Displaying publications 41 - 60 of 3939 in total

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  1. Abdullah, A.L., Lim, H.S., Yasin, Z., Razalli, N.M.
    ASM Science Journal, 2014;8(1):44-53.
    MyJurnal
    Chlorophyll-a concentrations (mg/l) in surface waters of Songsong Islands were mapped using an optically derived remote sensing model. Landsat TM imagery dated 8 October 2008 was used in the classification process and in situ measurements made on 19 May 2012 during spring tidal condition (HW: 2.6 m, LW: 0.9 m) served as ground truthing data. The temporal difference between data used will be useful to review the robustness of the model. Three classes of chlorophyll-a concentrations were mapped: Class 1: 10 mg/l. Considering the dynamic nature of coastal and marine waters particularly the shallow region, and the temporal difference between the Landsat TM imagery used in classification and the field data, results of chlorophyll-a mapping using the developed remote sensing model was high at 83.3%, with producer’s accuracy of 50%–100% and user’s accuracy of 80%–100%. Kappa coefficient of agreement, Kˆ , calculated was 57.1%.
    Matched MeSH terms: Water
  2. Ahmad Zaidee Laidin, Loganathan, P.
    ASM Science Journal, 2011;5(1):77-77.
    MyJurnal
    Awareness and sensitivity on the subject of green technology are currently commanding the attention of the world in the light of rising energy costs and the threat of global warming. Many countries are now recognizing the benefits of researching into and using green technology to reduce their carbon and water footprints and to minimize waste. (Copied from article).
    Matched MeSH terms: Water
  3. Dinesh, S.
    ASM Science Journal, 2010;4(1):62-73.
    MyJurnal
    Studies conducted on the various geometric properties of skeletons of water bodies have shown highly promising results. However, these studies were made under the assumption that water bodies were static objects and that they remained constant over time. Water bodies are actually dynamic objects; they go through significant spatio-temporal changes due to drought and flood. In this study, the characterization of skeletons of simulated drought and flood of water bodies was performed. It was observed that as the drought level increased from 1 to 9, the average length of the skeletons decreased due to reduction in the size of the water bodies and increase in the number of water bodies. As the drought level increased from 9 to 15, the average length of the skeletons increased further due to vanishing of small water bodies. Flood caused an increase in the average length of the skeletons due to merging of adjacent water bodies. Power law relationships were observed between the average length of the skeletons of the simulated drought/flood and the level of drought/flood. The scaling exponent of these power laws which was named as a fractal dimension, indicated the rate of change of the average length of the skeletons of simulated drought/flood of water bodies over varying levels of drought/flood. However, errors observed in the goodness of fit of the plots indicated that monofractals were not sufficient to characterise the skeletons of simulated drought and flood of water bodies. Multifractals and lacunarity analysis were required for more accurate characterisation.
    Matched MeSH terms: Body Water
  4. Suratman, S., Tawnie, I., Sefei, A.
    ASM Science Journal, 2011;5(2):101-107.
    MyJurnal
    A study to determine the impact of leachate from operating and closed landfills into the surface water and groundwater systems in the state of Selangor was conducted in the year 2009. Groundwater was a major source of water for various uses in Selangor, Malaysia and was especially important for industrial purposes. The presence of high numbers of landfill sites was seen to have increased the risk of groundwater contamination. There were 20 landfill sites in the state of Selangor and seven of them were still operating and 13 closed. The landfills are classified into four categories, which were: (a) landfills operating at critical stages without controls to prevent pollution into the environment; (b) open dumpsites that have the capacity to continue to accept waste but needed to be upgraded to manage leachate and gas; (c) landfills that were closed but no safety closure plan was carried out; and (d) engineered landfills with up to date technologies. As most of the landfills were built prior to 1989, they were not subjected to the Environmental Impact Assessment requirements, hence, they were being poorly managed and were badly sited. The non-engineered sites had no proper pollution controls such as cover materials, liner materials, groundwater monitoring wells, leachate collection ponds and treatment, and methane gas collection pipes. This study revealed that the surface water and groundwater at and nearby the landfill sites were contaminated at various levels due to the landfill sites and operation. A comparison between the current quality of surface water and groundwater with their respective standards and background levels was carried out to survey the trend of the contamination. However, the limited financial resources hindered a very thorough investigation and restricted the number of samples collected and parameters analysed.
