Ring Length Research Articles

Fast oxidative desulfurization of fuel oil using dialkylpyridinium tetrachloroferrates ionic liquids

In this work, a series of Lewis acidic ionic liquids (ILs), dialkylpyridinium tetrachloroferrates [C43MPy] FeCl4,[C83MPy] FeCl4, and [C83MPy] FeCl4), was synthesized and utilized as extractant and catalyst to investigate the oxidative removal of dibenzothiophene (DBT) from model oil, with 30wt% hydrogen peroxide (H2O2) solution as oxidant. The effects of reaction time, temperature, H2O2/DBT molar ratio, initial sulfur content, IL/oil mass ratio, and alkyl chain length of IL cation ring on the DBT removal of model oil were investigated in detail. Dialkylpyridinium tetrachloroferrates ILs presented good catalytic activity and high extraction performance on the desulfurization of model oil, with the advantages of fast reaction equilibrium, high sulfur removal of 100%, low temperature, and low mass ratio of IL/oil. The desulfurization system could be recycled twice without a significant decrease in desulfurization activity. Kinetics of oxidative desulfurization of DBT by H2O2 and [C43MPy] FeCl4 is first-order with an apparent rate constant of 0.9951min−1 at 1/3 IL/oil mass ratio and 298K. [C83MPy] FeCl4 can reduce sulfur content in actual gasoline from 468ppm to 261ppm with a sulfur removal of 44% at IL/gasoline mass ratio of 1/3. The present work shows that fuel oil can be purified into ultralow sulfur fuels through further deep oxidative desulfurization using acidic ILs after hydrodesulfurization.

A comparative study of semi-squaraine and squaraine dyes using computational techniques: tuning the charge transfer/biradicaloid character by substitution

Semi-squaraines (SMSQ) are known as donor-acceptor (D-A) type molecules whereas squaraines (SQ), which differs from SMSQ by an extra donor group, are more or less biradicaloids in nature. The effect of the additional donor group in SQ, which changes the nature of the molecule, on geometrical and electronic structure are studied here and compared with the corresponding SMSQ. It is noticed from the geometrical parameters that, a strong resonance exists in SQ whereas disparity in carbon-carbon bond lengths of central C4 ring is seen in SMSQ dyes. The increasing and decreasing of antibonding interactions between central C4 ring and side donor groups cause destabilization of HOMO and stabilization of LUMO respectively in case of SQ compared to SMSQ molecules. This leads to decreasing the HOMO-LUMO gap and promotes biradicaloid character of SQ. The absorption maxima obtained by using TD-DFT method with BLYP, B3LYP, BHandHLYP, CAM-B3LYP and M06-2X functionals are not in good agreement with experimental results. On the other hand SAC-CI method gives better results for all the molecules. From this work we can evolve a design principle of these molecules which play a role as sensitizers in dye sensitized solar cells.

An Optimal Algorithm for Conflict-Free Coloring for Tree of Rings

An optimal algorithm is presented about Conflict-Free Coloring for connected subgraphs of tree of rings. Suppose the number of the rings in the tree is |T| and the maximum length of rings is |R|. A presented algorithm in [1] for a Tree of rings used O(log|T|.log|R|) colors but this algorithm uses O(log|T|+log|R|) colors. The coloring earned by this algorithm has the unique-min property, that is, the unique color is also minimum.

Circulating currents in a metallic ring with two quantum dots

We analyze a system constituted by two single level quantum dots embedded in a metallic ring connected to external electrodes. The energy levels of the dots are controlled by an external gate potential. Additionally, the external electrodes are under the effect of an external applied potential. In these conditions, a circulating current appears in the ring. We show that this current appears when the gate potential is such that the electron-hole symmetry is broken. The direction of circulation depends upon the sign of the external potential and which dot has greater energy. The maximum value of this current is very sensitive to the gate and applied potentials, but it remains finite as the connection between the leads and the ring goes to zero. Therefore, although the circulating current is directly related to the applied potential, it demands a negligible current from the leads. The current is shown to be independent of the ring length, as opposed to the case of a persistent current induced by a magnetic field. It is not a nanoscopic phenomenon, and, as a consequence, it can be orders of magnitude larger than a typical persistent current in a metallic ring.

