Thin Glass Tubes Research Articles

Preparation and photocatalytic performance of micro/nano structured β2-SiW11Mn doped polyaniline

Micro/nano-structural polyaniline materials were prepared by using thin glass tubes as template in the presence of β2-SiW11Mn and ammonium persulfate, which were used as dopant and oxidant, respectively, in this system. The materials were characterized by IR, UV-Vis, XRD, TG-DTA and SEM techniques. The photocatalytic performance of polyaniline, β2-SiW11Mn and β2-SiW11Mn/PANI composite obtained was investigated using photodegradation of crystal violet as model reaction. The results showed that the photocatalytic activity of β2-SiW11Mn/PANI composite was much higher than polyaniline and β2-SiW11Mn due to a synergy between the two. The degradation rate of crystal violet was 91.19%.

Plasma generation for controlled microwave-reflecting surfaces in plasma antennas

The idea of replacing metal antenna elements with equivalent plasma objects has long been of interest because of the possibility of switching the antenna on and off. In general, two kinds of designs have so far been reported: (a) Separate plasma “wires” which are thin glass tubes filled with gas, where plasma appears due to discharge inside. (b) Reflecting surfaces, consisting of tightly held plasma wires or specially designed large discharge devices with magnetic confinement. The main disadvantages of these antennas are either large weight and size or too irregular surfaces for proper reflection. To design a microwave plasma antenna in the most common radar wavelength range of 1–3 cm with a typical gain of 30 dB, a smooth plasma mirror having a 10–30 cm diameter and a proper curvature is required. The plasma density must be 1012–1014 cm−3 in order to exceed the critical density for the frequency of the electromagnetic wave. To achieve this we have used a ferromagnetic inductively coupled plasma (FICP) source, where a thin magnetic core of a large diameter is fully immersed in the plasma. In the present paper, we show a way to adapt the FICP source for creating a flat switchable microwave plasma mirror with an effective diameter of 30 cm. This mirror was tested as a microwave reflector and there was found no significant difference when compared with a copper plate having the same diameter.

Preparation and Properties of Micro/Nanostructural Polyaniline Doped with α-SiW<sub>11</sub>Co

Micro/nano-structural polyaniline were prepared by using thin glass tubes as template in the presence of α-SiW11Co and ammonium persulfate, which were used as dopant and oxidant, respectively, in this study. The structure and morphology of Micro/nano-structural polyaniline were characterized by means of IR, UV-Vis spectrum, XRD pattern and SEM images. The conductivity and fluorescence property were determined, and thermal stability was studied. The experimental results showed that the conductivity of the materials was 0.86 S·cm-1 at room temperature（20°C）. The images of scanning electron microscopy show that the materials have microspheres morphology. The spectra data indicate that polyaniline doped with α-SiW11Co exhibits fluorescence property. The photocatalytic degradation of gentian violet on α-SiW11Co/PANIin an aqueous solution was carried out to investigate the catalytic activity. The results indicated that the sensitizing effect of PANI can improve the light response of α-SiW11Co and enhance the separation efficiency of electron and hole pairs which in turn promotes the photocatalytic ability of the composites materials. This novel photocatalyst exhibits very high photocatalytic activities to decompose gentian violet in aqueous system under 30W ultraviolet light irradiation. After extraction, the photocatalytic activity under UV irradiation and gentian violet degraded by 90.41% within 150 min.

Experimental Study of Heat Transfer in Micro Glass Tubes Mediated by Surface Phonon Polaritons

We report a temperature measurement of the surface of micro structured glass tube, affected by surface phonon polaritons' (SPPs) energy enhancement. The glass tubes were designed to guide monochromatic thermal energy to improve heat conduction or serve as radiative source. The simulation results show strong enhancement of the Free Path when a wave guide radius is between 2.0 and 10 μm. Absorption of enhanced SPPs energy on the waveguide areas with high absorptivity has some possibility to cause local rise in temperature. Various shapes of micro glass tubes are simply fabricated, and heated by using a Pt wire in a vacuum chamber. Surface temperatures of glass tubes are measured by infrared digital thermo microscope as well as by using a micro-thermocouple to investigate the temperature distribution on both tapered and thin micro glass tubes.

Optical calibration protocol for an x-ray and optical multimodality tomography system dedicated to small-animal examination

A small-animal multimodality tomography system dedicated to the coregistration of fluorescence optical signal and x-ray measurements has been developed in our laboratory. The purpose of such a system is to offer the possibility of getting in vivo anatomical and functional information simultaneously. Moreover, anatomical measurements can be used as a regularization factor to achieve more accurate reconstructions of the biodistribution of fluorochromes and to speed up treatment. A dedicated acquisition protocol has been established, and the methodology of the reconstruction of the three-dimensional distribution of the biomarkers under cylindrical geometry consistent with classic computed tomography has been implemented. A phantom study was conducted to evaluate and to fix the parameters for the coregistration. These test experiments were reproduced by considering anesthetized mice that had thin glass tubes containing fluorochromes inserted into their esophagus. The instrument is also used for an in vivo biological study conducted on mice with lung tumors, tagged with near-infrared optical probes (targeting probes such as Transferin-AlexaFluor750).

