to 2～5 times of particle diameter. In addition, the pressure drop is composed of solid-fluid and solid-solid friction loss, which dominate the hydrodynamic performance at different stages.     

Lifetime prediction of a blue PE100 water pipe

The traditional method to assess the lifetime of plastic pipes is based on hydrostatic pressure testing. A complementary approach has been conducted to monitor the depletion of antioxidants and initiation of thermo-oxidative degradation on a PE100 blue water pipe that had been exposed to hydrostatic pressure in water at low test temperatures (maximum 80 °C).Depletion of antioxidants was monitored using OIT testing and initiation of thermo-oxidative degradation was assessed by iodometric detection of hydroperoxides. An empirical model based on the Arrhenius fit of the data was developed to extrapolate the lifetime of the PE100 pipe material at various service temperatures (10-25 °C). Associated activation energies, E_a, were determined and appeared to be in line with the values obtained from experiments carried out at low test temperatures. The combination of pressure testing and chemical analyses proved to be a very powerful tool to extrapolate the lifetime of plastic pipes.     

The Influence of Corona Electrodes Thickness on the Efficiency of Plasmachemical Oxidation of Acetone

Current–voltage characteristics (CVC) and acetone vapors oxidation in atmospheric pressure corona discharge (CD) of negative and positive polarity were studied in double wires-to-plate geometry. Negative CD was more stable than positive one towards breakdown and allowed to reach higher current. CVC for negative CD can be well described by model for cylindrical geometry with correction in one coefficient only. The ignition voltage of negative CD obeys Peek’s law. The rate of acetone vapors oxidation increased with the increase of corona wire radius in the range of discharge power 15–60 W. The highest oxidation rate was obtained at power 60 W, negative polarity and wire radius 400 μm but the highest energetic efficiency (g/kWh) was obtained at maximum wire radius (400 μm) and minimum power level (15 W). The oxidation rate was directly proportional to the volume of discharge area which grows together with the increase of wire radius.     

Effect of pressure on solute capacity factor in HPLC using a non-porous stationary phase

Summary The pressure applied in liquid chromatography (LC) can influence the capacity factor of analytes. Using commercial equipment, column (33×4.6 mm) and 1.5 μm non-porous, tetradecyl (C₁₄) coated silica particles, a moderate but significant change in the capacity factor was observed with increasing pressure. Depending on the experimental conditions the relationship was found to be either linear or non-linear. In the latter case the retention increased at first, but later tended to decrease at still higher pressure. The results direct attention to the role of the pressure (and hence of flow rate and heat of friction) in determining capacity factors. Presented at Balaton Symposium on High Performance Separation Methods, Siófok, Hungary, September 1–3, 1999     

Classifying formulations of crosslinked polyethylene pipe by applying machine‐learning concepts to infrared spectra

Crosslinked polyethylene (PEX‐a) pipes are emerging as promising replacements for traditional metal or concrete pipes used for water, gas, and sewage transport. Understanding the relationship between pipe formulation and performance is critical to their proper design and implementation. We have developed a methodology using principal component analysis (PCA) and the machine learning techniques of k‐means clustering and support vector machines (SVM) to compare and classify different PEX‐a pipe formulations based on characteristic infrared (IR) spectroscopy absorbance peaks. The application of PCA revealed that a large percentage (89%) of the total variance could be explained by the first three principal components (PC1‐PC3), with distinct clustering of the data for each formulation. By examining the contribution of the individual IR bands to the PCs, we determined that PC1 could be attributed to different peroxide crosslinkers, whereas PC2 and PC3 could be attributed to differences in the additives. Using the PCA results as input to k‐means clustering and SVM resulted in very high accuracy of classifying the different pipe formulations. Our approach highlights the advantages of using PCA and machine learning techniques to characterize different formulations of PEX‐a pipes, which is important to achieve a detailed understanding of the pipe formulation and manufacturing process. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019 , 57, 1255–1262     

Capillary electrophoresis-atmospheric pressure chemical ionization-mass spectrometry using an orthogonal interface: Set-up and system parameters

