Glass Pipe Research Articles

Pharmacological effects of methamphetamine and other stimulants via inhalation exposure

The effects of methamphetamine–HCl, methcathinone–HCl, cocaine and ephedrine on locomotor stimulation were compared between inhalation exposure and i.v. injection in mice. Methamphetamine–HCl was readily volatilized upon heating at 300°C in a glass pipe with only trace amounts of amphetamine being produced. The ED50 dose (9.4 and 6.5 μmol/kg for inhalation exposure and i.v. injections, respectively) and biodisposition of methamphetamine–HCl were similar for both routes of administration. Methcathinone–HCl and cocaine were readily volatilized. Their dose response profiles also appeared similar for both routes of administration. Ephedrine did not appear to be easily volatilized and was only effective in stimulating locomotor activity after i.v. administration. These findings indicate that inhalation exposure to methamphetamine–HCl, cocaine and methcathinone possess similar pharmacological characteristics as the i.v. route of administration. In particular, this model may have implications in predicting the pharmacological activity of various stimulants via the inhalation route of administration.

Untersuchung komplexer Strömungen mit MRA-Techniken und Vergleich mit theoretischen Strömungsanalysen

In this methodological paper we investigate the systematic loss of MR signals due to complex flow conditions subsequent to a stenosis in comparative phantom studies with different flow optimized imaging sequences. To understand the hemodynamic effects on the MR signal's behaviour, numerical flow analysis was calculated in two dimensions referred to the incompressible Navier-Stokes equation. Based on the calculated data the experimental results could be simulated.To generate complex flow conditions in a model situation, a flow phantom was constructed with water flowing through glass pipes with strictures of different diameters. The signal of the flowing fluid was acquired using FLASH sequences either with or without flow compensation. The investigations were carried out under variation of the echo time on two tomographs with different gradient system performance.The experiments as well as the numerical simulations of the measurements show that the signal loss due to stationary and non stationary current vortices can be reduced significantly by using flow-compensated sequences. The images acquired with sequences without flow compensation show a strong dependence on the signal loss from the echo time even with constant gradient duration which is induced by instationary flow conditions.

