The main purpose of this study is to determine shoreline change in Bengkalis Cape, Riau Province, Indonesia using sediment samples analysis, satellite images, and oceanographic parameters. The samples were collected at five stations by using sediment grab and oceanographic observation was also carried out at each station in November 2015. The southern part of Bengkalis Cape is characterised by fine-grain sediments (mud) and high rate of accretion that reaches 29.77 metre/year, and is influenced by weak tidal currents with a velocity of less than 0.06 m/s and low wave energy. In contrast, the northern part is occupied by coarse-grain sediments (sand) which is characterised by high rate of abrasion as shown in the image data for 20 years; 1995-2015 reaches 38.02 metre/year, and is under the influence of strong tidal current (0.16 m/s) and high wave energy. The major contributing factor for the shoreline change is the current system which flowing from Malacca strait to the shore area and sediments deposition in the area.
During the Miocene, extensive carbonate deposition thrived over wide latitudinal ranges in Southeast Asia despite perturbations of the global climate and thermohaline circulation that affected the Asian continent. Nevertheless, the mechanisms of its emergence, adaptability in siliciclastic-dominated margins and demise, especially in southern South China Sea (SCS), are largely speculative and remains enigmatic along with a scarcity of constraints on paleoclimatic and palaeoceanographic conditions. Here we show, through newly acquired high-resolution geophysical data and accurate stratigraphic records based on strontium isotopic dating, the evolution of these platforms from ~15.5-9.5 Ma is initially tied to tectonics and eustasy, and ultimately, after ~9.5 Ma, to changes in the global climate patterns and consequent palaeoceanographic conditions. Our results demonstrate at least two paleodeltas that provided favourable substratum of elevated sand bars, which conditioning the emergence of the buildups that inadvertently mirrored the underlying strata. We show unprecedented evidences for ocean current fluctuations linked to the intensification of the Asian summer monsoon winds resulting in the formation of drifts and moats, which extirpated the platforms through sediment removal and starvation. This work highlights the imperative role of palaeoceanography in creating favourable niches for reefal development that can be applicable to carbonate platforms elsewhere.
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.
The purpose of this study was to examine the effect of viscous dissipation on mixed convection flow of viscoelastic
nanofluid past a horizontal circular cylinder. Carboxymethyl cellulose solution (CMC) is chosen as the base fluid and
copper as a nanoparticle with the Prandtl number Pr = 6.2. The transformed boundary layer equations for momentum
and temperature subject to the appropriate boundary conditions are solved numerically by using Keller-box method. The
influenced of the dimensionless parameters such as Eckert number, mixed convection parameter, nanoparticles volume
fraction and viscoelastic parameter on the flow and heat transfer characteristics is analyzed in detail and presented
graphically. The results come out with the velocity profiles are increased while the temperature profiles are decreased
by increasing the values of nanoparticles volume fraction and viscoelastic parameter, respectively. The graph shows
that, increasing Eckert number the skin friction is also increases. The values of skin friction are increased by increasing
mixed convection parameter, but the values of Nusselt number produce an opposite behavior. The present study has many
applications especially in heat exchangers technology and oceanography. Therefore, in future, it is hoping to study the
viscoelastic nanofluid flow past a different geometric such as sphere and cylindrical cone.