Lateral Water Research Articles

Multi-scale analysis of functional plankton diversity in floodplain wetlands: Effects of river regulation

Riverine floodplains are among the most diverse and dynamic ecosystems, but river regulation measures have altered the natural hydrological regime threatening their ecological integrity. We compared spatial patterns of phyto- and zooplankton functional diversity and of environmental heterogeneity between floodplain wetlands located in free-flowing and impounded stretches of the Danube River (Austria). We included two nested spatial scales (different habitats and water sections within wetland areas) and two contrasting hydrological conditions (post-flood, no flood). Environmental heterogeneity was lower in the wetland in the impounded stretch than in the free-flowing ones. At post-flood conditions, increased alpha diversity of rotifers and microcrustaceans and decreased beta diversity of phytoplankton and rotifers occurred in the impounded stretch as compared to the wetlands in free-flowing one. Beta diversity was higher between water sections than between habitats in free-flowing wetlands and similar across scales in the wetland in the impounded stretch. Regarding functional composition, the wetland in the impounded stretch hosted more homogeneous communities, as some ecological traits were nearly absent. Our results indicate that patterns of functional diversity in floodplain wetlands affected by river regulation are altered, highlighting the major role of the gradient of lateral connectivity and dynamic water level fluctuations as drivers for planktic diversity in river floodplains. This study contributes with essential knowledge to optimize restoration and diversity conservation measures in riverine ecosystems.

Lateral water structure connects metal oxide nanoparticle faces

Abstract

Investigating lake-area dynamics across a permafrost-thaw spectrum using airborne electromagnetic surveys and remote sensing time-series data in Yukon Flats, Alaska

Lakes in boreal lowlands cycle carbon and supply an important source of freshwater for wildlife and migratory waterfowl. The abundance and distribution of these lakes are supported, in part, by permafrost distribution, which is subject to change. Relationships between permafrost thaw and lake dynamics remain poorly known in most boreal regions. Here, new airborne electromagnetic (AEM) data collected during June 2010 and February 2016 were used to constrain deep permafrost distribution. AEM data were coupled with Landsat-derived lake surface-area data from 1979 through 2011 to inform temporal lake behavior changes in the 35 500- km2 Yukon Flats ecoregion of Alaska. Together, over 1500 km of AEM data, and roughly 30 years of Landsat data were used to explore processes that drive lake dynamics across a variety of permafrost thaw states not possible in studies conducted with satellite imagery or field measurements alone. Clustered time-series data identified lakes with similar temporal dynamics. Clusters possessed similarities in lake permanence (i.e. ephemeral versus perennial), subsurface permafrost distribution, and proximity to rivers and streams. Of the clustered lakes, ∼66% are inferred to have at least intermittent connectivity with other surface-water features, ∼19% are inferred to have shallow subsurface connectivity to other surface water features that served as a low-pass filter for hydroclimatic fluctuations, and ∼15% appear to be isolated by surrounding permafrost (i.e. no connectivity). Integrated analysis of AEM and Landsat data reveals a progression from relatively synchronous lake dynamics among disconnected lakes in the most spatially continuous, thick permafrost to quite high spatiotemporal heterogeneity in lake behavior among variably-connected lakes in regions with notably less continuous permafrost. Variability can be explained by the preferential development of thawed permeable gravel pathways for lateral water redistribution in this area. The general spatial progression in permafrost thaw state and lake area behavior may be extended to the temporal dimension. However, extensive permafrost thaw, beyond what is currently observed, is expected to promote ubiquitous subsurface connectivity, eventually evolving to a state of increased lake synchronicity.

