scholarly journals Experimental determination of the curvature-induced intra-wall polarization of inorganic nanotubes

Nanoscale ◽  
2021 ◽  
Author(s):  
Marie-Claire PIGNIE ◽  
Sabyasachi Patra ◽  
Lucie HUART ◽  
Aleksandar Milosavljevic ◽  
Jean-Philippe Renault ◽  
...  

Inspired from a natural nano-mineral known as imogolite, aluminosilicate inorganic nanotubes are appealing systems for photocatalysis. One is completely hydrophilic (IMO-OH), while the other has a hydrophilic exterior and a...

1872 ◽  
Vol 20 (130-138) ◽  
pp. 34-35

A galvanic current passes from the batteries at the Royal Observatory, Cape Town, at 1 o’clock, and discharges a gun at the Castle, and through relays drops a time-ball at Port Elizabeth. It appeared to the author that a valuable determination of the velocity of sound might be obtained by measuring upon the chronograph of the Observatory the interval between the time of the sound reaching some point near the gun and that of its arrival at the Observatory. As there is only a single wire between the Observatory and Cape Town, some little difficulty was experienced in making the necessary arrangements, without any interference with the 1 o’clock current to Port Elizabeth; but this difficulty was overcome by a plan which the author describes, and which was brought into successful operation on Feb. 27, 1871. The experiments could not have been carried out, on account of the encroachment they would have made on the time of the Observatory staff, had it not been for the assistance of J. Den, Esq., the acting manager of the Cape Telegraph Company, to whom the author is indebted for the preparation of a good earth-connexion near the gun, for permission to Mr. Kirby, a gentleman attached to the telegraph office, to assist in the experiments, and for a general superintendence of the arrangements at Cape Town. The observed times of hearing the sound were recorded on the chronograph by two observers, situated one (Mr. Kirby) at a distance of 641 feet from the gun, the other (Mr. Mann) at the Observatory, at a distance of 15,449 feet from the gun. The former distance was sufficient to allow the connexion of the main wire to be broken at the telegraph office after the gun had been fired, but before the sound reached the first observer.


Author(s):  
Pezhman Hassanpour ◽  
Monica Weaser ◽  
Ray Colquhoun ◽  
Khaled Alghemlas ◽  
Abdullah Alrashdan

This paper presents the analysis of the mass moment of inertia (MMI) of a flywheel using experiment data. This analysis includes developing two models for determining the MMI of the flywheel. The first model considers the effect of mass moment of inertia only, while the second model takes the effect of friction in the ball bearings into consideration. The experiment results have been used along with both models to estimate the MMI of the flywheel. It has been demonstrated that while the model with no friction can be used for estimating the MMI to some extent, the model with friction produces the most accurate result. On the other hand, an effective application of the model with friction requires several experimental measurements using different standard masses. This translates into more expensive method in terms of experiment time and equipment cost.


2014 ◽  
Vol 659 ◽  
pp. 262-267
Author(s):  
Marian Truta ◽  
Marin Marinescu ◽  
Octavian Alexa ◽  
Radu Vilau ◽  
Valentin Vinturis

Present paper aims at revealing a way to determine the cinematic misfit within a 4x4 vehicle’s inter-axle driveline, which is eventually the reason of the self-generated torque occurrence. We used experimental methods to determine the magnitude of the cinematic misfit. Within this frame, we used a vehicle that has a longitudinal (inter-axle) differential and we locked it, actually forcing the longitudinal transmission to work without differentiating the angular speeds on its output shafts. On the other hand, the tire radii were different, inducing the above-mentioned cinematic misfit that we were looking for. We also present the way we fit the transducers on the vehicle’s driveline components to measure the needed parameters. The paper also presents some theoretical considerations regarding the occurrence of the cinematic misfit and its way of generating closed power loops within the vehicle’s transmission.


2011 ◽  
Vol 133 (10) ◽  
Author(s):  
Krithiga Ganesan ◽  
Wojciech Lipiński

Abstract Overall transmittance of porous cerium dioxide is measured in the spectral range of 900–1700 nm using dispersive spectroscopy. Dense and porous samples of cerium dioxide with average porosities of 0.08 and 0.72, respectively, are investigated. The transmittance of both sample types increases with decreasing thickness, and this trend is more pronounced for the dense samples. The on-average spectrally increasing transmittance of the dense samples is attributed to the decreasing absorption by bulk cerium dioxide with radiation wavelength. The transmittance of the porous samples, on the other hand, remains approximately constant over the spectrum. Porous samples attenuate radiation stronger than the dense samples at any wavelength in the considered range, and it is hypothesized that this effect is due to more intense scattering. Sharp local variations of the transmittance are observed for both sample types.


