An experimental study of the field emission from nitrogen doped Diamond-Like-Carbon (DLC) thin films prepared by plasma Chemical Vapor Deposition (CVD) was carried out for the purpose of investigating the characteristic of field electron emission from the surface of nitrogen doped DLC thin film. Thin DLC film was deposited on silicon using the plasma CVD method, from a mixture of Methane (CH4), Helium (He) and Nitrogen (N2) at room temperature. Emission current was measured while high volume of voltage was applied between the cathode-anode diode structures. Barrier height was obtained by current density-electric field (J-E) characteristic in the relation of Fowler-Nordheim equation. The value of barrier height in range of 0.03eV to 0.06eV was obtained and considered as low barrier.
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.
The use of microemulsion in the development of nanoparticle based on acrylated palm oil product is demonstrated. Acr ylated palm oil microemulsions were prepared using ionic surfactant. Combination methods of emulsion polymerization and radiation crosslinking were applied to the microemulsion system for synthesizing nanoparticle. The ionizing radiat ion technique was introduced to generate a crosslinking reaction in the development of nanoparticle. The nanoparticle was evaluated in terms of particle diameter, surface charge, pH and conductance. Their image was captured using Tra nsmission electron microscopy (TEM). Results show that the size, charge and shape of the particles are influenced by c oncentration of surfactants, monomer concentration, radiation dose and time of storage. The study showed a promising method to produced nanoparticle. This nano-sized product has the potential to be utilized as controlled-drug-release-carrier.
The aim of this study is to design radon irradiation technique in the field of hematology for an invitro study. In addition, deposit of alpha particles into the human blood surface and its effects on the thrombocytopenia estimated using nuclear track detectors (NTDs). In this technique, amount of radon gas (2210±5.1Bq/m 3 ) collected in a tight PVC container with the appropriate engineering dimension using two sources of radium (5μCi). Blood samples (10 male and 10 female) and CR-39NTDs (40 pieces) are exposed to radon gas at various exposure time. Complete blood test and the computer scanning for each piece of CR-39NTDs before and after exposure has done. The results show that the present technique has a good efficiency (96%) to the invitro exposure of human blood. When the radon gas moved on the surface of blood sample, alpha tracks registered into CR-39NTDs. Thus, this technique improved that the comparative method to evaluate alpha particle density into exposure blood samples is an effective way; this depended on the geometry of design and the sensitivity of CR-39NTDs to track registration. Radon detector version 7 (RAD7) used to make a certain suitability of CR- 39NTDs. Amount of radon concentration losses during the exposure process, in the present work it was variable from 0.41% to 1.4%. Radon concentration effected on the thrombocytopenia; this depended on time of exposure and alpha energy loss into the blood and CR-39 through the atomic displacements. At the time of exposure of 10 minutes, rate of absorption dose was 2.255±0.11μSv (39%), and the platelet (PLT) cont reduced rapidly (high effected on reduce PLT, this makes thrombocytopenia.
Since the world’s first nuclear reactor major breakthrough in December 02, 1942, the nuclear power industry has undergone tremendous development and evolution for more than half a century. After surpassing moratorium of nuclear power plant construction caused by catastrophic accidents at Three-Mile Island (1979) and Chernobyl (1986), today, nuclear energy is back on the policy agendas of many states, both developed and developing nations, signaling nuclear revival or nuclear renaissance. Selection of suitable nuclear power technology has thus been subjected to primary attention. This short paper attempts to draw preliminary technology assessment for the first nuclear power reactor technology for Malaysia. Methodology employed is qualitative analysis collating recent finding of TNB-KEPCO Preliminary Feasibility Study for Nuclear Power Program in Peninsular Malaysia and other published presentations and/or papers by multiple experts.
The results suggested that the pressurized water reactor (PWR) is the prevailing technology in terms of numbers and plant performances, and while the commercialization of Gen IV reactors is remote (e.g. not until 2030), Generation III/III+ NPP models are commercially available on the market today. Five (5) major steps involved in reactor technology selection were introduced with a focus on introducing important aspects of selection criteria. Three (3) categories for the of reactor technology selection were used for the cursory evaluation. The outcome of these analyses shall constitute deeper and full review analyses of the recommended reactor technologies for the intended full feasibility study in the near future. Recommendations for reactor technology option were also provided for both strategic and technical recommendations. The paper shall also postulate or rather implore what could be the best way for Malaysian and also other aspiring new entrant nations to select systematically their first civilian nuclear power reactor.