A New Method for Fabrication of Functionally Gradient Materials

Functionally gradient materials (FGM) are a new kind of composite material, which were introduced as the thermal barrier materials of spacecraft, and have been found to be of great use as medical materials, electronic materials, nuclear energy materials, etc. Design and techniques of fabrication are the foundation of FGM and its applications. Up to now, a great many means have been developed to obtain functionally gradient materials [1, 2]: chemical vapor deposition (CVD), physical vapor deposition (PVD), plasma spraying (PS), self-propagating high temperature synthesis (SHS), and powder metallurgy (PM). In these processes, the powder metallurgy has been researched by many investigators and is considered to be one of the promising methods for fabricating large size FGM samples. In current powder metallurgy processes, however, the gradient of composition and=or structure is formed by the stage ®lling. According to the composition gradient designed, mix the two powders used to prepare the sample of functionally gradient material into several compositions, and tier the powders in a compacting tool set, and then compact and sinter it to obtain the gradient material. It is clear that the distribution of composition in the samples prepared by the stage ®lling process is not continuous, and there are some interfaces of step change in composition in it. Therefore, the powder metallurgy method by stage ®lling is not only dif®cult for operation but also inadequate for thermal stress relief. This paper reports a new process, co-sedimentating method for fabrication of functionally gradient materials, by which the continuous distribution of composition can be formed, and the gradient layer of free size and free thickness can be prepared. It is well known that the sedimentating behavior of powder in a liquid can be discussed by the Stokes equation. The sedimentating velocity of a powder particle in a liquid medium is mainly dependent on the size and density of the particle. When a kind of powder sedimentates, the particles of larger size have greater velocities. When two (or more than two) kinds of powders sedimentate together, the particles of larger size or=and larger density sedimentate more quickly. Accordingly, a deposit layer with a continuous change in composition can be obtained by the co-sedimentation of two kinds of powders through conditioning the parameters of sedimentation (the density and viscidity of the liquid medium used for sedimentating, the sedimentating height, etc.), the size, and the size distribution of the powders. In this paper, a functionally gradient material of metal=ceramics is fabricated by the co-sedimentation of metal and ceramics powders in ethanol. The ceramics powder is the 3 mol % yttria partially stabilized ZrO2(3Y-PSZ) powder of particle size 0.3 im, which has been granulated into the particle size 30 im. The stainless steel powder is Japanese SUS 316 powder, whose particle size is 8 im. The concentrations of the 3Y-PSZ and SUS 316 in the ethanol are 45 3 10y3 g=ml and 90 3 10y3 g=ml, respectively. The sedimentation was carried out in a glass pipe of internal diameter 40 mm, and length 200 mm. After drying and compacting (150 MPa), the deposit layers were sintered at 1300 8C for 1 h in argon atmosphere to obtain the samples of SUS 316=3Y-PSZ gradient material. The optical microscope and the graphical analysis instrument were used to observe the microstructure and measure the distribution of composition. The samples of SUS 316=3Y-PSZ functionally gradient material prepared by the process described in this paper are disks of diameter 33 mm and thickness 2±5 mm. Fig. 1 shows the microstructure of the cross-section in a sample of thickness 3.5 mm (black PSZ, white stainless steel). The distribution curve of composition is shown in Fig. 2, which is measured by a graphical analysis instrument. It can be seen from Fig. 1 that a compactive structure and good interface binding between stainless steel and ceramics have been obtained after sintering. Both the microstructure and the distribution curve of composition show a continuous distribution of composition in the sample. It is important and necessary for thermal stress relief and property design that the composition distribution (gradient) in functionally gradient materials can be designed and conditioned. In the cosedimentating method, the composition distribution (gradient) can be controlled by the properties (particle sizes and distributions) of the two powders and the conditions for sedimentating (the density and viscidity of the liquid used as the sedimentating medium, the sedimentating height, and the contents of two powders, etc.). If the sedimentating behaviors of the two powders do not interfere together and a

Stability of Annular Liquid Film in Microgravity.

Behavior of gas and liquid was observed during the experiments, where a horizontally oriented closed glass pipe filled with air and well-wetting liquid was suddenly set in microgravity using a drop shaft facility. Just after it was set in microgravity, the liquid first crept up the inner surface of the pipe to form a liquid film and then broke into a number of groups to form liquid plugs with a nearly equal spacing. The mechanism of this interesting behavior was explained by the linear stability analysis of an annular liquid film, where the average pitch of these liquid plugs agreed well with the most-dangerous wavelength of disturbance obtained by the analysis. The theory was also checked by the microgravity experiment for an annular downward film flow as a initial condition in normal gravity.

Gas-liquid flow in slightly inclined pipes

The modified apparent rough surface (MARS) model is presented, which facilitates prediction of liquid holdup and pressure gradient in gas-liquid flow through horizontal and slightly sloping pipes. The model is based on two steady-state, one-dimensional momentum balance equations, which include the superficial velocities and transport properties of gas and liquid, the diameter of the pipe and its angle from the horizontal. Separate correlations are proposed for the interfacial friction factor f i , the liquid-to-wall friction factor f L , the interfacial perimeter S i and the wetted perimeter S L . Predicted values of liquid holdup and pressure gradient are verified against results of 2400 carefully performed, laboratory experiments in horizontal and sloping glass pipes (−3 ≤ β ≤ +6°) of 15, 26 and 51 mm diameter. The liquid holdup ϵ L ranges from 0 to 0.42, and the superficial liquid velocity u LS from 0 to 0.06 m s −1 and the superficial gas velocity u GS from 1.8 to 34 m s −1. The gas-liquid systems used are air/water and air/tetradecane ( n-C 14H 30) at atmospheric pressure and room temperature. Significant effects of small inclination angles were found at low gas flow rates, leading to an eightfold increase in liquid holdup and more than a fourfold increase in pressure gradient compared to horizontal flow. Nevertheless, the average relative error in the prediction of liquid holdup and pressure gradient is less than 10%.

