The uniaxial compressive strength test is a destructive and time consuming test. A number of non-destructive methods using portable testing equipment are more applicable and easier to conduct. This paper presents the results of a systematic approach to determine the uniaxial compressive strength of rock material using the Schmidt hammer rebound test. A total of five distinct locations (Graham Coast, Davis Coast, Nanson Island, Danco Coast and Trinity Island) were tested using the Schmidt rebound hammer test. Peninsula Antarctic located at northwest of Antarctic region comprising of igneous and metamorphic rocks. Statistical analysis of the results at 95% confidence level showed the Schmidt rebound value of the Graham Coast ranges from 40±1.7 to 41±1.3 with standard deviation of 8.2 to 6.4. The rebound value for Davis Coast was 39±1.6 with standard deviation of 7.7. Rocks from Nanson Island and Danco Coast have the Schmidt rebound value of 54±1.7 with standard deviation of 8.0 and 36±1.3 with standard deviation of 6.2, respectively. The Schmidt rebound value of rocks at Trinity Island ranges from 29±1.4 to 32±1.7 with standard deviation of 6.8 to 8.1. Thus, the respective uniaxial compressive strengths of rock materials from Graham Coast, Davis Coast, Danco Coast, Nanson Island and Trinity Island were 73-108, 50, 59, 164 and 45-59 MPa. The respective ISRM strength classification of rock materials of Graham Coast, Davis Coast, Danco Coast, Nanson Island and Trinity Island were strong (R4) to very strong rock (R5), medium strong rock (R3), strong rock (R4), very strong rock (R5) and medium strong (R3) to strong rock (R4). The results showed a mean of quantification of rock material strength based on the Schmidt Hammer rebound test in Antarctic Peninsula.
Carbon spheres (CSs) were synthesized from sucrose by hydrothermal reaction. The synthesized materials were further
activated with potassium hydroxide (KOH) at different concentrations. The effects of KOH concentration on the surface area
and morphology were investigated. The route for pore formation and structural deformation in carbon spheres during
activation has been proposed and discussed based on micrographs and porosity trends. It was suggested that the pore
formation and structural deformation phenomena were due to the intercalating power of energized K+ into the carbon.
This work provides an insight of the pore formation in carbon spheres for the development of adsorbents as well as for
the understanding of the structural deformation of such materials at higher KOH concentrations.
Parameter kekuatan ricih seperti sudut geseran permukaan ketakselanjaran batuan merupakan antara data penting bagi reka bentuk struktur kejuruteraan batuan seperti pengorekan bawah tanah dan cerun potongan. Ujian ricih terus beban normal tetap telah dilakukan pada permukaan buatan potongan gergaji batuan granit segar dan terluluhawa sedikit untuk menentukan sudut geseran asas permukaan satah ketakselanjaran. Sampel granit diperoleh dari Kuari Kajang Rock, Semenyih, Ulu Langat, Selangor, Lebuhraya Silk Kajang (km 14.6), Selangor, Jalan Pos Selim-Kampung Raja (km 30-29), Cameron Highland, Pahang/Perak dan Kuari JKR Bukit Penggorak, Kuantan, Pahang. Sebanyak 84 ujian ricih terus telah dijalankan pada batuan granit iaitu 65 ujian pada batuan segar dan 19 ujian pada batuan terluluhawa sedikit. Untuk batuan granit segar, sudut geseran asas ialah 42° ± 0.6° dengan sisihan piawai sebanyak 2.26 dan pekali penentuan, R2 sebanyak 0.98. Untuk granit terluluhawa sedikit, sudut geseran asas ialah 38° ± 1.9° dengan sisihan piawai sebanyak 3.99 dan pekali penentuan, R2 sebanyak 0.97. Nilai-nilai ini adalah lebih tinggi daripada nilai yang selalu dianggap untuk batuan granit segar iaitu 30°-35°.
The effects of the X-ray irradiation and chemical etching on the physical and optical properties of cR-39 plastic detectors were investigated for different doses of X-ray. cR-39 detectors were etched in the solution of the 3 M of NaOH after irradiation for revelations of the track. The tracks formed on cR-39 either by irradiated X-ray or due to the effect of environment. The changes in the thickness after exposed have significant decrease in 60 kVp and started to increase in the range of 70 kVp up to 100 kVp due to the formation of oxidation layer on surface by free radicals. The optical band gaps before etching and after etching were determined by using Ultraviolet-visible (uv-Vis) spectroscopy. The optical band gap is attributed to the indirect transition due to its amorphous nature which is significantly decline trend energy in increase of the energy fluence of radiation. The Urbach's energy, is defined as the width of the tail localized states in the forbidden band gap which change increment trend as increase in dose delivered due to the distortion structure of the cR-39 in terms of the electron charges in valences electron hence attributes to the induced modification of angle bond between the neighboring atoms.