Novel electromagnetic repeated launch locking/unlocking device (RLLUD) based on self-locking for magnetic bearing flywheel

Although magnetic bearings seem capable of holding the rotor during launch by electromagnetic forces, most available magnetic bearing flywheels are equipped with an additional launch locking/unlocking device (LLUD). As the ground environmental test and transport, flywheel systems need multiple locking/unlocking. Therefore, to remedy the limitation of one-off LLUD which cannot repeat locking/unlocking, a novel electromagnetic repeated launch locking/unlocking device (RLLUD) based on self-locking to keep locking and springs to carry out unlocking is presented in this paper. Its composition, operating principle and functional performance requirements are introduced. First, the self-locking condition and spring parameters are designed. Subsequently, by comparatively analyzing four electromagnetic forces corresponding to four steps including carrying out locking/unlocking and keeping locking/unlocking, the internal permanent magnet is adopted as actuator of RLLUD. Second, based on equivalent magnetic circuit method, the mechanics models of electromagnet under four steps are established, and two high-sensitivity parameters including magnetic ring length and permanent magnet magnetization length are obtained. Upon this, by taking into account spring elastic forces, the four electromagnetic forces are calculated and designed in detail by using finite element method (FEM). It ensures the repeated locking/unlocking of RLLUD. The prototype RLLUD is manufactured and verified by environmental mechanics tests. The results show that no resonant vibration occurs and the maximum vibration displacement between stator and rotor is 40μm, far less than the protection gap of 200μm. It indicates the novel RLLUD can effectively carry out the protection function for magnetic bearing flywheel.

Measuring the bunch frequency multiplication at the 3rd CLIC Test Facility

The CLIC Test Facility 3 (CTF3) is being built and commissioned by an international collaboration to test the feasibility of the proposed Compact Linear Collider (CLIC) drive beam generation scheme. Central to this scheme is the use of RF deflectors to inject bunches into a delay loop and a combiner ring, in order to transform the initial bunch frequency of 1.5 GHz from the linac to a final bunch frequency of 12 GHz. To do so, the machine's transverse optics must be tuned to ensure beam isochronicity and each ring's length can finally be adjusted with wiggler magnets to a sub millimeter path length accuracy. Diagnostics based on optical streak camera and RF power measurements, in particular frequency bands, have been designed to measure the longitudinal behaviour of the beam during the combination. This paper presents the diagnostics and recent commissioning measurements.

Multiscale Entanglement in Spherically Confined DNA Rings

Knots are frequent in biological systems, and particularly in DNA, where they can be a major hindrance for biological functions. In particular it is argued that the presence of tight knots in viral genome can prevent its ejection from the capsid thus stopping the life cycle of the virus.Inspired by those problems we investigate the interplay of geometrical and topological entanglement in knotted DNA rings confined inside a spherical cavity using advanced numerical methods.We show that the complex interplay between the length of the knotted portion of DNA, the contour length of the DNA ring, and the radius of the enclosing sphere can be encompassed by a simple scaling argument based on deflection theory.Furthermore, we show that with increasing confinement the entanglement acquires a multi-scale character which can be rationalised using the same scaling argument.

Jumping ring experiment: effect of temperature, non-magnetic material and applied current on the jump height

The jumping ring experiment is an outstanding demonstration of Faraday's laws of electromagnetic induction and also of Lenz's law. A conducting non-magnetic ring is placed over the extended vertical core of a solenoid. When ac power is applied to the solenoid, the ring is thrown off or held in a state of levitation. This phenomenon happens because the induced current in the ring flows in the direction to counter that of the solenoid current. Consequently, two magnetic fields repel each other, giving rise to the jump effect. The induced current is corresponding to the jump height of a ring. In this work, the jump heights of brass, copper and aluminium rings subjected to different parameters such as temperature, vertical length of ring and applied solenoid current were investigated.