The feasibility of atmospheric pressure chemical ionization (APCI) as an alternative ionization technique for capillary electrophoresis-mass spectrometry (CE-MS) was investigated using a grounded sheath-flow CE-MS sprayer and an orthogonal APCI source. Infusion experiments indicated that highest analyte signals were achieved when the sprayer tip was in close vicinity of the vaporizer entrance. The APCI-MS set-up enabled detection of basic, neutral, and acidic compounds, whereas apolar and ionic compounds could not be detected. In the positive ion mode, analytes could be detected in the entire transfer voltage range (0–5 kV), whereas highest signal intensities were observed when the corona discharge current was between 1000 and 2000 nA. In the negative ion mode, the transfer voltage typically was 500 V and the optimum corona discharge current was 6000 nA. Analyte signals were raised with increasing nebulizing gas pressure, but the pressure was limited to 25 psi to avoid siphoning and current drops. Signal intensities appeared to be optimal and constant over a wide range of sheath liquid flow rate (5–25 μL/min) and vaporizer temperature (200–350 °C). APCI-MS signals were unaffected by the composition of the background electrolyte (BGE), even when it contained sodium phosphate and sodium dodecyl sulfate (SDS). Consequently, BGE composition, sheath-liquid flow rate, and vaporizer temperature can be optimized with respect to the CE separation without affecting the APCI-MS response. The analysis of a mixture of basic compounds and a steroid using volatile and nonvolatile BGEs further demonstrates the feasibility of CE-APCI-MS. Detection limits (S/N = 3) were 1. 6–10 μM injected concentrations.     

Improved sintering and electrical properties of La-doped CeO<Subscript>2</Subscript> buffer layer for intermediate temperature solid oxide fuel cells using doped LaGaO<Subscript>3</Subscript> film prepared by screen printing process

Effects of a sintering agent for La-doped ceria (LDC) as a buffer layer to prevent a chemical reaction between Ni in anode and Sr- and Mg-doped lanthanum gallate (LSGM) electrolyte during sintering were studied for improving sintering and electrical properties. Electrochemical performance of anode-supported solid oxide fuel cells (SOFCs) using LDC and LSGM films prepared by screen printing and co-sintering (1,350 °C) was also investigated. The prepared cell with dense LDC (ca. 17 μm) and LSGM electrolyte (ca. 60 μm) films showed an open circuit voltage close to the theoretical value of 1.10 V and a high maximum power density (0.831 W cm^–2) at 700 °C. The addition of 1 wt.% LSGM to porous LDC buffer layer was effective for improving the sintering density and electrical conductivity, resulting in the high power density due to the decreased internal resistance loss.     

Determination of the long-term hydrostatic strength of multilayer pipes

In this paper, a new methodology for prediction of the long-term (creep rupture) behavior of multilayer pipes under internal hydrostatic pressure is presented. For this purpose, a procedure using the three dimensional theory of thick-walled multilayer pipes together with a combined quadratic/linear regression analysis is used. The theory of thick walled tubes is used to assess the role of each layer in carrying the internal pressure and also the onset of the creep rupture in the composite pipe. For long-term extrapolation, a combined quadratic and linear regression analysis was used and the contribution of each component to the long-term strength of the composite pipe was quantitatively assessed. Using this procedure, the layer at which the creep rupture under internal pressure first initiates would be identified and the additional capacity of the remaining layer would be quantitatively assessed. This procedure is already incorporated in the pipe software called ADAP dealing with the automated design and analysis of pipelines. An example showing this procedure using ADAP is presented. The proposed methodology overcomes the limitations in the existing testing and extrapolation standards and, thus, can be used as a new extrapolative procedure for prediction of the service life of multilayer plastic pipes and pipe fittings. As particular applications, the procedure can be used for the estimation of the long-term behavior of multilayer pipes with metallic inter-layers and also single layer as well as structured pipes.     