Role of Lateral Terrestrial Water Flow on the Regional Water Cycle in a Complex Terrain Region: Investigation With a Fully Coupled Model System

AbstractRecent developments in hydrometeorological modeling aim toward a more sophisticated treatment of terrestrial hydrologic processes. The objective of this study is to investigate the role of lateral terrestrial water flows on the regional atmospheric and terrestrial water cycle in a humid region of Central Europe. This is accomplished by evaluating model results from both the standard Weather Research and Forecasting (WRF) model and the hydrologically enhanced version WRF‐Hydro, which allows for a more comprehensive process description of the interdependencies between water and energy fluxes at the land‐atmosphere interface. To account for internal model variability, an ensemble for each model variant is generated for a 3‐month study period in the summer of 2005. The regional water cycle in the simulation domain is investigated by evaluating the ensemble results with a joint atmospheric‐terrestrial water budget analysis. We focus on six differently sized river catchments located in Southern Bavaria (Germany) and the southerly adjacent Eastern Alps, where simulation results are compared to observations of precipitation, near‐surface temperatures, and streamflow. Most prominently, WRF‐Hydro increases (near‐) surface runoff and decreases percolation, resulting in a reduced total runoff amount. Accordingly, soil moisture storage and evapotranspiration are increased. Domain‐averaged precipitation differences between WRF and WRF‐Hydro are essentially related to differences in atmospheric moisture inflow and outflow, which is the signature of internal model variability and is potentially enhanced in the WRF‐Hydro ensemble. Driven only at the boundaries of the outermost domain, the fully coupled model system shows good performance in the reproduction of observed streamflow.

Optical calcium test for measurement of multiple permeation pathways in flexible organic optoelectronic encapsulation.

Organic photovoltaic (OPV) devices and other organic electronics have the promise to provide lightweight, flexible alternatives to traditional rigid semiconductor technologies. However, organic electronics often degrade rapidly upon exposure to oxygen, water, light, and combinations thereof, as well as upon exposure to elevated temperatures. This requires the use of high gas barrier packaging in order for devices to have operational lifetimes on the order of years. To meet the challenge of transparent high gas barrier materials which maintain the flexibility of organic optoelectronics, many different materials and encapsulation schemes have been developed including the lamination of devices between flexible multi-layer barrier films. Because of their excellent barrier properties, these materials often require specialized testing for permeation measurements which evaluate materials independently. In this work, we demonstrate the use of an optical calcium test, which uses a sample geometry that closely mimics an OPV device, to evaluate a complete encapsulation scheme and to elucidate the relative importance of different permeation pathways. Using an encapsulation scheme of laminating a device between two multi-layer barrier films using an adhesive, measurements were made for water vapor permeation through the barrier film, the bulk adhesive, and along the adhesive-to-barrier film interface. The results show that the combined lateral permeation, including through the bulk adhesive and along the adhesive-to-barrier film interface, can constitute over 50% of the total permeation for small devices (4.5 cm × 4.5 cm). The adhesive-to-barrier film interface was also found to be a very important pathway as it was deemed responsible for more permeation than the bulk adhesive. The technique was also used to evaluate encapsulation design variables such as the effects of adhesive thickness and surface treatments on the lateral water permeation. We demonstrate that decreasing the adhesive thickness leads to a decrease in the lateral water permeation.

Attribution of the growth of a distinct population of Synechococcus to the coverage of lateral water on an upwelling

Attribution of the growth of a distinct population of <i>Synechococcus</i> to the coverage of lateral water on an upwelling

