Smooth Cross Section Research Articles

Properties and Antioxidant Capacity of Anchovy (Engraulis encrasicholus) By-Product Protein Films Containing Thyme Essential Oil.

In this study, some properties and antioxidant capacity of anchovy (Engraulis encrasicholus) by-product protein films with added 0.5, 1.0 and 1.5% of thyme essential oil were investigated. The films with thyme essential oil had higher elongation at break, water vapour permeability and oxygen permeability, lower solubility and tensile strength than control film (p<0.05). The incorporation of thyme essential oil affected transparency values of the films, but only the addition of 1.5% of thyme essential oil significantly reduced the transparency (p<0.05). In the film matrix, molecular organisation and intermolecular interaction were changed by thyme essential oil addition. The films with thyme essential oil had a heterogeneous surface and a relatively smooth cross-section structure. Slightly higher phase transition and lower glass transition temperatures were observed in films with thyme essential oil. The antioxidant capacity of the films was improved by incorporating thyme essential oil depending on its volume fraction.

A Source-Model Technique for Analysis of Scattering by a Periodic Array of Penetrable Cylinders Partially Buried in a Penetrable Substrate

A computational technique for analysis of scattering by an array of penetrable cylinders with smooth arbitrary cross section is described, for cylinders that are partially buried in a penetrable half-space substrate. In fabricated devices, cylinders may be partially buried due to side effects of the fabrication process, or anchored intentionally for some applications. Our suggested method is a rigorous full-wave frequency-domain source-model technique. The cornerlike intersections of the cylinders with the substrate and superstrate cause computational difficulty, owing to rapid spatial variations of the fields in their vicinity. They are addressed with particular care, by intricately locating properly modulated fictitious sources using a novel algorithm. We show that expanding the scattered fields with the fields of these sources satisfies all boundary conditions and energy conservation requirements within very low error thresholds. The respective software tool is robust to the choice of materials, geometric parameters, and incident excitation. Sample results are presented for circular and trianglelike cylinders. These examples demonstrate the importance of precise geometric modeling for analyzing partially buried arrays. For instance, as a larger portion of the array is buried, quantities such as scattered and dissipated power change rapidly but not necessarily monotonously as a function of the burial depth.

Collapse mechanism of deep tunnels with three-centered arch cross section

The possible collapse of different circumstances is derived with the help of the limit analysis theory. Analytical equations related to collapsing mechanisms in deep tunnel with smooth three-centered arc cross sections are derived on the basis of Hoek-Brown failure criterion and upper bound limit analysis. The pore water pressure is considered in the analysis, as a work rate of external force. Numerical results about the shape of detaching curve and the weight of collapsing block per unit length corresponding to different parameters are obtained with the help of mathematical software. The shapes of collapsing block are drawn with respected to different parameters. Furthermore, the effects of different parameters on the shape of detaching curve and the weight of the collapsing block are discussed.

Anisotropic Thermal Transport in Thermoelectric Composites of Conjugated Polyelectrolytes/Single-Walled Carbon Nanotubes

We report a method to determine the thermal conductivities of polymer composites with single-walled carbon nanotubes (SWNTs) using time-domain thermoreflectance. Both through-plane and in-plane thermal conductivities were determined. Two types of CPEs used in these studies are of the same conjugated backbone but with either cationic (CPE-PyrBIm4) or anionic (CPE-Na) pendant functionalities. The CPE-Na/SWNT composites are p-type conductors, whereas the CPE-PyrBIm4/SWNT counterparts exhibit n-type charge transport. The CPE/SWNT films were prepared through a filtration method that preferentially aligns the SWNTs in the in-plane direction. Attaching the composites onto glass substrates with a precoated heat transducer allows one to measure the through-plane thermal conductivity of materials with rough surfaces. The in-plane thermal conductivity can be measured by embedding thick samples into epoxy followed by microtoming to expose the relatively smooth cross sections. The thermal conductivity along the in-pla...

On the quantum mechanics of a particle constrained to generalized cylinders with application to Möbius strips

The intrinsic geometric approach to quantum mechanics has been applied to study nanostructures, as well as aromaticity and other electronic properties of molecules. Usually strong hypotheses on the geometry are made in order to allow for analytical solutions. We undertake the problem of stability, with respect to smooth deformations, of the spectra obtained under such simplifying hypotheses. In this article we show that symmetries can sometimes be removed by solving the problem of a particle constrained to a right cylinder with an arbitrary smooth cross section considering the effects of intrinsic geometry. The topology of the cross section, rather than its geometry, is shown to play a key role in this context. Our solution is applied to a generalized Mobius strip when the median curve is nearly a circle of diameter sufficiently large compared to the width of the strip. We also provide a systematic method for ordering the quantum states of generalized right cylinders according to their energies and apply this method to order the spectra of Mobius strips whose diameters are much larger than their widths. Finally, for the sake of comparison, our results are used to calculate the \(\uppi \) electron energy spectra of five aromatic molecules (benzene, pyrazine, pyridine, 1,3 diazyne and 1,3,5 triazyne), showing a fair agreement with experimental data and quantum chemistry calculations.

