A study on water quality and aquatic insects has been conducted at the Lower Kinabatangan River Catchment, Sabah,
Malaysia. The quality of water surface and aquatic insects’ composition were studied in streams near to oil palm plantation
(OP), secondary forest (SF) and oxbow lake (OB). The study also aims to identify the seasonal variation in the aquatic
insects’ composition during the weak La Niña event. A total of 135 water samples and 1678 aquatic insect individuals
(four orders and 14 families) were collected during fieldwork campaign that spanned over the inter-monsoonal period,
wet and dry seasons between October 2004 and June 2005. OP has the highest abundance of aquatic insects particularly
during the dry season. Biological indices showed that all stations were in moderate water category. The water quality
index (WQI) was calculated and indicated that the quality of the river categorised into Class II. Discriminant analysis
(DA) was employed to classify the independent variables into mutually-exclusive groups. Suspended sediment (SS) and
chemical oxygen demand (COD) were high during the wet season. Suspended sediment was high in oxbow lake and could
be a strong reason behind low abundance of aquatic insects. Precipitation anomalies were found to affect seasonal
variations of water quality and aquatic insects at the Lower Kinabatangan River.
In the present study, capability of water hyacinth in removing heavy metals such as Cadmium (Cd), Chromium (Cr), Copper (Cu), Zinc (Zn), Iron (Fe), and Boron (B) in ceramic wastewater was investigated. The metal removal efficiency was identified by evaluating the translocation of metals in roots, leaves and shoot of water hyacinth. The heavy metal removal efficiency followed the order Fe>Zn>Cd>Cu>Cr>B during the treatment process. Water hyacinth had luxury consumption of those 6 elements. This study used the circulation system with 3 columns of plants which functioned as bioremediation of the sample. The concentration of metals in roots is much higher 10 times than leaves and stems. Roots give the result of metalR>metalL. The removal concentration from water hyacinth was estimated under pH of 8.21 to 8.49. This study proves water hyacinth to be a best plant for phytoremediation process
Vermicomposting for 140 days by using Lumbricus rubellus was conducted after 21 days of natural pre-composting. Five treatments in different ratio of goat manure: spent mushroom substrate were prepared as feed materials with four replicates for each treatment namely; 20:80 (TA), 40:60 (TB), 50:50 (TC), 60:40 (TD) and 80:20 (TE). As for control, each treatment without earthworm was prepared. On the basis of nutrient elements, goat manure and spent mushroom substrate can be decomposed through both methods of vermicomposting and natural composting. Findings of this study indicated that the higher usage of goat manure with longer duration resulted in the production of improved organic fertilizer.
This study focuses on the potential of electric arc furnace (EAF) steel slag and copper mine tailings as asphalt paving materials with respect to issues of volumetric properties and leaching. In this study, four different asphalt mixes were investigated; each contained EAF steel slag and copper mine tailings of various proportions. Apart from the microstructure analysis of the materials, a toxicity characteristics leaching procedure (TCLP) test was conducted on both the mixes and the aggregates. All the mixes were evaluated by the following parameters: Voids in the mineral aggregates (VMA), voids in total mix (VTM), voids filled with asphalt (VFA), Marshall stability and flow and specific gravity. F-test ANNOVA was used to evaluate the degree of significance of the mixes with each of the evaluated standards. It was observed that the mixes containing either EAF steel slag or copper mine tailings or both gave better results than the control mix. In terms of the TCLP test, none of the detected hazardous elements exceeded the standard limits, which indicates the possibility of using them as construction materials.
