Three-dimensional photoelastic study of the load-carrying capacity/face width ratio of Wildhaber-Novikov gears for automotive applications

Wildhaber-Novikov gears are becoming more and more popular for heavy load applications. They have been tried as speed-reducing gears, in spite of heavy noise generation, in aircraft jet engines, marine engines and agricultural machinery. These circular-arc gears, though stronger than involute geras, have the disadvantage of needing larger face width. Axial face width required can be minimized only at the expense of load-carrying capacity. This is not a serious disadvantage with stationary engines. But in the case of automotive applications, this fact limits the load-carrying capacity of Wildhaber-Novikov gears, since space problem is very critical in these applications and large face widths, therefore, cannot be used for such gear-reduction units. The face width is determined by the helix angle and, therefore, a thorough investigation of the dependence of the load-carrying capacity on helix angle is necessary, if these special types of gears have to make headway into the automotive field. In this experimental investigation, three-dimensional photoelastic technique has been employed to study the load-carrying capacity/face width ratio. Three-dimensional gear models made of epoxy castings (Araldite B) were loaded in a specially built gear-loading fixture and were stress frozen. Gear cutters of Wildhaber-Novikov gears developed at the laboratory were used for the preparation of these three-dimensional gear models. The stress-frozen models were analyzed using the conventional slicing technique to study the contact and bending-stress distribution along the face width. The load-carrying capacity in terms of contact stress and bending stress has been studied for different face widths and helix angles. Twenty-deg pressure angle, 14-mm module gears of alladdendum type of Wildhaber-Novikov gears with different helix angles up to 40 deg were tested. The helical-overlap ratio used was 1.0. The conventional profile parameters were employed for the manufacture of gear cutters of end-mill type. The decrease in contact and bending strength with increase in the helix angle or decrease in the face width, as obtained from this photoelastic method of stress analysis has been compared with existing theoretical results. © 1977 Society for Experimental Mechanics, Inc

Synthesis and characterization of Ru(II) complexes with polyfunctional quinazo line-(3H)-4-ones

1066-1069A few Ru(II) complexes of the type Ru (O – N - O)2 with tridentate O – N - O donors and of the type RuCl2(O-N)2 with bidentate O - O and O – N donors have been synthesized and characterized on the basis of analytical, conductivity, thermal, magnetic, IR, electronic and PMR spectral data. The IR and PMR spectral data of the metalcomplexes indicate that the ligands like 2-methyl/phenyl-3- (2'-hydroxybenzalamino) quinazoline-(3H)-4-one (MHBQ/ PHBQ) act as uninegative tridentate, 2-methyl/phenyl- 3-(carboxymethyl) quinazoline-(3H)-4-one (MCMQ/PCMQ) as uninegative bidentate and 2-methyl/phenyl-3-(furfuralamino) quinazoline-(3H)-4-one (MFQ/PFQ), 2-methyl/phenyl-3-(acetamino) quinazoline-(3H)-4-one (MAQ/PAQ), 2-methyl/phenyl 3-(uramino) quinazoline- (3H)-4-one (MUQ/PUQ) and 2-methyl/phenyl-3- thiouramino)quinazoline-(3H)-4-one-(MTUQ/PTUQ) as neutral bidentate ligands.The electronic spectral data of the complexes indicate that the arrangement around Ru(II) is octahedral

Genetic variations among ecologically diverse species of Anurans at the level of genus based on ISSR marker

Anurans (frogs and toads) collected from South Kanara, Udupi and North Kanara districts, Karnataka viz: Euphlyctis cyanophlyctis (an aquatic), Fejervarya rufescens (a burrowing), Duttaphrynus melanostictus (a terrestrial), Fejervarya caperata (a semi aquatic), Ramanella montana (a semi arboreal) and Polypedates maculatus (an arboreal) belonging to five genera placed under four families were compared using Inter Simple Sequence Repeat (ISSR) marker to analyze genetic variability and relationship between the investigated taxa. ISSR profile obtained exhibited 100% presence of polymorphic bands.The ISSR bands could also be categorized as high (H), moderate (M) and light (L) based on the intensity of amplification. Dendrograms were generated using similarity coefficient and relationship coefficient values based on the count of only high or high and moderate or high, moderate and light bands in each case. Analysis of the data suggests that the genetic relatedness between the taxa as exhibited in the generated dendrograms varies based on the type of amplified bands considered. The clustering pattern obtained in the case of high and moderate bands was more close to the conventional taxonomical pattern of grouping based on thephenotypic characters. The specific unique bands present in each case may be of importance as molecular markers. Observed genetic variability (presence/absence, total number, intensity of amplification and size of polymorphic bands) among taxa probably provide factors contributing partially to diverse adaptive fitness supporting varied ecological demands. However, an intensive study incorporating more representive species from each of the habitat is needed to pinpoint the importance of the unique bands as the genus/species/ecological molecular markers

Variability and genetic diversity among selfed lines (S1) of onion (Allium cepa L.)