1/fαdensity fluctuation at the slugging transition point of granular flows through a pipe

By changing the packing rate of metallic spheres inside a pipe, we experimentally investigated a density fluctuation of metallic spheres that fall through a vertical glass pipe filled with liquid. We found that only at the intermediate packing rate p\ensuremath{\sim}0.18 the power spectrum of the density fluctuation of falling metallic spheres P(f) obeys a power law as P(f)\ensuremath{\sim}1/${\mathrm{f}}^{\mathrm{\ensuremath{\alpha}}}$, where f is a frequency and \ensuremath{\alpha} is a positive constant. This intermediate packing rate corresponds to a slugging transition point from the low-packing-rate region where metallic spheres fall almost freely to the high-packing-rate region where density waves (slugs of granular materials) emerge and so metallic spheres fall in a group very slowly. We also compare our experimental results with the jamming transition and the 1/f noise that appear in a crowded traffic flow.

Pharmacological potency and biodisposition of phencyclidine via inhalation exposure in mice

The purpose of the present study was to characterize the pharmacological effects and biodisposition of phencyclidine (PCP) following inhalation exposure to mice. Results from these studies indicate that PCP was easily volatilized when heated in a glass pipe. Volatilization was efficient with no significant formation of pyrolytic products. Exposure to the volatilized PCP resulted in a dose-dependent impairment in motor performance in both the rotorod and inverted-screen tests. PCP was equally effective in disrupting performance on the inverted-screen and rotorod with ED 50 values corresponding to the volatilization of 10.7 and 13.2 μmol, respectively. The time courses were comparable to those produced following intravenous (i.v.) administration of PCP. In order to determine the dose of drug absorbed by inhalation, mice were exposed to [ 3H]-PCP. The ED 50 values of PCP following i.v. administration were 4.1 and 6.2 μmol/kg in the inverted screen and rotorod, respectively. The biodisposition of PCP following inhalation exposure was similar to that after i.v. injections. At doses that produced approximately 50% of the maximum motor impairment by either administration route, higher ratios of the total drug equivalents were found following i.v. injection than that after inhalation, with the brain/plasma ratios of 1.3 ± 0.2 versus 0.58 ± 0.02, and brain/body ratios of 0.59 ± 0.06 versus 0.35 ± 0.1 for i.v. and inhalation, respectively. However, the brain/plasma ratios of the concentrations of PCP were similar, 1.1 versus 0.9. The body concentration of PCP equivalents that produced 50% of the maximum effect after inhalation was 4.7 ± 0.6 μmol/kg. These results indicate that inhalation of PCP produces a similar pharmacological profile to that of i.v. administration and suggest that the drug is equipotent by these two administration routes. Moreover, these findings are consistent with the observation that smoking is becoming the most common route of administration among drug users.

Self-organized critical density waves of granular particles flowing through a pipe

Density waves of granular material which flows through a pipe have been investigated. Granules (mainly sand) were drained from a hopper through a vertical glass pipe. The flow looked intermittent over the length of the pipe except for the uppermost part where the granules streamed smoothly and homogeneously from the hopper aperture. Transmission light intensity across the pipe was measured as time-series signals. The FFT power spectra were found to change from white-noise-like form to a stable and robust power-law form of 1/fα with α≊1.5 as the measuring position was varied from just below the hopper to the pipe end. This indicates the occurrence of self-organized critical density waves in the granular flow through a pipe. It is pointed out that the back-flow of air is responsible for the occurrence of the density waves.

