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In order to select the heterogeneous multicore fiber (MCF) configuration with ultra-low crosstalk and low peak bending radius, comparative crosstalk analysis have been done for the three possible core configurations, namely, Configuration 1 - different refractive index (R.I.) and different radius, Configuration 2 - different R.I., and Configuration 3 - different radius. Using the coupled mode equation and the simplified expressions of mode coupling coefficient (MCC) for different configurations of heterogeneous cores, the crosstalk performance of all the heterogeneous MCF configurations along with the homogeneous MCF have been investigated analytically with respect to core pitch (D) and fiber bending radius ( R b ). Further, these expressions of MCC have been extended to obtain the simplified expressions of MCC for the estimation of crosstalk levels in respective trench-assisted (TA) heterogeneous MCF configurations. It is observed from the analysis that in Configuration 1, crosstalk level is lowest and the rate of decrease in the crosstalk with respect to the core pitch is highest compared to the other configurations of heterogeneous MCF. The values of crosstalk obtained analytically have been validated by comparing it with the values obtained from finite element method (FEM) based numerical simulation results. Further, we have investigated the impact of a fixed percent change (5%) in the core parameters (radius and/or R.I.) of one of the core of a homogeneous MCF, to realize the different heterogeneous MCF configurations, on the variations in crosstalk levels, difference in the mode effective refractive index of the core 1 and core 2 ( Δ n e f f = n e f f 1 − n e f f 2 ), and the peak bending radius ( R p k ). For the same percent variations (5%) in the core parameters (radius and/or R.I.) of different configurations of cores (Config. 1-Config. 3), Config. 1 MCF has highest variation in Δ n e f f value compared to other configurations of MCF. Further, this highest variation in Δ n e f f value of Config. 1 MCF results in smallest peak bending radius. The smaller value of peak bending radius allows MCF to bend into smaller radius. Therefore, Configuration 1 is the potential choice for the design of MCF with smaller peak bending radius and ultra-low crosstalk level compared to the other configurations of SI-heterogeneous MCF. [ABSTRACT FROM AUTHOR]

The impacts of core count/layout on the mode effective refractive index ( n eff ), bend- and twist-induced differential group delay (DGD) of different cores, worst-case DGD, and intercore DGD ( DGD IC ), in weakly coupled homogeneous multicore fibers (WC-HMCFs), have been analyzed to select the proper core layout with low DGD value for a particular core count. The core counts such as 3-core, 4-core, 6-core, and 12-core and the core layouts namely linear, triangular, square, rectangular, circular one ring structure (ORS), circular dual ring structure (DRS), hexagonal ORS, and square lattice structure (SLS) have been considered in the investigation. Moreover, in order to calculate the DGD IC values, the generalized expressions of core pitch (Λ) for the different core layouts have been derived. Further, the impacts of core radius (a ), relative refractive index difference (Δ ), and Λ on the n eff and DGD levels for the 3-core WC-HMCFs, with linear and triangular core layouts, have been analyzed numerically by using the finite element method-based FemSIM simulation platform, and MATLAB. It is observed that for a certain core count value, the core layout and Λ have significant impacts on the DGD levels, while the variations in the values of a and Δ have no significant impact on the DGD levels. Further, increase in core count normally increases the DGD levels in all core layouts. On the other hand, for the fixed values of core count, cladding diameter (D), and outer cladding thickness (OCT), the core layout which has the lowest core pitch leads to the lowest value of DGD IC , as compared to the other core layouts. The investigations carried out in this work may provide the guidelines in different MCF applications, such as MCF-based multi-parameter sensing and signal processing in microwave photonics. [ABSTRACT FROM AUTHOR]

Finite element method and bending experiments were carried out to survey the influence of bending radius on forming quality of H62 brass tubes in free bending process，which are widely used as key components of pipeline system in aerospace, aviation and automotive fields. Different bending radiuses ranged from 45 mm to 100 mm with an interval of 5 mm were employed to survey the forming defects. The results illustrated that both cross-section distortion and wall thickness variations at sections with angles in range of 10–20° and 160–170° were larger than other regions. The severe deformation behaviors usually occurred at the end of the tubes. Moreover, similar to the variation tendency of cross-section distortion, the changing of wall thickness decreases gradually with the increase of bending radius. Furthermore, the positions with the severer forming defects gradually moved towards to two terminals of the tubes with increasing bending radius. The variations of these deformation behaviors were mainly caused by the tangential stress and axial stress which were decomposed by an extra thrust introduced by the bending die. Based on the above force analysis and experimental results, the credible analytical equations were derived to quantify the effect of bending radius on forming precision during the practical bending process. [ABSTRACT FROM AUTHOR]

