Noraina Adam

Muon sites in Ce(Ru,Rh)2Al10 investigated by using Density Functional Theory from the view point of electronic potential

Numerical investigations on muon sites in Ce-based Kondo semiconductors, Ce(Ru,Rh)2Al10 were carried out by using the Density Functional Theory. From the view point of simple electrostatic potential calculations, we found all the previously reported muon sites, suggested by different groups (Kambe S et al. 2010 J. Phys. Soc. Jpn. 79 053708 and Khalyavin D D et al., 2010 Phys. Rev. B 82 100405(R)), can be possibly chosen as muon stopping sites. We also investigated the changes in the potential of the Rh-doped case. We discovered that the electronic potential around the nearest Ru atom to the substituted Rh atom is affected and the potential becomes asymmetric around the nearest Ru ion. Although big changes in hyperfine fields at muon sites have been reported (Guo H et al. 2013 Phys. Rev. B 88 115206), the muon positions estimated from the potential calculations do not change much.

Muon Site Estimations by DFT Calculations in Metal and Insulating Systems

A way to estimate muon sites in materials is reported. Since the muon has a positive charge, one easiest and conventional way to estimate muon positions is to calculate minimum potential positions. We applied our developed method to estimate those potential minimum positions to some systems which have been studied by mons at the RIKEN-RAL Muon Facility and showed well defined muon-spin precession behavior in magnetically ordered states. Tentative calculation results by using the density functional theory are reported.

A review of incorporating Nd:YAG laser cleaning principal in automotive industry

Abstract Laser cleaning has been identified as an ideal technology to replace conventional chemical techniques in the motorcar coating removal process to maintain the sustainability of our environment. This is due to the unique characteristics of this cleaning technique, such as being versatile, precise, controllable, lack of waste generation, and environmental friendly process. This laser technique can remove the coating layers without using chemical products and prevents the metal substrate surfaces from defect. This paper reviews the potential of incorporating pulsed Nd:YAG laser and its principals in coating removal for automotive industry with respect to these characteristics.

Determination of Indoor 222 Rn Concentrations Level on Different Room Sizes in Academic Building at Universiti Malaysia Kelantan Jeli Campus

The objectives of this study are to briefly monitor the 222Rn concentration in selected study area and to investigate its correlation with the environmental factors (pressure, humidity and temperature). 222Rn concentrations were monitored in three different sizes of lecture rooms known as BK 6, BK 7 and BK 8 at academic building, Universiti Malaysia Kelantan (UMK) Jeli Campus. Radon monitor known as Sentinel 1030 has been used to collect 210 readings of 222Rn concentration data. Environmental factors for each study areas was analyzed by using Pearson correlation. The average 222Rn concentrations for BK 6, BK 7 and BK 8 were found at 0.29 pCi/L, 0.31 pCi/L and 0.72 pCi/L, respectively. BK 8 with 277.97 m³ obtained higher 222Rn concentrations than BK 6 with 440.98 m³, followed by BK 7 with 292.67 m³. From the results, 222Rn concentration in BK 6 and BK 7 are influenced by temperature and pressure, correspondingly. However, no correlation of environmental factors found in BK 8.

Investigations of Outdoor and Indoor 222Rn Concentrations Level in Academic Building at Universiti Malaysia Kelantan Jeli Campus

Radon (222Rn) is radioactive gas emanates from soil, rock sand and enter the building through cracks, construction joint, gas in suspended floors and also from the building materials itself. 222Rn gas in high concentrations is hazardous as it can affect the human organ and tissues due to the emission of alpha particles. This study aims to determine the outdoor and indoor 222Rn concentrations in academic building, Universiti Malaysia Kelantan (UMK) Jeli Campus as well as to identify any possible factors influenced the gas progenies. Radon Sentinel 1030 was placed in open space between the lecturer’s rooms and inside closed room (Lecture Hall 4) on the first floor of the building for data collections. The total of 224 data of 222Rn concentrations reading has been collected for outdoor and indoor spaces with 0.5 hours time interval. The outdoor and indoor 222Rn concentrations were found in ranges between 0.23 pCi/L to 0.48 pCi/L and 0.73 pCi/L to 1.13 pCi/L, respectively.