PREDICTION OF SOIL WETTING PATTERN FOR THREE SOIL TYPES UNDER DRIP IRRIGATION

This study was carried out by identifying and selecting three soil types around the University of Agriculture, Makurdi, Nigeria to determine their physicochemical properties. Drip Irrigation is considered as one of the most efficient irrigation systems, provided the system is designed to meet the soil and plant condition. Information on wetting patterns under point source drip emitters is a prerequisite for the design and operation of the drip systems. This is to ensure precise placement of water and fertilizer in the active root zone. The objective of this study was to develop models that can help to determine the wetting radius (r), wetting depth (z) from surface point drip irrigation of three soil types (clay loam, sandy loam and sandy clay loam). Water was applied to each soil type using drip irrigation set up at a constant flow rate of 1.3 l/hr. The maximum duration of water application was 10 hrs. At intervals of 30 minutes, there was excavation to monitor the wetted radius and depth. The field data was subjected to statistical analysis using SPSS version 22.0 to formulate the models that relates the duration, flow rate, volume and hydraulic properties to wetted radius and depth. Results show that lateral water movement was highest in the clay loam while vertical movement was highest in sandy loam. The highest wetted depth in clay loam, sandy loam and sandy clay loam were 17, 26, and 25 cm while the wetted radius were 26, 24, and 22 cm, respectively. Models for the three soil types were developed, the R2 values for the three soils were between 0.7and0.9 which are close to 1. The ANOVA shows that the models were statistically significant as the P values are less than 0.05. The results obtained showed that the wetted depth and wetted radius of these soil types are influenced by the flow rate, duration and volume of water application within the range under consideration and can fit into irrigation of vegetable crops.

Inventory and distribution of tritium in the oceans in 2016

Tritium concentrations in oceans were compiled from the literature, online databases and original measurements in order to determine the global distribution of tritium concentrations according to latitude and depth in all oceans.The total inventory of tritium decay corrected in 2016 has been estimated using evaluation of the natural and artificial contributions in 23 spatial subdivisions of the total ocean. It is determined equal to 26.8 ± 14 kg including 3.8 kg of cosmogenic tritium. That is in agreement with the total atmospheric input of tritium from nuclear bomb tests and the natural inventory at steady-state estimated from natural production rates in the literature (27.8–29.3 kg in the Earth). We confirm the global increase in tritium according to latitude observed in the Northern hemisphere since 1967 with a maximum in the Arctic Ocean. The minimum tritium concentrations observed in the Southern Ocean were close to steady-state with known natural tritium deposition.We focused on the temporal evolution of surface (0 to 500 m) tritium concentrations in a selected area of the North Atlantic Ocean (30°N–60°N) where we found the 2016 concentration to be 0.60 ± 0.10 TU (1σ). Results showed that in that area, between 1988 and 2013, tritium concentrations: i) decreased faster than the sole radioactive decay, due to a mixing with lower and lateral less concentrated waters, and ii) decreased towards an apparent steady state concentration. The half-time mixing rate of surface waters and the steady state concentration were respectively calculated to be 23 ± 5 years (1σ) and 0.38 ± 0.07 TU (1σ). This apparent steady-state concentration in the North Atlantic Ocean implies a mean tritium deposition of 1870 ± 345 Bq·m−2 (1σ), five folds higher than the known inputs (natural, nuclear tests fallout and industrial releases, ~367 Bq·m−2) in this area.

Failure mechanism of joint waterproofing in precast segmental tunnel linings

Water leakage is a major issue for shield tunnels in both the construction and operational stages. The practical solution in industry with relation to the prevention of groundwater penetration is to implement ethylene-propylene-diene monomer (EPDM) gaskets at tunnel joints. Although a few past research has focused on joint waterproof performance, this paper proposes a sealant mechanism based on the finite element analysis. A conceptual model is first established to identify sealant behavior of gasketed joint subjected to lateral water pressurization. A nonlinear finite element model is developed to simulate the gasket-in-groove sealant behavior, and the performance of the model is validated with experimental data. Results of the nonlinear numerical analyses (incorporating a hyperelastic constitutive model of the gasket, complex contact properties, and large deformation) demonstrate the failure mechanism of joint waterproofing. Emphasis is placed on quantifying the effects of joint opening, joint offset and joint rotation on waterproof capacity. The computed results indicate that joint waterproofing capacity significantly decreases with increasing joint opening or joint rotation. The waterproofing capacity varies under different joint offset scenarios because of change of contact interfaces. For the prototype tunnel, it is suggested to control a 6.42 mm joint opening, a 0.0505 rad positive joint rotation or a 0.0141 rad negative joint rotation to maintain its waterproofness.