ISPRS Commission V Symposium: Close Range Image Measurement Techniques

The Photogrammetric RecordVolume 26, Issue 136 p. 381-383 Editorial ISPRS Commission V Symposium: Close Range Image Measurement Techniques Jon P. Mills, Jon P. Mills Newcastle upon Tyne, Tyne and Wear, EnglandSearch for more papers by this authorDerek D. Lichti, Derek D. Lichti Calgary, Alberta, CanadaSearch for more papers by this authorNorbert Pfeifer, Norbert Pfeifer Vienna, AustriaSearch for more papers by this author Jon P. Mills, Jon P. Mills Newcastle upon Tyne, Tyne and Wear, EnglandSearch for more papers by this authorDerek D. Lichti, Derek D. Lichti Calgary, Alberta, CanadaSearch for more papers by this authorNorbert Pfeifer, Norbert Pfeifer Vienna, AustriaSearch for more papers by this author First published: 19 December 2011 https://doi.org/10.1111/j.1477-9730.2011.00662.x Frontispiece. Close range image measurement techniques. An image from each of the six papers in this ISPRS Commission V 2010 Newcastle Symposium special issue. Top left: cross sections of colour-coded vector lengths of a simulated vortex ring (Westfeld and Maas). Top right: the Adorazione dei Magi painting by Giorgio Vasari in the church of Bosco Marengo in Alessandria, Italy, surveyed using a ShapeGrabber laser scanner (Remondino et al.). Centre left: the hilltop archaeological site of Drapham Dzong, Bhutan, surveyed (inset) by a Microdones md4-200 quadrotor UAV (Eisenbeiss and Sauerbier). Centre right: interactive web application for analysing Buddhist stone inscriptions of sutra in China with overlaid interpretation text (Schmidt et al.). Bottom left: modelling using Rhino software of the octagonal first Belvedere of the main spire of Milan Cathedral, Italy (Fassi et al.). Bottom right: changes in the volume of sand deposited near a screen on the Dutch coast over a 32-hour period as monitored by a terrestrial laser scanner (Lindenbergh et al.). Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Volume26, Issue136Special Issue: ISPRS COMMISSION V SYMPOSIUM 2010 CLOSE RANGE IMAGE MEASUREMENT TECHNIQUESDecember 2011Pages 381-383 RelatedInformation

Resonator micro optic gyro with double phase modulation technique using an FPGA-based digital processor

Experiments on resonator micro-optic gyro (RMOG) with a digital proportional integral (PI) feedback scheme are performed. In this experimental setup, the key rotation sensing element is a polarization maintaining silica waveguide ring resonator (WRR) with a ring length of 7.9 cm and a diameter of 2.5 cm. A good linearity of 0.0015% over a wide range of ± 2 × 10 4 °/s can be achieved for the RMOG theoretically. The optimal digital PI feedback scheme is adopted in the frequency servo loop to reduce the reciprocal frequency fluctuations due to the WRR resonance frequency and laser frequency drifts. Residual equivalent input fluctuation can be reduced as low as 0.03 °/s/√Hz based on the optimal digital PI feedback scheme, which is close to the shot noise limited spectral density 0.02 °/s/√Hz of the RMOG with the input optical power of 0.2 mW. Relationship between RMOG output signal and angular rate is obtained from ± 0.1 °/s to ± 5 °/s. The standard deviation of the residuals between RMOG output results and linear fit curve is 0.066 °/s. For an integration of the processing circuit, all the processing circuit is implemented by a field programmable gate array (FPGA) instead of instruments. The output of this digitalized RMOG is obtained over a range of ± 550 °/s. The linearity of this digitalized RMOG is 0.0169%.

