Average Gap Width Research Articles

Application of Local Flaps in Repairing Total and Near-Total Lower Lip Defects of Young Patients.

It has always been a great challenge for clinical doctors to reconstruct total and near-total lower lip defects. Compared with elderly patients, the repair operation in young patients is more difficult where free flaps are usually used for transfer. In order to obtain better postoperative results, the authors combined two kinds of local skin flaps for operation purpose, and evaluated their postoperative clinical effects. From April 2011 to May 2019, a total of 5 young patients with lower lip tumor or trauma were included in this study, with an average age of 30.4 years old. The lesion was all resected and resulted in a defect of 87% to total area of the lower lip, accompanied by a partial defect of the chin each. To repair the defect of the lower lip, the authors firstly used the modified Bernard flap. Then the authors designed the double Abbe flap to perform the operation according to the recovery of the patient 3 months later than the first operation. Finally, the outcomes of either operation were compared upon slit width, mouth opening height, aesthetics, and function of the patients, and statistically analyzed the results. All patients underwent the repair of modified Bernard flaps and double Abbe flaps of with no hemodynamic disorder of the flaps and well-recovery. At 3 months after the operation, the average gap width of lip was 4.34 ± 0.24 cm, the average opening height was 3.18 ± 0.28 cm, the average aesthetic score was 7.98 ± 0.51 (full score of 10), and the average functional score was 11.4 ± 0.55 (full score of 12). The 5 patients showed no obvious scar but a good shape on the lower lip. The function of eating, pronunciation, expression of feelings and smiling change were close to normal. Three patients had mild numbness in the lower lip, while the other two had normal sensory function. Combined modified Bernard flap and double Abbe flaps can bring out promising reparative outcomes of near-total or total lower lip defects in lower lip in young patients with good aesthetic and functional recovery, which is recommended while considering surgical alternatives.

Numerical modelling of boudinage under pure shear: Implications for estimating viscosity ratios and finite strain from natural examples

Numerical experiments of torn boudinage reworking under layer-parallel stretching are reported. In our simulations, we have reproduced the whole spectrum of previously reported boudin shapes due to reworking, and we also report some new structures, including field examples. The results show that boudin shape depends on both the boudin to matrix viscosity ratio and the initial gap width normalized upon the layer thickness. Central bulges develop within the interior boudin faces for intermediate gap widths, in the range of between 0.05 and 0.15 of the initial layer thickness. Convex interiors are reported for initially very narrow separations of about 0.01 the initial layer thickness. The initial normalized gap width together with the viscosity ratio control the internal deformation and separation of the boudins. Lowering the viscosity of the gap infill strongly influences boudin shape evolution and it suppresses the bulging of the interior faces. Boudin aspect ratio has only minor influence on the developing boudin shape. The non-linear viscous reworking of boudins is not significantly different to the one observed in linear viscous materials. We show a natural example of how the geometry of the developing bow-tie vein combined with boudin shape and separation can be used to infer strain and rheological properties. Rhomboidal boudins under layer-parallel stretching exhibit rotation and they tend to produce monoclinic structures, which are similar to structures forming due to layer-parallel shear. We caution the use of asymmetric boudins as shear sense indicators.

Effect of the Endwall Motion on a Hydrofoil with Various Widths of Clearance

This paper is devoted to evaluate the effects of the relative motion between the blade tip and casing wall with different widths of gap. The steady non-cavitating simulations around a sharp tip hydrofoil in tunnel with a moving endwall are implemented and another calculation with the stationary wall is carried out as a contrast. Overall, the endwall motion moves the trajectory of the tip leakage vortex (TLV) much closer to the foil but brings small effect on the streamwise vorticity and the minimum pressure in the TLV. The influence of the gap width is taken into account with the normalized gap width withinτ=0.02∼0.4. The flow features on a cross section inside the gap suggest that the endwall motion causes a little lower leakage flow rate and velocity in pitchwise direction. Inside a wider gap like τ=0.2, the pressure of the tip separation vortex (TSV) is a little higher and the direction of the velocity gradient for the streamwise flow is changed under the effect of the moving wall. The foil loading characteristics are revealed by the lift and drag coefficients which are a slightly lower under the effect of the endwall motion.

