2,432 research outputs found

    Mangrove species' association and distribution patterns in Tumpat, Kelantan Delta, east coast of peninsular Malaysia

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    We studied mangrove vegetation at Tumpat to estimate different tree structural parameters (e.g., stem density and basal area) at selected sites (PCQ-Method). There were 5 dominant taxa in the vegetation, i.e., Sonneratia caseolaris, Nypa fruticans, Avicennia alba, Rhizophora mucronata, and Bruguiera gymnorrhiza in order of importance. Total tree density varied between 79 and 132 stems 0.1ha-1, and basal area from 0.14 to 4.9m2 0.1ha-1. Based on species composition and stem density, the mangrove sites could be separated into two groups (Bray-Curtis similarity: 60%). While Group-1 (sites G9, J5, K4, N6 and O4), dominated by S. caseolaris and N. fruticans, was distributed throughout the forest, Group-2 (sites C6 and G6), represented largely by A. alba, is present close to the bay-mangrove boundary. Elevation measurements indicate that Group-1 species occupied lowlying to elevated grounds (0.87-2.23m above the mean sea level) with a (mean) salinity between 0.38 and 14.6psu, whereas Group-2 occurred preferentially at low to medium elevations (0.86-1.29m) and high salinity (14.6psu). Discrete mangrove associations (=groupings) were discerned, wherein the distribution of species is governed by factors such as proximity of land or sea, freshwater input and elevation

    Optimization and designing collimator for boron neutron capture therapy at the thermal column of rtp

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    Boron Neutron Capture Therapy (BNCT) is a promising method to cure cancer by using interaction between boron compound and the slow neutron beam obtained from nuclear power reactor, nuclear research reactor and neutron generator. Based on the previous feasibility study shows that the thermal column can generate higher thermal neutrons for BNCT application at the TRIGA MARK II reactor. Currently, the facility for BNCT are planned to be developed at thermal column. Thus, the main objective was focused on the optimization of thermal neutron and epithermal neutron flux at the thermal column by designing collimator. This paper briefly goes through the characterization of collimator for the ideal neutron collimator design. Several collimators with variable geometries have been designed using Monte Carlo Simulation Codes of MCNPX. The results are then compared in term of thermal neutron, epithermal neutron and gamma fluxes yielded and the ideal collimator then optimize based on aperture size, shielding thickness and collimator condition This research is useful in the selection of neutron collimator design BNCT facility at the TRIGA MARK II reactor

    Investigation of groundwater table under rock slope by using electrical resistivity imaging at Sri Jaya, Pahang, Malaysia

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    Over the years, rock slope will undergo the natural phenomenon of weathering, leading to the weakening of strength and physical properties of the slope material. In Malaysia, one of the causes of the weathering of rock is due to the presence of water, which can form groundwater table in the subsurface of rock slopes. The weathering of rock material in slopes can have significant effect on the stability. In Sri Jaya, Pahang, a large body of rock is exposed in cut slope, where different weathering grade was observed on the surface. The study aims to investigate the groundwater table under the rock slope surface and determine the extent of weathering of the rock slope. For that purpose, the electrical resistivity imaging (ERI)was chosen as a geophysical method to map the subsurface condition of the slope. Resistivity values from the survey were interpreted based on established work that correlates weathering condition of rock material with resistivity value. Different zones of weathering grade and groundwater were determined based from the profile

    Effect of mismanagement towards abandoned project in Malaysia

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    Over the years, Malaysian government has placed significant emphasis on the need for citizens to have their own house. Unfortunately, the abandoned housing projects are indeed a major hiccup for purchasers who dreams to have their own home become reality. The abandonment of housing projects has resulted in many adverse consequences to the economy, society and environment. Therefore, this paper discuss on the effects of mismanagement in contribution to the abandoned housing project. Together, the suitable solutions to mitigate the abandonment issues will also be proposed. The studies focus on collecting the data form local authorities and also by doing a questionnaire. The data was analyse based on the Likert's scale and using relative of important index. This study found that the mismanagement is cause by the inexperienced developer with lack of management skill will contribute to the abandoned housing project

    Measurement and QCD analysis of double-differential inclusive jet cross sections in pp collisions at s = 8 \backslashsqrt{s}=8 TeV and cross section ratios to 2.76 and 7 TeV