A study to determine the effects of ultraviolet-C (UV-C) irradiation on fruit quality, antioxidant compounds and activities of Musa AAA Berangan was carried out. The mature green fruits were exposed to UV-C doses of 0, 0.01, 0.02, 0.03 and 0.04 kJ/m2 and allowed to ripen at 25±2o C for 5 days. Peel and pulp color, water loss, firmness, soluble solids concentration (SSC), titratable acidity, pH, vitamin C, total phenolic contents (TPC) and antioxidant activity (assay using ferric-reducing antioxidant power (FRAP), 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2’-azinobis-(3-ethyl-benzothiazoline-6-sulfonic acid) (ABTS) free radical-scavenging) were analyzed at day 0, 1, 3 and 5 after ripening. The peel color (L*, C* and ho) of Berangan banana decreased as UV-C irradiation dose increased. UV-C irradiated fruit has lower water loss, firmer pulp and lower SSC than control. The fruit could undergo normal ripening albeit the quality of fruit has been affected by UV-C irradiation. There was significant interaction between UV-C radiation x day after ripening on TPC of Berangan banana. Fruit irradiated with UV-C showed significant higher of TPC as compared with control at later stage of ripening. Antioxidant activities measured with the three assays showed a significant decrease as ripening progressed. The results of this study showed that UV-C radiation as low as 0.01 kJ/m2 is able to reduce water loss, slow down starch conversion and softening and enhanced TPC of Berangan banana.
As researchers seek to determine the cellular mechanisms underlying biological processes, they have turned to analyze the functional role of microRNAs to understand this process in details. Here, we investigated the expression pattern of two microRNAs, miR-124 and -134 in maturing neurons and found that the choice of endogenous controls influenced the observed expression levels of these microRNAs. We have cultured rat hippocampal neurons and performed quantitative PCR on the microRNAs using Taqman gene expression assays. The expression of miRNAs was normalised with selected endogenous controls. Using BestKeeper and NormFinder software, we found that 18S rRNA and 5S rRNA to be unsuitable as endogenous controls in this system, while normalising to U6 snRNA produced more consistent results. Our study would like to highlight the importance of empirically testing proposed endogenous controls in any model system before data interpretation is carried out.
The objective of this study was to identify the exogenous variables of risk and investment management efficiency by using a two-stage data envelopment analysis (DEA) method. The first stage involves obtaining the efficiency scores of risk and investment management via DEA that requires only the traditional inputs and outputs. In the second stage, the Tobit regression analysis is conducted in which the efficiency score obtained from the first stage is treated as a dependent variable, while the exogenous factors are considered to be independent variables. The exogenous factors consist of operating systems, organizational form, consumer preference and size. The results showed that the mutual company as well as the takaful system demonstrate better risk management performance than their stock and conventional system counterparts. In addition, size is also a significant indicator for risk management efficiency in which the larger insurer/takaful operator exhibits better risk management performance than the smaller one. However, consumer preference is found to be insignificantly correlated with the efficiency of risk management. In contrast, with risk management, organizational form, operating system and size are not indicators of the investment management efficiency, but consumer preference is significantly and positively associated with investment management efficiency.
McIntyre was the first to suggest ranked set sampling (RSS) method for estimating the population mean. In this paper, we modify RSS to come up with new sampling method, namely, two stage ranked set sampling (TSRSS) for samples of size m=3k (k=1,2,..). The TSRSS is suggested for estimating the population median in order to increase the efficiency of the estimators. The TSRSS was compared to the simple random sampling (SRS), ranked set sampling (RSS), extreme ranked set sampling (ERSS), median ranked set sampling (MRSS) and balance groups ranked set sampling (BGRSS) methods. It is found that, TSRSS gives an unbiased estimator of the population median of symmetric distributions and it is more efficient than SRS. Also, it is more efficient than RSS, ERSS, MRSS and BGRSS based on the same number of measured units. For asymmetric distributions considered in this study, TSRSS has a small bias and smaller variance than SRS, RSS, ERSS, MRSS and BGRSS methods.