Numerical evaluation of the clearance geometries effect on the flow field and performance of a hydrofoil

The blade tip leakage flow with efficiency losses and cavitation phenomena is a concern for the low-head tidal power units. A simplified case of NACA0009 hydrofoil in a water tunnel is used to investigate the effects of tip clearance geometries including the foil tip shape and gap width on the flow features and foil performance. Steady non-cavitating simulations are implemented for a round tip foil and a sharp tip foil with two incidence angles (α = 10° and 5°) and different normalized gap width (τ). The minimum pressure is used to reflect the normalized vortex intensity (Γ*) and cavitation characteristics. The Γ*-τ curves at different streamwise positions show that the sharp tip foil generates relatively weaker tip leakage vortex with more flat curves, but its higher Γ* of tip separation vortex in wider gaps increases the risk of clearance cavitation. The flow features on a cross section inside the gap suggest that the sharp tip reduces the leakage flow losses and increases the velocity gradient due to the boundary layer separation. The lift coefficient is a little higher for the sharp tip foil than the round tip foil, with small differences for α = 5° but noticeable deviations for α = 10° especially within 0.3<τ < 1.

Flexural wave band gaps and vibration reduction properties of a locally resonant stiffened plate

A locally resonant stiffened plate is constructed by attaching a two-dimensional periodic array of spring-mass resonators to a traditional periodic stiffened plate. A method based on the finite element method and Bloch theorem is presented for calculating the flexural wave dispersion relation and forced vibration response of the proposed locally resonant stiffened plate. The method is validated by comparing the predictions with simulations by FEM software COMSOL. The effects of the spring-stiffness and mass ratio of local resonators on the flexural wave band gap and vibration reduction performance are analysed, which can facilitate the design of the locally resonant stiffened plate for vibration-reduction applications in engineering. The main findings of this work are as follows. 1) The local resonator can have a significant effect on the propagation of flexural wave in stiffened plate. On the one hand, the local resonator is able to create a low-frequency local resonance band gap; on the other hand, it can enhance the high-frequency Bragg band gap. Within the band gap frequency range, the vibration of the locally resonant stiffened plate can be reduced remarkably. 2) The spring-stiffness of local resonators shows a notable influence on the band gap and vibration reduction performance of the locally resonant stiffened plate. As the spring-stiffness gradually increases, the nature frequency of local resonator is gradually tuned to higher frequency, and the phenomenon of band-gap transition and band-gap near-coupling may arise. Under the near-coupling condition, the pass band between two band gaps turns narrow, and it seems that these two band gaps form a super-wide pseudo-gap (within which only a very narrow pass band exists). This behaviour is of great interest for the broad band vibration reduction applications. Moreover, the complete band gap will disappear if the nature frequency of local resonator is tuned to a higher value than a threshold frequency, which is dependent on the geometrical and material parameters. 3) The influence of the additional mass ratio of local resonator on the band gap behavior is highly relevant to the nature frequency of local resonator. If the nature frequency of resonator is lower than the band-gap near-coupling frequency, both the local resonance band gap and Bragg band gap are broadened with increasing the additional mass ratio of resonator. When the nature frequency of resonator is close to the band-gap near-coupling frequency, the phenomenon of band-gap near coupling and band-gap transition may arise or disappear as the additional mass ratio of resonator gradually changes. When the nature frequency of resonator is higher than the band-gap near-coupling frequency, on the one hand, the lower frequency band gap will disappear rapidly with increasing the mass ratio of resonator. However, it will be present again if the mass ratio of resonator increases up to a large enough value. On the other hand, the higher frequency band gap is broadened with increasing the mass ratio, but if the mass ratio is tuned to a larger value than a specific value, this band gap will transform from local resonance band gap to Bragg band gap, and the normalized gap width of this band gap will be narrowed with increasing the mass ratio.