Protocorm-like bodies (PLBs) of an orchid (Oncidium lanceanum) were irradiated using 220 MeV 12 C 5+ ions, accelerated by AVF cyclotron at JAEA, Japan in 2005. Five different doses were applied to the PLBs; 0, 1.0, 2.0, 6.0 and 12.0 Gy. Following irradiation, these PLBs were maintained in cultures for germination and multiplication. Irradiation effects on growth and seedling regeneration patterns as well as molecular characteristics of the in vitro cultures were monitored and recorded. In general, average fresh weights of the irradiated PLBs increased progressively by irradiating the explants at 1.0, 2.0 and reached the maximum at 6.0 Gy. The figure however dropped when the explants were irradiated at 12 Gy. Surprisingly, although the highest average fresh weight was recorded on PLBs irradiated at 6.0 Gy, most of these PLBs were not able to regenerate into complete shoots. On average, after 4 months of irradiation, only 21 seedlings were successfully regenerated from each gram of these PLBs. The highest shoot regeneration was recorded on cultures irradiated at 2.0 Gy in which 102 seedlings were obtained from one gram of the PLBs. Some morphological changes were seen on in vitro plantlets derived from PLBs irradiated at doses of 1.0 and 2.0 Gy. Most of the regenerated seedlings have been transferred to glasshouse for further morphological selection. Molecular analysis showed the presence of DNA polymorphisms among the seedlings from different doses of irradiation.
Spatial and temporal variations in concentrations of several metals and isotopes in sediment cores from around Penang Island, an area with economically important biological resources off the northwest coast of peninsular Malaysia, are reported. Because of a typical, monazite rich mineralogy in surrounding drainage basins, sedimentary metal enrichment factors relative to global average materials, enrichment factors (EFs) of ˃1.0 do not always indicate significant anthropogenic metal inputs. Because of extensive metal solubilization in the hot, organic carbon rich area, EFs of < 1.0 may be observed for several metals despite significant anthropogenic contributions. Comparison of metal-Al relationships in Penang area surface sediments with those in nearby and presumed uncontaminated Strait of Malacca sediments more accurately correct for atypical regional solubilization and mineralogical effects than comparison to global average materials. Such comparisons show concentrations of Cd, Cu, Pb, Ni, Cr, As, Sb, Zn and V have changed by less than a factor of two by anthropogenic discharges. Sedimentary concentration profiles of Pb, Zn and Cu, ratioed to Sc to normalize for variations in grain size and mineralogy, have subsurface maxima suggestive of modest and recently reduced anthropogenic inputs. Mn, U, As and Sb have Sc-normalized concentration profiles clearly affected by diagenetic processes. Sc-normalized profiles of Cr, Th, Ce and Sm show only small changes with depth, confirming insignificant anthropogenic inputs and undetectable postdepositional diagenetic mobility.
Excess ²¹⁰Pb activities and fluxes in Penang area sediments are limited by supply of this radionuclide, in contrast to sediments of both the northwestern U.S.A. and Amazon continental shelves, where they are limited by particle scavenging reactions.²¹⁰Pb activities in sediments of
the shallow, dynamic Penang area often show erratic or unconvincing changes with depth that
cannot be reliably modeled by assuming steady state, constant deposition rate of particles of
uniform chemistry, mineralogy and initial unsupported ²¹⁰Pb, and that mixing is limited to a
recognizable surface layer and resemble a diffusive process.