The aim of this study is to identify the predominating lactic acid bacteria (LAB) in a spontaneous fermented wheat sourdough. At the same time, an investigation towards volatile compounds that were produced was also carried out. Lactobacillus plantarum has been identified as the dominant species of lactobacilli with characters of a facultative heterofermentative strain. The generated volatile compounds that were produced during spontaneous fermentation were isolated by solvent extraction method, analysed by gas chromatography (GC), and identified by mass spectrophotometer (MS). Butyric acid has been found to be the main volatile compound with relative abundance of 6.75% and acetic acid at relative abundance of 3.60%. Esters that were formed at relatively low amount were butyl formate (1.23%) and cis 3 hexenyl propionate (0.05%). Butanol was also found at low amount with relative abundance of 0.60%. The carbohydrate metabolism of Lactobacillus plantarum may contributed to the production of acetic acid in this study via further catabolism activity on lactic acid that was produced. However, butyric acid was not the major product via fermentation by LAB but mostly carried out by the genus Clostridium via carbohydrate metabolism which needs further investigation
Studies have shown that some characters, such as morphological, biochemical and behavioural characteristics were shared among con-specifics of closely related frog species. It is hypothesized that closely related frogs would have similar vocal apparatus structure to produce similar call characteristics, in order to be recognized by con-specifics. The vocal apparatus structures of the frogs from Ranidae were, thus, investigated and calls were recorded from various locations in Sarawak, Borneo. The vocal apparatus was sliced and stained using haematoxylin and eosin staining method. The prepared slides were scanned using Dotslide System Olympus BX51. Captured images were further measured using Microscope Olympus BX51. The results showed that the vocal apparatus structure of ranids in Sarawak differed in length between pulvinar vocale and posterior margin (pvpm) or known as vocal cord stricter. This character was deemed to be the most significant character to discriminate the Sarawak ranids. It is suggested that histological analysis is also a good method for study of phenotypic variation of frog species, as shown by the vocal apparatus structure of the anurans. This study provides an alternative method to differentiate taxonomic identity among frog species.
The classical problems of forced convection boundary layer flow and heat transfer near the stagnation point on a permeable stretching/shrinking surface in a nanofluid is studied theoretically. The similarity equations were solved numerically for two types of nanoparticles, namely copper and silver in the base fluid of water with the Prandtl number Pr = 6.7850 to investigate the effect of the solid volume fraction or nanoparticle volume fraction parameter φ of the nanofluid. Also the case of conventional or regular fluid (φ = 0) with Pr = 0.7 is considered for comparison with previously known results from the open literature. The comparison showed excellent agreement. The skin friction coefficient, the Nusselt number and the velocity and temperature profiles were presented and discussed in detail. It was found that the nanoparticle volume fraction substantially affects the fluid flow and heat transfer characteristics.
The scarcity of land based oil reserves has necessitated the exploration of off shore oil. This exploration is often carried out in pristine waters and the use of green chemicals is essential to reduce environmental degradation. In the recovery of oil and gas from rocky formations, well bore fluids such as packer fluids, fracturing fluids, conformance and permeability control fluids are extensively employed. Potassium oleate as viscoelastic surfactants gives a low partition coefficient when in contact with hydrocarbon. Bromination of the oleate chain has been shown in this work to increase the partition coefficient and still maintaining its viscoelasticity. The partition coefficient increased to ca 8% compared to negligible for potassium oleate. A gel was formed when a 20% solution of potasssium 9-bromo stearate was mixed with 8% KCl. Contacting this gel with hydrocarbon resulted in a loss of viscosity due to the improved solubility of the brominated compound in hydrocarbon. This facilitates the removal of the surfactants after its use as a fracturing fluid. The viscoelastic properties were demonstrated using a Bohlin rheometer. The graph of viscosity vs shear rate shows at first a shear rate independence up to a shear rate of 0.2 s-1 and then falling with shear rate typical of a viscoelastic fluid. The zero shear viscosity η0 varied from 18 Pa s to 220 Pa s whilst the shear viscosity at 100 s-1 ranged from 0.16 Pa s to 1.5 Pa s for surfactant concentration from 5 to 20%.
This paper investigates the application of visco-hyperelastic model to soft rubberlike material, that is gluten. Gluten is a major protein in wheat flour dough (a mixture of flour and water) which exists as long network fibers and undergo large deformation under uniaxial tension and compression. The visco-hyperelastic model is represented by a combination of the viscoelastic Prony series and the hyperelastic extended tube model. Calibration of the visco-hyperelastic model to gluten tests result suggests that gluten can be modelled as a finite viscoelastic material.