Dihexyl-sexithiophene (DH6T) was doped with tris (8-hydroxyquinolinate) aluminum (Alq3) to prepare blends of DH6T/ Alq3 by dissolving the mixture in the chloroform/hexane co-solvent. Solid films with different thickness deposited on quartz substrates were obtained from the blends via casting process. Optical absorption spectroscopy has been performed to measure the optical band gap of pure and doped DH6T as well as variations in the band gap with dopant concentration (weight %). This variation in optical band gap with dopant concentration was determined quantitatively with fitted and extrapolated techniques and observed qualitatively from the red shift appeared along the optical absorption spectra. The results showed that within a specific dopant content, the optical energy gap, Eg of DH6T decreases from 2.69 eV to 1.8 eV with increasing dopant concentration to 23.1%.
Sembilan aktinomiset endofit telah berjaya dipencilkan daripada pokok yang mempunyai nilai ubatan dari beberapa tempat di Semenanjung Malaysia. Pencilan tersebut telah dikenalpasti melalui pemerhatian morfologi, amplifikasi gen 16S rRNA dan analisis penjujukan 16S rRNA. Saringan awal terhadap aktiviti antimikrob telah dilakukan dengan menggunakan teknik calitan plat. Pembentukan miselium substrat dan aerial, warna jisim spora, pigmen larut dan morfologi rantai spora pada semua pencilan menyerupai Streptomyces sp. dan Microbispora sp. Analisis filogenetik jujukan separa 16S rRNA mendapati pencilan SUK 08, SUK 10 dan SUK 15 saling berkaitan dengan Streptomyceseurythermus ATCC 14975T. Walau bagaimanapun pencilan ini telah dipencilkan dari tumbuhan yang berbeza. Pencilan ini didapati mempunyai aktiviti antimikrob terhadap bakteria dan kulat kajian. Empat pencilan aktif iaitu SUK 08, SUK10, SUK 12 dan SUK 15 berupaya untuk membunuh dan merencat sehingga 100% satu atau lebih organisma patogen seperti Bacillus subtilis, Aspergillus fumigatus, Aspergillus niger, Fusarium solani, Rhizoctonia solani dan Trichoderma viride. Kajian ini mengesahkan bahawa tumbuhan etnoperubatan adalah sumber pencarian aktinomiset endofit bioaktif yang berupaya menjadi sumber novel dalam pencarian agen antibakteria dan antimikotik.
As a natural anti-oxidant source, Tualang honey, produced by wild bees nesting on the Tualang tree (Koompassia excelsa) is expected to have positive influence on health, including memory. This study investigated the effect of Tualang honey on the cell count of memory formation related hippocampal pyramidal neuron and on spatial memory performance (SMP) of rats using the radial arm maze (RAM). Sprague Dawley male rats (n=24), 7-8 weeks old were divided into two groups; experimental group group force-fed 1 mL/100 g body weight with 70% honey (HG); and the control group with 0.9% saline (CG) for 12 weeks. Nissl staining technique (with cresyl violet) was employed for neurohistological analysis of the hippocampal tissue. Six randomly selected rats from each group were used for the neuronal soma counting of pyramidal cell layer CA1, CA3a and CA3c regions. Two-way ANOVA analysis showed positively significant differences between treatment and control groups for SMP comparison of working memory and reference memory components, as well as the number of pyramidal neurons. Hence, this positive effects of Tualang honey, as demonstrated behaviorally and neurohistologically, supported report that Tualang honey could improve memory and deter hippocampal morphological impairments; possibly due to its high anti-oxidant properties.
Glufosinate ammonium or ammonium salt (ammonium-(2RS)-2-amino-4- (methylphosphinato) butyric acid; C5H15N2O4P) is a commonly used polar herbicide in Malaysia and present in a variety of environmental waters at the sub-ppb level. Thus, glufosinate ammonium is analyzed in soil and water using high-performance liquid chromatography (HPLC), which is a complex yet the most powerful analysis tool. HPLC is tremendously sensitive and highly automated and HPLC instrumentation and machinery have improved over the years. However, typical problems are still encountered. HPLC users and advanced learners require help in identifying, separating and correcting typical problems. All HPLC systems consist of similar basic components. Although it is a modular system, trouble can occur in each component and change the overall performance. Resolving these problems may be expensive. This review describes the different aspects of HPLC, particularly troubleshooting, common problems and easy guidelines for maintenance.