    Matched MeSH terms: Water; Groundwater; Water Wells
  5. Devendra, C.
    ASM Science Journal, 2011;5(2):139-150.
    MyJurnal
    The effects of anticipated climate change and the potential impact on animal production are discussed in the context of varying biophysical features, agro-ecological zones (AEZs), ecosystems, land use, and responses in animal genetic diversity and production. The AEZs in Asia have great diversity in their links to food production in crop-animal small farm systems, the poverty complex and livelihoods of the poor. In these environments. climate change effects on animals were mediated through heat stress, water availability, quantity and quality of the available feed resources, type of production system and productivity. The responses to heat stress are tabulated and they vary according to species, breeds within-species, AEZs, physiological and nutritional status, genetic potential and multifunctionality. Among ruminant production systems, dairy production was especially vulnerable to heat stress. Interestingly in India, buffalo numbers owned largely by the landless and small farmers in the semi-arid and arid regions have grown twice as fast as the buffalo population in the irrigated areas. The implications and strategies to cope with climate change involve mitigation, adaptation and policy. The principal strategy is targetting to the reduce on in greenhouse gas (GHG) emission from the agricultural sector from enteric fermentation and manure, and ways to intensify C sequestration. An important link is that of breeding and conserving indigenous animal genetic resources as a means to mitigate climate change, with associated benefits to the trade of live animals and animal products. Improved integrated tree crops-ruminant systems are an important pathway to enhance C sequestration. The opportunities for research and development (R&D) are enormous and they would need policy support and large investments to provide improved understanding of ways to ensure sustainable animal production systems. Coping with the totality of the effects and impact of climate change constitutes the challenges for agricultural R&D and the improved livelihood of the resource-poor in the future.
    Matched MeSH terms: Water
  6. Malek, M. A., Heyrani, M., Juneng, Liew
    ASM Science Journal, 2015;9(1):8-19.
    MyJurnal
    In this study, the implementation of the Regional Climate Model into the hydrodynamic model has been applied for streamflow projection on a river located at the south of Peninsular Malaysia within the years 2070 till 2099. The data has been obtained from a Regional Climate Model (RCM), named Précis, on a daily basis. It begins by comparing historical rainfall data generated from Précis versus the actual gauged recorded rainfall data from Department of Irrigation and Drainage Malaysia (DID). The bias of the generated rainfall data has been reduced by statistical techniques. The same has been applied to the future generated rainfall data from 2070 to 2099. Using the generated precipitation data as input to the hydrological model, results in the daily output of river discharge identified as the main contributor of flood occurrences. Based on the results of the hydrological model utilised, e.g. HEC-HMS, comparison was made between the future and historical generated discharge data using Précis between the years 1960 till 1998. Dividing a year into three segments, e.g. January-April, May-August, SeptemberDecember, the results show that there would be a significant drop of peak discharge in the third segment and an increase in discharge during the second segment. The first part remains almost with no changes. As an addition, the drop of the peak shows reduction in the probability of flood occurrences. It also indicates the reduction in water storage capacity which coherently affects the water supply scheme
    Matched MeSH terms: Water; Water Supply
  7. Devendra, C.
    ASM Science Journal, 2015;9(1):1-20.