Copyright of Wool Textile Journal is the property of National Wool Textile Science & Technology Information Center and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this paper, an autonomous navigation strategy is proposed for unmanned aerial vehicles (UAVs) based on consideration of dynamic sampling and field of view (FOV). Compare to search-based motion planning, sampling- based kinodynamic planning schemes can often find feasible trajectories in complex environments. Specifically, a global trajectory is first generated with physical information, and an expansion algorithm is constructed regarding to kinodynamic rapidly-exploring random tree* (KRRT*). Then, a KRRT* expansion strategy is designed to find local collision-free trajectories. In trajectory optimization, bending radius, collision risk function, and yaw angle penalty term are defined by taking into account onboard sensor FOV and potential risk. Then, smooth and dynamic feasible terms are penalized based on initial trajectory generation. Trajectories are refined by time reallocation, and weights are solved by optimization. Effectiveness of the proposed strategy is demonstrated by both simulation and experiment. [ABSTRACT FROM AUTHOR]

As the front end of the intake system, the intake dirty pipe is responsible for delivering sufficient and stable air to the air filter. Therefore, in order to meet the requirements of low intake resistance, it is necessary to correspondingly improve the flow resistance performance of the intake dirty pipe. In this study, the main research object was the intake pipe in the intake system of gasoline engine vehicles, and the internal gas flow field was simulated and analyzed. The results show that there are clear discrete velocity regions at the inlet and elbow, which affect the uniformity of the overall fluid flow and cause a certain pressure loss. After structural optimization, the total pressure difference at the inlet and outlet of the pipeline was reduced by 22.67% compared to the original model, and the total pressure loss was significantly reduced. A simplified model was used to make samples of the intake dirty pipes before and after performance improvement, and flow resistance tests were conducted respectively. The difference between test data and simulation data is within a reasonable range, and the simulation results are relatively reliable. [ABSTRACT FROM AUTHOR]

In this research paper, we design and simulate the Silicon Oxycarbide (SiOC) channel waveguides and a photonic passive device such as a directional coupler. SiOC channel waveguides are designed for different values of width and height at a shorter wavelength band that is a 1310 nm wavelength window with a refractive index of SiOC (ncore) =2.2 µm and SiO2 (nclad) = 1.444 µm. TE and TM fundamental modes are achieved at width = 1.5 microns and height = 0.5 microns to understand the single mode operation of SiOC channel waveguides. The minimum bending radius of SiOC waveguide is found to be 30 microns which are large enough to integrate large-scale devices. A directional coupler is designed to measure the coupling power between waveguides with gaps of 0.6, 0.7, and 0.8 microns that give the 3 dB coupling at 20, 40, and 100 microns. In this research, Silicon Oxycarbide (SiOC) is presented as a potential material platform for the highly efficient photonic devices that will be used for shorter wavelength bands instead of the 1550 nm transmission wavelength window where bandwidth demand is increasing every day. Due to this shorter wavelength band is sufficient to develop and design SiOC waveguides to meet the future bandwidth requirement. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Henan University of Science & Technology, Natural Science is the property of Editorial Office of Journal of Henan University of Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

As the front end of the intake system, the intake dirty pipe is responsible for delivering sufficient and stable air to the air filter. Therefore, in order to meet the requirements of low intake resistance, it is necessary to correspondingly improve the flow resistance performance of the intake dirty pipe. In this study, the main research object was the intake pipe in the intake system of gasoline engine vehicles, and the internal gas flow field was simulated and analyzed. The results show that there are clear discrete velocity regions at the inlet and elbow, which affect the uniformity of the overall fluid flow and cause a certain pressure loss. After structural optimization, the total pressure difference at the inlet and outlet of the pipeline was reduced by 22.67% compared to the original model, and the total pressure loss was significantly reduced. A simplified model was used to make samples of the intake dirty pipes before and after performance improvement, and flow resistance tests were conducted respectively. The difference between test data and simulation data is within a reasonable range, and the simulation results are relatively reliable.

