Increase In Bending Angle Research Articles

Textile composites with integrated optical fibres: quantification of the influence of singleand multiple fibre bends on the light transmission using a Monte Carlo ray-tracingmethod

Monte Carlo ray-tracing simulations of the propagation of light rays along bent multimodeoptical fibres indicate that, for optical fibres integrated into composite components, theinfluence of macroscale bends induced by the component shape on the light transmission isrelatively small. Mesoscale bends caused by integration of the fibres into the reinforcementfabric structure applying textile processes may cause significant transmission losses, whichdecrease exponentially with increasing ratio of bending radius and fibre radius and increasewith increasing bending angles. Based on geometrical models of optical fibres integratedin woven fabric structures, which show multiple mesoscale bends, simulationsprove that the lowest bending losses occur for fabrics with a low degree of crimp.

Bending buckling of single-walled carbon nanotubes by atomic-scale finite element

This paper employs the atomic-scale finite element method to study bending buckling of single-walled carbon nanotubes (SWNTs). As the bending angle increases, kinks will appear and the morphology of the SWNT will change abruptly. The (15, 0) SWNT changes into a one-kinked structure, and finally contains two kinks; while the (10, 0) SWNT changes into a one-kinked structure, then into a two-kinked one, and finally contains three kinks. Strain energy grows initially as a quadratic function of bending angle, then increases gradually slowly, and finally changes approximately linearly. The energy releases suddenly at morphology bifurcations and the amount depends on degree of morphology change. The simulation shows that the appearance of kinks associated with the large deformation nearby reduces the slope of the strain energy curve in the post-buckling stages and hence increases the flexibility of the SWNTs.

Effects of hardness and thickness of polyurethane foam midsoles on bending properties of the footwear

In sports shoe design to achieve better athletics performance, the bending stiffness of a footwear is an important parameter. Its bending stiffness is mostly dependent on its midsole material. Specifically, hardness and thickness of the midsole material are the major factors on its bending stiffness. Hence, this study focuses on studying the effect of hardness and thickness on bending stiffness of sports shoes by using polyurethane(PU) foam midsole. The results from the experiments show that the bending moment increases as the bending angle increases. Increased hardness and increased thickness of midsole also cause a greater bending moment of the sports shoe, respectively. Moreover, the effect of hardness and thickness of midsole on bending moment measured with assembled shoes is much greater than the one measured with midsoles alone. Therefore, low bending stiffness of the midsole material can not be ignored in shoe design because it could result in high bending stiffness of an assembled shoe.

Indentation behavior of aluminum processed by equal channel angular extrusion: Effect of bending angle

Microindentation has been used to characterize the indentation behavior of aluminum processed by ECAE (equal channel angular extrusion). The bending angles of the ECAE dies are 90°, 120° and 150°. Using dislocation dynamics, it is found that the initial dislocation density increases with the decrease in the bending angle at the macroscopic yielding during the indentation. For the same indentation load, the plastic energy dissipated in the indentation increases with increasing bending angle.

The bending-kinking analysis of a single-walled carbon nanotube—a combined molecular dynamics and continuum mechanics technique

This paper investigates the deformation mechanism of a single-walled carbon nanotube in pure bending. The molecular dynamics analysis and continuum mechanics characterisation were used together to achieve a deeper understanding. It was found that at a bending angle of 24° the nanotube buckles locally, forming a kink in the middle of the nanotube. As the bending angle increases, the kink progresses along the nanotube and varies its shape in both longitudinal and circumferential directions. The kink formation can be considered as the result of rotations of planes/surfaces about the moving and stationary hinge lines. It was also found that the kink deformation influences the load bearing capacity of the nanotube.

