Integration of GPS with a WiFi high accuracy ranging functionality

High accuracy seamless positioning is required to support a vast number of applications in varying operational environments. Over the last few years, the global positioning system (GPS) has become the de facto technology for positioning applications. However, its performance is limited in indoor and dense urban environments due to multipath as well as signal attenuation and blockage. A number of techniques integrating GPS with other positioning technologies have been developed to address the limitations of standalone GPS in these difficult environments. While most of the developed techniques cover the outages of GPS in such environments, they do not provide acceptable performance, in terms of positioning accuracy, especially for some mission-critical (e.g. safety) applications. This paper proposes a tightly coupled (i.e. in the measurement domain) GPS/WiFi integration method which, in addition to addressing GPS outages, improves the overall positioning accuracy to the meter-level, thus satisfying the requirements of a number of location based services and intelligent transport systems applications. The performance of the proposed GPS/WiFi integration method is assessed for a number of scenarios in a simulation environment for an identified dense urban area in London, UK.     

Reactive Transport Modeling of ZVI Column Experiments for Nickel Remediation

MIN3P, a multicomponent reactive transport model for variably saturated porous media, is used to simulate the outputs of column tests carried out using zero valent iron (ZVI) for nickel contaminated groundwater remediation. The objective of this study is to investigate the main chemical reactions involved in contaminant removal and the main causes of the reactivity decline of ZVI over time. According to the results of the model the major causes of ZVI reactivity loss is identified in the mineral precipitation of α‐FeOOH on iron surface that probably caused ZVI passivation and led to a decline of the electron transfer rate. An existing empirical relationship between mineral precipitation and the reactivity loss of ZVI, included in the model, reproduced the changes in nickel removal observed during different laboratory column tests.     

Continental Oxygen Isotopic Record of the Last 170,000 Years in Jerusalem

A long radiometrically dated oxygen isotopic record of continental climatic variations since the penultimate glaciation was obtained from a stalagmite deposited in a sealed cave in Jerusalem. This record shows that speleothems have the potential of assigning dates to long- and short-term climatic events, with possible refining of Milankovitch tuning of ice and marine records which themselves are not datable. Short-term (1000-yr) events are very significant in the region, reaching 50% of glacial/interglacial fluctuations. The Mediterranean Sea was the most probable source of local precipitation throughout the last glacial cycle.     

Early evolution and transformation of organic matter in the active continental Jordan Rift Valley

A sequence of alternating lacustrine marls, peat and basalts was penetrated in the Notera-3 well in the northern part of the Jordan Rift, Israel. The 2781 m thick sequence, ranges from Upper Miocene to Recent, reflects high sedimentation rate in the active continental rift associated with the Dead Sea Transform. The deep burial and the relatively high geothermal gradient (40°C km⁻¹) compensate for the short time span so that coalification expressed by vitrinite reflectance consistently increases with depth, from about 0.32% Ro at 1040 m to 0.48% Ro at 2495 m.Analysis of the peat reveals that the O/C, S/C and δ¹³C of the humic acids (HA) and the heavy to light normal alkane ratios are the only parameters sensitive enough to express this slight maturation increase with depth. A sharp δ¹³C change from about − 18‰ prevailing in the uppermost meters to an average of − 27.5‰ at 15 m and deeper reflects a change in the higher plant source of the peat (from C4 to C3 plants) rather than an early diagenetic modification.The δ¹³C, O/C, S/C and N/C ratios are usually lower in the kerogens than in the corresponding HA. The decrease in the δ¹³C and the O/C ratios are explained by elimination of oxygen-containing functional groups during transformation and by polymerization effects. The gradual decrease in the ¹²C and the O/C of the HA with depth are attributed to decarboxylation coupled with kinetic effects. The N/C depletion during the transformation from HA to kerogens probably results from the breakdown of amino acids. The S/C ratio which decreases both during this transformation and also with maturation is most readily explained by the breakdown of ester sulfate-containing groups such as sulfated polysaccarids, which formed diagenetically during the humification process.     

Flood forecasting and analysis within the Ulus Basin, Turkey, using geographic information systems

Floods have been the most severe natural disasters in the West Black Sea Region of Turkey for many years; therefore Ulus Basin is selected as a study area for a thorough hydrologic flood analysis. The lack of embankments around the Ulus River and careless changes to the riverbed made by villagers, resulted in major flood events in the basin, causing significant damage in the area. In this study, the hydrodynamic characteristics of the basin and the riverbed are determined by calibrating the hydraulic module of the MIKE 11 modeling system with the observed 1991 flood. Then, for the 25-, 50- and 100-year floods the highest water levels in the river are forecasted by integration of the MIKE 11 hydrologic and hydraulic modules. Afterwards, inundation maps are obtained by using together the hydraulic and GIS modules of the MIKE 11 system.     