Recently, flexible organic light-emitting devices (OLEDs) have become more and more popular. However, the force distribution and deformation are very complex during the bending process, and it is difficult to analyze the stress and strain by theoretical analysis and direct experiment. In this paper, finite element analysis of the bending model for the flexible screen was performed. For common U-shaped bending, it was shown that the maximum Mises stress increases rapidly as the bending radius decreases, and the redistribution of the tensile zone and the compression zone should be the key to the layer material selection. The results were verified by an imaging experiment. Further, a water-drop-shaped bending mode was analyzed to reduce the risk of structure failure. [ABSTRACT FROM AUTHOR]

Choosing a suitable bending structure is an important way to optimize flexible AMOLED. In this article, we proposed and established a drop‐shape model through nonlinear finite element analysis software, comparing it with the "U"‐shaped bending model. The mechanical stress conditions under different bending radius are analyzed and compared. Aiming to find a better module folding track, we output the influence of the bending radius on the stress and strain of the device layer, so that these data and research can provide reliable support for future material selection and structural optimization. The super‐elastic and viscoelastic behaviors of optically clear adhesive are described by polynomial reduced integral and Prony series model, respectively. Both U‐shaped various layers of film and overall flexible screen module strains increase fast with the decreasing of bending radius and smaller radius will increase the fatigue damage risk. The stress and strain of the drop shape did not change significantly with the decrease of the radius. During the bending process, the most stressed part appears in the outermost TP layer. In a small radius, it can be optimized from a curved structure, and water drop and wedge shapes can be prioritized. [ABSTRACT FROM AUTHOR]

Endoscopy is an important modality in medical imaging. Thin flexible endoscopes are for example used to examine the upper airways, for gastroscopy procedures or lung inspection. With standard flexible endoscopes one can change the direction of view by bending the tip with the disadvantage of large space required due to the bending radius. With first experiences of a concept of a moveable camera head on the tip of rigid endoscopes, we now propose a novel design employing a swiveling camera for flexible endoscopes. This concept is based on the use of a shape memory wire used to control the movement of the camera, a flexible plastic flap joint for tight rotation and flexible printed circuits for the electronic connection. The prototype was realized in a first low cost setup using a 5,5 mm HD chip on the tip camera with LED light. The motion and imaging performance of the prototype allowed swiveling of the camera on the endoscope tip from straight view to 100° side view. The space needed in fully rotation was limited to 9mm with an overall diameter of the endoscope in straight view of only 5,6mm, but could even be further reduced in a more professional setup. The image quality is good, but close-up views appear blurry due to the fixed focus point of the low-cost camera. The presented steering concept of the camera is promising, as it could potentially improve imaging of narrow cavities using flexible endoscopes. Especially for “in office” examinations this principle could add value to diagnosis and patient comfort.

Aims of research. This paper deals with the problem of determining the radius of the neutral surface of the bending strip at the same time the action of tensile stresses. Methods. In the development of technological processes of sheet bending and the calculation of the initial billet (sweep), most often considered a flat stress state and preference is given to the theory of pure bending, providing uniform curvature of the individual layers of metal under the action of the bending moment and neglecting the action of transverse tensile forces. However, in reality, bending is always accompanied by sliding of the metal along the deforming tool, causing the appearance of friction forces and creating a complex loading in the form of plastic bending with stretching in the metal, which will additionally displace the neutral surface, forcing the experienced one to adjust the technology of manufacturing bent parts. Provides an overview and analysis of the most famous works dedicated to the topic, specifying the distribution of the contact stresses from the inner surface to the center of curvature and developed the theory of complex bending, which allows to specify the radius of the neutral surface in conditions of stretching of the flexible strip of the additional tangential stresses. Results. The results obtained will allow to simulate the stress state of the metal in the development of technological processes of sheet stamping and, in particular, to assess the specific braking force during the bending (straightening) of the strip in the process of pulling through the thresholds and brake edges of the die tooling to eliminate possible defects in the elongated parts and to clarify the dimensions of the workpiece and the finished profile.