Using the Microtox bioassay toxicity was determined in 16 areas located in eight sites: In contaminated areas, in areas
with natural recovery, after bioremediation and phytoremediation projects and in control areas (uncontaminated). These
areas correspond to the following ecosystems: mangrove, fresh water swamp (Pachira aquatica), marsh and pasture (in
the coastal plain and Pliocene-Pleistocene terraces). A significant toxicity was detected in uncontaminated organic
soils (22.2-49.1 toxicity units (TU)) which were comparable to levels found in hydrocarbon contaminated areas (22.3-
42.0 TU). Generally, the toxicity in organic soils was much higher than that found in mineral soils (which was from
below quantification levels to 9.3 TU). In an area restored by phytoremediation, the simple method used by Petróleos
Mexicanos achieved recovery and superficial detoxification in the treated plot, exhibiting a toxicity reduction of 2.4 times
with respect to untreated soil and a toxicity even slightly lower than the uncontaminated control in the same ecosystem
(22.2 TU). Likewise, a bioremediation project in pasture resulted in a toxicity reduction down to levels comparable to
uncontaminated soil (from below quantification levels to 7.9 TU). A tendency to decrease toxicity in organic soils during
the rainy season was observed, toxicity drop in 80% of the areas sampled. Based on these findings, recommendations
are presented for use of this test method in regional diagnostic studies.
Two core sediment samples collected from Tanjung Lumpur mangrove forest were analysed for lead, copper and manganese using the sensitive Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). The average concentrations of Pb, Cu, and Mn in core samples were 36.28±7.04 μg/g dry weights, 50.17±5.84 μg/g dry weights, and 110.41±14.48 μg/g dry weights, respectively. From the calculated enrichment factors (EF), only Mn was considered to be predominantly terrigeneous in origin, while Pb and Cu have slightly higher EF values which were related to anthropogenic input.
A study was conducted to investigate the duration of growth stages and flowering behaviour of a landscape tree,
Xanthostemon chrysanthus (F. Muell.) Benth. This species is known as golden penda and locally known as jambu kuning.
It is widely planted for urban beautification due to its distinctive coloured flowers. Under local climate condition, this
species flowers throughout the year. However, the flowering of this species has not been studied extensively. In the present
study, the growth of selected trees aged approximately six years after planting was monitored for a year. The growth
duration was determined using the extended Biologishe Bundesanstalt, Bundessortenamt and Chemical Industry (BBCH)
scale. Percentages of flower and fruit and new leaf abundances were expressed as estimated percentage of each stage as
compared to total surface area of the tree crown. The vegetative and reproductive stages of the species required 198 and
176 days, respectively. The flowering period took about 40 days from inflorescence bud swelling to drying and senescence
of stamens and petals. Unsynchronized flowering was observed among the trees. The occurrence of flowers was also
influenced by the development of new leaves or fruits. The information on the duration of each growth stage and the
flowering behaviour of the species may enhance a more detailed study related to flowering of urban trees in Malaysia.
In a laboratory trial three chickpea varieties viz, Karak-I, Karak-III and Shenghar were tested against the phytotoxicity of five weed species: Parthenium hysterophorus L., Phragmites australis (Cav.) Trin., Datura alba L., Cyperus rotundus L. and Convolvulus arvensis L.in January 2013. The weed extracts were prepared at the rate of 120 g/L (w/v) after shade dry. The results indicated highly significant inhibitory effect of all the tested weed species on the chickpea varieties. The results also showed that the chickpea variety Karak-III was more susceptible to the phytotoxcity of the tested weed extracts. Among the extract, C. arvensis proved much toxic in term of inhibition of germination by giving only 43.33% germination in comparison with control where 97.50% germination was recorded. On the other hand, the effect of P. australis extract was found a little stimulator by speeding the seed germination in all varieties and giving a low (2.21) mean germination time (MGT) value. From the current results it can be concluded that the infestation of C. arvensis can pollute the soil by accumulating toxic chemicals that leads to the germination failure and growth suppression in chickpea. Therefore, the prevention and removal of C. arvensis in the chickpea growing areas could be recommended. In addition, P. australis must be tested against chickpea weeds (chickpea varieties withstand against its phytotoxcity), so that it can be popularized as bioherbicide in chickpea if it gave promising results in controlling chickpea weeds.