    MyJurnal
    The natural environment embraces agriculture and all its components-crops, animals, land, water,
    forestry and fisheries. It is the most important user of environmental resources, made more complex
    by the interactions of the various systems, biophysical elements and their implications. Increased food
    production, especially of animal protein supplies are unable to meet current and projected future needs
    for humans, including about 15 %of the world population being malnourished. Agriculture is currently
    waning, and a coordinated and concerted technologically-driven transformation is necessary. Poorly
    managed agriculture for example, can lead to serious environmental degradation and exacerbate
    poverty. Land and water are considered to be the most limiting factors in the future. Non- irrigated
    rainfed areas can be divided into high potential and low potential areas; the former offers considerable
    promise to expand food production. This paper argues for increased Research and Development (R&D)
    focus that can maximise improved natural resource management(NRM), and whether agricultural
    development can maximise productivity yields .Other opportunities include expanding crop–animal
    production systems in less favoured areas (LFAs), intensifying land use for silvopastoral systems in
    rainfed areas , and enhance carbon sequestration. Ruminants can be used as an entry point for the
    development of LFAs, and the presence of about 41.5% of the goat population found in the semi-arid/
    arid AEZs X provides good opportunities for expanding food security and human well-being. Communitybased
    interdisciplinary and systems approaches are essential to provide the solutions. The legacy of
    continuing malnutrition and food insecurity must be overcome by effective development policy, multidonor
    resource allocation, governance and political will that target food insecurity and poverty. The R&D
    agendas and resource allocations are compelling, but dedicated vision can lead the way for sciencedriven
    sustainable environment, efficiency in NRM, and self-reliance to the extent possible , in harmony
    with nature and the environment.
    Matched MeSH terms: Water
  8. Mehamod, F.S., Kadir, M.A., Jusoh, N., Yusof, N.F., Suah, F.B.
    ASM Science Journal, 2018;11(101):114-123.
    MyJurnal
    The development of new adsorbent has rapidly increased in order to overcome the problem
    of waste water treatment from heavy metal pollution. The ability of nickel (II)-ion imprinted
    polymer (Ni-IIP) as an alternative adsorbent for the removal of nickel ion from aqueous has
    been investigated. The Ni-IIP was prepared via bulk polymerization by using functional
    monomers; methylacrylic acid (MAA) with picolinic acid as a co-monomer. Nickel ion was
    used as template, AIBN as initiator and EGDMA as cross-linking agent. Non-imprinted control
    polymer (NIP) was prepared in the same manner as Ni-IIP but in the absence of nickel
    ion. The resultant of Ni-IIP and NIP were characterized by using Fourier Transform Infrared
    (FTIR) spectroscopy and Scanning Electron Microscope (SEM). Result showed that, the adsorption
    of nickel ion onto Ni-IIP increased as the adsorbent dosage increased and contact
    time is prolonged. The adsorption isotherm model for Ni-IIP and NIP were fitted well with
    Freundlich and Langmuir, respectively. Kinetic study for both Ni-IIP and NIP were followed
    the pseudo-second order, indicates that the rate-limiting step is the surface adsorption that
    involves chemisorption. Selectivity studies showed that the distribution coefficient of Ni2+
    was higher compared to Zn2+, Mg2+ and Pb2+. The present work has successfully synthesized
    Ni-IIP particles with good potential in recognition of Ni2+ ions in an aqueous medium.
    Matched MeSH terms: Water; Water Purification; Waste Water
  9. Mamat, M., Abdullah, M.A.A., Jaafar, A.M., Soh, S.K.C., Lee, C.E.
    ASM Science Journal, 2018;11(101):105-113.
    MyJurnal
    As textile production flourishes nowadays, the amount of dyed wastewater entering the
    water body has also increased. Dyes could have serious negative impacts to the environment
    and also the human health, hence, they need to be removed from the water body. In this
    study, layered double hydroxide (LDH) of manganese/aluminium (MnAl) was synthesised
    to be used as a potential adsorbent to remove methyl orange (MO) dye due to its unique
    lamellar structure which provides LDH with high anion adsorption and exchange ability.
    MnAl was synthesized by using co-precipitation method and characterized by powder X-ray
    diffraction (PXRD), Fourier-Transform Infrared Spectroscopy (FTIR), Inductively coupled
    plasma atomic emission spectroscopy (ICP-AES) and Carbon, Hydrogen, Nitrogen, Sulphur
    (CHNS) elemental analysers, and Accelerated Surface Area and Porosity Analyzer (ASAP).
    Adsorption studies were conducted at different contact times and dosages of MnAl to evaluate
    the performance of MnAl in removing MO from water. Kinetic and isotherm models were
    tested using pseudo-first order, pseudo-second order, Langmuir isotherm and Freundlich
    isotherm. MnAl LDH was found to be perfectly fitted into pseudo-second order and Langmuir
    isotherm.