The adsorption equilibrium time and effects of pH and concentration of ¹⁴C-labeled chlorpyrifos
O,O-diethyl O-(3, 5, 6 trichloro-2-pyridyl)-phosphorothiote in soil were investigated. Two types of Malaysian soil under oil palm were used in this study; namely clay loam and clay soil obtained from the Sungai Sedu and Kuala Lumpur International Airport (KLIA) Estates, respectively. Equilibrium studies of chlorpyrifos between the agricultural soil and the pesticide solution were conducted. Adsorption equilibrium time was achieved within 6 and 24 hours for clay loam and clay soil, respectively. It was found that chlorpyrifos adsorbed by the soil samples was characterized by an initial rapid adsorption after which adsorption remained approximately constant. The percentage of ¹⁴C-labeled chlorpyrifos adsorption on soil was found to be higher in clay loam than in clay soils. Results of the study demonstrated that pH affected the adsorption of chlorpyrifos on both clay loam and clay soils. The adsorption of chlorpyrifos on both types of soil was higher at low pH with the adsorption reduced as the pH increased. Results also suggest that chlorpyrifos sorption by soil is concentration dependent.
Many studies were carried out throughout the world on radon measurement in water especially drinking water for it can cause problem to human health. This study is an attempt to measure the level of radon present in water collect from rivers and lakes. Data gathered from this study provides important information about radiation levels in water at selected sites, because radon gas is the largest contributor to natural radioactive radiation exposure to humans. Exposure to radon gas can cause lung cancer. Liquid scintillation counting (LSC) has been applied to determine the activity concentration of radon ( 222 Rn) in water. Water samples were collected from, ex-mining lake in Perak, Sok River in Kelantan, Tembeling River in Pahang. Water samples were prepared in polyethylene bottles mixed with liquid scintillator and stored for 3 weeks to allow 222 Rn and its progeny to reach the equilibrium, and the activity concentrations ranged from 0.24-1.27 Bq/L, and 0.029 – 0.155 Bq/L for radon and radium respectively.
Muhammad Akmal Asraf Mohamad Sharom, Zainol Abidin Ibrahim, Wan Ahmad Tajuddin Wan Abdullah, Megat Harun Al Rashid Megat Ahmad, Faridah Mohamad Idris, Abdul Aziz Mohamed
Small angle neutron scattering (SANS) is used for probing the microstructure of materials in the range between 1-100 nm in dimension. The scattered neutrons from the target material were detected by a 128 x 128 array area sensitive, Helium gas-filled proportional counter, which is known as Position Sensitive Detector (PSD). The small angle neutron scattering (SANS) facility in Malaysian Nuclear Agency has been developed since 1995. The data acquisition system of this prototype facility consists of the two-dimensional Position Sensitive Detector (2D-PSD) and neutron monitor as a data grabber, TDC Histogram as a memory processing processor, two units of ORTEC 994 as a counter and timer and a computer as a data acquisition controller via GPIB interfacing protocol. This paper will describe on the development of GPIB interface for data acquisition of the SANS instrument on Windows based platform. The GPIB device interface and graphical user interface (GUI) for this data acquisition is developed using WaveMetrics Igor software.
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 trial study had been conducted to determine the particulate form of 137 Cs in seawater surrounding East Malaysia. Large volume of seawater was filtered at a flow rate of 15 liters/min through the copper hexacyanoferrates (II) impregnated filters. These filters were ashed and counted using the gamma spectrometry system to determine the dissolved 137 Cs activity. It was found that the particulate form of 137 Cs consists of 20 to 49 % of the total 137 Cs activity concentrations. Some reasonable explanations for higher particulate percentage such as sampling locations, high water flow-rate, and large volume of seawaters were further discussed. It is hope that the result of this study will help to build a better understanding about the usage of impregnated filters to study dissolved 137 Cs activity concentrations.
Environmental radiation protection program is important in the effort to limit radiation dose to the public to be as low as reasonably achievable. As water is an important factor of transfer of radionuclide to human, therefore it is important to measure natural radionuclide concentrations in rivers. 20 water samples were collected randomly from the main rivers in Kota Tinggi district. The water samples collected were analysed using ICP-MS technique to determine uranium, thorium and potassium concentration in river water. Radionuclide concentrations obtained were compared with the terrestrial gamma radiation dose rate measured in the area. Significance of the results obtained is discussed.
One of the non-destructive methods used for the identification and verification of metals is by the energy-dispersive X-ray fluorescence (EDXRF) technique. EDXRF analysis provides several important advantages such as simultaneous determination of the elements present, enable to analyse a very wide concentration range, fast analysis with no tedious sample preparation. The paper shows how this technique is developed and applied in the identification and verification of different grades of stainless steels. Comparison of the results obtained from this analysis with certified reference standards show very small differences between them.