Water transport secrets of the dragon’s blood trees revealed through sap flow measurements following partial stem incision

Dragon’s blood trees have long been prized for their red resin, and are consequently subjected to traditional practices for its harvesting which involves inflicting numerous, deep stem wounds. Nevertheless, these iconic monocots have continued to survive such drastic treatments. Partial stem incision (PSI) treatment effectively imitates stem wounding, which when combined with sap flow measurements monitored in a close distance of few centimeters above PSI, may significantly improve our understanding of water transport efficiency after stem damage in monocots. As it is impossible to conduct these experiments on protected adult Dracaena species native to remote sites, we demonstrated this approach on young Dracaena draco L. and Dracaena cinnabari Balfour f. plants ex-situ. The goal of this study was to simulate the effects of serious stem wounding on water transport of these woody monocots by applying PSI under permanent sap flow monitoring by the heat field deformation (HFD) method using multi-point sensors. This allowed us to simultaneously monitor sap flow in both wounded and intact stem parts. It was observed that PSI applied in stems up to one-half of the total stem diameter did not reduce sap flow in D. species in any of the monitored stem part indicating efficient bypassing interrupted axial xylem transport by lateral water movement. The dense three dimensional network of interconnected vascular bundles and abundant ground tissue with large simple pits could play an important role in such high transport effectivity of Dracaena species. Synchronous sap flow and nuclear magnetic resonance measurements would be especially useful for the revealing of water flow complexity of Dracaena species in future.

Why Do Large‐Scale Land Surface Models Produce a Low Ratio of Transpiration to Evapotranspiration?

AbstractMost land surface models (LSMs) used in Earth System Models produce a lower ratio of transpiration (T) to evapotranspiration (ET) than field observations, degrading the credibility of Earth System Model‐projected ecosystem responses and feedbacks to climate change. To interpret this model deficiency, we conducted a pair of model experiments using a three‐dimensional, process‐based ecohydrological model in a subhumid, mountainous catchment. One experiment (CTRL) describes lateral water flow, topographic shading, leaf dynamics, and water vapor diffusion in the soil, while the other (LSM like) does not explicitly describe these processes to mimic a conventional LSM using artificially flattened terrain. Averaged over the catchment, CTRL produced a higher T/ET ratio (72%) than LSM like (55%) and agreed better with an independent estimate (79.79 ± 27%) based on rainfall and stream water isotopes. To discern the exact causes, we conducted additional model experiments, each reverting only one process described in CTRL to that of LSM like. These experiments revealed that the enhanced T/ET ratio was mostly caused by lateral water flow and water vapor diffusion within the soil. In particular, terrain‐driven lateral water flows spread out soil moisture to a wider range along hillslopes with an optimum subrange from the middle to upper slopes, where evaporation (E) was more suppressed by the drier surface than T due to plant uptake of deep soil water, thereby enhancing T/ET. A more elaborate representation of water vapor diffusion from a dynamically changing evaporating surface to the height of the surface roughness length reduced E and increased the T/ET ratio.

Walking of spider on water surface studied from its leg shadows**Project supported by the National Natural Science Foundation of China (Grant Nos. 51323006 and 51425502) and the Tribology Science Fund of State Key Laboratory of Tribology (Grant No. SKLTKF17B18).

Different from sculling forward of water striders with their hairy water-repellent legs, water spiders walked very quickly on water surfaces. By using a shadow method, the walking of water spiders had been studied. The three-dimensional trajectories and the supporting forces of water spider legs during walking forward were achieved. Results showed that the leg movement could be divided into three phases: slap, stroke, and retrieve. Employing an effective strategy to improving walking efficiency, the sculling legs supported most of its body weight while other legs were lifted to reduce the lateral water resistance, which was similar to the strategy of water striders. These findings could help guiding the design of water walking robots with high efficiency.