Techniques to manage geometry characteristics of hollow-fiber membranes

The process of the dry-wet spinning of asymmetric hollow-fiber membranes has been studied. The set of the parameters of spinning process, which allows the preparation of the smooth, round, and symmetric cross section of a fiber and the given inner and outer diameter so that the hollow-fiber membrane would finally appear as a smooth hollow cylinder, has been determined. The procedure was carried out using the fabrication of hollow fibers from poly(2,6-dimethyl-1,4-phenylene oxide) as an example. The samples with the oxygen permeance Λ/δ (O2) = 400 L/(m2 h bar) and the separation factor corresponding to the properties of material, α(O2/N2) = 4.5, have been obtained. The effective thickness of the selective layer of this membrane is 100 nm. The maximum diameter ratio that has been attained upon dry-wet spinning is 1.4 for the studied polymer solution–internal coagulant system.

A New Solvent for the Industrial Production of Cellulose Fibers: Quaternary Ammonium Acetate

Tetrabutylammonium acetate, a new solvent, can dissolve cellulose (8 wt%) within 5 min at 40°C with dimethyl sulfoxide as coslovent without any pretreatment or inert gas atmosphere. The dissolution detail was recorded by Confocal Laser Scanning Microscope. And the viscosity of cellulose solution prepared from the new solvent was only 10% of that prepared from [BMIM]Cl. Moreover, the influence of molecular weight on the rheology of the cellulose solution was investigated. With the increase of the molecular weight, the viscosity was increasing and the cross-over point of the storage modulus (G′) and loss modulus (G′′) curves shifted to the lower angular frequency. The structure and mechanical properties of the fibers prepared from the cellulose solution were characterized by FT-IR, XRD, SEM and DSC. During the dissolution process, the crystalline region of the cellulose was destroyed and the celluloseIbecame amorphous. However, part of amorphous cellulose transformed into celluloseII by the wet spinning, indicated by FT-IR and XRD spectrum. SEM images showed that the resulting fibers were homogeneous with smooth surfaces and circular cross-sections. Meanwhile, the cellulose fibers had good thermal stability, measured by DSC. This work provided a promising way to prepare cellulose fibers with good physical properties, which was green, low cost and suitable for industrial production.

Tensile Properties and Fracture Reliability of Melt-extracted Gd-rich Amorphous Wires

Gd60Al20Co20 amorphous wires with smooth surfaces and circular cross-sections were fabricated by a melt-extraction technique. The mechanical properties of the extracted microwires were evaluated by tensile tests and their fracture reliability was estimated by using Lognormal and two- or three- parameter Weibull analysis, respectively. The microwires exhibit a tensile fracture strength ranging from ~788 to ~1196 MPa, with a mean value of 1008 MPa and a standard variance of 121 MPa. Lognormal method of statistical analysis presents that the average stress of microwires is ~1012 MPa. Weibull statistical analysis indicates that the two-parameter tensile Weibull modulus is 8.5 and the three-parameter Weibull modulus is 5.3 with a threshold value ~365 MPa for as-extracted amorphous microwires. Our results show that the extracted Gd-based wires possess excellent tensile properties and high fracture reliability, with a high potential for applications in and magnetic refrigeration.

Torsion of an arbitrarily shaped nanosized bar

We investigate the Saint-Venant torsion problem of a nanosized bar with arbitrary smooth cross section by enhancing the classical continuum-based model with a theory of surface elasticity based on a version of the Gurtin–Murdoch surface/interface model. An elegant analytical solution is derived by means of conformal mapping, Faber series, Fourier series, and simple matrix algebra. Our solution leads to the establishment of a complex torsion function which, in turn, allows for a concise expression for the torsional rigidity. Our results clearly demonstrate that both the stress field and the normalized torsional rigidity are size dependent. An approximate formula for the size-dependent torsional rigidity is also proposed.