This paper studies the use of gamma irradiation for textile waste water treatment. Prior to irradiation, the raw wastewa ter was diluted using tap water to targeted concentration of COD 400 mg/l. The sample was irradiated at selected dose between the ranges of 2kGy to 100kGy. The results showed that Irradiation was effective in removing the highly colored refractory organic pollutants. The COD removal at lowest dose, 2kGy is about 310 mg/l. Meanwhile, at highest dose, 1 00kGy the COD reduced to 100mg/l. The degree of removal influenced by the dose introduced during the treatment pro cess. As the dose increased, higher removal of organic pollutant was recorded. On the other hand, other properties of t he wastewater such as pH, turbidity, suspended solid, BOD and color shows tremendous changes as the dose increases. This shows the concentration of pollutants and dose of irradiation applied are directly proportional to each other.
Neutrino is one of the nuclear particles that are necessary for the correct description of nuclear beta decay. The standard idea is that it is a massless neutral particle and its existence was postulated in order to save the conservation of ener gy principle. This particle was later detected experimentally and it is now known that neutrino has mass. The problem of astrophysical neutrino detection has produced a new phenomenon of neutrino oscillation where the three neutrino flav ours can oscillate between themselves. This paper studies the two component neutrino oscillation problem. We study the neutrino oscillation by using the Lagrangian formulation. In our study, we assume that the neutrinos are produced as n eutrino mass eigenstate and propagate in the vacuum in the superposition of two neutrino flavour state. The Lagrangian for neutrinos with their mass and the oscillation terms were obtained. By using the mass matrix in the Lagrangian, we formulate the time evolution operator in the interaction picture. The neutrino oscillation probability obtained by using the Lagrangian formulation have the same result with the one obtained by using quantum mechanics formulation. This study hopes to gain some deeper understanding into the behaviour of neutrino beyond the Standard Model.
Polymer blends of 60/40 NR/HDPE were prepared using Brabender PL2000 Plasticorder with 60g capacity. The blends were added with radiation-sensitive natural rubber (NR)-based compatibilizer, known as LENRA. They were irradiated with electron-beam radiation at various doses. The efficacy of the compatibilizer was monitored by measuring various properties of the blends such as physical and dynamic mechanical properties including morphological studies by electron microscopic technique. Early results show that the addition of LENRA improves the properties of the TPNR blends.
Surface free energies have been evaluated from Young’s moduli and lattice parameter data of five aluminium alloys with varying amounts of stanum to determine the inter-correlation with anode capacity of the alloys. The composition containing ~1.47%Sn exhibits a minimum in the surface free energy which accounts for the decrease in the tendency of the alloy to undergo passivation thus resulting in a higher anode capacity of 2478Ah/kg at ≈ 0.08mA/cm 2 , current density. The results showed that aluminium alloy containing certain amount of stanum has lowered surface free energy, leading to reduction in passive film thickness and reduces metal/oxide bond strength. These factors in turn result in a better cathodic protection property of aluminium alloy containing stanum.
This work focuses on the use of X-ray tomography in investigating the flow distribution in a structured packed bed. Cross sections of the liquid hold up distribution in a 10 cm diameter column packed with Katapak-SP12 are obtained at various column heights for different liquid flow rates. The repartition of the liquid hold up between baskets and corrugated sheets is quantified. Wall wipers and column wall effects are visualized. Results are obtained from an initially dry column without gas flow.
The microstructure, tensile fracture and creep fracture of as-cast beta phase contained γ-TiAl with nominal composition of Ti-48Al-4Cr (at.%) was investigated. The effect of beta phase on tensile and creep strength was determined from fracture analysis. Tensile test were performed at room temperature whereas constant load tensile creep test were performed at temperature 800 0 C and initial stress of 150MPa. Initial as-cast microstructure, microstructure and fracture surface after tensile and creep test were examined using scanning electron microscopy technique. Analysis shows brittle fracture after room temperature tensile test whereas ductile fracture after high temperature creep test. The role of beta phase was discussed. It is concluded that beta phase is sensitive to temperature and detrimental at both room and high temperature.