563-568Onion is a highly cross-pollinated crop, high variability could possibly come from traditional seed production by out-crossing or by open pollination and it could lead to more diversity and variation. The high phenotypic, genotypic variation coefficients reveal high-quantifiable variation of traits in S1 lines. Selection of lowest premature bolting and split bulbs producing genotypes, least incidence of purple blotch incidence and thrips incidence with the highest weight of ten bulbs and maximum plot yielding genotypes were more appropriate for genetic improvement of onion. The traits aided the yield witnessed high traits heritability (h2) and maximum genetic-advance-mean (GAM) and isolation of S1 lines in terms of selection indices fixed for higher values of measurement. Whereas traits like premature bolting, split bulbs, purple blotch incidence, thrips incidence and were selected at least values although these traits were high heritability (h2) and GAM could contribute for additive-gene-action and hence it indicates the straight mass selection be more effective for genetic improvement of onion genotypes or lines. The genetic distance was highly flanked by Cluster-II and –IV groups and was highly divergent. Hence, the selection of parental lines from these groups is more appropriate for traditional heterosis breeding

Variability and genetic diversity among selfed lines (S1) of onion (Allium cepa L.)

Onion is a highly cross-pollinated crop, high variability could possibly come from traditional seed production by out-crossing or by open pollination and it could lead to more diversity and variation. The high phenotypic, genotypic variation coefficients reveal high-quantifiable variation of traits in S1 lines. Selection of lowest premature bolting and split bulbs producing genotypes, least incidence of purple blotch incidence and thrips incidence with the highest weight of ten bulbs and maximum plot yielding genotypes were more appropriate for genetic improvement of onion. The traits aided the yield witnessed high traits heritability (h2) and maximum genetic-advance-mean (GAM) and isolation of S1 lines in terms of selection indices fixed for higher values of measurement. Whereas traits like premature bolting, split bulbs, purple blotch incidence, thrips incidence and were selected at least values although these traits were high heritability (h2) and GAM could contribute for additive-gene-action and hence it indicates the straight mass selection be more effective for genetic improvement of onion genotypes or lines. The genetic distance was highly flanked by Cluster-II and –IV groups and was highly divergent. Hence, the selection of parental lines from these groups is more appropriate for traditional heterosis breeding

Deficiency of 25-Hydroxyvitamin D and Dyslipidemia in Indian Subjects

Background. Vitamin D deficiency is widespread throughout the world. Several reports have incriminated vitamin D deficiency as the cause of rickets, osteomalacia, and other chronic diseases. Recent studies have suggested a possible link between deficiency of 25-hydroxyvitamin D and dyslipidemia. Aim. To investigate the association between 25-hydroxyvitamin D deficiency and dyslipidemia in Indian subjects. Methodology. We recruited 150 asymptomatic consecutive subjects from patients' attendees at the Departments of Neurology and Medicine in Yashoda Hospital, Hyderabad, India. Study period was from October 2011 to March 2012. All subjects underwent 25-hydroxyvitamin D assay by chemiluminescent microparticle immunoassay, fasting blood sugar and lipid profile, calcium, phosphorus, alkaline phosphatase, and C-reactive protein (CRP). Results. Out of 150 subjects, men were 82 (54.6%), and mean age was 49.4 (±15.6) years. Among risk factors, hypertension was noted in 63/150 (42%), 25-hydroxyvitamin D deficiency in 59/150 (39.3%), diabetes in 45/150 (30%), dyslipidemia in 60 (40%), smoking in 35/150 (23.3%), and alcoholism in 27/150 (18%). Deficiency of 25-hydroxyvitamin D was significantly associated with dyslipidemia ( = 0.0001), mean serum glucose ( = 0.0002) mean CRP ( = 0.04), and mean alkaline phosphatase ( = 0.01). Multivariate analysis showed that 25-hydroxyvitamin D deficiency was independently associated with dyslipidemia (odds ratio: 1.9; 95% CI : 1.1-3.5). Conclusions. We found that deficiency of 25-hydroxyvitamin D was independently associated with dyslipidemia in Indian subjects

Photoelastic Optimization of the Profiles of Wildhaber-Novikov Gears

Wildhaber-Novikov gears having circular flanks hold out a very promising future in the field of gearing for power transmission in very heavily loaded machineries. In order to optimize the profile parameters of these gears, a photoelastic investigation was carried out. Models of Wildhaber-Novikov gears made of photoelastic material, Araldite-D, were used in the investigation. Included were the models with various profile radii and fillet radii at different pressure angles. The flank and bending stresses of these gears were determined in each case and were compared with those of involute gears. From this investigation, it was concluded that the load-carrying capacity of circular-arc gears is 3.5 times that of involute gears. It was found that with profile radius up to 1.5 module, the bending stresses of these gears are lower than those of corresponding involute gears, under identical conditions of loading. It was observed that high pressure angles, when used for Wildhaber-Novikov gears having comparatively smaller profile radii, produce high flank stresses. Gears with larger profile radii, at smaller pressure angles were seen to have a high value for the ratio of flank stress to the bending stress. On the other hand, gears with smaller profile radii, at higher pressure angles, were observed to have a smaller value for this ratio of stresses

Machine design databook, 2nd.ed/ Lingaiah

xx, 1.1-27.83 hal.: ill.; 24 cm