    Matched MeSH terms: Water; Waste Water
  10. Lee SY, Pereira BP, Yusof N, Selvaratnam L, Yu Z, Abbas AA, et al.
    Acta Biomater, 2009 Jul;5(6):1919-25.
    PMID: 19289306 DOI: 10.1016/j.actbio.2009.02.014
    A poly(vinyl alcohol) (PVA) hydrogel composite scaffold containing N,O-carboxymethylated chitosan (NOCC) was tested to assess its potential as a scaffold for cartilage tissue engineering in a weight-bearing environment. The mechanical properties under unconfined compression for different hydration periods were investigated. The effect of supplementing PVA with NOCC (20wt.% PVA:5vol.% NOCC) produced a porosity of 43.3% and this was compared against a non-porous PVA hydrogel (20g PVA: 100ml of water, control). Under non-hydrated conditions, the porous PVA-NOCC hydrogel behaved in a similar way to the control non-porous PVA hydrogel, with similar non-linear stress-strain response under unconfined compression (0-30% strain). After 7days' hydration, the porous hydrogel demonstrated a reduced stiffness (0.002kPa, at 25% strain), resulting in a more linear stiffness relationship over a range of 0-30% strain. Poisson's ratio for the hydrated non-porous and porous hydrogels ranged between 0.73 and 1.18, and 0.76 and 1.33, respectively, suggesting a greater fluid flow when loaded. The stress relaxation function for the porous hydrogel was affected by the hydration period (from 0 to 600s); however the percentage stress relaxation regained by about 95%, after 1200s for all hydration periods assessed. No significant differences were found between the different hydration periods between the porous hydrogels and control. The calculated aggregate modulus, H(A), for the porous hydrogel reduced drastically from 10.99kPa in its non-hydrated state to about 0.001kPa after 7days' hydration, with the calculated shear modulus reducing from 30.92 to 0.14kPa, respectively. The porous PVA-NOCC hydrogel conformed to a biphasic, viscoelastic model, which has the desired properties required for any scaffold in cartilage tissue engineering.
    Matched MeSH terms: Water/chemistry*
  11. Suleiman Gwaram N, Khaledi H, Ali HM, Olmstead MM
    Acta Crystallogr C, 2011 Jan;67(Pt 1):o6-9.
    PMID: 21206084 DOI: 10.1107/S0108270110046317
    The title compound, C(4)H(6)N(4)O·H(2)O, crystallized simultaneously as a triclinic and a monoclinic polymorph from an aqueous solution of 2,4-diaminopyrimidin-6-ol. Previously, an orthorhombic polymorph was isolated under the same experimental conditions. The molecular geometric parameters in the two present polymorphs and the previously reported orthorhombic polymorph are similar, but the structures differ in the details of their crystal packing. In the triclinic system, the diaminopyrimidinone molecules are connected to one another via N-H···O and N-H···N hydrogen bonding to form infinite chains in the [011] direction. The chains are further hydrogen bonded to the water molecules, resulting in a three-dimensional network. In the monoclinic system, the diaminopyrimidinone molecules are hydrogen bonded together into two-dimensional networks parallel to the bc plane. The water molecules link the planes to form a three-dimensional polymeric structure.
    Matched MeSH terms: Water/chemistry*
  12. Ganesan K, Alias Y, Ng SW
    Acta Crystallogr C, 2008 Sep;64(Pt 9):o478-80.
    PMID: 18758014 DOI: 10.1107/S0108270108023111
    Crystallization of the ionic liquid 3,3'-dimethyl-1,1'-(1,4-phenylenedimethylene)diimidazolium bis(tetrafluoroborate), C(16)H(20)N(4)(2+).2BF(4)(-), (I), from its solution in water has permitted the first single-crystal study of an imidazolium-based ionic liquid having a tetrafluoroborate ion as counter-ion. Despite the expectation that the anion would not participate in nonclassical hydrogen bonding, the ionic liquid features C-H...F hydrogen bonds. The dication lies about a center of inversion. The ionic liquid 3,3'-di-n-butyl-1,1'-(1,4-phenylenedimethylene)diimidazolium bis(trifluoromethanesulfonate), C(22)H(32)N(4)(2+).2CF(3)SO(3)(-), (II), features both C-H...F and C-H...O hydrogen bonds.