Seven species of tropical seagrass found at seagrass bed located in Johor, Malaysia were analysed for As, Cu and Cd accumulation. The species were identified as Enhalus acoroides, Halophila minor, Halophila spinulosa, Halophila ovalis, Thalassia hemprichii, Halodule uninervis and Cymodocea serrulata. Seagrass plant is rapidly becoming one of the methods to determine the overall health condition of aquatic environment. Each seagrass samples were collected and divided into three parts i.e roots, rhizomes and leaves. Samples were grinded, digested and the correlation between each part was analysed using SPSS version 16. Each part of seagrass tissues have the ability to assimilate metals for example the concentration of As, Cu and Cd in tropical seagrass were in the range of 5-48, 6-60 and 10-69 μg/gDW, respectively. Halophila minor and Halophila ovalis indicates positive correlations to translocate metals (As, Cu and Cd) in plants parts (leaves-rhizomes, rhizomes-roots and roots-leaves). Seagrass can accumulate metals depending on pollution that occur, seasonal variation and internal capabilities to translocate metals. The seagrass species especially Halophila ovalis and Halophila minor can act as bioindicator for metal pollution.
Titanate nanotubes were prepared by a rapid hydrothermal method in the presence of triethanolamine (TEA) using TiO2 nanoparticles as a precursor. The addition of TEA significantly reduced the formation time of the titanate nanotubes from 24 to 6 h. The crystalline structure of the titanate nanotubes was revealed to be H2Ti2O5 through the X-ray diffraction (xRD) measurement. The morphology of the titanate nanotubes was confirmed using transmission electron microscopy (TEM) while the surface area was characterized using Brunauer-Emmett-Teller (BET) surface area analysis. The titanate nanotubes produced were several hundred nanometers in length and had an average outer diameter of - 11.5 nm, inner diameter of -5.0 nm, interlayer spacing of 0.93 nm and surface area of >250 m2Ig. The photocatalytic activity of the titanate nanotubes was studied using methylene blue as a model dye; the titanate nanotubes showed better photocatalytic performance as compared to TiO2 nanoparticles.
ABSTRACT
Triclopyr is a post emergence herbicide used to control woody plants. After application, the excess amount will enter the soil and water bodies and it is present in ppb level thus making extraction very difficult. The extraction of triclopyr 3, 5, 6-trichloro-2-pyridinyl residue from soil, sediment and water samples under different solid phase extraction (SPE) sorbent efficiency was studied for better recovery. Four different SPE sorbents i.e.: Oasis HLB, Water Sep-Pak, Cromabond (cation/anion PS-H+ /OH-), Isolute ENV+ and a series of solvent i.e. potassium dihydrogen phosphate (KH2PO4 0.1M), sodium hydroxide (NaOH 0.2M), potassium hydroxide (KOH 0.5 & 0.6M), ammonium acetate, methanol and water were used as extraction solution. Sample clean-up performance was evaluated using high performance liquid chromatography (HPLC, Agilent 1220 infinity LC) with variable wavelength detector (VWD) 290 nm. Cromabond®H+/OHcolumn with 0.6 M KOH was the most suitable for the clean-up in view of the overall feasibility of the analysis. The highest recovery was 89.32%.
Oleic acid (OA) capped wolfram (VI) oxide, WO3 nanoparticles were chemically synthesized and characterized by means of Fourier Transform-Infrared spectroscopy (FT-IR) and transmission electron microscopy (TEM). The tribological properties of the capped WO3 nanoparticles as an additive in base oils were investigated using a four-ball machine. Results show that OA-capped WO3 nanoparticles are able to prevent water adsorption and capable of being dispersed stable in organic solvents which is base oils. The as-prepared capped WO3 nanoparticles have an average size of 15 nm. In addition, OA-capped WO3 nanoparticles as an additive in base oils perform good anti-wear (AW) and anti-friction (AF) properties owing to the formation of a boundary film.
This study attempts to trace changes in the wet spells over Peninsular Malaysia based on the daily rainfall data from 32 selected rainfall stations which include four sub-regions; northwest, west, south and east, for the period of 1975 to 2004. Six wet spells indices comprising of the main characteristics (maximum, mean, standard deviation), the persistency of two consecutive wet days and the frequency of the short and long duration of wet spells will be used to identify whether or not these indices increase or decrease over Peninsular Malaysia during the monsoon seasons. The study indicates that the eastern areas of the peninsula could be considered as the wettest areas since almost all the indices of wet spells over these areas are higher than over the other regions during the northeast monsoon (NE). The Mann-Kendall (MK) trend test revealed that almost all of the stations located in the eastern areas of the peninsula exhibited a positive trend in the mean, variability and persistency of wet spells indices during the NE monsoon, while a negative trend was observed during the southwest monsoon (SW) in these areas. Moreover, these indices showed a positive trend, and at the same time a decreasing trend was observed in the frequency of the long wet spells in most stations located over the west coast of Peninsular Malaysia during the SW monsoon for the period of 1975 to 2004.
