Rotation measure variations for 20 millisecond pulsars

We report on variations in the mean position angle of the 20 millisecond pulsars being observed as part of the Parkes Pulsar Timing Array (PPTA) project. It is found that the observed variations are dominated by changes in the Faraday rotation occurring in the Earth??s ionosphere. Two ionospheric models are used to correct for the ionospheric contribution and it is found that one based on the International Reference Ionosphere gave the best results. Little or no significant long-term variation in interstellar RM was found with limits typically about 0.1 rad?m^?2?yr^?1 in absolute value. In a few cases, apparently significant RM variations over timescales of a few 100 days or more were seen. These are unlikely to be due to localised magnetised regions crossing the line of sight since the implied magnetic fields are too high. Most probably they are statistical fluctuations due to random spatial and temporal variations in the interstellar electron density and magnetic field along the line of sight.     

Extreme wind gust hazard in Australia and its sensitivity to climate change

For consideration of structural design of buildings and infrastructure in Australia, this paper presents hazard modelling and mapping of extreme wind gusts under the current climate and likely future climate change. Statistical and probabilistic approaches are applied to analyse the daily extreme wind gust data recorded between 1939 and 2007 at 545 anemometer stations around Australia. The estimated hazards are compared with the regional design wind speeds specified by the structural design standard, AS/NZS 1170.2:2011. Our results indicate that, under the current climate, structures in the areas on the west of and around Brisbane, Queensland and Newcastle, New South Wales, may be under higher gust hazard than they are designed for. Sensitivity study shows that these areas are also sensitive to the projected synoptic wind intensity changes. When subjected to ±20 % intensity change and ±50 % occurrence frequency change of tropical cyclones, the northwest coast of Western Australia, the northern part of Northern Territory, and the northeast coast between Cairns and Townsville, Queensland, will experience around ±10 m/s changes in extreme wind gust speeds of 500-year return period.     

Anchoring to determine negotiated catch limits: a case study of an industrial fishery in Oman

Despite refinement in scientific methods of setting total allowable catches (TACs), the choice of values is affected by uncertainty that arises as a result of incomplete information and the behavioural intentions of resource users, among others. In this context, this paper promotes ‘anchoring’ – which is a subject of behavioural economics and is generally practised in decision-making when faced with uncertainty – as an approach to TAC setting. We estimate a set of anchor points for nine demersal species by employing two modelling scenarios, the first using catch-and-effort data and the second only catch data collected from the demersal trawl fishery. A non-parametric test yielded no significant difference between the sets of anchor points generated from the two models. It is hoped that the use of anchoring would constitute a proactive management approach that could serve as a mechanism of promoting knowledge integration and effective communication, developing mutual trust, and improving management outcomes in the future.     

Application of desingularized approach to water wave propagation over three-dimensional topography

A numerical approach based on desingularized boundary element method and mixed Eulerian–Lagrangian formulation [Zhang et al., 2006. Wave propagation in a fully nonlinear numerical wave tank: a desingularized method. Ocean Engineering 33, 2310–2331] is extended to solve the water wave propagation over arbitrary topography in a three-dimensional wave tank. A robust damping layer applicable for regular and irregular incident waves is employed to minimize the outgoing wave reflection back into the wave tank. Numerical results on the propagation of regular and irregular incident waves over the flat bottom and linear incident waves over an elliptical shoal show good concurrence with the corresponding analytical solutions and experimental data.     

The Recovery of Two Long-logged Headwaters in Temengor Reservoir,Perak,Malaysia

A study on water quality of the two long-logged and abandoned headwaters in Temengor Reservoir was conducted to determine their natural recovery.In this study,we used National Water Quality Standards for Malaysia prepared by Malaysian Department of Environment as an indicator for water quality recovery.The parameters measured were dissolved oxygen（mg/L）,water temperature（℃）,pH,conductivity（mS/cm）,total dissolved solids（mg/ L）,water velocity（m/s）,ortho-phosphate（PO₄-P）,nitrite-nitrogen（NO₂-N）,nitrate-nitrogen（NO₃,-N）and alkalinity. In general,water quality in Sungai Enam and Sungai Telang were in ClassⅠ,indicating water quality in both streams have recovered.Based on the t-test,Sungai Enam and Sungai Telang differed significantly in all parameters except for dissolved oxygen,NO₂-N and NO₃-N.In spatial analyses（upper,middle and lower reaches comparisons）, the two-way ANOVA analysis shows that there were significant differences in all studied parameters between the two rivers except for dissolved oxygen,total dissolved solids,NO₂-N and NO₃-N.Stream flow,hydrologic pathways,geomorphology,physical and environmental characteristics are essential elements in understanding the dynamics of water systems in Sungai Enam and Sungai Telang.Due to the recovery,these two headwaters are thus suitable for fish conservation and restoration sites.     