The PAM-Stamp 2G software package is used to simulate the tool bending of a workpiece made of an AMg5 aluminum alloy with and without taking into account the heat-affected zone (HAZ) formed during laser cutting of a sheet. The option of calculating welded workpieces is adapted to describe the HAZ. The state of stress in the workpiece during bending at various bending radii is analyzed with allowance for various HAZ widths. The influence of HAZ up to 4.5 mm wide on the workpiece thickness during bending is found to be insignificant. [ABSTRACT FROM AUTHOR]

With the increasing application of the advanced high strength steel material in the automobile industry, the thickness reduction of the bending area has attracted more and more attention since the product strength is highly influenced by the quality of the bending region. In this paper, three major factors, the thickness reduction, the variation of the local bending radius within the bending zone, and the tooling mark on the product's surface, are investigated through three different loading patterns for a free U-bending profile numerically and experimentally. The results demonstrate a thinning pattern consists of three peaks over the bending region for large bending ratio (R/t = 2.14) and only one peak for small bending ratio (R/t = 0.5). Corresponding valleys for the local radius are found to match the thinning pattern. Further, the use of finite element simulation can successfully predict the location and the severity of the wear on the product. From the experiment results, even if the metal blank only experienced one stroke, the tooling mark contains both adhesive and abrasive wear. A better understanding of the characteristics of the bending zone is achieved, and the findings can help in improving the design process for forming strategies. [ABSTRACT FROM AUTHOR]

Although the development of REBCO coated conductor has proved its superiority of critical current in high-field background, mechanical issues caused by electromagnetic forces are still big challenges. Large-scale magnets call for robust and high-J e cables for simplicity of the system. To meet the requirements, here we report a round cable comprised of a stack of 2 mm wide high-temperature superconducting (HTS) tapes inserted into a copper tube and all soldered with Sn 63 Pb 37. The two prepared samples include five HTS tapes and four copper strips in untwisted manner. Self-field critical current at 77 K was analyzed both numerically and experimentally. The characteristics of in-plane (hard) and out-of-plane (easy) bending were analyzed by finite element method (FEM) and compared to experimental measurements. Good agreement was found between the analysis and experimental results on critical bending radius, which is about 200–215 mm. Our results indicate the robustness of the round strand and its potential for use in large-scale magnets. [ABSTRACT FROM AUTHOR]

The relevance. There are thermonuclear reactions inside the Earth. This causes displacement of the earth's surface. In the areas of shear tectonic plates – geodynamic zones – there is a change in position of underground pipelines. Changing the position of the main pipeline leads in its turn to a change in its stress-strain state. After activation of the faults, the blocks start moving. At first they move slowly, then the rate of movement increases, the pipelines that are under long-term operation get into the risk zone, so the control of the stress-strain state of the pipelines at the intersections with the geodynamic zones is relevant. The main aim of the research is to develop and implement a technology for identifying sections of pipelines at their intersection with geodynamic zones, providing for identification of potentially hazardous areas to assess the stress-strain state of the pipe. The objects: areas of passage of the main pipelines on the territory of the Republic of Bashkortostan at the intersections with geodynamic zones. Methods: analysis of the results of in-line inspection with measurement of bending radii of pipelines, identification of potentially dangerous areas, analytical calculation of the stress-strain state of pipelines. Results. The paper introduces the technology of revealing sections of pipelines with flexural stresses at their intersection with geodynamic zones. The technology involves determination of actual position of the main pipeline, direct measurement of the bend radius. Having the data on the sections of pipelines with non-normative bending radii of 500D and less the authors have proposed to identify potentially hazardous areas from the reports on in-line flaw detection in the work; re-skip of in-tube flaw detectors, every 2–3 years will allow estimating the dynamics of the change in bend radii, and identifying as well active geodynamic zone.

Recently, flexible organic light-emitting devices (OLEDs) have become more and more popular. However, the force distribution and deformation are very complex during the bending process, and it is difficult to analyze the stress and strain by theoretical analysis and direct experiment. In this paper, finite element analysis of the bending model for the flexible screen was performed. For common U-shaped bending, it was shown that the maximum Mises stress increases rapidly as the bending radius decreases, and the redistribution of the tensile zone and the compression zone should be the key to the layer material selection. The results were verified by an imaging experiment. Further, a water-drop-shaped bending mode was analyzed to reduce the risk of structure failure.

The use of a bending machine acquired a high level of importance as a consequence of increasing the level of the industry. This paper aims to develop a more accurate and precise bending machine. The proposed bending machine has achieved brilliant output products, in which three main manufacturing parameters have been examined for the production of an equilateral triangle, which are flange length, bending angle and bending radius. The main point depends on the proposed algorithm, which has been developed based on separating the process, in which the central controller is responsible mainly for controlling the sub-controller, where the sub-controllers are programmed using PID to control the entire mechanisms of feeding and bending separately and ensure that the outcomes of these mechanisms are compatible with the input data from the central controller. Ten different dimensions of an equilateral triangle design sample with ten tries for each dimension (variable flange length, fixed bending angle equals to 60 degrees and bending radius equals to 3 mm) have been selected being produced using the bending machine, and the products have been formed two times. Firstly, using the proposed bending machine, in which the proposed algorithm is applied. Secondly, using the bending machine implemented without applying the proposed algorithm. The results have been compared in terms of error rates with respect to the standard design of products designed using CAD/CAM application. An enhancement has been recorded in terms of product accuracy and precision for the parameters of flange length, bending angle and bending radius. The overall accuracy level reaches up to 98.85228 % for a product manufactured using the proposed machine by applying the proposed algorithm compared with a product made with the machine designed without the proposed algorithm [ABSTRACT FROM AUTHOR]