Deterioration of polyethylene pipes exposed to water containing chlorine dioxide

Chlorine species used as disinfectants in tap water have a deteriorating effect on many materials including polyethylene. There are only very few scientific reports on the effect on polyethylene pipes of water containing chlorine dioxide. Medium-density polyethylene pipes stabilized with hindered phenol and phosphite antioxidants were pressure tested with water containing 4 ppm chlorine dioxide at 90 °C and pH = 6.8 as internal medium. The stabilizers were rapidly consumed towards the inner pipe wall; the rate of consumption was four times greater than in chlorinated water (4 ppm, pH = 6.8) at the same temperature. The depletion of stabilizer occurred far into the pipe wall. A supplementary study on a polymer analogue (squalane) containing the same stabilizer package showed that the consumption of the phenolic antioxidant was 2.5 times faster when exposed water containing chlorine dioxide than on exposure to chlorinated water. The subsequent polymer degradation was an immediate surface reaction. It was confirmed by differential scanning calorimetry, infrared spectroscopy and size exclusion chromatography that in the surface layer which came into contact with the oxidising medium, the amorphous component of the polymer was heavily oxidized leaving a highly crystalline powder with many carboxylic acid chain ends in extended and once-folded chains. Scanning electron microscopy showed that propagation of cracks through the pipe wall was assisted by polymer degradation.     

Chemical and physical analysis of cotton fabrics plasma-treated with a low pressure DC glow discharge

This paper focuses on the modification of cotton fabrics using a low pressure DC glow discharge obtained in air. The influence of different operating parameters such as treatment time, discharge power and operating pressure on the chemical and physical properties of the cotton fabrics is studied in detail. Surface analysis and characterization of the plasma-treated cotton fabrics is performed using vertical wicking experiments, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and weight loss measurements. The cotton fabrics show a significant increase in wicking behaviour; an effect which increases with increasing treatment time, increasing discharge power and increasing pressure. Results also show that low pressure DC glow treatment leads to surface erosion of the cellulose fibres, accompanied by an incorporation of oxygen-containing groups (C–O, C=O, O–C–O and O–C=O) on the cotton fibres. The DC glow treatment has thus the potential to influence not only the chemical but also the physical properties of cotton fabrics and this without the use of water or chemicals.     

<Emphasis Type="Italic">E. coli</Emphasis>, <Emphasis Type="Italic">P. aeruginosa</Emphasis>, and <Emphasis Type="Italic">B. cereus</Emphasis> Bacteria Sterilization Using Afterglow of Non-Thermal Plasma at Atmospheric Pressure

We developed and employed a new geometrical structure of dielectric barrier discharge in atmospheric pressure for bacterial broad spectrum sterilization. We utilized a plasma source having an AC power supply at 50 HZ and 5,400 V (rms value). We prepared suspensions of the Gram-negative bacteria species (Escherichia coli, Pseudomonas aeruginosa) and a Gram-positive of Bacillus cereus with Luria–Bertani broth media up to OD_600 nm = 0.25 of McFarland standard. Afterglow of non-thermal atmospheric pressure plasma treated these suspensions. The influence of the atmospheric plasma afterglow on the species was assayed in different time durations 5, 10, and 15 min. The spectroscopic results of this investigation indicated that the survival reduction of the species can reach to 100% for P. aeruginosa in an exposure time of 10 min, E. coli and B. cereus in an exposure time of 15 min.     

Investigations on analyte losses in systems suited for large-volume on-column injections

Summary Use of a large-volume injection system with a solvent vapour exit (SVE) requires optimisation. An appropriate strategy is to determine the evaporation rate by increasing the injection time at a fixed injection speed, injection temperature and head pressure. When measuring the flow rate in the carrier gas supply line to the on-column injector, optimisation can be very rapid: some five injections of pure solvent will be sufficient. When working under partially concurrent solvent evaporation conditions, loss of volatiles is often observed if no retaining precolumn is used between the retention gap and the SVE. To investigate the requirements (length and stationary phase) of the retaining precolumn, C8–C18n-alkanes inn-hexane were used. The minimum length of the retaining precolumn (0.32 mm diameter) needed to prevent substantial losses of volatiles was 2 m. Experiments with retaining precolumns with and without stationary phase gave identical results. This shows that there is no need to coat the capillary as it only acts as a restrictor.     

The appearance of electrification of hydrocarbons flowing in a tube

The appearance of a substantial potential difference in a dielectric liquid (∼1000 V) flowing through a tube 6 mm in diameter was observed using metallic electrodes situated along the flow. The effect was called hydroelectric. According to the oscillograms obtained, the electric signal was high-frequency, could not be synchronized, and the potential difference between the entrance and exit of the capillary reached 200 V for positive pulses and 700 V for negative pulses. The potential difference decreased as the temperature of the liquid increased to 30–35°C and hydrostatic upthrust grew. A mechanism of the appearance of potential difference based on the predominant role played by electrokinetic phenomena was developed.     

