Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 3

XRF Related Abstracts

3 Experimental and Numerical Investigation of “Machining Induced Residual Stresses” during Orthogonal Machining of Alloy Steel AISI 4340

Authors: Theena Thayalan, K. N. Ramesh Babu


Machining induced residual stress (RS) is one of the most important surface integrity parameters that characterize the near surface layer of a mechanical component, which plays a crucial role in controlling the performance, especially its fatigue life. Since experimental determination of RS is expensive and time consuming, it would be of great benefit if they could be predicted. In such case, it would be possible to select the cutting parameters required to produce a favorable RS profile. In the present study, an effort has been made to develop a 'two dimensional finite element model (FEM)' to simulate orthogonal cutting process and to predict surface and sub-surface RS using the commercial FEA software DEFORM-2D. The developed finite element model has been validated through experimental investigation of RS. In the experimentation, the orthogonal cutting tests were carried out on AISI 4340 by varying the cutting speed (VC) and uncut chip thickness (f) at three levels and the surface & sub-surface RS has been measured using XRD and Electro polishing techniques. The comparison showed that the RS obtained using developed numerical model is in reasonable agreement with that of experimental data.

Keywords: Machining, Residual Stress, FEM, XRF

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2 Geochemical Study of Claystone from Nunukan Island, North Kalimantan of Indonesia

Authors: Mutiara Effendi


Nunukan Island is located on North Kalimantan of Indonesia. The region is one of Indonesia’s cross-border with Malaysia. In conjunction with its strategic geographic location, its potential as the new oil and gas resources has brought many researchers to do their studies here. The research area consists of claystone which criss-crossed with quarts sandstone. There are also rocks claystone-grained which are the weathering product of basaltic volcanic rocks. In some places, there are argillic clays which are the hydrothermal-altered product of Sei Apok ancient volcano. Geochemical study was established to learn the origin of the claystones, whether it came from weathering, hydrothermal alteration, or both. The samples used in this research are fresh rock, weathering rocks, hydrothermally-altered rock, and claystones. Chemical compositions of each sample were determined and their relations was studied. The studies encompass major and minor elements analysis using X-Ray Fluoresence (XRF) method and trace elements analysis, specifically rare earth elements, using Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) method. The results were plotted on certain graphics to learn about the trend and the relations of each sample and element. Any changes in chemical compositions, like increase and decrease of elements or species, was analysed to learn about geological phenomenon that happens during the formation of claystones. The result of this study shows that claystones of Nunukan Island have relation with volcanic rocks of its surrounding area. Its chemical composition profile corresponds to weathering product of volcanic rocks rather than hydrothermally-altered product. The general profile also resembles claystone minerals of illite or montmorillonite, especially in the existence of aluminum, iron, potassium, and magnesium. Both minerals are formed in basic condition and commonly happen to shales. It is consistent with the fact that claystone was found mixing with shales and silt to clay grained mudstones in field exploration. Even though the general profile is much alike, the amount of each elements is not precisely the same as theoretically claystone mineral compositions because the mineral have not formed completely yet.

Keywords: Geochemistry, XRF, ICP-MS, claystone

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1 [Keynote Talk]: Determination of Metal Content in the Surface Sediments of the Istanbul Bosphorus Strait

Authors: Durata Haciu, Elif Sena Tekin, Gokce Ozturk, Patricia Ramey Balcı


Coastal zones are under increasing threat due to anthropogenic activities that introduce considerable pollutants such as heavy metals into marine ecosystems. As part of a larger experimental study examining species responses to contaminated marine sediments, surface sediments (top 5cm) were analysed for major trace elements at three locations in Istanbul Straight. Samples were randomly collected by divers (May 2018) using hand-corers from Istinye (n=4), Garipce (n=10) and Poyrazköy (n=6), at water depths of 4-8m. Twelve metals were examined: As, arsenic; Pb, lead; Cd, cadmium; Cr, chromium; Cu, Copper; Fe, Iron; Ni, Nickel; Zn, Zinc; V, vanadium; Mn, Manganese; Ba, Barium; and Ag, silver by wavelength-dispersive X-ray fluorescence spectrometry (WDXRF) and Inductively Coupled Plasma/Mass Spectroscopy (ICP/MS). Preliminary results indicate that the average concentrations of metals (mg kg⁻¹) varied considerably among locations. In general, concentrations were relatively lower at Garipce compared to either Istinye or Poyrazköy. For most metals mean concentrations were highest at Poyrazköy and Ag and Cd were below detection limits (exception= Ag in a few samples). While Cd and As were undetected in all stations, the concentrations of Fe and Ni fall in the criteria of moderately polluted range and the rest of the metals in the range of low polluted range as compared to Effects Range Low (ERL) and Effects Range median (ERM) values determined by US Environmental Protection Agency (EPA).

Keywords: Marine Sediments, XRF, effect-range classification, ICP/MS

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