Introduction: Flexible ureteroscopy is a mainstay of upper urinary tract stone treatment. Holmium laser lithotripsy is a particularly common and notable technique for the dusting and fragmenting of renal stones. During ureteroscopy, optical fibers are subject to sharp bends in pursuit of stones, particularly those at the lower pole. Following from principles of fiber optics, subjecting these fibers to sharp bending angle has the potential to reduce the efficiency of power transmission at the fiber tip. Due to the potential implications this hypothesis could have on endourological practice and research, we aimed to explore the potential impact of fiber bending on end-fiber power output. Materials and Methods: Using a highly sensitive oscilloscope and a urological holmium laser, we assessed the end-fiber power output under a variety of bending conditions. To ensure maximal confidence in our results, the maximal bending conditions explored substantially exceeded any condition, which could occur during ureteroscopic surgery. Results: We found evidence that bending radius alone has a clinically insignificant impact on the light power transmission in the fiber. At certain bending conditions, we observed a clinically unimportant but statistically significant reduction in power transmission. This was verified using two commonly used delivery fiber types exposed to 8-second bursts for each bending condition. [ABSTRACT FROM AUTHOR]

• A new theoretical analysis of free bending is proposed to analyze the material flow and changes in the bending radius during the nontangential contact between the bending die and the tube. • The deformation mechanism of the tube under the combined effects of additional tangential force from the bending die, and axial propulsive force is characterized and analyzed. • The influence of rotation angle on the displacement of strain NL is analyzed. • Different combinations of motion parameters corresponding to the bending die position within a specific range led to the same bending radius. • Most of the increase or decrease of the rotation angle has minimal impact on the inner and outer wall thickness distributions. The free-bending process of a metal tube involves a geometric relationship between the eccentricity, the rotation angle of the bending die, the deformation zone length, and the bending radius. Ideally, during the forming process, the contact position between the bending die, and the outer bend of the tube remains tangent. However, due to factors such as the clearance of the bending die and material properties, the rotation angle can be adjusted within a specific range while still ensuring smooth tube formation. The tangential state is disrupted when the rotation angle changes, resulting in overbending or underbending. Thus, in this study, a new theoretical analysis of the free bending process, accounting for clearance, was developed to analyze the material flow and changes in the bending radius during the nontangential contact between the bending die and the tube. In addition, the reasons for achieving smooth tube bending even after adjusting the rotation angle were explained, and the deformation mechanism of the tube under the combined effects of additional tangential force from the bending die and axial propulsive force was analysed. Furthermore, the impact of the rotation angle on the bending radius and the displacement of the strain neutral layer (strain NL) was determined. Afterwards, finite element (FE) modeling and forming experiments were conducted to verify the proposed theoretical analysis under different deformation zone lengths and eccentricities conditions. Besides, the distribution of the inner and outer wall thicknesses of the tube under the nontangential rotation of the bending die was further analysed. The simulation and experimental results fit well with that obtained from theoretical analysis. [Display omitted] [ABSTRACT FROM AUTHOR]

Computers nowadays have different components for data storage and data processing, making data transfer between these units a bottleneck for computing speed. Therefore, so-called cognitive (or neuromorphic) computing approaches try combining both these tasks, as is done in the human brain, to make computing faster and less energy-consuming. One possible method to prepare new hardware solutions for neuromorphic computing is given by nanofiber networks as they can be prepared by diverse methods, from lithography to electrospinning. Here, we show results of micromagnetic simulations of three coupled semicircle fibers in which domain walls are excited by rotating magnetic fields (inputs), leading to different output signals that can be used for stochastic data processing, mimicking biological synaptic activity and thus being suitable as artificial synapses in artificial neural networks.