Shape retention in porcine and rabbit nasal septal cartilage using saline bath immersion and Nd:YAG laser irradiation

The process of altering the shape of cartilage using heat has been referred to as thermoforming, and presents certain clinical benefits in reconstructive surgical procedures within the head and neck. Thermoforming allows cartilage in the upper airway and face to be reshaped without the use of classic surgical maneuvers such as carving, morselizing, or suturing. The goal of this study was to determine the dependence of cartilage shape change on both temperature and laser dosimetry using two thermoforming methods: saline bath immersion and laser irradiation. Ex-vivo rabbit and porcine nasal septal cartilages were mechanically deformed and reshaped using the two thermoforming methods. With saline bath immersion using rabbit cartilage, each specimen was deformed by securing it to a small copper tube (outer diameter 8 mm) using dental bands. For porcine cartilage immersed in a saline bath, each sample was mechanically deformed between two pieces of wire mesh attached to a semicircular acrylic block. With both porcine and rabbit cartilage, the specimen and apparatus were then immersed in a hot saline bath for time intervals varying from 20 and 320 seconds and at constant temperatures between 62 and 74 degrees C. In laser reshaping, the cartilage specimens were mechanically deformed on a jig and consecutively irradiated with an Nd:YAG laser (lambda = 1.32 microm) in several spots for 6-16 seconds and irradiances of 10.2-40.7 W/cm2 per spot. After either saline bath heating or irradiation, cartilage specimens were immersed in room temperature saline for 15 minutes, then upon removal from the jig the length between the ends of each specimen was measured in order to calculate the resulting bend angle. The transition zone for cartilage reshaping was defined as where a significant increase in bend angle was observed between consecutive times of immersion/irradiation at the same temperature/irradiance. For the saline bath experiments, the transition zone was observed between 59-68 degrees C and 62-68 degrees C for porcine and rabbit cartilage, respectively. Similar transition zones occurred with laser irradiation below irradiances of 20.4 W/cm2 for both porcine and rabbit cartilage. In addition, the dosimetry pairs in the transition zones produce peak temperatures below the thresholds determined from the saline bath immersion studies. The critical transition temperature region was determined by the sharp increase in bend angle at consecutive times of immersion at the same temperature. This range was determined to be 59-68 degrees C and 62-68 degrees C for porcine and rabbit cartilage, respectively. Similar transition zones for dosimetry occurred below 20.4 W/cm2 during cartilage irradiation in both species.

Ser and Thr Residues Modulate the Conformation of Pro-Kinked Transmembrane α-Helices

Functionally required conformational plasticity of transmembrane proteins implies that specific structural motifs have been integrated in transmembrane helices. Surveying a database of transmembrane helices and the large family of G-protein coupled receptors we identified a series of overrepresented motifs associating Pro with either Ser or Thr. Thus, we have studied the conformation of Pro-kinked transmembrane helices containing Ser or Thr residues, in both g+ and g− rotamers, by molecular dynamics simulations in a hydrophobic environment. Analysis of the simulations shows that Ser or Thr can significantly modulate the deformation of the Pro. A series of motifs, such as (S/T)P and (S/T)AP in the g+ rotamer and the TAP and PAA(S/T) motifs in the g− rotamer, induce an increase in bending angle of the helix compared to a standard Pro-kink, apparently due to the additional hydrogen bond formed between the side chain of Ser/Thr and the backbone carbonyl oxygen. In contrast, (S/T)AAP and PA(S/T) motifs, in both g+ and g−, and PAA(S/T) in g+ rotamers decrease the bending angle of the helix by either reducing the steric clash between the pyrrolidine ring of Pro and the helical backbone, or by adding a constrain in the form of a hydrogen bond in the curved-in face of the helix. Together with a number of available experimental data, our results strongly suggest that association of Ser and Thr with Pro is commonly used in transmembrane helices to accommodate the structural needs of specific functions.

