[en] An airtight chamber was designed and constructed in order to determine the emanation and the activity concentration of radon and to optimize measurement of radon emanation in terms of temperature, pressure and humidity. In this study, an airtight chamber in size of 0.50 m(width)x0.40 m(depth)x0.35 m (height) with total chamber volume of about 0.07 m³ was built by using a perspex material with 6 x 10^-3 m of thicknesses. A Continuous Radon Monitor (CRM) Sun Nuclear model 1029 was used to measure the emanation of radon in the chamber. This homemade chamber has a rectangular opening with two key systems to insert and remove samples and continuous radon monitor to prevent any of disturbances to the flow of air in the chamber. An efficiency and leakage tests were carried out before radon activity was measured. Xenotime mineral was inserted into the chamber as a source of radon (²²²Rn). Radon measurements were done for each hour over 96 hours counting time. The results indicated that the background of radon concentration in an empty chamber was 21.0±4.8 Bq m^-3. The usage of 0.15 kg, 0.25 kg and 0.50 kg of xenotime mineral recorded 249.6±119.1 Bq m^-3, 400.0±187.6 Bq m^-3, 2236.6±213.8 Bq m^-3 of radon activities respectively.The effect of volume of the homemade radon chamber, the mass of xenotime, temperature, pressure and humidity to the radon emanation will be discussed in this paper. (author)

[en] This research was carried out to investigate the effectiveness of polydimethylsiloxane (PDMS) and hexamethyldisiloxane (HMDSO) as compatibilizing agent in producing wood composites of betel nut fiber/ polypropylene (BNF/ PP) and betel nut fiber/ polystyrene (BNF/ PS). Wood composite was prepared by blending 40 % of matrix polymer and 60 % of treated and untreated BNF using internal mixer Brabender Plasticoder at 170 degree Celsius with 50 rpm rotor speed for 13 minutes. The treatment was done prior to blending the materials by immersing the BNF in PDMS and HMDSO solutions with 1 %, 3 % and 5 % of concentrations for 24 hours. The effects of 1 % HMDSO treatment on BNF/ PP composite contributed to high flexure strength and impact strength which are 19.2 MPa and 7.9 kJ/M2 respectively while the percentage of water absorption showed the minimum value of 6.7%. The impact strength of BNF/ PS composite treated with 3% HMDSO showed maximum value that is 4.7 kJ/ M² and minimum percentage of water absorption, 6.8 %. However, the flexure strength of untreated BNF/ PS composite is higher than treated BNF/ PS composite with value of 4.7 MPa. The morphology of treated BNF/ PP composites from SEM micrographs showed better interface interaction between fibers and matrices. FTIR spectra showed the presence of siloxane groups such as Si-O, Si-CH₃, Si-(CH₃) and Si(CH₃) as a result of HMDSO and PDMS treatment. Based on the characterization analysis, HMDSO treated composite of BNF/ PP showed more effective interfacial interaction between BNF and matrices. (author)

[en] Separation of methanol extracts of the fruits and stem bark of Styrax benzoin using various chromatography (vacuum liquid chromatography, column chromatography and preparative thin layer chromatography) gave four benzofuran glycosides namely egonol gentiobioside (1), egonol gentiotrioside (2), egonol glucoside (3) and masutakeside (4). The compounds were identified by spectroscopic analysis (NMR, mass and infra-red spectral data) and by comparison of the data with that of the literature. Isolation of compounds from this plant has never been reported before. (author)

[en] Ionic liquids (ILs) are of great interest as potential solvents for the production of fuels from lignocellulose biomass which is a potential source of bio fuels. To study the effects of pretreatment, 1-butyl-3-methylimidazolium chloride ([B mim]Cl) was used to pretreat woody plants, kempas (Koompassia malaccensis) and jelutong (Dyera costulata), and non-woody plants, kenaf (Hibiscus cannabinus) and rice husk (Oryza sativa) at 120 degree Celsius for 24 h. Cellulose was regenerated by the addition of water. The cell wall composition and structure of the lignocellulose bio masses before and after the ILs pretreatment were observed and characterized using field emission scanning electron microscopy (FESEM), attenuated total reflectance fourier transform infrared (ATR FT-IR) spectroscopy, and X-ray diffraction (XRD). After the pretreatment, enzymatic hydrolysis was carried out to identify the total reducing sugars (TRS) yields using dinitrosalicylic acid (DNS) method. Regenerated lignocellulose bio masses resulted in high TRS yields compared to their counter-parts which are in agreement with the findings of FESEM, ATR FT-IR and XRD that exhibited regenerated cellulose were less crystalline and more amorphous upon IL pretreatment. Therefore, kempas and jelutong can be alternate sources for the bio fuels production. (author)

[en] Colour is one important characteristic to food products as it dictates consumers first perception on the foods flavour and quality. In the current food industry, most of the colorants used were derived from synthetic sources. However, due to negative health impacts of the synthetic colorants, the urgency to find natural colorants and impose it to food products is of great importance. In this study, a group of plant pigments which are potentially introduced as natural food colorants were quantified from 24 species of local traditional vegetables (ulam), characterized as neoxanthin, violaxanthin, lutein, zeaxanthin, β-cryptoxanthine, α-carotene and β-carotene by using HPLC. It was shown that Sauropus androgynous contained the highest amount of neoxanthin, violaxanthin and β-cryptoxanthine at 142.40±3.57, 28.06±0.65 and 0.07±0.00 mg/ g dry weight (DW), respectively. In contrast, highest content of lutein and α-carotene were observed in Centella asiatica at 16.53±0.97 and 2.14±0.12 mg/ g DW, accordingly. Meanwhile, Piper sarmentosum contained the highest zeaxanthin level (123.45±12.3 mg/ g DW) and Oenanthe javanica has the largest amount of β-carotene (3.09±0.06 mg/ g DW). The extracted yellow-to-red lipid soluble pigments can be further developed into commercial food colorant to replace the synthetic colorants in the market thus improving social awareness towards natural products as well as strengthening the national economy. (author)