Copyright of China Petroleum Machinery is the property of China Petroleum Machinery Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A strong and even side illuminating effect is required for plastic optical fibers (POFs) in illuminating applications. In consideration of good flexibility and illumination, side emitting POFs with 2 and 3 mm core diameters are preferred, especially in active illuminating safety textiles. However, the side illumination intensity of side emitting POF varies significantly along the fiber length. Fluorescent polyester (PET) fabric rather than traditional surface modifications is employed to enhance and even the side illuminating effect of POFs based on the emitting principle of phosphors. Two testing methods of side illumination intensity are carried out on semi-automatic devices. The results indicate that 2 mm side emitting POFs might take the place of 3 mm side emitting POFs by using fluorescent PET fabric, with a similar side illuminating effect in applications under certain circumstances. [ABSTRACT FROM AUTHOR]

The quality of seed dosage to the furrow depends on the uniformity of seeds location on the seed disk. A new design of a seeding machine which provides better sowing was suggested at the Department of Agricultural Machinery of Central Ukrainian National Technical University. The main feature of the new seeding machine is the application of the seed disk with a peripheral arrangement of cells with the blades on its inner surface. The blades are used for the forced seizure of the seeds by the disk in the working chamber and their further transportation to the dropping zone. In order to determine the rational parameters of the seed cells of the seed disk, an experimental appliance was made and studies were conducted to determine the desired value of the coefficient of filling cells with seeds of different sizes. The experiments were conducted using disks with cell radii of 5.0 mm and 6.0 mm which correspond to their areas of 9.6 mm2 and 16.3 mm2, respectively. The vacuum in the vacuum chamber was 0.2 kPa and the peripheral velocity of the cells was 2 m/s. Taking into account the experiments conducted, it can be stated that in order to ensure the seeding of sugar beet, the radii of the cells' rounding should be within the limits of 5…6 mm which in general is consistent with the results of theoretical studies. According to them the radius of the whole is 5.7 mm. [ABSTRACT FROM AUTHOR]

Low temperature polycrystalline silicon (LTPS) TFT with stress-absorbing (SA) structure for reducing the strain on a flexible polyimide (PI) substrate was successfully developed and demonstrated. It shows a good flexible TFT performance even under the bending radius of 2 mm for 100,000 bending times. [ABSTRACT FROM AUTHOR]

We report an approach developed for deriving 3D structural information of 2D membrane folds based on the recently-established quantitative transmission electron microscopy (TEM) in combination with density functional theory (DFT) calculations. Systematic multislice simulations reveal that the membrane folding leads to sufficiently strong electron scattering which enables a precise determination of bending radius. The image contrast depends also on the folding angles of 2D materials due to the variation of projection potentials, which however exerts much smaller effect compared with the bending radii. DFT calculations show that folded edges are typically characteristic of (fractional) nanotubes with the same curvature retained after energy optimization. Owing to the exclusion of Stobbs factor issue, numerical simulations were directly used in comparison with the experimental measurements on an absolute contrast scale, which results in a successful determination of bending radius of folded monolayer MoS 2 films. The method should be applicable to characterizing all 2D membranes with 3D folding features. [ABSTRACT FROM AUTHOR]

Organic/inorganic multilayer structures were fabricated for extreme flexibility as well as enhanced moisturebarrier property. The organic and inorganic layers for the structures were formed by plasma polymerization and atomic layer deposition, respectively. The layers were grown alternately to form the organic/inorganic multilayer structures on a plastic substrate. To accomplish extreme flexibility of the barriers, ultra-thin aluminum oxide layers were grown by the atomic layer deposition and sandwiched by a flexible plasma-polymer layer. The moisture-barrier films were then confirmed to retain the initial barrier property even after 10,000 times of bending at a radius as small as 3mm when the barrier structure was located at a neutral plane. [ABSTRACT FROM AUTHOR]

This paper shows the effect of bending radius and bending location on Insertion Loss (IL) in Single Mode Fibers (SMFs) and Polarization Maintaining Fibers (PMFs). Five FC/UPC PMF patchcords were tested for the effect of bending radius on IL, by being coiled from 0 (as reference) to 5 loops at bending radii of 7.5 mm to 17.5 mm in a step of 2.5 mm. Based on the significant IL changes at 7.5-mm radius and no change starting at 15-mm radius, these two radii were chosen for the study of bending location. Fifteen patchcords (5 FC/UPC PMF, 5 LC/UPC PMF and 5 LC/UPC SMF) were coiled for 1 full loop located at 20 cm to 100 cm in a step of 10 cm. At 7.5-mm radius, PMFs reveal their major IL variations strongly depending on bending location, while SMFs have minor variations. In contrast, no IL variations are observed at 15-mm radius for both PMFs and SMFs. This radius was then selected for the final study on a number of coils. All 15 patchcords were coiled up to 15 loops at 15-mm radius. The results exhibit insignificant IL increase for PMFs, but a small increase proportional to the number of coils for SMFs. Consequently, the benefit of these IL studies will validate the proper testing conditions for SMF and PMF patchcords, especially in PMFs, where the measurement of Polarization Extinction Ratio is correlated with IL. [ABSTRACT FROM AUTHOR]