Vegetation and terrain drivers of infiltration depth along a semiarid hillslope

An improved understanding of the drivers controlling infiltration patterns in semiarid regions is of key importance, as they have important implications for ecosystem productivity, retention of resources and the restoration of degraded areas. The infiltration depth variability (ΔInf) in vegetation patches at the hillslope scale can be driven by different factors along the hillslope. Here we investigate the effects of vegetation and terrain attributes under hypothesis that these attributes exert a major control in ΔInf within the patches. We characterise the ΔInf within vegetation patches at a semiarid hillslope located at the Jornada Experimental Range at dry antecedent conditions preceding two winter frontal rainfall events. We measured these events that are typical during winter conditions, and are characterised by low intensity (0.67 and 4.48 mm h−1) and a total rainfall of 10.4 and 4.6 mm. High precision geo-referenced wetting front depth measurements were taken at various locations within the vegetation patches using differential GPS. Vegetation and terrain attributes were analysed to explain the ΔInf among the vegetation patches. The infiltration depths in the periphery of the patches were in general considerably deeper than those in the centre. The observations suggest that the upslope margin of the patches received additional water in the form of runon from upslope adjacent bare soil. Patch orientation with regard to the slope dictated the effect of the rest of the patch attributes and the distance to the hillslope crest on ΔInf. We found that primarily patch orientation, followed by shape and size modulate lateral surface water transport through their effects on overland flow paths and water retention; something that would be obscured under more simplistic characterisations based on bare versus uniform vegetated soil discrimination.

A High‐Resolution Land Model With Groundwater Lateral Flow, Water Use, and Soil Freeze‐Thaw Front Dynamics and its Applications in an Endorheic Basin

AbstractHuman water regulation, groundwater lateral flow, and the movement of frost and thaw fronts (FTFs) affect soil water and thermal processes, as well as energy and water exchanges between the land surface and atmosphere. Reasonable representation of these processes in land surface models is very important to improving the understanding of land‐atmosphere interactions. In this study, mathematical descriptions of groundwater lateral flow, human water regulation, and FTFs were synchronously incorporated into a high‐resolution community land model, which is then named the Land Surface Model for Chinese Academy of Sciences (CAS‐LSM). With a series of atmospheric forcings and high‐resolution land surface data from the Heihe Watershed Allied Telemetry Experimental Research (HiWATER) program, numerical simulations of the period 1981–2013 using CAS‐LSM with 1‐km resolution were conducted for an endorheic basin, the Heihe River Basin in China. Compared with observations, CAS‐LSM reproduced the distributions of groundwater, evapotranspiration, and permafrost reasonably and well matched the temporal changes in ground temperature, heat fluxes, and FTFs. Results illuminate the temporal and spatial characteristics of frozen soil and the changes in the land‐atmosphere exchange of carbon, water, and energy. The permafrost and seasonally frozen soil were distinguished. In the seasonally frozen areas, the maximum soil frost depth increased by 0.65 mm/year within natural areas and decreased by 2.12 mm/year in human‐dominated areas. The active layer thickness increased 8.63 mm/year for permafrost. In the permafrost zone evapotranspiration and latent heat flux increased, and the sensible heat flux declined. In the human‐dominated areas water use raised the latent heat flux and reduced the sensible heat flux, net ecosystem exchange, and streamflow recharging to the eco‐fragile region in the lower reaches. Results suggested that the land surface model CAS‐LSM is a potential tool for studying land surface processes, especially in cold and arid regions experiencing human interventions.

The influence of mining on hydrology and solute transport in the Elk Valley, British Columbia, Canada

Previous research has established that surface mining affects downstream water quality. However, there remains limited information and understanding about the interaction of hydrology and geochemistry in surface mined areas. This paper presents an analysis of a multi-year dataset of geochemistry across a gradient of surface mining in an alpine environment. This work formed part of an R&D program examining the influence of mining on hydrological and water quality responses in the Elk Valley, British Columbia, Canada, aimed at informing effective management responses. Results indicate that water from waste rock dumps has a consistent ionic profile that is distinct from reference catchments. The export of weathering solutes did increase with the degree of mine affected area, and was consistently limited more strongly by transport capacity than by supply. Geographical location of waste rock within the catchment (headwaters or outlet) did not affect chemical concentrations or the timing with which chemically distinct waters reported to basin outlets. The dominance of transport capacity over source as limiting to solute export highlights the importance of limiting water input to waste rock piles. However, results strongly suggest that lateral water inputs do not mobilize significant amounts of weathering solutes.