Volumetric and Viscosimetric Measurements for Methanol + CH 3 –O–(CH 2 CH 2 O) n –CH 3 ( n = 2, 3, 4) Mixtures at (293.15–303.15) K and Atmospheric Pressure: Application of the ERAS Model

Densities, $$\rho$$, and kinematic viscosities, $$\nu$$, have been determined at atmospheric pressure and at 293.15–303.15 K for binary mixtures formed by methanol and one linear polyether of the type CH3–O–(CH2CH2O)n–CH3 (n = 2, 3, 4). Measurements on $$\rho$$ and $$\nu$$ were carried out, respectively, using an Anton Paar DMA 602 vibrating-tube densimeter and an Ubbelohde viscosimeter. The $$\rho$$ values were used to compute excess molar volumes, $$V_{{\text{m}}}^{{\text{E}}}$$, and, together with the $$\nu$$ results, dynamic viscosities ($$\eta$$). Deviations from linear dependence on mole fraction for viscosity, $$\Delta \eta$$, are also provided. Different semi-empirical equations have been employed to correlate viscosity data. Particularly, the equations used are the: Grunberg–Nissan, Hind, Frenkel, Katti–Chaudhri, McAllister and Heric. Calculations show that better results are obtained from the Hind equation. The $$V_{{\text{m}}}^{{\text{E}}}$$ values are large and negative and contrast with the positive excess molar enthalpies, $$H_{{\text{m}}}^{{\text{E}}}$$, available in the literature, for these systems. This indicates that structural effects are dominant. The $$\Delta \eta$$ results are positive and correlate well with the difference in volumes of the mixture compounds, confirming the importance of structural effects. The temperature dependences of $$\eta$$ and of the molar volume have been used to calculate enthalpies, entropies and Gibbs energies, $$\Delta G^{*}$$, of viscous flow. It is demonstrated that $$\Delta G^{*}$$ is essentially determined by enthalpic effects. Methanol + CH3–O–(CH2CH2O)n–CH3 mixtures have been treated in the framework of the ERAS model. Results for $$H_{{\text{m}}}^{{\text{E}}}$$ are acceptable, while the composition dependence of the $$V_{{\text{m}}}^{{\text{E}}}$$ curves is poorly represented. This has been ascribed to the existence of strong dipolar and structural effects in the present solutions.     

Effect of flow rate on the sorption breakthrough behaviors of uranium(VI), phosphate,and fulvic acid onto a silica column

Five column experiments have been carried out to investigate the effect of flow rate on the breakthrough curves (BTCs) of phosphate, fulvic acid, and uranium(VI) onto a silica column. Both BTCs of phosphate and fulvic acid, and three BTCs of uranium(VI) in the presence and absence of phosphate or fulvic acid at high flow rate published in the previous paper [1] were compared with corresponding initial parts of BTCs at low flow rate in this paper. Each BTC in this paper was expressed as both C/C_o–t and C/C_o–V/V_o plots, where C and C_o are the concentrations in the influent and the effluent respectively, t and V are the time and the effluent volume from the start of injection of pulse solution respectively, V_o is the pore volume of the SiO₂ column. Based on the experimental results and the relationship among V, t, and flow rate F, it was found that there are advantages to using C/C_o–V/V_o plot as BTC to study the effect of flow rate. Based on these comparisons of C/C_o–V/V_o plots at different flow rates and the theoretical analysis from the Bohart–Adams sorption model, it was found that the right shift (increase in V/V_o of breakthrough), the left shift (decrease in V/V_o of breakthrough), and the non-shift (non-change in V/V_o of breakthrough) of initial parts of BTCs with increasing flow rate are certain to occur instead of only left shift and that three different trends of shifts can be mainly attributed to different rate-controlling mechanisms of sorption process.     