The research calculates the rolling process conditions in a 3-roll bending machine. Initially, structure and mechanical properties of the highstrength steel to be processed are determined in an experimental manner. Then, equations that allow determining the relationship between thickness and width of the steel to be bent are established, taking into consideration strength features of the bending machine. Finally, some graphs that help achieving an efficient and adequate processing of the steel are presented, choosing width/height and strength required for the plate forming, according to its thickness. The information obtained will allow having a number of welding joints needed to obtain final height/length of the component, from the design process of a part to be formed. [ABSTRACT FROM AUTHOR]

Incremental in-plane bending (IIB) is a new and advanced flexible manufacturing technology for small-lot production of strip with various bending radii. The strip of sheet metal is bent incrementally by a beating inclined punch. The bending radius is strongly affected by mechanical properties of the material, geometry of the strip, and processing parameters. It is difficult to predict the bending radius due to the complex synergistic effects of the controlling parameters. How to predict the bending radius accurately has therefore become a key point to be urgently solved in the development of this advanced forming technology. In this paper, a model based on a back propagation neural network (BPNN) is introduced to reveal the relationship of bending radius with angle of die α, indentation s, pitch p, and width of strip w. Out of 14 different BPNN architectures trained, the 4-9-9-1 BPNN with two hidden layers having nine neurons trained with the Levenberg-Marquardt algorithm (trainlm) is found to be the optimum network model, and the prediction error is less than 2 % on average. Otherwise, a 1-9-9-4 reverse BPNN is developed to build the processing window for a given bending radius. Meanwhile, taking section moment of inertia I as a quantitative index of forming stability, α, p, s, w are optimized as design variables in order to make objective functions of I maximized simultaneously. Finally, to verify its predictive capability, the present approach is applied to a case study, and the optimal combination of parameters for stable forming during IIB is obtained. [ABSTRACT FROM AUTHOR]

In this study, a novel design of porous octagonal photonic crystal fibre with a metal‐coated central hole is investigated and analysed in the terahertz (THz) range. The suggested structure is analysed near a frequency of 1.0 THz by using the full vectorial finite difference method. The effects of the structure geometrical parameters and bending radius on the mode effective index, effective mode area and attenuation of the proposed design are investigated. The numerical results reveal that the effective mode area with a metal‐coated central hole is smaller than that of porous core without a metal‐coated central hole by 80%. In addition, very low attenuation can be obtained because of the porosity inside the core region. [ABSTRACT FROM AUTHOR]

There considered questions concerning determination of stress field during form alteration of wheel crowns from steel cylindrical works at the first pass of radial- rotary profiling. There also fulfilled process analysis of drawing process of cylindrical pieces made of sheet metal. Determination of stresses at bending radius of profiling roll while shaping and on stretching edge of die body while drawing is of great interest, as coupling areas of various profile elements of crown are the most loaded and on the value of meridian stress depends the possibility of getting of high-quality piece per stretching pass. Results of theoretical research allow to analyze stresses, which arise while deforming, and determine group of technological and constructional parameters of profiling and stretching process, which affect greatly the value and distribution of normal and shear stresses. [ABSTRACT FROM AUTHOR]

Influence of the bending radius on the measurement of radiation induced attenuation in glass optical fibres is discussed in this paper. Radiation induced attenuation measured in two single-mode fibre types shows discrepancies when coiled around a low bending radius spool: the observed attenuation is lower than expected. A series of dedicated tests reveals that this invalid measurement is related to the displacement of the mode field towards the cladding when the fibre is bent with a low radius, and to the different radiation resistances of the core and cladding glasses. For irradiation tests of optical fibres, the spool radius should therefore be carefully chosen. [ABSTRACT FROM PUBLISHER]