Thin porous glass tubes

Thin porous glass tubes were prepared by extruding a polymer solution containing suspended glass powder to a tubular precursor at room temperature, which was then heat treated at elevated temperatures to remove the polymer and sinter the particles to a porous or dense structure with sufficient mechanical strength. In extruding these thin tubular precursors, polyethersulfone (PESF) and N-methyl-2-pyrrolidone (NMP) were used as the polymer binder and the solvent, respectively. Porous glass tubes can be obtained directly by sintering the tubular precursor at relatively lower temperatures. Heated at higher temperatures (i.e. 900 °C), the glass tubes became gas tight. Subsequently, the sodium borosilicate glass tubes were leached in hot water to remove the soluble phase formed by phase separation during cooling. The characterizing technique involved XRD, SEM and gas permeation measurements. SEM examination indicated that during leaching, the glass developed pores of about 0.1 μm size consistent with gas permeation measurements.

Preparation of Polyaniline Nanotubes via “Thin Glass Tubes Template” Approach and its Gas Response

AbstractPANI nanotubes were successfully prepared by using thin glass tubes as a single template in the presence of H4SiW12O40 and ammonium persulfate, which were used as dopant and oxidant, respectively, in this system. The structure and morphology of the PANI were characterized by IR spectrum, XRD pattern, SEM images, and TEM images. The inner diameter of PANI nanotubes was between 50 and 100 nm. This method employed here was a simple and effective way to prepare multifunctional PANI nanotubes. The gas response of the PANI nanotubes to a series of chemical vapors such as NH3, N2H4, and (C2H5)3N was studied. The results indicate that the PANI nanotubes show superior performance as chemical sensor.magnified image

Effective breakage of phage .LAMBDA. DNA by shearing with ceramic-coated needle of syringe

The loss of biological activity of phage lambda DNA was much greater when the DNA was sheared using a ceramic-coated needle attached to a syringe compared with a conventional stainless steel needle. Inactivation of the biological activity was due to breakage at the middle of the molecule. The thickness of the ceramic-coating was a crucial factor for the breakage. Because approximately the same level of inactivation was observed with a non-coated needle as with thin glass and quartz tubes, it was concluded that the unknown characteristic(s) of the silicon nitride (SiNx) coating itself resulted in the effective breakage of lambda DNA molecules by shearing force.

Patterning Trends and Chaotic Behavior in Co2+/NH4OH Liesegang Systems

Co(OH)2 Liesegang patterns from Co2+ and NH4OH in gelatin are studied in thin glass tubes. The experiments are performed in the limit of large initial concentration difference (Δ) between the interdiffusing electrolytes. Patterning trends are investigated as the initial concentration product σ = [Co2+ ]0[NH4OH is varied (we keep [NH4OH]0 constant and vary [Co2+]0 in the limit of large Δ). Time series of the total number of bands in the pattern show a random distribution apparently indicating the chaotic character of that variable. When the bands are counted in the bottom portion of the pattern (the last 4 cm measured from the last band), their number (denoted ν therein) decreases monotonically with time at all concentrations. The pattern thus regularizes itself in that region. The spacing between the bands is measured as a function of distance from the junction between the co-precipitate solutions, at different initial concentrations. The variation of spacing with distance is found to fit a quadratic equation. The variation of spacing with concentration at a given location is also studied and is found to involve an exponential term. Then a generalized equation expressing the spacing as a function of concentration and distance is determined. A three-dimensional plot is constructed to represent the obtained variations. Our results are then compared with previous experimental findings and theoretical formulations of Liesegang preciptation phenomena.

Transmittance Study of a Tubular Cover Collector

Transmittance of a tubular cover collector has been calculated for a particular orientation. Tilt of the collector is optimised for the four typical days (two equinoxes and two solstices) at Delhi and Madras, a high and low latitude station respectively. Only the two nearest neighbouring tube elements are considered, in order to take into account the shadowing effect. In the present system, where the thickness of the tube and the flat glass sheets, has been taken to be the same, the transmittance of the tubular cover has been found to be comparitively less than that of a cover formed by two parallel sheets of window glass. However, because of its cylindrical geometry, very thin glass tubes can be used for all practical purposes, thereby, increasing the transmittance to a great extent. It has also been concluded that for all tubular covers including this system, hour angle instead of angle of incidence is an exact parameter to study the variation of effective transmittance. The difference in the mode of variation of transmittance with hour angle in the present system, with that in case of tubular collector, is attributed to the variation of average angle of incidence (local) with hour angle.

