One of the major component in neutron radiography is a collimator that is used to collimate the neutron in parallel beam with less gamma ray contamination and high thermal neutron flux. The collimator consists of seven components and the interest component is an aperture as it is used to prevent the thermal neutron from entering the beam except through the center hole. In this study, the collimator design was taken from radial beam port at NR facilities at ANM with the collimation ratio is 46.4. In order to increase the collimation ratio, optimization of the aperture component has been done on four different material and 1-5 cm diameter parameters. The optimization of apertures shows that the cadmium with 1 cm diameter yields the thermal neutron flux at the collimator inlet and outlet with 1.78 x103 n cm-2 s-1 and 5.90 x102 n cm-2 s-1 while the gamma ray contamination was 10.7 μSv hr-1. The optimization succeed to produce high L/D ratio however the thermal flux was low and the gamma contamination was higher that original design but satisfied the ICRP 74 condition for radiation worker.
Boundary element method (BEM) is a numerical technique that used for modeling infinite domain as is the case for galvanic corrosion analysis. The use of boundary element analysis system (BEASY) has allowed cathodic protection (CP) interference to be assessed in terms of the normal current density, which is directly proportional to the corrosion rate. This paper was present the analysis of the galvanic corrosion between Aluminium and Carbon Steel in natural sea water. The result of experimental was validated with computer simulation like BEASY program. Finally, it can conclude that the BEASY software is a very helpful tool for
future planning before installing any structure, where it gives the possible CP interference on any nearby unprotected metallic structure.
Thermoplastic natural rubber sample is found isotropic based on Small Angle X-Ray Scattering (SAXS) pattern. Morphological interpretation was deduced based on ideal lamellar morphology using 1-D correlation function. The fitting was carried out using Porod tail model and Vonk for backextrapolated model. It is found that the long period value is 15. 7nm which is comparable to results obtained from Lorenzt corrected profile, 20nm. Crystalline thickness and amorphous thickness was found as 13.4 and 2.31nm respectively.
Ultrasound technology progressed through the 1960’s from simple A-mode and B-mode scans to today’s M-mode and Doppler two dimensional (2-D) and even three dimensional (3-D) systems. Modern ultrasound imaging has its roots in sonar technology after it was first described by Lord John Rayleigh over 100 years ago on the interaction of acoustic waves with media. Tomography technique was developed as a diagnostic tool in the medical area since the early of 1970’s. This research initially focused on how to retrieve a cross sectional images from living or non-living things. After a decade, the application of tomography systems span into the industrial area. However, the long exposure time of medical radiation-based method cannot tolerate the dynamic changes in industrial process two phase liquid/gas flow system.. An alternative system such as a process tomography system, can give information on the nature of the flow regime characteristic. The overall aim of this paper is to investigate the use of a small scale ultrasonic tomography method based on ultrasonic transmission mode tomography for online monitoring of liquid/gas flow in pipe/vessel system through ultrasonic transceivers application. This non-invasive technique applied sixteen transceivers as the sensing elements to cover the pipe/vessel cross section. The paper also details the transceivers selection criteria, hardware setup, the electronic measurement circuit and also the image reconstruction algorithm applied. The system was found capable of visualizing the internal characteristics and provides the concentration profile for the corresponding liquid and gas phases.
The soil plant transfer coefficient or f factor of 14 C-carbofuran pesticide was studied in outdoor lysimeter experiment consisting of Brassica sp. vegetable crop, riverine alluvial clayey soil and Bungor series sandy loam soil. Soil transfer coefficients at 0-10 cm soil depth were 4.38 + 0.30, 5.76 + 1.04, 0.99 + 0.25 and 2.66 + 0.71; from 1X recommended application rate in alluvial soil, 2X recommended application rate in alluvial soil, 1X recommended application rate in Bungor soil and 2X recommended application rate in Bungor soil, respectively. At 0-25 cm soil depth, soil plant transfer coefficients were 8.96 + 0.91, 10.40 + 2.63, 2.34 + 0.68 and 6.19 + 1.40; from 1X recommended application rate in alluvial soil, 2X recommended application rate in alluvial soil, 1X recommended application rate in Bungor soil and 2X recommended application rate in Bungor soil, respectively. At 77 days after treatment (DAT), the soil plant transfer coefficient was significantly higher in riverine alluvial soil than Bungor soil whereas shoot and root growth was significantly higher in Bungor soil than in riverine alluvial soil. At both 0-10 cm Brassica sp. rooting depth and 0-25 cm soil depth, the soil plant transfer coefficient was significantly higher in 2X recommended application rate of 14 C-carbofuran as compared to 1X recommended application rate, in both Bungor and riverine alluvial soils.