The effects of altitude levels on 222Rn concentration in academic building at Universiti Malaysia Kelantan Jeli campus

Highly continuous exposure to Radon (222Rn) concentrations can affects human health and cause lung cancer. This study aims to briefly monitor 222Rn concentration at different level altitude and to investigate correlation between their environmental parameters sort of temperature, humidity and pressure in indoor space. Lecture rooms known as BK 4 in the first floor and BK 8 in the third floor at academic building Universiti Malaysia Kelantan (UMK) Jeli Campus were selected as the study areas. The total of 210 readings indoor 222Rn concentrations data have been collected for the whole study using Radon Sentinel Model 1030. Average 222Rn concentration in BK 4 and BK 8 were found to have range from 0.36 pCi/L to 0.73 pCi/L and 0.40 pCi/L to 0.93 pCi/L, respectively. 222Rn concentration is higher at BK 8 with height 14.4 meter than BK 4 with height 4.8 meter from the ground. Negative correlations were obtained between 222Rn concentrations over pressure, temperature and humidity at BK 4. Meanwhile, 222Rn concentrations over pressure and humidity at BK 8 have shown positive correlation and negative correlation with temperature.

The RIKEN-RAL Muon Facility and the Application of Muons for Studies of Magnetic Properties of Nano-Materials

An overview of the RIKEN-RAL Muon Facility is reported. The RIKEN-RAL Muon Facility has been established at the Rutherford-Appleton Laboratory in the UK in 1992 and started to be in used for material science studies from 1994 by applying intense pulsed muon beams. More than 380 publications have been published in international journals and more than 100 domestic and international collaborations have been organized. As an example of those collaborative studies, a preliminary result of one recent experimental study on the magnetism in gold nano-cluster is reported. Additionally, a recent computational result on a local effect induced by an injected muon is reported in order to show how the presence of the muon leads to a local deformation of the crystal structure, thus changing the muon’s own position in finding the final stopping site self consistently.

Magnetic Moments and Ordered States in Pyrochlore Iridates Nd2Ir2O7 and Sm2Ir2O7 Studied by Muon-Spin Relaxation

Magnetic-ordered states of the pyrochlore iridates Nd2Ir2O7 (Nd227) and Sm2Ir2O7 (Sm227), showing metal–insulator transitions at 33 and 117 K, respectively, were studied by both the muon-spin-relax...

μSR Study of Organic Superconductor λ-(BETS)2GaCl4

Muon-spin-relaxation (μSR) measurements in the transverse-field (TF) of 30 G were carried out from 7 K down to 1.8 K on the non-magnetic anion-based organic superconductor λ-(BETS)2GaCl4. The TF-μSR time spectrum showed a significant increase with the Gaussian-type damping behavior below the superconducting transition temperature TC = 5 K confirming the bulk SC state with the full volume fraction. The zero-field (ZF) μSR time spectrum did not show any change against the temperature down to 1.7 K, suggesting that the time reversal symmetry of the Cooper pair might not be broken.

Assessment of femur length for fetal biometry in Malaysian pregnant women

The fetal biometry assessment of femur length (FL) was developed in most countries to evaluate the foetus growth. In this study, the FL values for Malaysia population were determined. A prospective study was conducted and a number of 6501 pregnant women were involved with 12372 FL data were collected, performed at antenatal care clinic of Hospital Pulau Pinang, Malaysia. The SPSS software version 17 (regression analysis and paired sample t-test) were used for analysis. The FL values of this study were constructed and rapid FL growth rate in second trimester (2.59 mm/week) than third trimester (1.43 mm/week) was observed. By ethnicity, no significant difference (p ≥ 0.05) was found between the FL values for fetuses of Malay and Indian ethnic’s mother (t = −2.042), however these two groups shows significantly (p < 0.05) higher values than those of Chinese ethnic’s mother (t = 4.019, 4.083; accordingly). The FL values of Malaysian resulted as significant difference with the common reference FL values from US...