    Matched MeSH terms: Water
  13. Usman A, Chantrapromma S, Fun HK, Poh BL, Karalai C
    Acta Crystallogr C, 2002 Mar;58(Pt 3):o136-8.
    PMID: 11870305
    In the title 1/2/2 adduct, C(4)H(12)N(2)(2+) x 2C(6)H(3)N(2)O(5)(-) x 2H(2)O, the dication lies on a crystallographic inversion centre and the asymmetric unit also has one anion and one water molecule in general positions. The 2,4-dinitrophenolate anions and the water molecules are linked by two O-H...O and two C-H...O hydrogen bonds to form molecular ribbons, which extend along the b direction. The piperazine dication acts as a donor for bifurcated N-H...O hydrogen bonds with the phenolate O atom and with the O atom of the o-nitro group. Six symmetry-related molecular ribbons are linked to a piperazine dication by N---H.O and C---H.O hydrogen bonds.
    Matched MeSH terms: Water
  14. Usman A, Nayar CR, Unnikrishnan PA, Sreeja PB, Prathapachandra Kurup MR, Fun HK
    Acta Crystallogr C, 2002 Dec;58(Pt 12):o724-6.
    PMID: 12466626
    The title molecule, C(13)H(13)N(3)O(3).H(2)O, is in the form of a monohydrated zwitterion. The tetrahydropyridinium ring adopts an envelope conformation and is nearly coplanar with the plane of the imidazoline ring. The water solvate molecule plays an important role as a bridge between zwitterions, forming molecular chains running along the c direction, which are interconnected by N-H.O hydrogen bonds into molecular ribbons. The crystal packing is further stabilized by another N-H.O and one O-H.N hydrogen bond, which interconnect the molecular ribbons.
    Matched MeSH terms: Water
  15. Chantrapromma S, Usman A, Fun HK, Poh BL, Karalai C
    Acta Crystallogr C, 2002 Nov;58(Pt 11):o675-7.
    PMID: 12415179
    In the title adduct, 1,3,5,7-tetraazatricyclo[3.3.1.1(3,7)]decane-4-nitrobenzene-1,2-diol-water (1/2/1), C(6)H(12)N(4).2C(6)H(5)NO(4).H(2)O, the hexamethylenetetramine molecule acts as an acceptor of intermolecular O-H.N hydrogen-bonding interactions from the water molecule and the hydroxy groups of one of the two symmetry-independent 4-nitrocatechol molecules. The structure is built from molecular layers which are stabilized by three intermolecular O-H.O, two intermolecular O-H.N and four intermolecular C-H.O hydrogen bonds. The layers are further interconnected by one additional intermolecular O-H.N and two intermolecular C-H.O hydrogen bonds.
    Matched MeSH terms: Water
  16. Usman A, Chantrapromma S, Fun HK
    Acta Crystallogr C, 2001 Dec;57(Pt 12):1443-6.
    PMID: 11740112
    The title compound, 3,5,7-triaza-1-azoniatricyclo[3.3.1.1(3,7)]decane 2,4-dinitrophenolate monohydrate, C6H13N4+*C6H3N2O5-*H2O, the 1:1 hydrate adduct of hexamethylenetetramine (HMT) and 2,4-dinitrophenol, undergoes a temperature phase transition. In the room-temperature phase, the adduct crystallizes in the monoclinic P2(1)/m space group, whereas in the low-temperature phase, the adduct crystallizes in the triclinic P1 space group. This phase transition is reversible, with the transition temperature at 273 K, and the phase transition is governed by hydrogen bonds and weak interactions. In both these temperature-dependent polymorphs, the crystal structure is alternately layered with sheets of hexamethylenetetramine and sheets of dinitrophenol stacked along the c axis. The hexamethylenetetramine and dinitrophenol moieties are linked by intermolecular hydrogen bonds. The water molecule in the adduct plays an important role, forming O-H...O hydrogen bonds which, together with C-H...O hydrogen bonds, bridge the adducts into molecular ribbons. Extra hydrogen bonds and weak interactions exist for the low-temperature polymorph and these interconnect the molecular ribbons into a three-dimensional packing structure. Also in these two temperature-dependent polymorphs, dinitrophenol acts as a hydrogen-bond acceptor and HMT acts as a hydrogen-bond donor.