Structure and Dynamics of Ring Polymers: Entanglement Effects Because of Solution Density and Ring Topology

The effects of entanglement in solutions and melts of unknotted ring polymers have been addressed by several theoretical and numerical studies. The system properties have been typically profiled as a function of ring contour length at fixed solution density. Here, we use a different approach to investigate numerically the equilibrium and kinetic properties of solutions of model ring polymers. Specifically, the ring contour length is maintained fixed, while the interplay of inter- and intra-chain entanglement is modulated by varying both solution density (from infinite dilution up to \approx 40 % volume occupancy) and ring topology (by considering unknotted and trefoil-knotted chains). The equilibrium metric properties of rings with either topology are found to be only weakly affected by the increase of solution density. Even at the highest density, the average ring size, shape anisotropy and length of the knotted region differ at most by 40% from those of isolated rings. Conversely, kinetics are strongly affected by the degree of inter-chain entanglement: for both unknots and trefoils the characteristic times of ring size relaxation, reorientation and diffusion change by one order of magnitude across the considered range of concentrations. Yet, significant topology-dependent differences in kinetics are observed only for very dilute solutions (much below the ring overlap threshold). For knotted rings, the slowest kinetic process is found to correspond to the diffusion of the knotted region along the ring backbone.

The stapled hemorrhoidopexy syndrome: a new clinical entity?

Haemorrhoidal disease is a rather common disease of unknown cause. A new technique for treating prolapsing haemorrhoids known as the stapled hemorrhoidopexy (SH) or the "Longo procedure" is widely used. Serious adverse events were reported in 2000 and some discussion over the syndrome but nothing since. Two hundred and five patients underwent SH by our surgical team at the Interbalkan European Medical Center. Modified SH was performed. Despite the low incidence of postoperative complications (11/205), 36.58% of patients developed syndrome comprised of urgency to defecate, sensation of anal foreign body and incomplete defecation and mild cramp like anal discomfort, immediately after surgery or in the following 48 h. There is not statistically significant relationship between the presence of the syndrome and the gender, the presence of muscle fibres in the resected "ring" the degree of haemorrhoidal disease, age and ring length. Observations led us to conclude that the stapled hemorrhoidopexy syndrome (SHS) is probably caused by the irritating presence of the titanium staples in the rectal mucosa and by the resection itself.

Global dimension of Noetherian serial rings

The global dimension of Noetherian serial rings is studied. It is proved that if an indecomposable serial ring has infinite global dimension then it is Artinian and its quiver is a simple cycle. Using methods of the theory of right serial quivers, we give an upper estimate on the Loewy length of Artinian rings of finite global dimension. Applications to the calculation of the global dimension of tiled orders of width 2 are given.

Influence of Ring Length on Electric Field Distribution in CdZnTe Frisch-Ring Detector

The CdZnTe (CZT) devices with various screening depth in dimensions 3×3×6mm3 were fabricated. The influence of Ring length (screening depth) and length of crystal on the electric field distribution in CZT devices has been explored by finite element method. The results indicated that ring length (screening depth) plays an important role on the detecting performance of CZT Frisch-ring devices. Longer screening depth gives rise to an electric field which is compressed more greatly. Measured spectra indicated that extreme compressed electric field could reduce detecting resolution. A FWHM energy resolution of approximately 3.71% at 662 keV was obtained for a device with dimensions 3×3×6mm3 and 4.8mm screening depth.

Impact of Anastomotic Techniques on Airway Complications After Lung Transplant

Airway complications are a source of morbidity and expense after lung transplant. Posttransplant stenosis can occur when the donor bronchus is rendered ischemic and is dependent upon collateral flow from the pulmonary capillary system. By shortening the donor bronchus, the tissue at risk for ischemia is reduced. In an effort to reduce airway complications, one surgeon at our institution began dividing the donor bronchus at the lobar carina. This is a retrospective analysis of all transplanted patients over the 2-year period before and after the institution of the technique change. To adjust for covariates, we performed a propensity score analysis. Outcome endpoints were postoperative airway complications, specifically, the need for therapeutic bronchoscopy, dilation, stenting, or retransplant. After instituting the practice of dividing the bronchus at the lobar carina, the incidence of airway complication for the principle surgeon decreased from 13.2% (7 of 53) to 2.1% (1 of 48), resulting in an improved freedom from airway complication for that surgeon. Compared with all transplants performed during this period, the modified anastomosis resulted in fewer airway complications: 2.1% (1 of 48) versus 8.2% (19 of 231). The propensity analysis matched the 48 patients who received the modified anastomosis with 48 patients who received the standard two ring length anastomosis by surgical colleagues. The modified anastomosis group had fewer required interventions for airway complications and had significantly better freedom from airway complication when followed over time. Decreasing the amount of potentially ischemic tissue implanted from the donor bronchus can reduce posttransplant airway complications.