Accurate drawing of thin-walled glass tubing

A simple arrangement is described for making close tolerance, thin wall glass tubes of a quality at least adequate for Dewar construction.

Crystal Structure of Chromium Trioxide

SMALL thin red needles, heavily striated down the prism, were prepared by adding concentrated sulphuric acid to a cold concentrated solution of potassium dichromate. The crystals were sealed up separately in thin glass tubes to prevent deliquescence. Measurements on an ionisation spectrometer and from oscillation photographs gave the value of the cell size as a = 8.50 A., b = 4.73 A., c = 5.72 A., the probable error being not greater than ± 1 per cent. The density given by Groth is 2.73–2.82 and there are therefore 4 molecules per cell. The axial ratios given by Nordenskjöldl are a: b: c = 1: 0.69: 0.63. The relation between his ratios and ours is a: b: c (Wooster) = a: 3/4;b: c (Nordenskjöld). The only face from which he could obtain the ratio a: b should have been indexed (230) instead of (120). All the specimens which we have examined up to the present are mimetic twins on (110), closely simulating hexagonal symmetry.

The Rusting of Iron

DURING the past few months the study of the chemical changes involved in the rusting of iron has been coming to the fore. In 1888 Crum Brown pointed out that iron remained free from rust in an atmosphere of oxygen carbon dioxide, and water vapour so long as liquid water was prevented from condensing on its surface. Whitney, in 1903, confirmed the opinion that liquid water alone had no effect on the metal at ordinary temperatures. No mention was made, however, of the purity of the iron used. Last year Dunstan, Jowett, and Goulding con-firmed these results for polished iron plate (99.94 per cent. iron) in a series of carefully planned experiments. Since iron of such great purity as this is seldom used for com-mercial purposes, it seemed to me desirable to try the effect of water alone on different samples of varying qualities. Three such were chosen:—(1) cast iron from a piece of old piping; (2) wrought iron; (3) fairly pure iron (99.5 per cent.). The pieces were polished, and measured approximately 1 cm. long by 3 cm. broad and 0.2 cm. thick. They were dropped into flasks of boiling distilled water, and after five minutes the latter were closed with tightly-fitting india-rubber bungs, in the way indicated by Whitney. It was found that whilst the pure and wrought iron were unchanged, the cast iron invariably turned a shade darker in tint. The experiment was varied by employing thin glass tubes instead of flasks, and the surface of the metal was in some cases roughened with a coarse file. After the admission of the iron, the tubes were drawn out and finally sealed off. The results were invariably the same. I have kept these tubes for several months, but no further changes have taken place. This seems to indicate that, whilst neither warm nor cold water has any effect upon the purer forms of iron, they exert some slight action on the coarser cast iron.

Physical Properties of Matter in the Liquid and Gaseous States *

THE investigation to which this note refers has occupied me, with little intermission, since my former communication in 1869 to the Society, “On the Continuity of the Liquid and Gaseous States of Matter.” It was undertaken chiefly to ascertain the modifications which the three great laws discovered respectively by Boyle, Gay-Lussac, and Dalton undergo when matter in the gaseous state is placed under physical conditions differing greatly from any hitherto within the reach of observation. It embraces a large number of experiments of precision, performed at different temperatures and at pressures ranging from twelve to nearly three hundred atmospheres. The apparatus employed is, in all its essential parts, similar to that described in the paper referred to; and so perfectly did it act that the readings of the cathetometer, at the highest pressures and temperatures employed, were made with the same ease and accuracy as if the object of the experiment had been merely to determine the tension of aqueous vapour in a barometertube. In using it the chief improvement I have made is in the method of ascertaining the original volumes of the gases before compression, which can now be know with much less labour and greater accuracy than by the method I formerly described. The lower ends of the glass tubes containing the gases dip into small mercurial reservoirs formed of thin glass tubes, which rest on ledges within the apparatus. This arrangement has prevented many failures in screwing up the apparatus, and has given more precision to the measurements. A great improvement has also been made in the method of preparing the leather-washers used in the packing for the fine screws, by means of which the pressure is obtained. It consists in saturating the leather with grease by heating it in vacuo under melted lard. In this way the air enclosed within the pores of the leather is removed without the use of water and a packing is obtained so perfect that it appears, as far as my experience goes, never to fail, provided it is used in a vessel filled with water. It is remarkable, however, that the same packing, when an apparatus specially constructed for the purpose of forged iron was filled with mercury, always yielded, even at a pressure of forty atmospheres, in the course of a few days.