Welding input process parameters play a very significant role in determining the quality of the welded joint. Only by properly controlling every element of the process can product quality be controlled. For better quality of MIG welding of Ferritic stainless steel AISI 409, precise control of process parameters, parametric optimization of the process parameters, prediction and control of the desired responses (quality indices) etc., continued and elaborate experiments, analysis and modeling are needed. A data of knowledge - base may thus be generated which may be utilized by the practicing engineers and technicians to produce good quality weld more precisely, reliably and predictively. In the present work, X-ray radiographic test has been conducted in order to detect surface and sub-surface defects of weld specimens made of Ferritic stainless steel. The quality of the weld has been evaluated in terms of yield strength, ultimate tensile strength and percentage of elongation of the welded specimens. The observed data have been interpreted, discussed and analyzed by considering ultimate tensile strength ,yield strength and percentage elongation combined with use of Grey-Taguchi methodology.
H. S. Ginwal, Pradip Kumar, V. K. Sharma and A. K. Mandal
Results of a provenance trial of Eucalyptus camaldulensis Dehnh. laid out in 2001 at Seothi (30° N Lat., 76° E Long. and 250 m altitude) Haryana, a semi-arid region of India are reported and discussed. Six seed sources from Australia viz. Laura River, Emu Creek, Degrey River, Wiluna, Kennedy River, Morehead River were evaluated from nursery stage (3 months) to field performance (2 year). Two sources viz. E.tereticornis (Helenvele, Qld) and FRI-4 a local seed source were used as control (check material). Significant differences between the seed sources at nursery stage were observed for collar diameter (P < 0.05) and number of leaves (P < 0.01). At age 2 years, significant differences between the seed sources (P < 0.05) were observed for height and field survival. The two seed sources viz. Emu Creek Petford, QLD and Laura river, QLD ranked first and second for height and survival at this age. Results indicate that genetic differences exist between the sources of E. camaldulensis. None of the traits assessed (viz. height, collar diameter, number of leaves, number of branches and survival) was found to correlate with any of the geographical coordinates of the site (latitude, longitude and altitude). There were fair differences between phenotypic and genotypic coefficient of variability. Heritability values were fairly high for height and clear bole length in comparison to collar diameter, number of branches and survival. The relative performance of these provenances was fairly consistent throughout the period of observation. The two sources viz. Laura river, QLD and Emu Creek Petford, QLD are recommended for potential source for plantation programme under semi-arid conditions.
Gunjan Patwari, Pradip Kumar Kalita and Ranjit Singha
Al and Cu doped ZnO nanoparticles are considered as appropriate for modulation of structural and optoelectronic properties. Al atoms are found to substitute the host Zn whereas Cu dopants mainly segregate in grain boundaries and thereby determine the optical properties. The undoped as well as Al and Cu doped ZnO exhibit spherical well defined particles. The spherical nanoparticles change to rod type structures on co-doping. The average particle size decreases on doping what consequently results in an increment in band gap. Blue shift in UV absorption is governed by the functional group of glucose; further blue shift occurring on metal doping may be attributed to Burstein-Moss effect. PL spectra of doped and undoped ZnO show a dominant near band gap UV emission along with visible emission owing to the defects. The PL peak intensity increases on doping with Cu and Al. The linear I-V characteristics indicate the ohmic behavior of ZnO nanostructures.
H. S. Ginwal, Pradip Kumar, V. K. Sharma, A. K. Mandal and C. E. Harwood
Results of provenance cum progeny trials of Eucalyptus tereticornis Sm. laid out in 2002 at three sites viz. FRI Campus (Uttaranchal), Chiryanpur (Uttaranchal) and Midnapore (West Bengal) located in tropical region of India are reported and discussed. Thirteen provenances representing 91 families from Australia and Papua New Guinea (PNG) viz. Oro bay to Emo, PNG; Sirinumu Sogeri Plat, PNG; Warwick, QLD; Yurammie, SF, NSW; Buckenbowra SF, NSW; Selection flat SF559, NSW; Credition SF, QLD; Cardwell, QLD; Mitchell River MT Molloy, QLD; Mill stream archer creek, QLD; Helenvale, QLD; Walsh River, QLD; Burdekin River, QLD were evaluated from nursery stage to field performance (age 21months). As a local seed source open-pollinated seeds collected from selected interspecific Eucalyptus F1 hybrid trees of FRI-4, FRI-5 and Mysore gum (Eucalyptus teretirornis) were used to serve as check material (control). Significant differences between the provenances and families at age 21 months were observed for height, clean stem length, collar diameter and field survival. Significant provenance x site interaction was observed for height. In general the north Queensland provenances performed better and in particular two provenances viz. Walsh River, QLD and Burdekin River, QLD ranked the best in comparison to others at this age. Results indicate that significant genetic differences exist between the families and provenances of E. tereticornis. The growth traits were inter-correlated with each other. Geographic clinal variation pattern was observed in some of the growth traits viz. height, clean stem height and collar diameter. There were fair differences between phenotypic and genotypic coefficient of variability. Heritability (narrow sense) values were fairly good for height and clear stem length in comparison to collar diameter. The relative performance of the provenances was fairly consistent throughout test sites.
Weld quality mainly depends on the weld bead geometry and mechanical-metallurgical characteristics of the welded joint which has a direct relationship with the type of welding process being used and its input process parameters i.e. welding current, arc voltage, travel speed etc. In the present study, determination of tungsten inert gas (TIG) welding input parameters for achieving maximum tensile strength of 316L austenitic stainless steel is investigated. Box-Behnken design of response surface methodology has been employed to formulate the experimental plan to identify the effect of process parameters on tensile strength. Square butt joint configuration has been made using three factors - three levels of welding input parameters. Joint strength has been evaluated by notch tensile strength (NTS) and Unnotch tensile strength (UTS) method and correlated with microstructure and micro hardness of the weld. The results indicate that gas flow rate has greater influence on both NTS and UTS followed by welding current.