A study was carried out to determine short term diurnal radon concentration at five locations in Malaysia. Two locations (KG & AP) are former tin mining areas that has been converted to housing area and training centre respectively, one a relatively new city (SA), that was formerly a rubber and oil palm plantation area, one older cities (KB) and one housing complex by the sea (LP). The study was carried out in 2005, 2006 and 2007 using a diffused-junction photodiode sensor continuous radon monitor. The monitor is recognized by the USEPA. In each location, measurements were carried out on at least ten sites. Former tin mining areas of KG and AP shows up to seven times higher indoor average than the average in the other three locations. However the indoor average in all locations is still below the action level of 4 pCiL-1. For outdoor, the former tin mining areas average concentration was higher than the global average of 0.4 pCiL-1. For the twenty four hours temporal variation the trend indicated that former tin mining areas concentration are always higher, and at time up to six fold higher. The hourly variation of all locations follows an identical trend of high concentration during early to late morning and drop in the afternoon till evening. The outdoor twenty four hour temporal average of former tin mining areas is consistently higher than the outdoor global average of 0.4 pCiL-1. The strong correlation between indoor and outdoor concentration at AP, indicates that indoor radon might originates from outdoor environment. The study was also extended to estimate the effective dose (mSvyr-1) of Rn-222 to the public.
Some cortical bone specimens from the femurs of adult cows and sea coral of Porites species were studied by using Fourier Transform Infrared Spectroscopy, FTIR. Carbonate were shown to be present by indication of C-O stretch found between 1510-1410 cm -1 in both cortical bone and Porites. Based on the comparison of the relative intensity of CO3 2- bands with respect to the PO4 3- bands, peak intensity of Porites was found to be higher than peak intensity of cortical bone at carbonate band. This explains that Porites skeleton is made up of CaCO3 while bone consists of a mineral, hydroxyapatite Ca5(PO4)3OH with the present of carbonate ions, typically from 3 to 7 wt%.
Concentrations of Natural Occurring Radioactive Material (NORM) and terrestrial gamma radiation have been shown to be associated with certain lithology and soil types. An attempt was made to statistically predict and validate environmental gamma radiation dose rates based on limited number of actual field measurements using sodium iodide (NaI(Tl)) detector. Statistical analysis including the correlations between the actual and predicted dose were made based on 32 different lithology and soil type combinations. Results of field measurements, have shown that more than 50% of the predicted data were not significantly different from the actual measured data. The interpolation method in GIS was used to produce an isodose map based on the prediction equation. A correlation of multiple regression on the predicted versus lithology and soils dose rates gave relationships of DP = 0.35 DL + 0.82 DS – 0.02, r2 = 0.736. A predicted isodose map was subsequently plotted base on 4 dose rates classes, ranging from 0.1 – 0.3 μSvhr-1.
Structural and dielectric properties of barium strontium, titanate (Ba(ÿ)SrxTiO$) ceramics with x—
0.25, 0.5 and 0.75 were investigated. The Ba(i-xjSrxTiOs ceramics were synthesised by solid state
reaction method. Microstructure, surface morphology and dielectric properties of the synthesised
ceramics were examined using XRD, SEM and Impedance Spectroscopy respectively. XRD results
revealed that all samples contained BaTiOg as primary phase with tetragonal perovskite crystal
structure. The crystallite size slightly increased with the increasing of Sr contents. SEM micrographs
showed that the microstructure become denser when Sr contents increased. Impedance spectroscopy
showed dielectric constant for all samples were decreased with increasing temperature up to 200°C.
Barium strontium titanate (Ba0.7Sr0.3TiO3) powder was processed at temperature 80 o C by reacting titania sol in aqueous solutions that contained BaCl2, SrCl2 and NaOH at atmospheric pressure.
The structural characteristic of the powder and sintered pellet were studied using Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD) whereas the electrical characteristic was determined via Impedance Spectroscopy (IS) and LCR meter. The synthesized powder was found to have a tetragonal phase after heating at 1300 o C. XRD pattern also showed the presence of secondary phase BaTi2O5 (BT2). The SEM results shows the fine grain size was in the range of 0.2 Pm to 0.4 Pm whereas the large ones are approximately 0.8 Pm to 1.2 Pm The ac response of sample sintered at 1300 o C indicated that three electrically different regions. Element 1 can be assigned as a ferroelectric grain boundary region and it is actually BT2, element 2 as a ferroelectric bulk region and the third element is a conductive core which has a low resistance (200 :) and capacitance value.
Thin films of cerium oxide (CeO2) were prepared on silicon (Si) substrate by metal organic decomposition route. 0.25 M of cerium (III) acetylacetonate (acac) was used as starting materials with the addition of methanol and acetic acid as solvents. Oxide conversion of the film by thermal treatment was conducted at temperature ranging from 400 o C to 1000 o C for 15 min in argon ambient. X-ray diffraction (XRD) analysis utilizing Cukα radiation (Model Brukker’s Diffrac Plus ), Filmetrics system measurement, field emission scanning electron microscope (FE-SEM) (Model Zeiss Supra 35VP FE-SEM) and atomic force microscopy (AFM) (Model SII Nanonavi) were employed to characterize the phase formed and morphologies of the film produced.