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    A measurement of the double-differential inclusive jet cross section as a function of the jet transverse momentum p T and the absolute jet rapidity |y| is presented. Data from LHC proton-proton collisions at s = 8 \backslashsqrt{s}=8 TeV, corresponding to an integrated luminosity of 19.7 fb−1, have been collected with the CMS detector. Jets are reconstructed using the anti-k T clustering algorithm with a size parameter of 0.7 in a phase space region covering jet p T from 74 GeV up to 2.5 TeV and jet absolute rapidity up to |y| = 3.0. The low-p T jet range between 21 and 74 GeV is also studied up to |y| = 4.7, using a dedicated data sample corresponding to an integrated luminosity of 5.6 pb−1. The measured jet cross section is corrected for detector effects and compared with the predictions from perturbative QCD at next-to-leading order (NLO) using various sets of parton distribution functions (PDF). Cross section ratios to the corresponding measurements performed at 2.76 and 7 TeV are presented. From the measured double-differential jet cross section, the value of the strong coupling constant evaluated at the Z mass is α S(M Z)þinspace=þinspace0.1164 −þinspace0.0043 +þinspace0.0060 , where the errors include the PDF, scale, nonperturbative effects and experimental uncertainties, using the CT10 NLO PDFs. Improved constraints on PDFs based on the inclusive jet cross section measurement are presented

    Combined QCD and electroweak analysis of HERA data

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    A simultaneous fit of parton distribution functions (PDFs) and electroweak parameters to HERA data on deep inelastic scattering is presented. The input data are the neutral current and charged current inclusive cross sections which were previously used in the QCD analysis leading to the HERAPDF2.0 PDFs. In addition, the polarisation of the electron beam was taken into account for the ZEUS data recorded between 2004 and 2007. Results on the vector and axial-vector couplings of the Z boson to u- and d-type quarks, on the value of the electroweak mixing angle and the mass of the W boson are presented. The values obtained for the electroweak parameters are in agreement with Standard Model predictions.Comment: 32 pages, 10 figures, accepted by Phys. Rev. D. Small corrections from proofing process and small change to Fig. 12 and Table

    Measurement of the cross-section ratio sigma_{psi(2S)}/sigma_{J/psi(1S)} in deep inelastic exclusive ep scattering at HERA

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    The exclusive deep inelastic electroproduction of ψ(2S)\psi(2S) and J/ψ(1S)J/\psi(1S) at an epep centre-of-mass energy of 317 GeV has been studied with the ZEUS detector at HERA in the kinematic range 2<Q2<802 < Q^2 < 80 GeV2^2, 30<W<21030 < W < 210 GeV and t<1|t| < 1 GeV2^2, where Q2Q^2 is the photon virtuality, WW is the photon-proton centre-of-mass energy and tt is the squared four-momentum transfer at the proton vertex. The data for 2<Q2<52 < Q^2 < 5 GeV2^2 were taken in the HERA I running period and correspond to an integrated luminosity of 114 pb1^{-1}. The data for 5<Q2<805 < Q^2 < 80 GeV2^2 are from both HERA I and HERA II periods and correspond to an integrated luminosity of 468 pb1^{-1}. The decay modes analysed were μ+μ\mu^+\mu^- and J/ψ(1S)π+πJ/\psi(1S) \,\pi^+\pi^- for the ψ(2S)\psi(2S) and μ+μ\mu^+\mu^- for the J/ψ(1S)J/\psi(1S). The cross-section ratio σψ(2S)/σJ/ψ(1S)\sigma_{\psi(2S)}/\sigma_{J/\psi(1S)} has been measured as a function of Q2,WQ^2, W and tt. The results are compared to predictions of QCD-inspired models of exclusive vector-meson production.Comment: 24 pages, 8 figure

    Limits on the effective quark radius from inclusive epep scattering at HERA

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    The high-precision HERA data allows searches up to TeV scales for Beyond the Standard Model contributions to electron-quark scattering. Combined measurements of the inclusive deep inelastic cross sections in neutral and charged current epep scattering corresponding to a luminosity of around 1 fb1^{-1} have been used in this analysis. A new approach to the beyond the Standard Model analysis of the inclusive epep data is presented; simultaneous fits of parton distribution functions together with contributions of "new physics" processes were performed. Results are presented considering a finite radius of quarks within the quark form-factor model. The resulting 95% C.L. upper limit on the effective quark radius is 0.4310160.43\cdot 10^{-16} cm.Comment: 10 pages, 4 figures, accepted by Phys. Lett.

    Search for a narrow baryonic state decaying to pKS0{pK^0_S} and pˉKS0{\bar{p}K^0_S} in deep inelastic scattering at HERA

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    A search for a narrow baryonic state in the pKS0pK^0_S and pˉKS0\bar{p}K^0_S system has been performed in epep collisions at HERA with the ZEUS detector using an integrated luminosity of 358 pb1^{-1} taken in 2003-2007. The search was performed with deep inelastic scattering events at an epep centre-of-mass energy of 318 GeV for exchanged photon virtuality, Q2Q^2, between 20 and 100 GeV2\rm{} GeV^{2}. Contrary to evidence presented for such a state around 1.52 GeV in a previous ZEUS analysis using a sample of 121 pb1^{-1} taken in 1996-2000, no resonance peak was found in the p(pˉ)KS0p(\bar{p})K^0_S invariant-mass distribution in the range 1.45-1.7 GeV. Upper limits on the production cross section are set.Comment: 16 pages, 4 figures, accepted by Phys. Lett. B. Minor changes from journal reviewing process, including a small correction to figure