Effects of thermal ageing on mechanical and thermal behaviors of linear low density polyethylene pipe

The mechanical and thermal behaviors of linear low density polyethylene (LLDPE) pipe with variation in thermal exposure time were studied. The prolongation of thermal exposure time leads to a progressive increase, until 6000 h, in tensile strength and a slight increase in hardness, while a proportional decrease in elongation at break. These results can be explained by the increase of crystallinity, followed by the increase of crosslinking density and the decrease in chain mobility due to thermal oxidation as the exposure time increases. The additional ageing to the antioxidant-depleted LLDPE pipe induces the formation of T2 endotherm, which leads to a negative effect in mechanical properties. Long-term hydrostatic pressure test result implies the existence of transition point from ductile to brittle fracture in terms of the thermal exposure time. Chemiluminescence (CL) and oxidation induction time (OIT) tests are employed to monitor the thermo-oxidative degradation of LLDPE pipe. The CL emission intensity increases with increasing with thermal exposure time. Furthermore, the OIT result suggests that after 6000 h of the thermal ageing, the depletion of antioxidant originally added in LLDPE pipe occurs. Fourier transform-infrared spectroscopy results show the increase of carbonyl (-CO) and hydroxyl (O-H) function groups on the surface of thermally exposed LLDPE pipe. This result suggests that the hydrocarbon groups locally undergo the oxidation on the LLDPE surface due to thermal degradation.     

NMR imaging of polyethylene pipes

¹H nuclear magnetic resonance (NMR) imaging techniques have been used to image the extrusion aid (EA) in polyethylene (PE) pipe samples. The resulting two-dimensional images show the distribution of EA within the pipe. EA is found to be uniformly distributed in a normal pipe. Examples of degraded pipes, due to exposure to extreme conditions, show migration of EA to the pipes' wall surfaces. NMR images of a normal pipe and two examples of damaged pipes are presented. The imaging technique and the results are discussed. © 1995 John Wiley & Sons, Inc.     

Influence of the Plasma Chemistry on the Composition of ZrOx and NbOx Thin Films Deposited by Reactive Magnetron Sputtering

The plasma chemistry of magnetron sputtered Zr and Nb in an Ar/O₂ atmosphere has been measured as a function of the O₂ partial pressure. The previously reported composition of films deposited onto grounded non-intentionally heated substrates was correlated with the dominant positive and negative ion populations in the plasma. While the oxygen deficient films were grown in the Ar⁺ dominant mode, the close-to-stoichiometric films were grown in the O⁺/O⁻ dominant mode. The formation of close-to-stoichiometric ZrO_2.1 is observed in the compound mode (CM), while the formation of close-to-stoichiometric Nb₂O_4.7 thin films was reported in addition to the CM also in the transition mode (TM). This may be understood based on the 1.5–1.9 times higher power dissipated in the Nb–Ar–O₂ plasma as compared to the Zr–Ar–O₂ plasma. We suggest that at larger power O₂ dissociation may be more efficient and lead to the presence of sufficient atomic oxygen to fully oxidize the films. This finding may provide a pathway towards a deposition rate enhancement, since compound formation at the substrate is enabled in the TM of the higher power Nb–Ar–O₂ plasma and not only in the CM, as in the case of the lower power Zr–Ar–O₂ plasma.     

Quantitative analysis of eletriptan in human plasma by HPLC-MS/MS and its application to pharmacokinetic study

Authors developed a simple, sensitive, selective, rapid, rugged, and reproducible liquid chromatography–tandem mass spectrometry method for the quantification of eletriptan (EP) in human plasma using naratriptan (NP) as an internal standard (IS). Chromatographic separation was performed on Ascentis Express C18, 50 × 4.6 mm, 2.7 μm column. Mobile phase was composed of 0.1% formic acid: methanol (40:60 v/v), with 0.5 mL/min flow rate. Drug and IS were extracted by liquid–liquid extraction. EP and NP were detected with proton adducts at m/z 383.2→84.3 and 336.2→97.8 in multiple reaction monitoring (MRM) positive mode, respectively. The method was validated with the correlation coefficients of (r ²) ≥ 0.9963 over a linear concentration range of 0.5–250.0 ng/mL. This method demonstrated intra- and inter-day precision within 1.4–9.2% and 4.4–5.5% and accuracy within 96.8–103% and 98.5–99.8% for EP. This method is successfully applied in the bioequivalence study of 24 human volunteers.