A study of wear behaviour on anodised PM aluminium matrix composites (AMC) reinforced with Saffil™ alumina short fibres was done. AMC was fabricated by powder metallurgy methods (PM) with using Al flake powders and Saffil™ alumina short fibres. AMC reinforced with 15 wt % Saffil¥ alumina short fibre was selected because it showed optimum mechanical and physical properties. Sulphuric acid anodising process was performed and the objective is to obtain suitable parameters of sulphuric acid concentration, anodising voltage and anodising time on MMC. The study of anodising process was carried out with various sulphuric acid concentrations (from 0 to 20 % volume), anodising voltage (10 V to 20 V) and anodising time (from 0 to 60 minutes) at room temperature. Scanning electron microscope (SEM) was used to investigate coating morphology and thickness. From the research, anodising voltage of 18 V and 15 % vol H2SO4 in anodising time of 60 minutes were suitable parameters for sulphuric acid anodising of this AMC. SEM showed the coating thickness around 20 Pm. From the reserch, it was found that H2SO4 anodising was able to give good coating to MMC.
We put attention on Intrinsic Josephson Junction (IJJ) to study the fundamental physic for device applications. Convenient self-flux method was used to grow BSCCO single crystals. We investigated the lid effect to examine the single crystal growth of high TC (Critical Temperature). We found that for the crystal growth with no lid, two stage transitions of TC ≅ 61 K and 77 K were observed. While for the crystal growth with lid, the BSCCO has TC ≅ 80K, ΔTC = 10K and approximately average size5x2mm 2 . When we increased weight of lid, the single crystal have increased to TC =80K, ΔTC = 4K and the typical size was ≅7x3mm 2 . TC and the crystal growth show a tendency to increase by the effect of the lid. From observed quasi-particle characteristics, c-axis direction changed from semiconductor to intrinsic Josephson characteristic with decreasing temperature.
The purpose of this study is to measure and monitor the radon concentration from fabricated foamed light concrete, made of Portland cement, mine sand and granite. The concentration of radon released was measured using Radon Monitor Model 1027 from Sun Nuclear. The results of this research showed that the avearge radon concentration from foamed light concrete was 2.2 pCiL-1 L. Higher radon concentrations were detected after three days of measurements. Environment Protection Agency stated in its guidelines that radon concentration must lower than 4 pCiL-1 for a healthy environment. Thus, the use of foamed light concrete can be one of the alternatives to reduce radon concentration levels in human environment.
There are many essential and non-essential elements including metals and radionuclides present in vegetables. Howeve r, the accumulation of the several metals and radionuclides might cause the contamination to vegetables itself. Green m ustard (Brasissca rapa var. Parachinesis L.) was selected to represent the vegetable in this study. Objectives of this stud y are to determine the concentration of metals and radionuclides in the samples and to calculate the enrichment factor ( EF) and also to estimate the uptake, base on biological accumulation coefficient (BAC), for the various parts of selecte d vegetables. Three farmlands in the Cameron Highlands were studied namely Bharat, Kg Raja and Bertam area. The g reen mustard and soil samples were collected during the harvest season. Samples were dried, ground and sieved prior t o analysis. Analyses for both samples were done by using X-rays Fluorescence Spectroscopy (XRF) to measure the conc entration of Fe, Zn, Hg, U and Th. The concentration of all elements in the soils is lower than their concentration in the control soil, except for Zn, U and Th. The concentration of all elements in Green Mustard is lower than their concentrat ion in the soil where it was grown. The EF values in the Brasissca rapa var. Parachinesis L are lower than 2 except for U and Th, indicating some degree of contamination due to anthropogenic activities or naturally origin. The BAC values show that Zn and Hg were accumulated in the green mustard, depending on where the plant grows.
Radon-222 emanation from selected locally produced samples of building materials, used in Malaysia were measured using the Professional Continuous Radon Monitor Model 1027, which is a patented electronic detecting-junction photodiode sensor to measure the concentration of radon gas. Each sample was placed for 72 hours inside a 3.11 x 10 -2 m 3 sealed container. It was found that the average radon concentration Bqm -3 of air for concrete bricks, concrete brick with cemented coatings, concrete brick with cemented coatings and paint samples were, 303.7 Bq/m 3, 436.6 Bqm -3, and 410.7 Bqm -3, respectively. (Bqm -3 ) for brown clay brick, brown clay brick with cemented coatings, brown clay brick with cemented coatings and paint were 166.5 Bqm -3, 166.5 Bqm -3, and 148 Bqm -3, respectively. (Bqm -3 ) for sample of compact ceramic tile was 0 Bqm -3. The findings show that concrete brick samples are important source of radon emanation, while brown clay brick have been accepted as the recommendation of the U.S. Environmental Protection Agency (EPA), and ceramic tiles had no emanation of radon gas due to their compact surface, or the glazed layer created on the tile surface during the manufacturing process, which blocks radon emanation. A positive correlation between radon emanation and radium content has been observed for both brown clay brick and concrete brick samples whereas a negative correlation for ceramic tile has been observed. Consequently from the findings, in order to reduce radon emanation and radon exposure in house dwellings and in addition to EPA recommendation of sealed cracks and established good ventilation, we recommend concrete walls to be painted and concrete floors to be paved with ceramic tiles.