Laser forming of thin foil by a newly developed sample holding method

A sample holding method is newly developed for laser forming, in which the target material is held between two transparent plates. During laser beam scanning on the target, the target foil is kept flat. After the scanning is finished, the foil is detached from the holder; the foil bends toward the beam scanned surface. Experiments are carried out with a Nd:yttrium–aluminum–garnet laser beam for a spot size of 25μm and for a traverse speed of 10 mm/s. A bending angle of about 30° is obtained for stainless steel (AISI 304) foil of 10 μm in thickness with a power of 0.3 W and a scanning repetition number of 20. On the other hand, if the laser beam is focused and scanned on the convex side along the ridge line of a curved foil, it bends toward the concave side and the bending angle increases. The increment angle of about 20° for a prebent angle of 45° is obtained for stainless steel foil 20 μm in thickness under the conditions of the power of 1.3 W and scanning repetition number of 10. If the sample is rotated counterclockwise with the increase in bending angle, a total angle of 90° or more is easily obtained. A microcube, of which side length is about 500 μm, and other objects of complicated shapes are made on the basis of the bending characteristics obtained experimentally.

Diphasic Negative Phototropism of Sporangiophores of the Piloboloid Mutant of Phycomyces blakesleeanus

Ootaki, T., and Tsuru, T. 1993. Diphasic negative phototropism of sporangiophores of the piloboloid mutant of Phycomyces blakesleeanus. Experimental Mycology 17, 103-108. The sporangiophore (spph) of a piloboloid mutant of Phycomyces, the extension zone of which expands radially at the final developmental stage (stage IVb) as elongation comes to an end, bends away from light when its diameter exceeds about 210 μm. As spph diameter increases, negative phototropism becomes more marked, with the bending angle showing an asymptotic approach to -40° as the diameter approaches 360 μm. With still larger spphs there is a further rapid increase in bending angle to about -90°. This diphasic pattern of negative bending with the largest spph supports the hypothesis that the optical properties of the nearly transparent extension zone of the spphs are involved in determining the maximal bending angle as well as determining the phototropic direction in this fungus.

Characteristics of Bending Parts of Metal Plates Using Ultrasonic Bending Systems with a Vibration Punch and a Vibration Die

Characteristics of ultrasonic vibration bending of pure aluminum and anticorrosive aluminum plates of 2.0 to 3.0 mm thickness are studied using a 19 kHz longitudinal vibration punch and a 27 kHz vibration die. With ultrasonic vibration, the springback angle decreases to zero under sufficient vibration amplitude, bending angle increases and marked improvement of bending surface condition is obtained. Hardness of the specimen and elongation of the bending surface decrease, and roughness of the bending surface is decreased by vibration. Radius of curvature of the bending part increased to about double that without vibration.

Acoustic emission research on the fracture behaviour of plasma-sprayed Ni-Al coatings during bend testing

Abstract Preliminary results of acoustic emission research on the crack propagation processes in plasma-sprayed Ni-Al coatings during three-point bend testing are presented. It was shown that in all tests three groups of scoustic emission signals appear as the bending angle increases. Metallographic and scanning electron microscopic observations indicated that these three groups of acoustic emission signals can be correlated with three different stages of crack propagation. The first stage is the microcrack initiation at the primary defects of the surface region of the coating where the tensile stress is maximal. These cracks extend in the direction of the coating thickness and join together to give longer cracks in the second stage. The third stage corresponds to the cracks reaching the coating-substrate interface and the spalling of the coating. It was also shown that the bending angle required to initiate and propagate surface microcracks decreased as the coating thickness increased.

Inhibition of movement of trition-demembranated sea-urchin sperm flagella by Mg2+, ATP4-, ADP and P1.