Wavy‐to‐slug flow transition in slightly inclined gas–liquid pipe flow

AbstractA process‐engineering model is presented for the stratified‐wavy‐to‐intermittent (SW–I) flow‐pattern transition in slightly inclined gas–liquid pipe flow. The main parameter for predicting (in) stability of wavy flow in inclined pipes is the average liquid holdup, which was found to reach a maximum, critical value at flow‐pattern transition. Observed values of the critical liquid holdup vary between 0.07 and 0.42, depending on pipe diameter, angle of inclination and transport properties of the gas–liquid system. Measurements were performed in transparent glass pipes of 26‐ and 51‐mm dia., at ten angles of inclination (0.1° ≤ β ≤ 6.0°), using air/water and air/tetradecane (n‐C14H30) systems at atmospheric pressure. Flow‐pattern maps are presented for selected angles of inclination, showing excellent agreement between predicted and observed flow‐pattern boundaries.

Hydrodynamic modeling of vertical non-accelerating gas-solids flow

The one-dimensional steady-state model for vertical non-accelerating liquid-solids flow of coarse spherical particles recently formulated and verified (Grbavčić et al., Powder Technol., 53 (1992) 182) has been extended to vertical pneumatic transport. Experiments were performed by transporting spherical glass particles of 1.20, 1.94 and 2.98 mm diameter with air in a 30 mm i.d. glass pipe. Slip Reynolds number for the particles ranged from 592 to 3813 and the pipe Reynolds number from 16 200 to 49 000. The loading ratio was varied from to 5.4 to 30.8. For these ratios, line voidage ranged from 0.9153 to 0.9913 and superficial gas velocity was in the range (0.91–2.2) U t, where U t represents single particle terminal velocity. Model predictions of fluid-particle interphase drag coefficient and voidages in the transport line are in good agreement with experimental data for particle mass flux W p<250 kg/(m 2 s). A new correlation for particle-wall friction coefficient in an air-spherical glass particle-glass pipe system is presented.

Self-Organized Critical Density Waves of Granular Material Flowing through a Pipe

Fourier analysis has been applied to density waves of granular material (sand) which flows through a pipe. We let sand flow from a hopper through a vertical glass pipe due to gravity. The flow appeared intermittent, reminiscent of a chain of traffic jams on a crowded highway, over the length of the pipe except for the uppermost part where the sand flowed smoothly and homogeneously from the hopper. The FFT power spectra were found to change from a rather structureless form to a stable power-law form of 1/ f α with α≃1.5 as we varied the measuring position from the hopper down to the pipe end. This result shows the occurrence of self-organized critical density waves in granular material flow through a pipe.

Is bioluminescent turbulence an example of self-organized critically?

When mechanically stimulated by flow, some marine cells react by flashing blue light or bioluminescing. The flash response give a relatively non-invasive measure of turbulent behavior which lends itself readily and quantitatively to statistical models of fluid structure. We report substantial agreement between a series of experiments performed using stimulated light from the bioluminescence of seawater flowing through a glass pipe and theoretical predictions based on models proposed for describing a self-organized critical phenomenon. In this way, bioluminescent turbulent flow can be taken as a natural and potentially robust example connecting long-held scaling problems in turbulence to recent thinking on fractals and self-organized critically.

Characterization of the cross-sectional particle concentration distribution in pneumatic conveying systems

The development of the cross-sectional distribution of the concentration of fine powders in dilute phase pneumatic conveying through different pipe elements was examined in detail in order to characterize the degree of segregation. The pipe system considered involved horizontal and vertical pipes connected by pipe bends of different bend radii. Additionally, it was possible to change the configuration into a combination of horizontal pipe, pipe bend, and horizontal pipe. Measurements were performed using smooth glass pipes and stainless steel pipes with a known degree of roughness. The average conveying velocity was varied between 10 and 30 m/s, and particle mass loadings between 0.2 and 1.0 (kg dust/kg air) were considered. The particles used in the study were spherical glass beads with a number mean diameter of 40 μm. The laser-light sheet method combined with digital image processing was applied to characterize the degree of non-uniformity of the particle concentration distribution in the different pipe elements. With the light sheet intersecting the pipe cross-section at an angle of about 45°, it was possible to obtain an entire field picture of the intensity of the light scattered by the particles. Using a simplified theory, the power of the scattered light could be related to the particle concentration distribution in the cross-section of different pipe elements (e.g. horizontal and vertical pipes). Additionally, information on the particle velocity and the spatial development of the particle size distribution were obtained by phase-Doppler anemometry (PDA) which allowed single point measurements along a line through the pipe cross-section. Moreover, accurate particle concentration measurements were performed by PDA with a recently developed method. The results revealed the influence of the different flow conditions, i.e. conveying velocity and particle mass loading, on the cross-sectional distribution of the particle concentration in different pipe elements. It was furthermore found that the wall roughness has a considerable influence on the development of the particle concentration distribution.