In order to prepare Malaysia to be nuclear ready, the Malaysian 1 MW TRIGA MARK II research
reactor (RTP) located at the Malaysian Nuclear Agency was premeditated with the aim to effectually
actualize the multitude areas of basic nuclear research, labor training and education. To meet the
modern safety standards, analyses of a strong interaction between the thermal-hydraulic system
behavior and the space-dependent neutron kinetics are needed as mere thermal-hydraulics codes are
said to be incapable to succeed the present safety standards. This could be achieved through the
coupling of neutronic and thermal-hydraulic codes of the reactor. Previous studies had shown that the
coupled codes are able to successfully be employed for the correlation between thermal-hydraulic
analysis and neutron kinetics at transient and steady state. In this study, the coupling was achieved
through MCNP and TRIGLAV codes for neutronic and thermal-hydraulic respectively. Core-15 of
RTP was modeled for both of the codes; hence calculating the criticality, analysis of power and
neutron flux distribution. The consistency and accuracy of the developed Core-15 MCNP model was
established by comparing calculations to the experimental results and TRIGLAV code. The criticality
predictions for both codes are in very good agreement with the experimental results. The core reached
its criticality after 66 fuels. The highest hot rod power peaking factor was found to be 1.28. The
results are conservative and can be applied to show the reliability of MCNP and TRIGLAV codes.
In this study, natural Hydroxyapatite (HA) was extracted from clean cow bone by treatment with NaOH and heating at high temperature before ground into fine powder. The HA powder were than mixed together with binder for several hours. Dense HA were formed in die steel mould by using uniaxially pressing method. Sample was sintered at different temperature 1150, 1200, 1250 and 1300°C for several hours. The phases of specimen were identified using X-ray diffraction (XRD). The mechanical properties were analyzed using three-point bending testing and the microstructure was observed by scanning electron microscopy. From XRD results, natural HA shows phase of pure HA up to 1250 o C and fracture strength results indicated that the mechanical properties of specimen increase as temperature increase. From microstructure observation using SEM, HA specimen shows initial stages of sintering process at temperature 1150°C and show changes in microstructure evolution as temperature increase up to 1300°C.
Chitosan was chemically modified with bulky structure, cis-5-norbornene-2, 3-dicarboxylic anhydride and the characteristic of this modified chitosan was studied. The resulting material was analyzed by FTIR, TGA, DSC, XRD and SEM to study the effect of N-acylation to the polysaccharide structure. FTIR results show that the anhydride monomer was successfully bound to amine group of chitosan. Thermal analysis of the modified structure provides the chitosan fibers with thermal stability while XRD and SEM show the lost of crystallinity of modified chitosan. XRD of modified chitosan shows broader peak pattern and a considerable increase in a dimension while SEM of chitosan presented the single particle morphology while norbornene-chitosan shows aggromolarate behaviour due to the hydrophobic nature of norbornene pendant group which induced aggromolaration of the particles in modified structure.
Ceramic materials play key role in several biomedical applications. One of them is bone graft which is use in treating bone defect which caused by injury or osteoporosis. Calcium phosphates based ceramic are preferred as bone grafts in hard tissue engineering because of their chemical compositions are similar to the composition of human bone, superior bioresorbable and bioactivity. In this study, β-tricalcium phosphate (β-TCP) ceramic was synthesized by using sol-gel method. Phosphorous pentoxide (P2O5) and calcium nitrate tetrahydrate (Ca(NO3)2.4H2O) were used as calcium and phosphate precursors. The effects of calcination temperature on the synthesis powder were studied using the XRD, SEM-EDS and FTIR techniques. It was found that calcination temperature greatly influence the purity of the synthesized powders. The β-TCP was the dominant phase with the formation of α-TCP at calcination temperature from 600 to 800°C. Pure β-TCP was obtained at calcination of 900°C. As the temperature increased to 1000°C, the β-TCP was decomposed to for calcium phosphate oxide (CPO). The sol-gel method has some advantages over other methods, mainly its simplicity and ability to produce pure β-TCP at lower calcination temperature.