Three clinical patterns of inhibition of MgATP2--activated flagellar motility have been found by measuring the motility of Triton-demembranated sea-urchin spermatozoa beating with their heads attached to a glass surface. Inhibition of beat frequency by the reaction products, ADP and Pi, is competitive with the normal substrate, MgATP2-, and the inhibitory effects are similar to a reduction in MgATP2- concentration. Inhibition of beat frequency by ATP4- is competitive with MgATP2, but is accompanied by an inhibition of bending, as measured by the angle between the straight regions on either side of a bend, which is not seen when MgATP2- concentration is reduced. Inhibition of beat frequency by Mg2+ is not competitive with MgATP2-, and is accompanied by an increase in bend angle, so that there is no change in the rate of sliding between flagellar tubules. These differences suggest unexpected complexity of dynein ATPase action in flagella. The beat frequencies of both swimming and attached spermatozoa show a linear double reciprocal dependence on MgATP2- concentration, with identical slopes. The calculated sliding velocities between tubules also give linear relationships, but the slopes are different, suggesting that beat frequency may be the more fundamental dependent variable in this system.

The HeI photoelectron spectra of the isoelectronic molecules, cyanogen azide, NCN 3, and cyanogen isocyanate, NCNCO

The HeI photoelectron spectra of the isoelectronic molecules, cyanogen azide, NCN 3, and cyanogen isocyanate, NCNCO have been studied in detail. As expected the spectra are quite similar, however it is in the way in which they differ that the interest in the analysis lies. The molecules are both V-shaped but differ in that the angles at the middle N atom are 120° in NCN 3 and 140° in NCNCO. The combined study yields a good understanding of how photoelectron bands associated with orbitals, which in a linear configuration are degenerate, behave as the bending angle increases.

Studies on the Lodging of Rice Plant (5)

Studies were undertaken to compare the effect of rain water deposition with impact effect of rain drops on rice lodging. Paddy rice, Norin No. 29 cultured in pots, was used for the experiments. Plants in the yellow ripening stage were exposed to artificial rains under impact of rain drops or exclusive wetting condition for 5 minutes, and bending angle of the culms were measured before and after the rain treatments. On the other hand, the increase in bending angle of the culms in the rain treatment were expressed in terms of bending moment obtained from the loading test.1) Standard plant (S) before the rain treatment had a bending of about 18° and the bending angle increased by rain treatments. The increase of the bending angles varied with conditions of rain water deposition and impact of rain drops.In the plant exposed to a drizzle spouted from a sprayer on the ground and deposited a maximum amount of rain water (Rmax), the angle of the culms was about 47° and was 30° larger than that of standard plants. However, in the plant from which the rain water was waved off (Rmin), the angle was 35° and was 17° larger than that of standard plants. In the plants exposed to the strongest jmpact of rain drops (R) (5mm in diameter and about 9m/s of the terminal velocity and 60mm/hr. in intensity, which corresponded to a heavy rain and to the largest size of drop in the natural rain), the bending angle was 40° and was 22° larger than that of standard plants. The plants (R-H) kept out of the impact of rain drops in R-treatmentwas decreased the angle by 0.5 to 1.0° of R-plants. (Fig.2)2) From load test, mean bending moments were supposed to be 170g·cm for standard plants and 470 to 650g·cm for treated plants. The former is due to fresh weight of the areal part of the plant. and the latter is mainly due to both weight of plant, and deposited rain water, the former contributing 60 percent of the total moment. Impact moment of rain drops results in 2 percent or less of the gross moment. (Fig. 3)3) Resistance to breaking of the culm with leaf sheath is larger than the gross moment in the plants exposed to rain, so that the breaking type lodging can not occur by rain except for storm attack and for the weak plants.From the above results, a conclusion can be drawn that the rain water deposition has a great effect on increasing the bending angle of rice plants, but impact of rain drops has negligible effect on the lodging.