Experimental and finite difference modelling of borehole Mach waves1

AbstractA series of model experiments was performed in an ultrasonic laboratory to study the radiation of downhole sources in a variety of formations. Three models were used in the experiments. They were a Lucite model, a Lucite model with a free glass pipe in the centre, and a glass‐cased soil model. In addition, a finite‐difference modelling technique was used to simulate the wave propagation in these models and the results of the laboratory and numerical experiments are compared. In the Lucite borehole model the waveforms recorded in the experiment agree very well with the finite‐difference synthetics. The snapshots of the wavefield from the finite‐difference simulation show the radiation pattern of the P‐ and S‐waves in the Lucite formation. These patterns are consistent with the theoretical calculations. In the Lucite model with the free glass pipe, the finite‐difference synthetics are also in good agreement with the experimental observations, especially for the conical P‐wave arrival. The angle between the wavefront of the conical P‐wave and the borehole axis, observed from the snapshot, agrees with the theory. In the cased soil model, the arrival time of the finite‐difference synthetics is in good agreement with the laboratory measurements. The relative amplitudes of the P‐wave and the Mach wave are not correctly modelled because intrinsic attenuation is not included in the finite‐difference calculation. The Mach cone angle from the snapshot agrees with the theoretical prediction. Finally, a finite‐difference method was used to simulate Mach‐wave propagation in a formation with two horizontal layers. In the case of two slow layers, the Mach‐wave generated in the first layer is reflected back from and transmitted through the boundary and another Mach wave is generated at the second layer when the Stoneley wave travels into the second layer. In the case of a formation having one slow and one fast layer, the Mach wave generated in the slow layer is reflected back at the boundary and leaked into the fast layer. There is no Mach wave in the fast layer.

Photocatalytic Destruction of Chlorinated Solvents in Water With Solar Energy

Sandia National Laboratories and the National Renewable Energy Laboratory are developing a photocatalytic process to destroy organic contaminants in water. Tests with common water pollutants have been conducted at Sandia’s Solar Thermal Facility using a near commercial scale, single-axis tracking parabolic trough system with a glass pipe reactor mounted at its focus. Experiments at this scale provide verification of laboratory studies and allow examination of design and operation issues at a real-life scale. The catalyst, titanium dioxide (TiO2), is a harmless material found in paint, cosmetics, and toothpaste. Experiments were conducted to determine the effects of key process parameters on destruction rates of chlorinated organic compounds that are common water pollutants. In this paper, we summarize the engineering-scale results of these experiments and analyses.

Development of the engineered barriers for the deep geological disposal of high-level radioactive waste : Sasaki, N; Ishikawa, H; Miyahara, K; Yamada, K; Yuso, Y Proc 1st Annual Topical Meeting on High Level Radioactive Waste Management, Las Vegas, 8–12 April 1990V1, P675–682. Publ La Grange Park: ANS/ASCE, 1990

Vitrified waste, overpack and buffer material are under research and development as engineered barriers in the deep geological disposal system of high-level radioactive waste. Static leach tests were carried out to understand the leaching behavior of fission products and actinides from fully radioactive vitrified waste. Carbon steel and titanium which have been evaluated as candidate overpack material were studied on the corrosion behavior. Full-scale overpacks of forged carbon steel and porcelain were fabricated, and the welding of the lid was pointed out as the most important fabrication technology to be considered. Screening of commercially available bentonite in Japan was carried out, and fundamental properties were measured. The apparent diffusivities of cesium and tritium were determined in compacted sodium bentonite with various dry densities. Volcanic glass, smectite-illite deposit, old concrete and old steel pipes were studied as 'Natural Analogue' to estimate the long term stability of engineered barrier materials.