Spin-wave band gaps created by rotating square rods in triangular lattice magnonic crystals

Recently, magnonic crystals which are the magnetic counterparts of photonic crystals or phononic crystals are becoming a hot area of research. In this paper, band structure of two-dimensional magnotic crystal composed of square rods triangularly arranged are calculated by using the plane-wave expansion method. Spin-wave band structures of two-dimensional magnonic crystal composed of Fe triangularly arranged Fe in an EuO matrix. The results show that when the filling ratio f=0.4, only two absolute band gaps can be found in the case of θ=0°. The first gap appears between the first band and the second band, the second gap between the sixth band and the seventh band. However, the number of band gaps can be improved by rotating the square rods through θ=25°, there are eight absolute band gaps that can be found. The first gap appears between the first band and the second band, the fifth gap between the sixth band and the seventh band. The new band gaps can be found, the second gap appears between the third band and the fourth band, the third gap between the fourth band and the fifth band, the fourth gap between the fifth band and the sixth band, the sixth gap between the seventh band and the eighth band, the seventh gap between the eighth band and the ninth band, the eighth gap between the ninth band and the tenth band. These results show that it is possible to create spin-wave gaps by rotating square rods in a two-dimensional magnotic crystal. The numerical results of the normalized gap width ΔΩ/Ωg of the first gap between the first band and the second band always changes with filling fraction f and rotational angles θ. When f=0.6 we calculated the first normalized gap width ΔΩ/Ωg. when f=0.6 and θ=0°, the first gap width ΔΩ=0.812(μ0ω/g) and the normalized gap width ΔΩ/Ωg=0.9187. The results show that from the first normalized gap widths the largest one can be found when f=0.6 and θ=5°, the first gap width ΔΩ=0.937(μ0ω/g) and the normalized gap width ΔΩ/Ωg=0.9591. The results show that the numerical, rotating square rods can make the low frequency band gap widen in the triangular lattice of two-dimensional magnonic crystal.

Circulation cells in flow past a periodic wall

We present a long wavelength model in order to derive a simple formula for the amplitude at the onset of circulation cells in flow past a wavy wall. The flow takes place between a wavy wall and a plane wall and is driven by moving the plane wall. There is no amplitude restriction but the Reynolds number is small and the wavelength is long. We find recirculation cells at an amplitude of about 3/10 the average gap width. This is confirmed by a Stokes flow calculation which can be done for all wavelengths.At long wavelengths the circulation cells can be eliminated if, in addition to the moving wall, the flow is driven by gravity.

Micromachining techniques in developing high-frequency piezoelectric composite ultrasonic array transducers

Several micromachining techniques for the fabrication of high-frequency piezoelectric composite ultrasonic array transducers are described in this paper. A variety of different techniques are used in patterning the active piezoelectric material, attaching backing material to the transducer, and assembling an electronic interconnection board for transmission and reception from the array. To establish the feasibility of the process flow, a hybrid test ultrasound array transducer consisting of a 2-D array having an 8 × 8 element pattern and a 5-element annular array was designed, fabricated, and assessed. The arrays are designed for a center frequency of ~60 MHz. The 2-D array elements are 105 × 105 μm in size with 5-μm kerfs between elements. The annular array surrounds the square 2-D array and provides the option of transmitting from the annular array and receiving with the 2-D array. Each annular array element has an area of 0.71 mm(2) with a 16-μm kerf between elements. The active piezoelectric material is (1 - x) Pb(Mg1/3Nb2/3)O3-xPbTiO3 (PMN-PT)/epoxy 1-3 composite with a PMN-PT pillar lateral dimension of 8 μm and an average gap width of ~4 μm, which was produced by deep reactive ion etching (DRIE) dry etching techniques. A novel electric interconnection strategy for high-density, small-size array elements was proposed. After assembly, the array transducer was tested and characterized. The capacitance, pulse-echo responses, and crosstalk were measured for each array element. The desired center frequency of ~60 MHz was achieved and the -6-dB bandwidth of the received signal was ~50%. At the center frequency, the crosstalk between adjacent 2-D array elements was about -33 dB. The techniques described herein can be used to build larger arrays containing smaller elements.