低合金強靱鋼の熔接の研究(第5報)

In the study of oxy-acetylene gas cutting of low alloy high strength steel, the relation between crack sensitivity of heat affected zone and following subjects are researched applying bending tests.Gas cutting speedPre-heating temperaturePost-heating temperatureHardness of mother steelCondition of cutting surfaceComposition of steeletc.Experiments are made in this study, in order to know the metallergical nature of heat affected zone and its effect for weldability of mother steel. Following results are shown by these experiments.1. Increase of bending angle in bending test and decrease of maximum hardness at heat affected zone show that 100°C pre-heating gives remarkable effect to improve the crack sensitivity of steel.2. 200°C or over 400°C post-heating gives effect for the decreasing of crack sensitivity value, through 100°C pre-heating gives better effect.300°C post-heating which belongs to the range of temper brittleness should be avoidable.3. Less cutting speed gives better bending effect generally.4. Less hardness by high tempering temperature gives better bending effect to mother steel, just same as the effect of post-heating temperature. 300°C tempering gives less bending effect.5. Removing of cutting carf makes bending effect a little better, despite removing of heat affected zone gives remarkable effect.6. Value of bending test of rolled steel is far higher than cast steel.7. X-ray spectrochemical analysis and michro-structure proof the increase of Ni, Cu, Mo content and the decrease of C, Cr, Mn content on the gas cutting surface.8. It is suposed that the cementite zone and the high carboned zone inside made by carbon defusion out of mother steel.9. It became clear that the application of suitable gas cutting is quite effective for the welding edge of low alloy high strength steel.

低合金強靭鋼の熔接の研究(第1報)

In the study of oxy-acetylene gas cutting of low alloy high strength steel, the relation between crack sensitivity of heat affected zone and following subjects are researched applying bending tests.Gas cutting speedPre-heating temperaturePost-heating temperatureHardness of mother steelCondition of cutting surfaceComposition of steeletc.Experiments are made in this study, in order to know the metallergical nature of heat affected zone and its effect for weldability of mother steel. Following results are shown by these experiments.1. Increase of bending angle in bending test and decrease of maximum hardness at heat affected zone show that 100°C pre-heating gives remarkable effect to improve the crack sensitivity of steel.2. 200°C or over 400°C post-heating gives effect for the decreasing of crack sensitivity value, through 100°C pre-heating gives better effect.300°C post-heating which belongs to the range of temper brittleness should be avoidable.3. Less cutting speed gives better bending effect generally.4. Less hardness by high tempering temperature gives better bending effect to mother steel, just same as the effect of post-heating temperature. 300°C tempering gives less bending effect.5. Removing of cutting carf makes bending effect a little better, despite removing of heat affected zone gives remarkable effect.6. Value of bending test of rolled steel is far higher than cast steel.7. X-ray spectrochemical analysis and michro-structure proof the increase of Ni, Cu, Mo content and the decrease of C, Cr, Mn content on the gas cutting surface.8. It is suposed that the cementite zone and the high carboned zone inside made by carbon defusion out of mother steel.9. It became clear that the application of suitable gas cutting is quite effective for the welding edge of low alloy high strength steel.

低Mn系高抗張力鋼の熔接性に関する研究

Classifying weldability in the five classes, the authors made weldability tests on low manganese high tensile-strength steels and found the following reuslts.(1) It is recognized in each steel-plates under test that the close-relation respectively exists among Ceq, hardness in the vicinity of water-quenched end in Jominy test, max. hardness of heat-affected zone during welding, and bead-bend angles. When Ceq is located above 0.5%, weldability is apt remarkably to become worse.(2) The higher welding current, the lower welding speed, max hardness at the heat-affected zone is decreased and bend angle is increased propotionally. In the case of hardness below 300Hv, no measurable differences of bend angles are exhibited.(3) Using the low-hydrogen type electrode, satisfactory results are obtained in weldability.(4) With regard to influence upon elapsing time for bend angle of longitudial bead-bend test after welding, bend angle is found to be very small immediately after welding, in spite of various type of electrodes. When the low-hydrogen type electrode is used, bend angle is rapidly increased within following 24 hrs. However, the high cellulose type electrode is sluggish, concering increase in bend angle as compared with the former. It may be assumed that causes as above are due to effect of both hydrogen content absorbed during welding and residual hydrogen content retained after welding.