Oceanographic cruises in Pahang water in October 2003 and April 2004, monsoon transition months, produce data on water characteristics. The temperature in both months showed higher values in nearshore compared to the offshore stations. The nearshore salinity in both months is lower than offshore stations. Comparatively, there were smaller differences in temperature and salinity in October than in April, with very little variation between nearshore and offshore stations. T-S diagram showed significant differences between October and April water characteristics. According to the water characteristic observations, the temperature and salinity in October was lower than in April, while dissolved oxygen was higher than in April. The lower temperature and salinity taken during the sampling time in October suggested that during this time, the study area already received the influences of strong winds due to upcoming monsoon. The warmer and saltier water obtained in April showed that during this time, the study area was influenced by southwest monsoon. Winds related to rainfall were observed to have impact to the dynamics of water characteristics during both months.
Chlorophyll-a is one of the most widely used parameters to estimate trophic state of an aquatic environment. The purpose of this study was to investigate the changes in the planktonic chlorophyll-a concentrations in relation to environmental parameters in the east part of Iskenderun Bay (Northeastern Mediterranean Sea). Monthly measurements of chlorophyll-a and inorganic nutrients were done on two transects at 6 stations across the Bay. In addition, variations in temperature, salinity and some meteorological factors were also investigated, their correlation with chlorophyll-a were analyzed. The highest chlorophyll-a concentration (3.8 μg L-1) was found on coastal transect nearer to the bay. The first peak in chlorophyll-a occurred in May, a second smaller peak was recorded in September. The correlation of chlorophyll-a was significantly positive for Silicate-Si and Nitrate+nitrite-N but not important for Phosphate-P. No dramatic increase in chlorophyll-a levels was encountered in the area during the study period. It was concluded that, due to the hydrodynamic structure of the area, the land-based effects influence chlorophyll-a dynamics.
The values of beam quality correction factor kQ that were experimentally determined from year 2002 to 2008 were analysed. As kQ is the function of ionization chamber and beam quality, the analysis were based on three cases namely (a) kQ(NE2571, 6 MV x-rays) that were determined from 17 measurements in the duration of 69 months at 6 radiotherapy centres, (b) kQ(NE2571, 10 MV x-rays) from 7 measurements in the duration of 12 months at one radiotherapy centre, and (c) kQ(NE2581, 6 MV x-rays) from 5 measurements in the duration of 5 months also at one radiotherapy centre. The purpose is to examine, in each case, the variation kQ for all the measurements. In other words, to see variation kQ with time. Results obtained are 0.993(NE2571, 6 MV), 0.986(NE2571, 10 MV) and 0.986(NE2581, 6 MV). This shows that in each case, despite the difference in the experimental data in getting kQ for all measurement, kQ remains constant with time. Reasons for this are explained.
Grammatophyllum seeds are minute and lack endosperm. As with their other orchids counterpart, the seeds are dependent on mycorrhizal fungi for seed germination in nature. The ability to uptake nutrients from substrate is assisted by preferable fungal symbionts. Seeds of Grammatophyllum speciosum Blume. were used to determine the specificity of its fungus relationship using fungi isolated from roots of G. speciosum, G. stapeliiflorum and G. scriptum. A total of 31 different species of fungus was isolated and inoculated onto G. speciosum seed on Oat Meal Agar (OMA). The result obtained from the test demonstrated that seed germination rates were best when co-cultured with Fusarium sp. number 3 isolated from G. speciosum. An increment in 63.3% was measured when compared to the seed’s original size. The seed can also germinate when inoculated with fungus isolated from different species, implying that G. speciosum is a generalist in its association with fungal symbionts.
The culms of bamboo Bambusa rigida ranging from 1, 3 and 5 year old were obtained and investigated for anatomical characteristics in different ages, heights and zones in radial direction of culm wall thickness. The vascular bundles were denser and smaller at the top portion and outer zone of all age groups. No significant differences in vascular bundle frequency and size were found among the tree age groups. Metaxylem vessels did not vary significantly among ages. Fibre and parenchyma were longer in the middle portion of the height and middle zone in radial direction of culms wall. No significant differences in fibre and parenchyma length were observed in all age groups. The wall thicknesses of fibre and parenchyma were thicker in the top portion and outer zone. Furthermore, the wall thicknesses of fibre and parenchyma increased significantly from 1 to 3 year, showing that there is a maturing progress from 1 to 3 year.