Tailoring Plasmon Coupling in Self-Assembled One-Dimensional Au Nanoparticle Chains through Simultaneous Control of Size and Gap Separation

We investigated the near- and far-field response of one-dimensional chains of Au nanoparticles (NPs) fabricated with high structural control through template guided self-assembly. We demonstrate that the density of polyethylene glycol (PEG) ligands grafted onto the NP surface, in combination with the buffer conditions, facilitate a systematic variation of the average gap width (g) at short separations of g<1.1nm. The overall size (n) of the cluster was controlled through the template. The ability to independently vary n and g allowed for a rational tuning of the spectral response in individual NP clusters over a broad spectral range. We used this structural control for a systematic investigation of the electromagnetic coupling underlying the superradiant cluster mode. Independent of the chain length, plasmon coupling is dominated by direct neighbor interactions. A decrease in coupling strength at separations ≲0.5nm indicates the presence of non-local and/or quantum mechanical coupling mechanisms.

Dependency of the photonic band gaps in two-dimensional metallic photonic crystals on the shapes and orientations of rods

Photonic bands in two types of two-dimensional metallic photonic crystals (2-D MPCs), which are composed of dielectric rods embedded into a metallic background (type I MPCs) and metallic rods in a dielectric background (type II MPCs), are investigated theoretically using a method based on the frequency-dependent plane-wave expansion method. We discuss the maximization of the normalized gap width as a function of the rod shapes and orientations. In addition, we study the effect of dielectric constants of the rods and the background on the width of the photonic band gap. Four different shapes of rods-square, circular, diamond, and rectangular-are considered. The numerical results show that the type I MPCs have a higher normalized gap width than the type II MPCs. We observe that the rotation of the noncircular rods in the type I MPCs leads to a slight variation, less than 10%, in the normalized values of the gap width in the two lattice structures. However, rotating the metallic square rods arranged in a square lattice results in doubling of the normalized gap width. The normalized gap width can be tailored by changing the dielectric constant of the rods (background) in type I (type II) MPCs.

Complete band gaps of phononic crystal plates with square rods

Much of previous work has been devoted in studying complete band gaps for bulk phononic crystal (PC). In this paper, we theoretically investigate the existence and widths of these gaps for PC plates. We focus our attention on steel rods of square cross sectional area embedded in epoxy matrix. The equations for calculating the dispersion relation for square rods in a square or a triangular lattice have been derived. Our analysis is based on super cell plane wave expansion (SC-PWE) method. The influence of inclusions filling factor and plate thickness on the existence and width of the phononic band gaps has been discussed. Our calculations show that there is a certain filling factor (f=0.55) below which arrangement of square rods in a triangular lattice is superior to the arrangement in a square lattice. A comparison between square and circular cross sectional rods reveals that the former has superior normalized gap width than the latter in case of a square lattice. This situation is switched in case of a triangular lattice. Moreover, a maximum normalized gap width of 0.7 can be achieved for PC plate of square rods embedded in a square lattice and having height 90% of the lattice constant.

Lamb waves in two-dimensional phononic crystal plate with anisotropic inclusions

An analysis is given to the band structure of the two-dimensional phononic crystal plate constituted of a square array of elastic anisotropic, circular Pb cylinders embedded in elastic isotropic epoxy. The numerical results show that the band gap can be tuned by rotating the anisotropic material orientation. It is found that the influence of anisotropy on band gap of Lamb wave is clearly different from that on the band gap of bulk waves. The thickness of the system under study is a sensitive parameter to affect the influence of anisotropic materials on the normalized gap width.

Effects of Powder Sphericalization on DC Biased Properties of Powder Cores and Modeling

Effects of powder sphericalization on DC biased properties of powder cores have been investigated and simulated using a nonmagnetic grain boundary (NMGB) model. Water atomized iron powder and Fe-6.5 mass % Si powder have been sphericalized by a powder surface modification system. Aspect ratio has got smaller depending on rotational speed. Aspect ratio of the former at rotational speed 8000rpm and 180 sec have gotten as 1.29 equivalent to gas atomized iron powder and DC biased property has been improved. They have been compared with values calculated by the NMGB model. The relative inaccuracy has been within 4.23 %. Aspect ratio of the latter (Fe-6.5 mass % Si powder) has had smaller with higher rotational speed, while DC biased property has not been improved. They have been compared with values calculated by the NMGB model. The relative inaccuracy has been within 4.68 %. The gap width distribution has been compared between calculated and measured values. The relative inaccuracy of the average gap width has been 5.17 % on the iron powder core and 78.3 % on the Fe-6.5 mass % Si powder core.

