Parametric analysis of Asymmetric Spur Gear Tooth

Abstract Gear is a machine element used to transmit motion and power between rotating shafts by means of progressive engagement of projections called teeth. Gears are classified according to the relative position of the axes of the shaft, type of gearing, peripheral velocity of the gears and position of teeth on gear surface. Presently gears are suffered by backlash the amount by which the width of a tooth space exceeds the thickness of the engaging tooth on the pitch circles, undercut a condition in generated gear teeth when any part of the fillet curve lies inside of a line drawn tangent to the working profile at its lowest point and interference is an important aspect of kinematics of gearing. When the gear tooth tries to dig below the base circle of mating gear then the gear tooth action shall be non conjugate and violate the fundamental law of gearing this non conjugate action is called the interference . These defects can be eliminated by increasing the pressure angle, by increasing the addendum of mating gear and another way of increasing the load capacity of transmissions is to modify the involute geometry. This has been a standard practice in sophisticated gear design for many years. The nomenclature describing these types of gear modifications can be quite confusing with reference to addendum modification or profile shift. An additional alteration that is very rarely used is to make the gears asymmetric with different pressure angles for each side of the tooth. An asymmetric spur gear drive means that larger and smaller pressure angles are applied for the driving and coast sides. The two profiles of a gear tooth are functionally different for most gear drives. The workload on one side of profile is significantly higher than the other Gears. The main objective of this paper is to generate asymmetric spur gear tooth geometry for different pressure angles on drive and coast side using computer programme. Developed programme is used to create a finite element model of gear tooth to study the effect of bending stress at the critical section for different pressure angles, different number of teeth and module. To study the effect of above asymmetric spur tooth parameters Finite Element Analysis software ANSYS was used

Micropropagation of <i style="">Embelia ribes </i>Burm.f. using inflorescence segments

551-554An efficient micropropagation protocol was developed for a threatened medicinal plant, Embelia ribes using inflorescence explants. The immature ovaries of the inflorescence segments proliferated into luxuriant mass of callus on Murashige and Skoog’s (MS) medium supplemented with IBA (3.5 mg/L) and Kn (0.5 mg/L). The combination of Kn and NAA in the range of 2.0 to 4.0 mg/L and 0.2 to 0.6 mg/L, respectively provoked the calli to differentiate into both shoot and root initials from the ovary callus. Highest number of regenerants (25±0.81per callus) were obtained at the concentration of 3.0 mg/L Kn and 0.4 mg/L NAA. The regenerants were transferred to the pots containing sterilized soil and hardened for a week. A mean of 21.82±1.02 regenerants per harvest were well acclimatized to the natural conditions exhibiting a normal development

<smarttagtype namespaceuri="urn:schemas-microsoft-com:office:smarttags" name="place"> Micropropagation of <i style="">Entada pursaetha</i> DC-An endangered medicinal plant of Western Ghats </smarttagtype>

561-564A micropropagation protocol has been standardized for an endangered leguminous woody climber, Entada pursaetha using cotyledonary node explants. The synergetic effect of BAP (5 mg/L) with NAA (0.5 mg/L) induced a mean of 9.8±1.23 adventitious shoots from the cotyledonary node. The frequency of shoot production was highest (98.7%) in proximal transverse half of the cotyledon. The microshoots rooted well on MS half strength medium supplemented with 2 mg/L IBA. 70% of the hardened regenerants were acclimatized to the soil

Rapid Adventitious Organogenesis from Leaf Segments of Embelia ribes Burm.－a Threatened Medicinal Plant

An in vitro protocol was developed for rapid multiplication of plantlets via direct organogenesis from the leaf segments of Embelia ribes Burm. (Myrsinaceae), a rare woody medicinal shrub under threat of being extinct. Adventitious shoots were organized directly from the margin of the lamina on medium supplemented with 2 to 4 mg/L 6-furfuryl amino purine (FAP) and 0.2 to 0.6 mg/L naphthalene acetic acid (NAA). The frequency of shoot bud production was the highest (mean of 33.6 ± 3.63 shoots per explants) at the concentration of 3 mg/L FAP and 0.4 mg/L NAA. Rooting of microshoots was also noticed on the same medium in a single-phase culture. A mean of 30 ± 1.05 root intact plantlets was recovered per explant. The rooted plantlets were well accomplished with a survival frequency of 96%. Moreover, there were no phenotypic differences observed between the in vitro regenerated and in vivo plants

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Dielectric and magnetic properties of high porous Gd+3 substituted nickel zinc ferrite nanoparticles

We report on the synthesis and characterization of Gd+3 substituted Ni-Zn nano ferrites (Ni0.6Zn0.4 GdyFe2-yO4; y = 0, 0.1, 0.15, and 0.2) via low-temperature citrate gel auto-combustion method. The structural studies carried out by PXRD revealed a decrease in the lattice constant and crystallite sizes upon Gd+3 substitution with low concentration but increases with further increase in the concentration. We found the porosity of the samples decreases linearly as a function of Gd+3 concentrations. Well defined spherical grains with a higher porosity of the samples are confirmed by FESEM analysis. With an increase in the Gd+3 concentrations, the dielectric constant increased up to five folds in the magnitude. The contribution of grain boundary and other factors on the electrical properties was revealed by impedance spectroscopy. The reduced remanence ratios showed in the magnetic hysteresis imply the charge in change in the magnetic properties upon the substitution of Gd+3 in the prepared ferrite