豫西沙沟脉状Ag-Pb-Zn矿床地质特征和成矿流体研究

豫西沙沟薄脉状Ag-Pb-Zn硫化物矿床位于华北陆块南缘熊耳山地区,主要由多金属硫化物-石英-碳酸盐脉型和石英-碳酸盐-绢云母-多金属硫化物蚀变岩型两种矿化类型组成。主要矿脉的矿物共生序列可以分为成矿前的石英-黄铁矿阶段(Ⅰ)、闪锌矿-石英-方铅矿-少量银矿物阶段(Ⅱ1)、方铅矿-石英-闪锌矿-含铁白云石-银矿物阶段(Ⅱ2)和成矿后的方解石-(石英)阶段(Ⅲ)。对不同阶段的成矿流体研究表明,石英-黄铁矿阶段(Ⅰ)中的含氯化钠子晶三相(LVH)包裹体(Ⅰ1)可能是直接从饱和水的结晶岩浆熔体中出溶形成或是由岩浆流体的减压沸腾形成,显示该区很可能存在岩浆流体端元。多金属硫化物阶段(Ⅱ1Ⅱ2)捕获富液相包裹体(LV型)和个别CO2包裹体(C型),这两个阶段流体包裹体反映了主成矿阶段流体的基本特征,结合包裹体气相和液相成分色谱分析以及包裹体初融温度,认为成矿流体应该为中-低温低盐度含CO2的H2O-NaCl体系。其中,阶段(Ⅱ2)的均一温度(145～288℃,平均为194℃)比阶段(Ⅱ1)的均一温度(185～357℃,平均240℃)低46℃;同时,阶段(Ⅱ2)的盐度(1.91%～10.86%,平均6.38%)较阶段(Ⅱ1)盐度(4.65%～10.11%,平均7.77%)略低。对这一温度和盐度的总体下降趋势的合理解释是大气水的逐渐混入。多金属硫化物阶段(Ⅱ1Ⅱ2)之后的方解石-(石英)阶段普遍为富液相包裹体(LV型),该阶段显著降低的温度(129～208℃,平均165℃)和盐度(1.40%～4.03%,平均2.50%),进一步佐证大气水的不断混入。而且,流体混合可能在引起矿石矿物从热液中沉淀方面起到重要作用。     

Urban geography as pretext: Sociocultural landscapes of Kuala Lumpur in independent Malaysian films

Current independent filmmaking in Malaysia has the potential to be an alternative and viable space for creative and political expression, relative to mainstream national cinema (Malay cinema) and to the state. I focus on alternative imagery and sociocultural mappings of Kuala Lumpur in three ‘indie’ films. All three films contain documentary elements capturing social geographies of the city not represented in mainstream Malay cinema, or even if represented not subjected to a critical gaze by the filmmaker. The Big Durian centres on the perspectives of the city's urban middle class of all ethnicities; Bukak Api portrays the daily struggles of Malay transsexual sex workers in Chow Kit, a predominantly working‐class Chinese neighbourhood and red light district; and 18? highlights the opinions of the nongovernmental organization community, bohemians, artists, anarchists and media activists mostly in the cosmopolitan suburb of Bangsar. These representations of the Malaysian urban landscape are pretexts for and politicize the national landscape through a discussion of ethnicity and race politics, sexuality, and the lack of space for freedom of creative expression and critical thinking.     

A 3D fully coupled analysis of nonlinear sloshing and ship motion

This study investigates the coupling effects of six degrees of freedom in ship motion with fluid oscillation inside a three-dimensional rectangular container using a novel time domain simulation scheme. During the time marching, the tank-sloshing algorithm is coupled with the vessel-motion algorithm so that the influence of tank sloshing on vessel motions and vice versa can be assessed. Several factors influencing the dynamic behavior of tank–liquid system due to moving ship are also investigated. These factors include container parameters, environmental settings such as the significant wave height, current velocity as well as the direction of wind, wave and flow current acting on the ship. The nonlinear sloshing is studied using a finite element model whereas nonlinear ship motion is simulated using a hybrid marine control system. Computed roll response is compared with the existing results, showing fair agreement. Although the two hull forms and the sea states are not identical, the numerical result shows the same trend of the roll motion when the anti-rolling tanks are considered. Thus, the numerical approach presented in this paper is expected to be very useful and realistic in evaluating the coupling effects of nonlinear sloshing and 6-DOF ship motion.     

Seismic retrofit of reinforced concrete frames using buckling‐restrained braces with bearing block load transfer mechanism

A new method of retrofitting reinforced concrete (RC) frames with buckling‐restrained braces (BRBs) to improve frame strength, stiffness and energy dissipation is proposed. Instead of typical post‐installed anchors, load is transferred between the BRB and RC frame through compression bearing between an installed steel frame connected to the BRB, and high‐strength mortar blocks constructed at the four corners of the RC frame. This avoids complex on‐site anchor installation, and does not limit the allowable brace force by the anchor strength. Cyclic displacements of increasing amplitudes were imposed on two RC frame specimens retrofitted with different BRB strength capacities. In one of the frames, the bearing blocks were reinforced with wire mesh to mitigate cracking. A third RC frame was also tested as a benchmark to evaluate the retrofit strength and stiffness enhancements. Test results indicate that the proposed method efficiently transferred loads between the BRBs and RC frames, increasing the frame lateral strength while achieving good ductility and energy‐dissipating capacity. When the bearing block was reinforced with wire mesh, the maximum frame lateral strength and stiffness were more than 2.2 and 3.5 times the RC frame without the BRB respectively. The BRB imposes additional shear demands through the bearing blocks to both ends of the RC beam and column member discontinuity regions (D‐regions). The softened strut‐and‐tie model satisfactorily estimated the shear capacities of the D‐regions. A simplified calculation and a detailed PISA3D analysis were shown to effectively predict member demands to within 13.8% difference of the measured test results. Copyright © 2016 John Wiley & Sons, Ltd.