L-Shaped Machining of Anisotropic Woods with a Fine Wire Cutting Tool

A fret-saw blade is commonly used in micromachining or curve machining of various woods. However, there is a curvature limit for machining of free-form surfaces because a fret-saw blade has a thickness of several hundred microns and a width of several millimeters. Additionally, cutting with a fret-saw blade produces much wood meal as chips. If a fine wire cutting tool is used, more flexible machining, such as machining of high curvature free-form surfaces, is possible and the quantity of chip production drastically decreases. The main purpose of this study is to clarify the fundamental machinability of anisotropic materials cut with a fine wire tool. In this report, we describe the machinability of various woods that are naturally anisotropic materials using a fine wire cutting tool that has electrodeposited diamond grains on its surface. In addition, this report discusses the performance of a trial manufactured hand tool employing the same wire cutting tool. The main conclusions obtained in this study are as follows. Acceptable machining of anisotropic woods is possible using a fine wire cutting tool, and the kerf width produced with this wire tool is narrower than that produced with a fret-saw blade. Additionally, the wood species and the cutting direction with respect to the wood grain have a significant influence on the machinability of various woods. Moreover, a relatively smooth cross section is provided when wood is cut by the hand tool using the fine wire tool.

Failure criteria for cohesive‐frictional materials based on Mohr–Coulomb failure function

SummaryThis study presents two three‐parameter failure criteria for cohesive‐frictional materials based on the Mohr–Coulomb failure function. One proposed failure criterion can be linked to Mogi's empirical formula and incorporates the well‐known Von‐Mises, Drucker–Prager, and Linear Mogi criteria as special cases. Another one with smooth and convex cross sections contains a general Lode dependence in the deviatoric plane and includes the Matsuoka–Nakai and Lade–Duncan Lode dependences as special cases. The effect of the intermediate principal stress on the strength of the material can be taken into account in both criteria. The proposed criteria are numerically calibrated against polyaxial data sets of many different types of rocks and concrete. The comparison results show that the performance of the proposed criteria is excellent, and the failure criterion with a general Lode dependence performs better than the other one for concrete. Copyright © 2015 John Wiley &amp; Sons, Ltd.

Dissolution of cellulose with a novel solvent and formation of regenerated cellulose fiber

A new cellulose solution was prepared by a new cellulose solvent, tetrabutylammonium acetate (TBAA)/dimethyl sulfoxide (DMSO). A new kind of regenerated cellulose fibers was spun successfully for the first time from the cellulose solution by a wet spinning system. The dissolving process of cellulose in TBAA/DMSO was observed by confocal laser scanning microscope. The rheological of the cellulose dopes was determined by rotated rheometer, and the results showed that the cellulose/TBAA/DMSO solution was a typical shear-thinning fluid. In addition, the morphology, chemical structure and mechanical properties of the prepared cellulose fibers were characterized by scanning electron microscope (SEM), 13C CP/MAS NMR, Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and electronic tensile tester, respectively. The SEM patterns showed that the regenerated fibers possessed a smooth surface and circular cross section. The results from 13C NMR and XRD patterns indicated that the novel fibers mainly exhibited amorphous cellulose. Meanwhile, the novel fibers have good mechanical properties.

Effects of Medium Characteristics on Laser RCS of Airplane with E-Wave Polarization

Plane wave incidence should be postulated to have an authentic target detection. Practically, the plane wave is incapable usually of keeping its power in the far field especially when propagating through an inhomogeneous medium. Consequently, we assume an incident beam wave with a finite width around the target. In this work, we calculate numerically a laser radar cross section (LRCS) of conducting targets having smooth cross sections with inflection points such as airplane in random media. Effects of fluctuations intensity of random media on the LRCS performance are studied in this paper. E-wave polarization (E-wave incidence) is considered while the mean target size is approximately twice the wavelength.

In-situ observation of the growth of individual silicon wires in the zinc reduction reaction of SiCl4

We conducted in-situ monitoring of the formation of silicon wires in the zinc reduction reaction of SiCl4 at 950°C. Tip growth with a constant growth rate was observed. Some wires showed a sudden change in the growth direction during their growth. We also observed both the lateral faces and cross sections of formed wires using a scanning electron microscope. Although wires with smooth lateral faces had a smooth hexagonal cross section, those with rough lateral faces had a polygonal cross section with a radial pattern. The transition of lateral faces from smooth to rough was found even in a single wire. Because the diameter of the rough part became larger than that of the smooth part, we consider that the wire diameter is a key factor for the lateral faces. Our study revealed that both dynamic and static observations are still necessary to further understand the VLS growth of wires and nanowires.