Enhancing SWAT simulation of forest ecosystems for water resource assessment: A case study in the St. Croix River basin

Forests often cover a significant portion of a watershed and play an important role in water, carbon, and nutrient cycling. The widely-used Soil and Water Assessment Tool (SWAT) has not been thoroughly tested for simulating forest ecosystems and associated impacts on watershed-scale water resource assessment. Using the St. Croix River basin as a testbed, we examined SWAT simulations of forest biomass, net primary productivity (NPP), evapotranspiration (ET), and water yield with default and improved model settings. Model simulations with the default parameterization significantly underestimated forest biomass, ET, and NPP relative to benchmark data. With adjusted forest growth and development parameters, including radiation use efficiency, temperature control on plant growth, and leaf to biomass fraction, as well as a new phosphorus supply module, the SWAT model’s performance with respect to the above variables was substantially improved. These improvements also enhanced SWAT estimates of water yield, streamflow, and sediment loads at the watershed scale. Results of this study show the important role of forest ecosystems in watershed scale water balance and the connections between terrestrial and aquatic processes via lateral water and sediment fluxes. We suggested that watershed models, such as SWAT, should be assessed for both terrestrial and aquatic processes in order to provide credible water quantity and quality simulations at the watershed scale. Calibrated forest parameters and the phosphorus input algorithms will be applicable to future SWAT simulations of watershed hydrology.

Active slosh control and damping - Simulation and experiment

Future reignitable cryogenic upper stages perform long ballistic coasting phases in earth orbit. During those coasting phases, the tanks are loaded with liquid propellants and propellant sloshing occurs due to external disturbances or attitude change maneuvers. The sloshing propellant motion induces reaction forces and torques acting on the space vehicle structure, e.g. rocket upper stages. To keep the upper stage at the desired target attitude, the guidance, navigation, and control (GNC) algorithm commands thruster firings to counter the fluid forces. At ArianeGroup (AG), the Final Phase Simulator FiPS aims at simulating the coupling between fluid mechanics, GNC, and rigid body dynamics. To validate the coupling of GNC with linear lateral water sloshing, on ground experiments at the German Aerospace Center's Hexapod sloshing facility were performed. It was demonstrated that the developed control algorithm is able to damp the linear lateral sloshing within 4 s. FiPS simulations of the open and closed loop sloshing experiments showed that the experimental forces are matched with an uncertainty of less then 5% for open loop phases. For closed-loop phases the simulations match the experimental damping intervals with an accuracy of better than 5% and the force amplitude with an accuracy of about 20%.