Directional couplers are widely used as one of the key components of optical integrated circuits. However, the coupling efficiency of the conventional directional coupler is highly sensitive to wavelength. This sensitivity degrades the characteristics of devices that contain directional couplers for wavelength division multiplexing transmission. A curved directional coupler has been proposed using silica optical waveguide as one of the coupler which realize wavelength insensitive, small footprint and tolerant to fabrication. In this paper, we theoretically investigated this curved coupler using Si wire waveguide and got results that the curved coupler whose bending radius of 21 μm and coupling length of 7.40 μm can reduce the wavelength dependence and achieve about a sevenfold enhancement of operational bandwidth in the transmittance variation range of -3 ± 0.1 dB compared with conventional directional coupler. [ABSTRACT FROM PUBLISHER]

High strength and high electrical conductivity Cu–Nb tape was tested as the new type of stabilizing layer for YBCO-coated conductor. For electrical interconnection of stabilizing layer to coated conductor the soldering process was used and no degradation in critical current, Ic, of laminated coated conductor after soldering process was observed. The dependence of normalized transport critical current, Ic/Ic0, on the bending radius of coated conductors with and without Cu–Nb stabilizing layer was investigated using the bending test probe providing the uniform bend process at 77 K and under self-field conditions. The reversible and irreversible variations of Ic/I0 with inverse bending radius were found and the irreversible bending radius limit was observed to depend on the neutral axis shift. The generation of the cracks appears to be the primary reason for the Ic/Ic0 degradation that was supported by ScanHall technique investigations. [ABSTRACT FROM PUBLISHER]

We proposed and experimentally demonstrated a cost-efficient and easy-to-fabricate flexible thin-film nanocrystal quantum dot (NCQD) photodetector, by sandwiching a piece of NCQD-soaked tracing paper between two PEDOT:PSS electrodes. The highly conductive and transparent multilayer polymer electrodes are printed with an office inkjet printer without further patterning on commercial unmodified transparency films. The tracing paper is able to act as both the bed for NCQD attachment and the interspacing layer to prevent short-circuiting in vertical devices. Consistent increase in device performance is observed when the bending radius becomes smaller. Linear I-V characteristics are obtained, which show our device structure works as a photoconductor. [ABSTRACT FROM PUBLISHER]

This is a modeling work, which aims to show that negative chromatic dispersion (CD) may be obtained in a PCF by fiber bending. Results from the study of negative dispersion could be employed in a new dispersion compensating technique. The proposed method does not require doping in the core, and does not require external cores. The minimum negative dispersion achieved by this method was -185000 ps/nm/km. Problems of bending losses and sensitivity of the dispersion with respect to deviations of geometry were studied.

We report a multilayer moisture barrier structure comprised of alternating inorganic aluminum oxide and plasma-polymerized organic layers. The inorganic and organic layers were grown by atomic layer deposition (ALD) and plasma polymerization in vacuum, respectively. The inclusion of plasma-polymerized layers in the multilayer barrier structure enhanced the moisture barrier performance by around 15% for as-deposited samples. After being subjected to 10 000 bending cycles with a bending radius of 2 cm, however, the moisture barrier performance of the multilayer structure was improved by 50% from that of pure inorganic counterpart [ABSTRACT FROM AUTHOR]

A rigorous analysis of polarisation conversion in a novel design of cascaded bent silica photonic crystal fibre is proposed using full vectorial finite difference method as well as full vectorial finite difference beam propagation method. The influence of different structural geometrical parameters on the polarisation rotator performance is investigated. The numerical results reveal that by a careful adjustment of the structural geometrical parameters and bending radius, nearly a 100% polarisation conversion ratio with nine sections only and low bending losses can be achieved. [ABSTRACT FROM AUTHOR]

Instead of mechanical and chemical treatments, the side-illuminating effect of polymer optical fiber (POF) jacquard fabric was achieved by using the bending of POF in the weave structure. The relationship between side-emitting intensity and bending radius of POF was explored via theoretical derivation, simulation experiments and POF fabric experiments. A theoretical equation was deduced to quantify the correlation between the light emission efficiency and the bending radius of POF based on the bending losses theory in optical fiber. The results of simulation and fabric experiments reached good agreements with the theoretical analysis. In the real fabric structure, the side-emitting intensity was mainly determined both by the bending radius and the float of POF. Significantly, it was just right for designing side-illuminating figure POF jacquard fabric with the effect of a relative degree of lightness or darkness based on the weave and side-emitting intensity database. [ABSTRACT FROM PUBLISHER]