The settling behavior and benthic transport of fish feed pellets under steady flows

Settling and erosion experiments were carried out on a size range of fish feed pellets using an annular flume. A strong positive correlation was observed between settling rate and pellet dimension (pellet length, pellet dimeter, and equivalent sedimentation diameter). Erosion thresholds also showed a strong positive correlation with pellet dimensions. Experiments were also carried out to examine the effect of the number of pellets on erosion threshold of two sizes. The results show an asymptotic increase in erosion threshold with increasing number of pellets present, possibly due to sheltering effects. The chemical composition of the pellets was analyzed in terms of water and organic, carbon, and nitrogen contents as well as stable carbon and nitrogen isotopes. The results arising from this study will provide, information regarding potential tracers of waste feed material and help validate model predictions associated with dispersal of waste material.     

The March 25 and 29, 2016 landslide-induced debris flow at Clapar,Banjarnegara, Central Java

The Clapar landslide induced debris flow consisted of the Clapar landslide occurred on 24 March 2017 and the Clapar debris flow occurred on 29 March 2017. The first investigation of the Clapar landslide induced debris flow was carried out two months after the disaster. It was followed by UAV mapping, extensive interviews, newspaper compilation, visual observation and field measurements, and video analysis in order to understand chronology and triggering mechanism of the landslide induced debris flow in Clapar. The 24 March 2016 landslide occurred after 5 hours of consecutive rainfall (11,2 mm) and was affected by combination of fishponds leak and infiltration of antecedent rain. After five days of the Clapar landslide, landslide partially mobilized to form debris flow where the head scarp of debris flow was located at the foot of the 24 March 2016 landslide. The Clapar debris flow occurred when there was no rainfall. It was not generated by rainstorm or the surface erosion of the river bed, but rather by water infiltration through the crack formed on the toe of the 24 March 2016 landslide. Supply of water to the marine clay deposit might have increased pore water pressure and mobilized the soil layer above. The amount of water accumulated in the temporary pond at the main body of the 24 March 2016 landslide might have also triggered the Clapar debris flow. The area of Clapar landslide still shows the possibility of further retrogression of the landslide body which may induce another debris flow. Understanding precursory factors triggering landslides and debris flows in Banjarnegara based on data from monitoring systems and laboratory experiments is essential to minimize the risk of future landslide.     

Rotation, planets, and the 'second parameter' of the horizontal branch

We analyse the angular momentum evolution from the red giant branch (RGB) to the horizontal branch (HB) and along the HB. Using rotation velocities for stars in the globular cluster M13, we find that the required angular momentum for the fast rotators is up to 1–3 orders of magnitude (depending on some assumptions) larger than that of the Sun. Planets of masses up to 5 times Jupiter's mass and up to an initial orbital separation of ~2 au are sufficient to spin-up the RGB progenitors of most of these fast rotators. Other stars have been spun-up by brown dwarfs or low-mass main-sequence stars. Our results show that the fast rotating HB stars have been probably spun-up by planets, brown dwarfs or low-mass main-sequence stars while they evolved on the RGB. We argue that the angular momentum considerations presented in this paper further support the 'planet second parameter' model. In this model, the 'second parameter' process, which determines the distribution of stars on the HB, is interaction with low-mass companions, in most cases with gas-giant planets, and in a minority of cases with brown dwarfs or low-mass main-sequence stars. The masses and initial orbital separations of the planets (or brown dwarfs or low-mass main-sequence stars) form a rich spectrum of different physical parameters, which manifests itself in the rich varieties of HB morphologies observed in the different globular clusters.     

Supply limited sediment transport in a high-discharge event of the tropical Burdekin River, North Queensland, Australia

Interactions between catchment variables and sediment transport processes in rivers are complex, and sediment transport behaviour during high‐flow events is not well documented. This paper presents an investigation into sediment transport processes in a short‐duration, high‐discharge event in the Burdekin River, a large sand‐ and gravel‐bed river in the monsoon‐ and cyclone‐influenced, semi‐arid tropics of north Queensland. The Burdekin's discharge is highly variable and strongly seasonal, with a recorded maximum of 40 400 m³ s^?1. Sediment was sampled systematically across an 800 m wide, 12 m deep and straight reach using Helley‐Smith bedload and US P‐61 suspended sediment samplers over 16 days of a 29‐day discharge event in February and March 2000 (peak 11 155 m³ s^?1). About 3·7 × 10⁶ tonnes of suspended sediment and 3 × 10⁵ tonnes of bedload are estimated to have been transported past the sample site during the flow event. The sediment load was predominantly supply limited. Wash load included clay, silt and very fine sand. The concentration of suspended bed material (including very coarse sand) varied with bedload transport rate, discharge and height above the bed. Bedload transport rate and changes in channel shape were greatest several days after peak discharge. Comparison between these data and sparse published data from other events on this river shows that the control on sediment load varies between supply limited and hydraulically limited transport, and that antecedent weather is an important control on suspended sediment concentration. Neither the empirical relationships widely used to estimate suspended sediment concentrations and bedload (e.g. Ackers & White, 1973) nor observations of sediment transport characteristics in ephemeral streams (e.g. Reid & Frostick, 1987) are directly applicable to this river.