SOLOS FLORESTAIS EM FRAGMENTO DE FLORESTA URBANA NA MATA DE DOIS IRMÃOS, RECIFE, PERNAMBUCO, BRASIL

O remanescente florestal que compõe o Parque Estadual Dois Irmãos (PEDI) é considerado como um dos maiores fragmentos florestais urbanos do Brasil. Há relatos no Parque da ocorrência de frequentes quedas de árvores sadias em condições naturais na reserva, o que pode comprometer seu equilíbrio natural e sua função como fragmento florestal urbano. É provável que este fenômeno possa estar associado com características químicas e físicas dos solos que compõem o PEDI. A presente pesquisa teve como objetivo avaliar química e fisicamente os solos do PEDI, identificando, mapeando e analisando o solo nas áreas de ocorrência de queda das árvores no locus da pesquisa. Foram mapeados 12 pontos de coleta de amostras em área representativa do PEDI. Amostras deformadas foram coletadas nas profundidades 0-0,10 m; 0,10-0,30 m; e 0,30-0,60 m e amostras não deformadas foram coletadas nas profundidades 0-0,05 m e 0,10-0,15 m. Nas amostras deformadas determinaram-se todos os atributos químicos e parte dos atributos físicos. Em amostras não deformadas determinaram-se apenas atributos físicos. Os solos do PEDI apresentaram baixa fertilidade natural. Mostraram reação ácida e com elevadas concentrações de Al3+ até 0,60 m de profundidade, que podem formar barreiras químicas que prejudicam o crescimento das raízes das plantas e podem estar causando a frequente queda de árvores no Parque. Os solos foram, em sua maioria, classificados como de textura argilosa a muito argilosa, muito permeáveis ao movimento vertical e lateral de água. Apresentaram uma elevada variabilidade na condutividade hidráulica e redução abrupta de umidade volumétrica com aplicação de pequenas tensões em camadas superficiais, além de maior retenção de água pelo Latossolo em subsuperfície. Com a finalidade de ampliar as informações e criar um banco de dados para estudos futuros, sugere–se o monitoramento das espécies mais vulneráveis à queda, além de analisar outros elementos químicos e físicos do solo do PEDI, como a abertura de perfis para compreender a dinâmica das raízes pivotantes.

Desain dan fabrikasi patok rintangan lapangan golf bahan polymeric foam yang diperkuat serat tandan kosong kelapa sawit

A golf course with obstacles in the forms of water obstacle and lateral water obstacle marked with the stakes which are called golf course obstacle stake in this study. This study focused on the design and fabrication of the golf course obstacle stake with a solid cylindrical geometry using EFB fiber-reinforced polymeric foam composite materials. To obtain the EFB fiber which is free from fat content and other elements, EFB is soaked in the water with 1% (of the watre total volume) NaOH. The model of the mould designed is permanent mould that can be used for the further refabrication process. The mould was designed based on resin-compound paste materials with talc powder plus E-glass fiber to make the mould strong. The composition of polimeric foam materials comprised unsaturated resin Bqtn-Ex 157 (70%), blowing agent (10%), fiber (10%), and catalyst (10%). The process of casting the polimeric foam composit materials into the mould cavity should be at vertical casting position, accurate interval time of material stirring, and periodical casting. To find out the strength value of the golf course obstacle stake product, a model was made and simulated by using the software of Ansys workbench 14.0, an impact loading was given at the height of 400 mm and 460 mm with the variation of golf ball speed (USGA standard) v = 18 m/s, v =35 m/s, v = 66.2 m/s, v = 70 m/s, and v = 78.2 m/s. The clarification showed that the biggest dynamic explicit loading impact of Fmax = 142.5 N at the height of 460 mm with the maximum golf ball speed of 78.2 m/s did not experience the hysteresis effect and inertia effect. The largest deformation area occured at the golf ball speed v = 66.2 mm/s, that is 18.029 mm (time: 2.5514e-004) was only concentrated around the sectional area of contact point of impact, meaning that the golf course obstacle stakes made of EFB fiber-reinforced polymeric foam materials have the geometric functional strength that are able to absorb the energy of golf ball impact. Keywords: Composite, Polymeric Foam, EFB Fiber, Tension Distribution, Ansys Workbench 14.0

A new method for scour monitoring based on fiber Bragg grating

This paper introduces feasibility study of scour depth determination based on lateral soil pressure measurement. The method is used for sensors which are made of fiber Bragg grating (FBG) as the sensing element, where the front side is under soil pressure, and the back is under the water pressure. It can accurately monitor the lateral earth pressure by measuring the front and back of the pressure difference. The pressure in the horizontal direction is only water pressure in water, while it consists of lateral earth pressure and pore water pressure in the soil. Therefore the depth of the mud surface can be calculated by a plurality of sensors at different depth. The method can feedback erosion and siltation of hydraulic structure in time, and provide reliable data support for the safe operation of the hydraulic structure.