Fluctuations Above the Resonance Range in Evaluated Data of 55Mn

The evaluation procedures for 55Mn are elaborated, focusing on the issues related to the fluctuations in the cross sections above the resolved resonance range. Smooth cross sections are defined in the unresolved resonance range, based on the resolution-broadened total cross section measurements, where relevant. Above this energy fluctuations in the measured total cross section are introduced by scaling all reaction cross sections, but preserving the resolution-broadened total cross section. Special procedures are designed to match the observed structure in the average cosine of scattering by adjusting the ratio of the shape-elastic and compound-elastic contributions to the elastic scattering cross sections. The evaluated data file is being assembled and subjected to rigorous testing, verification and validation.

Comparison of Fatigue Characteristics of Structural Materials Obtained with Energy and Stress Controlled Parameter under Bending

The paper contains the results of fatigue tests of C45 steel and 2024 aluminum alloy under bending with the controlled amplitude of the moment and energy parameter. The circular smooth cross-section specimens were tested. All the fatigue tests were performed under a constant value of the nominal load ratio, R = - 1. The test frequency ranged from 11 to 15Hz. During the tests, histories of stress, strains, energy parameters and hysteresis loops, (σ-ɛ), were measured and registered. Then, the fatigue test results obtained with the controlled energy parameter and bending moment were compared.

Exponentially Converging Nyström Methods in Oblique Diffraction of Arbitrarily Polarized Waves by Bianisotropic/Chiral Cylinders With Arbitrary Smooth Cross Section

We study oblique diffraction of arbitrarily polarized plane waves by a uniform homogeneous bianisotropic cylinder with arbitrarily shaped smooth boundary. Following a boundary integral equations formulation we develop a 4 × 4 system of combined field integral equations and another 4 × 4 system of Muller-type Fredholm integral equations. Both these systems, having the tangential to the surface of the cylinder components of the electric and magnetic fields as the unknowns, are of the second kind and uniquely solvable. Efficient discretization via simple and rapidly converging Nystrom algorithms enables one to obtain highly accurate results even for electrically large objects. The proposed solution technique: a) fully accounts for the singular nature of the kernels; b) yields simple closed form expressions for all matrix elements; and c) appears to converge exponentially versus matrix size. The analogous diffraction problem for an arbitrarily shaped smooth chiral cylinder may be treated as a simple special case of the present analysis.

On uniqueness of tangent cones for Einstein manifolds

We show that for any Ricci-flat manifold with Euclidean volume growth the tangent cone at infinity is unique if one tangent cone has a smooth cross-section. Similarly, for any noncollapsing limit of Einstein manifolds with uniformly bounded Einstein constants, we show that local tangent cones are unique if one tangent cone has a smooth cross-section.

Fabrication of 17×17 box-like spectral response of an arrayed waveguide grating

In the fabrication of a polymeric arrayed waveguide grating (AWG) device, the cores of the channels and the arrayed waveguides exhibit smooth trapezoid cross-sections instead of originally designed rectangular ones after reactive ion etching and steam-redissolution. By employing the Marcatili theory, a method called “equivalent energy flow method” is proposed for analyzing the transmission characteristics of the polymeric AWG with trapezoid core cross-sections. The AWG parameters have been fixed, and a 17×17 polymeric AWG multiplexer has been designed and fabricated. Experimental results show that the central wavelength is 1550.83 nm, and the bandwidth at half maximum is about 0.478 nm; insertion loss is 10 to 13 dB, and crosstalk is about −21 dB .

Interdiffusion kinetics of miscible polymer/polymer laminates investigated by atomic force microscopy

The miscibility of poly(vinyl chloride)/poly(n-butyl methacrylate) (PVC/PnBMA) blend and the interdiffusion kinetics of PVC/PnBMA laminates have been investigated by differential scanning calorimetry (DSC) and atomic force microscopy (AFM), respectively. This blend exhibited a lower critical solution temperature behavior. Below 120 °C, DSC results showed each blend with different PVC contents exhibited only a single glass transition temperature which increased with PVC content, indicating that PVC and PnBMA were miscible. After PVC/PnBMA laminates were annealed at different temperature for different time, a smooth cross-section across interface was prepared by ultramicrotoming. Combined with topography and phase images of tapping mode AFM, the relative concentration profile, interface width and the relationship between interface width and annealing time could be obtained. In a regime of rubbery/rubbery interdiffusion, the diffusion obeyed a typical Fickian Case-I behavior where the interface width was proportional to the square root of annealing time. The mutual diffusion coefficient was in good agreement with that obtained from DSC and positron annihilation lifetime spectroscopy. However, in the regime of glassy/rubbery interdiffusion, the diffusion followed a typical Case-II behavior where the interface width was proportional to annealing time. These results imply that AFM is a reliable and powerful tool for the investigation of polymer/polymer interdiffusion at a level of polymer chain size.