The corotation gap in the Galactic H i distribution

We used the H i data from the LAB Survey to map the ring-shaped gap in H i density that lies slightly outside the solar circle. Adopting R0= 7.5 kpc, we find an average gap radius of 8.3 kpc and an average gap width of 0.8 kpc. The characteristics of the H i gap correspond closely to the expected ones, as predicted by theory and by numerical simulations of the gas flow near the corotation resonance.

P2X7-mediated Increased Intracellular Calcium Causes Functional Derangement in Schwann Cells from Rats with CMT1A Neuropathy

Charcot-Marie-Tooth (CMT) is the most frequent inherited neuromuscular disorder, affecting 1 person in 2500. CMT1A, the most common form of CMT, is usually caused by a duplication of chromosome 17p11.2, containing the PMP22 (peripheral myelin protein-22) gene; overexpression of PMP22 in Schwann cells (SC) is believed to cause demyelination, although the underlying pathogenetic mechanisms remain unclear. Here we report an abnormally high basal concentration of intracellular calcium ([Ca(2+)](i)) in SC from CMT1A rats. By the use of specific pharmacological inhibitors and through down-regulation of expression by small interfering RNA, we demonstrate that the high [Ca(2+)](i) is caused by a PMP22-related overexpression of the P2X7 purinoceptor/channel leading to influx of extracellular Ca(2+) into CMT1A SC. Correction of the altered [Ca(2+)](i) in CMT1A SC by small interfering RNA or with pharmacological inhibitors of P2X7 restores functional parameters of SC (migration and release of ciliary neurotrophic factor), which are typically defective in CMT1A SC. More significantly, stable down-regulation of the expression of P2X7 restores myelination in co-cultures of CMT1A SC with dorsal root ganglion sensory neurons. These results establish a pathogenetic link between high [Ca(2+)](i) and impaired SC function in CMT1A and identify overexpression of P2X7 as the molecular mechanism underlying both abnormalities. The development of P2X7 inhibitors is expected to provide a new therapeutic strategy for treatment of CMT1A neuropathy.

Growth and Application of Paired Gold Electrode Junctions: Evidence for Nitrosonium Phosphate During Nitric Oxide Oxidation

AbstractA bipotentiostatic gold electrodeposition process is developed to grow gold junctions between two adjacent 100 μm diameter platinum disc electrodes. Gold is electrodeposited simultaneously on both electrodes with an automated termination mechanism close to short‐circuit conditions. Gap junctions (average gap width ca. 4 μm) are obtained reproducibly and the behavior of the resulting generator–collector electrode system is investigated for two relevant redox systems. First, the chemically reversible oxidation of 1,1′‐ferrocenedimethanol in aqueous 0.1 M KCl is studied. Well‐defined feedback currents across the electrode junction in generator–collector mode are recorded down to sub‐micromolar analyte concentration. Electrochemically reversible voltammetric responses suggest fast heterogeneous electron transfer and this allows further gap geometry analysis. Second, the (apparently) chemically irreversible oxidation of nitric oxide in 0.1 M phosphate buffer solution (pH 7) at gold electrodes is re‐investigated and, perhaps surprisingly, generator–collector feedback currents are observed for a solution phase intermediate, here tentatively assigned to nitrosonium phosphate, NO+H2PO$\rm{ {_{4}^{-}}}$. The life time of this intermediate, ca. 10 ms, is surprisingly long, given a typical decay time for free NO+ in water of only nanoseconds. The results are consistent with an estimated nitrosonium phosphate association equilibrium constant, K≈107 mol−1 dm3. Without further optimization of the electrode junction gap geometry, the determination of nitric oxide down to ca. 10 μM concentration is achieved. The benefits of smaller junctions and potential analytical applications of paired nanojunction electrodes are discussed.

Optimization of the local resonant sonic material by tuning the shape of the resonator

The resonator shape dependence of the first resonance frequency (RF) and the normalized gap width of a layer local resonant sonic crystal was studied. The unit block of the local resonant sonic material, the three component resonator, extended from spherical symmetry to azimuthal symmetry. Both the least square collocation method and the Lagrange multiplier method were introduced to study the more complicated system. Based on numerical calculation, it was found that both the first RF and the normalized gap width can be optimized by adjusting the shape of the core or cavity of the resonator under certain conditions. The approach can be extended to more general cases.