The relaxed eddy accumulation method (REA) was applied for direct measurement of sulfate fluxes over mixed dipterocarp forest. The sampling system using a four-stage filter pack was designed to take updraft or downdraft air samples in the direction of the vertical wind velocity. The deadband of the velocity profile was set at ±0.5 σw in which an air sample with velocity within the set value is rejected. The forest site was located at a latitude of 13o 35’ 13.3’’N and longitude of 99o 30’ 3.9’’E Ratchaburi province in Thailand. The sampling period was set in 4 time intervals: 6-12, 12-18, 18-24 and 24-6 h for 3 consecutive days/month (n=144) throughout one year. All the micrometeorological parameters for flux estimation were measured in real time. The concentration and flux of sulfate were found to reach a peak value of 1.32 μg m-3 and 8.35 μg m-2 h-1, respectively, at noon time which indicated the effect of atmospheric instability caused by a high heat transfer during the day. The one-year average deposition velocity was observed to be 0.24 cm s-1.The coefficient β obtained under high ambient temperature and a humid environment in this tropical climate was 0.49. It has also been observed that βis relatively insensitive to atmospheric stability
This study investigated the spatial pattern and trends of the daily rainfall data in Peninsular Malaysia based on seasonal rainfall indices. Five rainfall indices which describe the main characteristics of rainfall, the total amount of rainfall, frequency of wet days, rainfall intensity, extreme frequency, and extreme intensity, were employed in this study. The statistics of rainfall indices were calculated in terms of their means for four regions in Peninsular Malaysia for the period 1975 to 2004. The findings indicate that the southwest monsoon had the greatest impact on the western part of the Peninsula, particularly in characterizing the rainfall pattern of the northwest region. During this season, the northwest region could be considered as the wettest region since all rainfall indices tested are higher than in other regions of the Peninsula. Otherwise, the northwest region is denoted as the driest part of the Peninsula during the northeast monsoon period. The northwest region is less influenced by the northeast monsoon because of the existence of the Titiwangsa Range, which blocks the region from receiving heavy rainfall. On the other hand, it is found that the lowlands areas such as the eastern part of the Peninsula are strongly characterized by the northeast monsoonal flow. Based on the results of the Mann-Kendall test, as the trend of the total amount of rainfall and the frequency of wet days during the southwest monsoon decrease at most of the stations, the rainfall intensity increases. In contrast, increasing trends in both the total amount of rainfall and the frequency of wet days were observed at several stations during the northeast monsoon, which give rise to the increasing trend of rainfall intensity. The results for both seasons indicate that there are significantly decreasing trends in the frequency of wet days during the extreme events for most of the stations on the peninsula. However, a smaller number of significant trends was found for extreme intensity.
Meiobenthos in Bidong Archipelago in coastal water of the South China Sea is hypothesised to have a certain trend of
distribution particularly in the island ecosystem where it is usually having different type of sea bottom. Nonetheless, since
it is located in a tropical area, the trend at the sub-tidal could be less obvious due to absent of clear season. Meiobenthic
sampling was carried out in Karah Island, an island in Bidong Archipelago, from the intertidal, towards the sub-tidal
zone covering the coral and non-coral area to see the trend in the density and composition. A transparent hand core
was used to collect benthos samples. Nematoda and harpacticoid copepods dominated the intertidal and sub-tidal zone
respectively. Harpacticoid copepods were higher in density in the non-coral sediment than the coral area. This could be
due to the high content of silt and clay in the coral area (2.98% of silt and clay). The 2-dimension MDS analysis on the
density data indicated the highest degree of scattering and an over-lapping condition for those intertidal and sub-tidal
samples respectively. ANOSIM result showed that the degree of similarity was lower at the intertidal (70%) than the subtidal
(reaching 90%) in the first sampling before both became no significant different in the second sampling. It could
indicate the stable condition in the subtidal than the intertidal ecosystem. The comparatively low density of meiobenthos
could indicate their response towards the environmental condition in the area which will only be confirmed by long term
ecological study.