[en] The kinetics of diffusion and healing efficiency of healable resins at different healing times or with different concentrations of healing agent (HA) were studied. The reduction in healing efficiency at concentrations of HA greater than 8.0 weight total percentage was demonstrated to be caused by phase separation. Thus, the HA need to be soluble in the epoxy resin network for optimum healing efficiency. (author)

[en] Agar wood oil is well known as expensive oil extracted from the resinous of fragrant heartwood. The oil is getting high demand in the market especially from the Middle East countries, China and Japan because of its unique odor. As part of an on-going research in grading the agar wood oil quality, the application of Artificial Neural Network (ANN) is proposed in this study to analyze agar wood oil quality using its chemical profiles. The work involves of selected agar wood oil from low and high quality, the extraction of chemical compounds using GC-MS and Z-score to identify of the significant compounds as input to the network. The ANN programming algorithm was developed and computed automatically via Matlab software version R2010a. Back-propagation training algorithm and sigmoid transfer function were used to optimize the parameters in the training network. The result obtained showed the capability of ANN in analyzing the agar wood oil quality hence beneficial for the further application such as grading and classification for agar wood oil. (author)

[en] A series of decanoyl thiourea derivatives, namely N-decanoyl-N^'-2-pyridine thiourea (D1), N-decanoyl-N^'-3-pyridine thiourea (D2) and N-decanoyl-N^'-4-pyridine thiourea (D3) were successfully synthesized and were applied as corrosion inhibitors. The compounds were characterized via elemental analyser, Fourier Transform Infra Red (FTIR) and ¹H and ¹³C Nuclear Magnetic Resonance (NMR) spectroscopies. The inhibition efficiency of each compound was studied on the corrosion of mild steel in 0.1 M H₂SO₄ with different concentrations of the compounds by using weight loss method and linear polarization resistance technique. From both techniques the results indicate that the corrosion process was significantly reduced with the presence of such compounds. It shows that compound D3 has the highest efficiency which is 85.84 % compared to D1 and D2. The effects of position of N atom located at ortho, meta and para in chemical structure of pyridine on the corrosion inhibition efficiencies of the compounds were also investigated. (author)

[en] Product of 2-ethylhexyl estolide ester formed from acid catalyst reaction was characterized by using Fourier Transform Infrared (FTIR) in conjunction to determine the functional groups presence. Meanwhile, Nuclear Magnetic Resonance (NMR) has been used to determine the structures compounds. The present of ester group at 1738.23 cm^-1 indicated that the formation of estolide ester has been occurred. The vibration peak of C-O occurred at 1174.60 cm^-1 and 1117.10 cm^-1 confirmed the formation of ester. Present of CH₂ bending indicated the existence of long-chain compounds. Existent of ester methine signal at 3.8669 ppm indicated the estolide linkage in the ¹H-NMR spectrum. On the other hand, two signals have been notified in the ¹³C-NMR spectrums. One signal appeared at 173.41 ppm indicated the existence of carbonyl acid compound while carbonyl esters signal appeared at 173.56 ppm. Chemical shift of ¹H and ¹³C for stimulation and experiment were matched with estolide structure. Result of pour point, flash point and viscosity indicated that estolide 2-ethylhexyl ester meet the lubricant criteria as they possesses low pour points (-6 degree Celsius), high flash point (246 degree Celsius) and optimum viscosity (179 cps). (author)

[en] Tin mining activities not only released metal contaminants into environment, but also radionuclides into the native soil and sediment. There is a possibility that radionuclides be transferred between sediment, water and biota as a result of exchanges between them through biological, physical and chemical processes. Fishes from former tin mining lakes in Kampung Gajah, have become main sources of protein supplies and economic profit to the local resident. The present study is to determine linkages between activity concentrations of natural radionuclides in biota (fish), water and sediment in one of the former tin mining lake. The study involved analysis of radionuclides in water, edible part of fish and sediment. Filtered and unfiltered water samples collected from the study area were filled into marinelli beakers, sealed and count using gamma spectrometry. Fish and sediment samples prior to measurement were dried, grind and sieved through 250 μm and kept in special container for measurement of radionuclides activity concentration using gamma spectrometry. The range of transfer ratio of ²²⁶Ra, ²²⁸Ra and ⁴⁰K from unfiltered water samples to fish are 1.95 to 3.42, 0.86 to 2.70 and 12.63 to 18.69, while, for sediment to fish are from 1.30 to 2.27 x 10^-2, 0.43 to 1.13 x 10^-2 and 9.08 to 13.45 x 10^-2 , respectively. Transfer ratio of ²²⁶Ra, ²²⁸Ra and ⁴⁰K from sediment to unfiltered water is 7.00 x 10^-3, 4.26 x 10^-3 and 7.30 x 10^-3, respectively. This present study shows that there is transfer for radionuclides from water to fish, sediment to fish and lastly sediment to water column. (author)