Improving the Content Uniformity of a Low-Dose Tablet Formulation Through Roller Compaction Optimization

In this investigation, the potency distribution of a low-dose drug in a granulation was optimized through a two-part study using statistically designed experiments. The purpose of this investigation was to minimize the segregation potential by improving content uniformity across the granule particle size distribution, thereby improving content uniformity in the tablet. Initial operating parameters on the Gerteis 3-W-Polygran 250/100/3 Roller Compactor resulted in a U-shaped potency function (potency vs. granule particle size) with superpotent fines and large granules. The roller compaction optimization study was carried out in two parts. Study I used a full factorial design with roll force (RF) and average gap width (GW) as independent variables and Study II used a D-optimal response surface design with four factors: RF, GW, granulating sieve size (SS), and granulator speed (GS). The planned response variables for Study I were bypass weight % and potency of bypass. Response variables for Study II included mean granulation potency with % relative standard deviation (% RSD), granulation particle size, sieve cut potency % RSD, tablet potency with % RSD, compression force at 7 kP crushing strength, and friability of 7-kP tablets. A constraint on GW was determined in Study I by statistical analysis. Bypass and observations of ribbon splitting were minimized when GW was less than 2.6 mm. In Study II, granulation potency, granulation uniformity, and sieve cut uniformity were optimized when the SS was 0.8 mm. Higher RF during dry granulation produced better sieve cut uniformity and tablets with improved uniformity throughout the run, as measured by stratified tablet samples taken during compression and assayed for potency. The recommended optimum roller compaction and milling operating parameters that simultaneously met all constraints were RF = 9 kN, GW = 2.3 mm, SS = 0.8 mm, and GS = 50 rpm. These parameters became the operating parameter set points during a model confirmation trial. The results from the confirmation trial proved that the new roller compaction and milling conditions reduced the potential for segregation by minimizing the granulation potency variability as a function of particle size as expressed by sieve cut potency % RSD, and thus improved content uniformity of stratified tablet samples.

Freezing of two-dimensional hard disks

We argue that structural rearrangements experienced by an assembly of hard disks under increasing disk density are accompanied by the mutual caging of each disk by its three alternating Voronoi nearest neighbors. This caging becomes effective at a packing fraction eta=pisqrt[3]8 approximately 0.680 when the average gap width between neighboring disks in the system shrinks to about 15% of the disk diameter. The freezing occurs when the fraction of caged disks is about 40%.

Preparation of a poly(3-hexylthiophene)-grafted indium tin oxide/poly(3-hexylthiopene) composite and its conductivity–temperature characteristics

The temperature–conductivity characteristics of poly(3-hexylthiophene) (P3HT) composites filled with P3HT-grafted indium tin oxide (ITO) particles were investigated in this work. The ITO particles were first treated with a silane coupling reagent of 3-aminopropyltriethoxysilane (APS), and then thiophene rings were introduced through a condensation reaction between the ending amino groups of APS and the carboxylic groups of thiophene-3-acetic acid. The composites were prepared by the polymerization filling of the 3-hexylthiophene (3HT) monomer with the thiophene-ring-introduced ITO particles. Elemental analysis, Fourier transform infrared, and X-ray photoelectron spectroscopy were used to confirm the grafting reaction on the ITO surface. The longer the polymerization time was or the higher the 3HT/ITO feeding ratio was, the more P3HT was grafted. The influence of the grafted amount on the electrical properties of ITO particles was attributed to the wrapping effect formed by the grafted P3HT on the surface of the ITO particles. The conductivity change of the P3HT-grafted ITO/P3HT composites was proved to be subject to the change in the average gap width of ITO interparticles, which was determined by the filling ratio of P3HT to ITO in the polymerization and the volume expansion effect of a P3HT thin film between neighboring ITO particles during the heating process. In comparison with the ungrafted ITO/P3HT composites, the grafting treatment enhanced the interaction between the particles and polymer matrix, and this was helpful for obtaining a more homogeneous dispersion structure for the composites and thus afforded a higher positive temperature coefficient intensity and better reproducibility. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1881–1888, 2006