Countercurrent Flooding in Pipes Containing Multiple Elbows and an Orifice.

Flooding in three piping systems containing multiple elbows and an orifice was experimentally investigated using a 51mm glass pipe and an air/water system. The vertical-to-horizontal geometry with multiple horizontal sections connected by 90°elbows yielded the most limiting flooding gas velocities due to the prolonged formation of the hydraulic jump caused by the added hydraulic resistance of the multiple elbows. Inclining one of the piping sections downward to 45°from the horizontal or to the vertical in the other two geometries eliminated the hydraulic-jump-induced flooding mechanism and increased the flooding gas velocities for the system at high liquid flow rates. The orifice placed in the horizontal section was seen to generally lower flooding gas velocities, with the greatest effect seen for the smallest orifice tested. A new method based on a superposition principle was also proposed for prediction of flooding in complex piping systems.

Theoretical consideration of intensity of an x-ray microbeam formed by a hollow glass pipe

Intensities of x-ray microbeams formed by the 250-mm-long hollow glass pipes of inner diameters of 27.4, 23.0, and 18.8 μm have been theoretically investigated, by taking account of the slope distribution of microprojections (surface roughness) on the pipe inner wall, using the Monte Carlo method. The intensities for all the pipes calculated on the supposition that each pipe inner wall is perfect (i.e., zero rms of the slope distribution) have been much greater than the experimental values in the x-ray energy region from 6.93 to 19.6 keV. Assuming the slope rms from 2.5×10−4 rad to 3.3×10−3 rad, the calculated results have agreed with the experimental values. Discussions on the results for all the pipes are given in relation to the x-ray anomalous dispersion, the penetration of x rays, the intensity distribution on the x-ray sources used, undulation of the pipes, and the presence of microdust in the pipes.

Application of acoustic emission to condition monitoring: Proceedings of the 16th European Working Group on Acoustic Emission Conference, London (United Kingdom), 13–18 Sep. 1987, pp. 2951–2960. Edited by C.B. Scruby and R. Hill, Proceedings of the 4th European Conference on Non-Destructive Testing, London (United Kingdom), 13–17 Sep. 1987, Vol. 4, Pergamon Press, 1988

With the aim of applying AE technology to condition monitoring, the phenomena producing AE in the materials and acoustic background noise present during plant and structure operation are analyzed. The main characteristics and the needs in performance and reliability of the instrumentation which has to work for a long period, continuous monitoring in hostile ambient are outlined. Experience accumulated by CISE in AE testing on real structures is described and the main conclusive results are reported. AE examinations during hydrotests of pressure vessels in pre-service and in-service inspection are considered. Particular attention is paid to problems related to AE continuous monitoring. Experimental activity carried out on reduced scale structures during fatigue tests (pressure vessels, offshore nodes), loading up to failure (steel vessels, fiber glass pipes, concrete beams) and stress corrosion (stainless steel pipes) is discussed. Finally the results obtained in leak monitoring on power plants are reported.

The stress-strain state of the edge zones of glass pipe in testing by internal pressure

Based on a finite-element calculation of the stress-strain state of pipe made taking into consideration the real conditions of fastening and loading of them in test devices the possibility of use of new methods of strength tests of glass pipe under internal hydrostatic pressure is theoretically based. It is shown that the test method presently specified does not make it possible to obtain sufficient information on the supporting capacity of glass pipe as a result of the fact that initiation of failure occurs under the influence of effects occurring in the end zones.