Kajian ini dijalankan untuk melihat variasi taburan 210Po dan 210Pb melalui profil menegak aktivitinya, serta nisbah aktiviti 210Po/210Pb di dalam teras sedimen yang diambil di beberapa stesen persampelan pesisir pantai perairan Sarawak. Didapati profil taburan radionuklid tersebut dalam teras sedimen adalah berubah-ubah mengikut lokasi persampelan dan telah dibuktikan melalui analisis ANOVA yang menunjukkan bahawa terdapat perbezaan bererti pada 95% aras keyakinan bagi aktiviti 210Po (p = 0.000), 210Pb (p = 0.035) dan 210Po/210Pb (p = 0.000) di semua lokasi kajian. Secara umumnya, aktiviti 210Po dan 210Pb yang diukur masing-masing dalam julat 337 ke 2460 Bq/kg, 11 ke 84 Bq/kg di SR 01; 224 ke 2008 Bq/kg, 6 ke 80 Bq/kg di SR 02; 119 ke 1595 Bq/kg, 6 ke 84 Bq/kg di SR 03; 241 ke 2294 Bq/kg, 5 ke 82 Bq/kg di SR 04 dan 175 ke 1340 Bq/kg, 4 ke 44 Bq/kg di SR 05. Merujuk kepada julat tersebut, didapati aktiviti 210Po adalah lebih tinggi daripada aktiviti 210Pb dengan purata nisbah 210Po/210Pb di semua stesen adalah melebihi satu, iaitu dalam julat 20 ke 35. Variasi profil taburan radionuklid tersebut dipercayai dipengaruhi oleh beberapa faktor sekitaran dan telah dibuktikan terdapat korelasi yang kuat di antara taburan radionuklid dengan komposisi sedimen jenis kelodak (210Po:r = 0.701 dan 210Pb: r = 0.648), kedalaman air (210Po: r = -0.647) dan jarak stesen dari daratan (210Po: r = 0.746 dan 210Pb: r = 0.975). Oleh itu, dapat disimpulkan bahawa faktor-faktor tersebut merupakan penyumbang utama ke atas perubahan yang berlaku kepada taburan 210Po dan 210Pb.
Ionosfera merupakan satu lapisan atmosfera bumi yang mengandungi elektron bebas dan boleh memberi kesan ralat
kepada perambatan gelombang elektromagnetik terutama kepada sistem kedudukan global (GPS). Kesan jumlah
kandungan elektron (TEC) dan fenomena melibatkan sistem suria-magnetosfera-ionosfera-termosfera kepada isyarat
satelit dan komunikasi radio sentiasa berubah. Kajian ini memfokuskan kepada perubahan TEC ketika aktiviti suria
di tahap minimum. Objektif utama kajian ini adalah untuk mengkaji variasi TEC di rantau Malaysia terhadap masa
harian, perubahan musim, aktiviti suria dan medan magnet bumi. Isyarat GPS yang disebarkan pada dua frekuensi
jalur L1 dan L2 mengandungi data kod dan fasa membolehkan pengiraan TEC diperoleh menggunakan GPS. Data GPS
pada tahun 2007 yang diperoleh daripada Jabatan Ukur dan Pemetaan Malaysia (JUPEM), digunakan dalam kajian ini.
Hasil kajian di Asia Tenggara menunjukkan ketika musim ekuinoks, nilai purata TEC dicatatkan tinggi iaitu 35 TEC unit
(TECU) berbanding dengan nilai purata TEC pada soltis yang mencatatkan bacaan 25 TECU. Aktiviti suria didapati lebih
memberi kesan kepada perubahan TEC berbanding dengan medan magnet bumi dengan faktor kolerasi antara aktiviti
suria adalah lebih tinggi iaitu 0.64 berbanding dengan medan magnet bumi iaitu 0.34 sahaja. Kajian ini tertumpu ketika
aktiviti suria di tahap minimum dengan keadaan medan magnet bumi secara puratanya adalah senyap. Ini seterusnya
membolehkan hasil kajian ini menjadi asas kepada maklumat mengenai ionosfera di Malaysia.