Author(s):  
Diego A. Zamora-Garcia ◽  
Luis Miguel Acosta-Carrion ◽  
Ma. Pilar Corona-Lira ◽  
Alejandro C. Ramirez-Reivich

Abstract Braided steel cables have the potential for improving the mechanisms providing them several advantages in comparison with rigid elements. Nevertheless, a limitation in the use of cable mechanism is that due to the inherent flexibility, the problem of vibration arises. In this research, we investigate the axial viscoelastic behavior of 1/32″ braided steel cables. The essential idea is to determine the parameters of elasticity (k) and viscosity (b) as a function of the length of the cable in its axial direction. It was achieved through the design and construction of a test bench and the design of an experiment. The test bench is a free vibration particular design machine. One end of the cable is fixed to the structure, and in the other end, a load is attached. Then, the load is released, and the free vibration of the cable in the axial direction is registered. The factor of the experiment is the length of the cable. There are six levels, and these were repeated four times. We demonstrated that the braided steel cables have a viscoelastic behavior like a Kelvin-Voigt. Also, we found a relation between the effective length of the cables and the parameters of elasticity and viscosity.


Geophysics ◽  
1976 ◽  
Vol 41 (4) ◽  
pp. 774-775
Author(s):  
Sven‐Erik Hjelt

The authors have introduced the concept of effective demagnetizing factor to be used when measuring susceptibilities of highly magnetized samples. They have used one experiment to show that the factor thus defined differs considerably from factors computed theoretically. From its definition, it seems obvious that the numerical value of the effective demagnetizing factor will depend on the measuring geometry and, more so, on the shape of the sample. Furthermore, the relation between the new demagnetizing factor and susceptibilities calculated using it on the one hand, and true magnetization on the other hand, is far from trivial.


1881 ◽  
Vol 32 (212-215) ◽  
pp. 247-249 ◽  

The method employed in this research to measure the velocity of light resembled the method of M. Fizeau, subsequently employed by M. Cornu. A revolving toothed wheel is employed in the same way to alter the intensity of the light reflected from a distance. In the present method, however, there are two distant reflectors instead of only one. They are separated by a distance of a quarter of a mile. The observing telescope and the two reflectors are almost in the same line. The observer sees two stars of light which go through their phases with different periods as the toothed wheel is revolved at increasing speeds. One star is increasing, while the other is diminishing, in intensity, with increase of speed of the toothed wheel. The speed required to produce equality of the lights is determined by means of a chronograph. By choosing such a speed as gives a maximum of one star at the same speed as a minimum of the other, a pair of observations eliminates all cause of doubt arising from varying brightness in the stars, and ratio of the width of a tooth to the width of a space. The distances were observed by triangulation with the Ordnance Survey 18-inch theodolite, using as a base line a side of one of the Ordnance Survey triangles. The source of light was an electric lamp. The velocities (uncorrected for rate of clock, and reduction to a vacuum) measured are as follows:— 187,707 188,405 187,676 186,457 185,788 186,495 187,003 186,190 186,830 187,266 188,110 188,079 Mean.................. 187,167 miles a second. The correction to vacunm is + 54 miles a second. The correction for rate of clock to a mean solar time is + 52 miles a second.


1894 ◽  
Vol 55 (331-335) ◽  
pp. 373-383 ◽  

The experiments with which this paper deals were carried out between the years 1883 and 1886 by Professor Kennedy and the author, with an instrument which the latter had originally designed for measuring local strains in metal structures, but which proved itself to be so exceedingly sensitive that it seemed capable of being applied to the measuring of the cross contraction of test pieces while these were subjected to a longitudinal pull, thus providing the means for measuring Poisson’s ratio direct. In its original form the instrument consisted of two small frames, which were secured to each other by means of two flat springs, in such a manner, that any relative motion was a perfectly parallel one. One of these frames carried a small piece of dark glass, and close to it, but on the other frame, a right-angled reflecting glass prism was secured.


Author(s):  
D.R. Rasmussen ◽  
N.-H. Cho ◽  
C.B. Carter

Domains in GaAs can exist which are related to one another by the inversion symmetry, i.e., the sites of gallium and arsenic in one domain are interchanged in the other domain. The boundary between these two different domains is known as an antiphase boundary [1], In the terminology used to describe grain boundaries, the grains on either side of this boundary can be regarded as being Σ=1-related. For the {110} interface plane, in particular, there are equal numbers of GaGa and As-As anti-site bonds across the interface. The equilibrium distance between two atoms of the same kind crossing the boundary is expected to be different from the length of normal GaAs bonds in the bulk. Therefore, the relative position of each grain on either side of an APB may be translated such that the boundary can have a lower energy situation. This translation does not affect the perfect Σ=1 coincidence site relationship. Such a lattice translation is expected for all high-angle grain boundaries as a way of relaxation of the boundary structure.


Author(s):  
Y. Ishida ◽  
H. Ishida ◽  
K. Kohra ◽  
H. Ichinose

IntroductionA simple and accurate technique to determine the Burgers vector of a dislocation has become feasible with the advent of HVEM. The conventional image vanishing technique(1) using Bragg conditions with the diffraction vector perpendicular to the Burgers vector suffers from various drawbacks; The dislocation image appears even when the g.b = 0 criterion is satisfied, if the edge component of the dislocation is large. On the other hand, the image disappears for certain high order diffractions even when g.b ≠ 0. Furthermore, the determination of the magnitude of the Burgers vector is not easy with the criterion. Recent image simulation technique is free from the ambiguities but require too many parameters for the computation. The weak-beam “fringe counting” technique investigated in the present study is immune from the problems. Even the magnitude of the Burgers vector is determined from the number of the terminating thickness fringes at the exit of the dislocation in wedge shaped foil surfaces.


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