    Matched MeSH terms: Water
  17. Razak IA, Usman A, Fun HK, Yamin BM, Keat GW
    Acta Crystallogr C, 2002 Jan;58(Pt 1):m31-3.
    PMID: 11781464
    In the title compound, [Zn(CH3COO)2(C4H8N2S)2]*H2O, the Zn atom is tetrahedrally coordinated in the ZnO2S2 form. N-H...O and O-H...O intramolecular and intermolecular hydrogen bonds are formed by the four N atoms and the water molecule. N-H...O intermolecular hydrogen bonds and C-H...S and C-H...O intermolecular interactions interconnect columns formed by the molecules into layers. Adjacent layers are then linked by other N-H...O and O-H...O intermolecular hydrogen bonds to form a three-dimensional framework throughout the structure. The orientations of the acetate planes are such that the Zn atom lies within them.
    Matched MeSH terms: Water
  18. Shanmuga Sundara Raj S, Fun HK, Lu ZL, Xiao W, Gong XY, Gen CM
    Acta Crystallogr C, 2000 Aug;56 (Pt 8):1013-4.
    PMID: 10944309
    The crystal structure of the title compound, C(15)H(14)N(2)O(2). H(2)O, is in the keto tautomeric form and the configuration at the azomethine C=N double bond is E. The molecule is non-planar, with a dihedral angle of 27.3 (1) degrees between the aromatic rings. The crystal structure is stabilized by extensive hydrogen bonding involving the water molecule and hydrazone moiety.
    Matched MeSH terms: Water
  19. Ahmad J, Abdul Halim SN, How FN
    Acta Crystallogr E Crystallogr Commun, 2015 Jun 1;71(Pt 6):o410-1.
    PMID: 26090195 DOI: 10.1107/S2056989015009159
    The title compound, Ph3(PhCH2)P(+)·Cl(-)·H2O, was obtained unintentionally as the product of an attempted synthesis of a silver di-thio-carbamate complex using benzyl-tri-phenyl-phospho-nium as the counter-ion. The asymmetric unit consists of a phospho-nium cation and a chloride anion, and a water mol-ecule of crystallization. In the crystal, the chloride ion is linked to the water mol-ecule by an O-H⋯Cl hydrogen bond. The three units are further linked via C-H⋯Cl and C-H⋯O hydrogen bonds and C-H⋯ π inter-actions, forming a three-dimensional structure.
    Matched MeSH terms: Water
  20. Yeo CI, Tan YS, Tiekink ER
    Acta Crystallogr E Crystallogr Commun, 2015 Oct 1;71(Pt 10):1159-64.
    PMID: 26594396 DOI: 10.1107/S2056989015016655
    The crystal and mol-ecular structures of the title salt, C8H8N3S2 (+)·Cl(-), (I), and salt hydrate, C8H7ClN3S2 (+)·Cl(-)·H2O, (II), are described. The heterocyclic ring in (I) is statistically planar and forms a dihedral angle of 9.05 (12)° with the pendant phenyl ring. The comparable angle in (II) is 15.60 (12)°, indicating a greater twist in this cation. An evaluation of the bond lengths in the H2N-C-N-C-N sequence of each cation indicates significant delocalization of π-electron density over these atoms. The common feature of the crystal packing in (I) and (II) is the formation of charge-assisted amino-N-H⋯Cl(-) hydrogen bonds, leading to helical chains in (I) and zigzag chains in (II). In (I), these are linked by chains mediated by charge-assisted iminium-N(+)-H⋯Cl(-) hydrogen bonds into a three-dimensional architecture. In (II), the chains are linked into a layer by charge-assisted water-O-H⋯Cl(-) and water-O-H⋯O(water) hydrogen bonds with charge-assisted iminium-N(+)-H⋯O(water) hydrogen bonds providing the connections between the layers to generate the three-dimensional packing. In (II), the chloride anion and water mol-ecules are resolved into two proximate sites with the major component being present with a site occupancy factor of 0.9327 (18).
    Matched MeSH terms: Water
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