Topological Signatures of Globular Polymers

Simulations in which a globular ring polymer with delocalized knots is separated in two interacting loops by a slipping link, or in two noninteracting globuli by a wall with a hole, show how the minimal crossing number of the knots controls the equilibrium statistics. With slipping link the ring length is divided between the loops according to a simple law, but with unexpectedly large fluctuations. These are suppressed only for unknotted loops, whose length distribution always shows a fast power-law decay. We also discover and explain a topological effect interfering with that of surface tension in the globule translocation through a membrane nanopore.

Volumetric properties and enthalpies of solution of alcohols CkH2k+1OH (k = 1, 2, 6) in 1-methyl-3-alkylimidazolium bis(trifluoromethylsulfonyl)imide {[C1CnIm][NTf2] n = 2, 4, 6, 8, 10} ionic liquids

We present a study on the effect of the alkyl chain length of the imidazolium ring in 1-alkyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ionic liquids, [C1CnIm][NTf2] (n=2 to 10), on the mixing properties of (ionic liquid+alcohol) mixtures (enthalpy and volume). We have measured small excess molar volumes with highly asymmetric curves as a function of mole fraction composition (S-shape) with more negative values in the alcohol-rich regions. The excess molar volumes increase with the increase of the alkyl-chain length of the imidazolium cation of the ionic liquid. The values of the partial molar excess enthalpy and the enthalpy of mixing are positive and, for the case of methanol, do not vary monotonously with the length of the alkyl side-chain of the cation on the ionic liquid – increasing from n=2 to 6 and then decreasing from n=8. This non-monotonous variation is explained by a more favourable interaction of methanol with the cation head group of the ionic liquid for alkyl chains longer than eight carbon atoms. It is also observed that the mixing is less favourable for the smaller alcohols, the enthalpy of mixing decreasing to less positive values as the alkyl chain of the alcohol increases. Based on the data from this work and on the knowledge of the vapour pressure of {[C1CnIm][NTf2]+alcohol} binary mixtures at T=298K reported in the literature, the excess Gibbs free energy, excess enthalpy and excess entropy could be then calculated and it was observed that these mixtures behave like the ones constituted by a non-associating and a non-polar component, with its solution behaviour being determined by the enthalpy.

Measuring efficiency of positive and negative ionic wind devices for comparison to fans and blowers

Abstract Many industries are pursuing alternate air moving devices to reduce the power consumption of their air cooled products. The literature suggests that ionic AMDs have low efficiency. The literature, however, does not define efficiency the same way the computer industry defines it for rotary AMDs. In this study, static efficiency of ionic AMDs was evaluated similar to rotary AMDs. Various emitter to collector distances and various ring lengths, were evaluated for positive and negative coronas. By controlling emitter to collector distance and collector length, efficiencies were obtained more reasonably compared to rotary devices.

Analysis of Influence of Design Parameters on Ultimate Bearing Capacity of the Steel Spatial Tubular Joint

Utilizing general finite element software ANSYS, the finite element computing model of the steel spatial tubular joint is built, which is used to analyze the mechanical properties under dead loads through changing its design parameters. According to the obtained and compared consequences, the different design parameters including stiffening ring thickness, cross-shaped ribbed plate thickness and stiffening ring length exert different influence on ultimate bearing capacity of the steel spatial tubular joint. Specifically, the ultimate bearing capacity under dead loads is affected by setting stiffening ring and changing cross-shaped ribbed plate thickness significantly. In contrast, if the thickness and length of stiffening ring are changed, the impact is insignificant. The results and conclusion can provide reference which is useful to optimize the design of steel spatial tubular joint in such category.

ChemInform Abstract: Samarium Diiodide Mediated Intramolecular Cyclization of Mixed Enone—Enoate Systems: A Simple Preparation of Spirocyclic Ethers.

AbstractThe cyclization of substrates with different ring size and length of the tether is achieved with 2 equiv.