SCOUR RATE FORMULA

I.INTRODUCTIONhiverchannelsaresubjecttocontinuouschangeingeometryduetoillteraCtionbetWeentheflowanderodibleboundaries.Ofconcerntothedesignersofoilpipelinesacrossariver,bridgesandhydraulicworksistheproblemofscourwhichcanunderminetheStructures.Scouratsiteofbridgesandhydraulicworksoccursduetoconstrictedflowandexistenceofbridgepiers.SuchatabOfscouroccursonlyinashortsection,usuallyillthesameorderofthelengthofthehydraulicworksorbridges.Therefore,thispatternofscouriscalledlocalscour.Man}rresea…     

Experimental Study on Hysucat Vessels

The paper contains the results of an experimental study on a planing catamaran. The aim of this study is resistance reduction with application of foils. Experiments are performed in different conditions and the results are compared with each other. The foils are used in different configurations and it is concluded that unsuitable design may result in larger resistance. But, it is also shown that, for a good design, the resistance may be reduced considerably.     

Mineralization at the Wallah Wallah Silver Mine,Rye Park,New South Wales and its metallogenic significance

Summary The Wallah Wallah lead-zinc-silver deposit near Rye Park, New South Wales, Australia, consists of epigenetic, vein-type mineralization developed in deformed Ordovician host rocks by deposition from medium temperature (280–380°C), low salinity fluids. In addition to dominant sphalerite, galena and arsenopyrite, the ores contain Ag-rich tetrahedrite, Ag-bearing stannite, teallite and trace cassiterite. The mineralogy and geochemistry of the ores, together with features of the geological setting and the regional metallogeny indicate that the oreforming fluids and metals were largely derived from a fractionated granitoid source, in or along the western margin of the Wyangala Batholith. The deposit appears to be part of a wider, but sporadically developed, magmatic-hydrothermal mineralising system, not previously recognised in this area.With 5 Figures     

Geologic relationships and mineralization of peralkaline/alkaline granite-syenite of the Zargat Na’am ring complex, Southeastern Desert, Egypt

Tungsten-bearing hydrothermal veins range from tensional veinlets to lodes containing multiple injections of hydrothermal quartz veins. Major composite lodes display greisen alteration envelopes characterized by enrichments in volatiles, K2O, Al2O3, Rb, L…     

Countermeasures for and Experiences in Seismic Hazard Mitigation in Uganda

For earthquake-prone countries of the world, it is crucial to develop countermeasures and to share experiences in seismic hazard mitigation. The measures for seismic hazard mitigation are related to many factors, e.g., social, economic, and political. Research focused on modern science and technology paves the way for a better understanding of the earthquake phenomenon and helps to plan against its effects in seismically active areas.In this paper, we consider some of the events that occurred in earthquake-prone countries, both developing and developed, which caused devastation to the society and economy. These are mainly major events that have affected a considerable portion of the gross domestic product of these economies.Measures to mitigate seismic hazard are stressed and suggested. In addition, experiences in seismic hazard mitigation in Uganda and the rest of the world are discussed in general terms. Attention is given to geotectonic settings as well as the work of seismic hazard and disaster mana     

Predicted Effects of Climatic Change on Distribution of Ecologically Important Native Tree and Shrub Species in Florida

A previously developed plant species-climatic envelope model was evaluated further and used to predict effects of hypothesized climatic change on the potential distribution of 124 native woody plant species in Florida, U.S.A. Twelve scenarios were investigated. These included mean annual temperature increases of 1 °C or 2 °C, achieved either by equal 1 °C or 2 °C increases on a monthly basis throughout the year, or by disproportionately larger seasonal increases in winter and smaller ones in summer. The various temperature increases were then combined with each of several precipitation changes, ranging from +10% to –20%, to produce the final set of scenarios. More detailed analysis involving six of the scenarios and a subset of 28 representative, ecologically important species suggested that (1) large decreases in the Florida range of many temperate species would result if 1 °C warming occurs predominantly in winter or with a 20% decrease in annual precipitation, or (2) if 2 °C warming occurs, with or without decrease in annual precipitation, and regardless of whether there is a uniform monthly warming pattern or one that is higher in winter than in summer. Available information concerning other factors that might also affect climatic-change responses suggests that these large predicted impacts on temperate Florida species may be underestimates. Subtropical Florida species will tend to move north and inland with warming but extensive human assistance may be needed, if they are to realize their newly expanded, potential natural ranges.     

Tests on Application of Soil Magnetic and Integrated Gamma Ray TLD and TC Methods to the Exploration of Sandstone-Type Uranium Deposits

This paper introduces the test results of the soil magnetic survey and the integrated gamma-ray TLD and TC methods for sandstone-type uranium exploration and describes the prospecting mechanism. The tests have proved that these approaches have yielded good results on classifying the sedimentary fades, defining the redox transitional zones and reflecting deep mineralization information. They may probably become new methods on searching for sandstone-type uranium deposits.     

Comparison of Extrapolation and Interpolation Methods for Estimating Daily Photosynthetically Active Radiation(PAR)——A Case Study of the Poyang Lake National Nature Reserve,China

Measurements of photosynthetically active radiation(PAR),which are indispensable for simulating plant growth and productivity,are generally very scarce.This study aimed to compare two extrapolation and one interpolation methods for estimating daily PAR reaching the earth surface within the Poyang Lake national nature reserve,China.The daily global solar radiation records at Nanchang meteorological station and daily sunshine duration measurements at nine meteorological stations around Poyang Lake were obtain...     

地球南北半球的非对称性

依据新的计算分析和空间观测数据,进一步论述了地球南北半球的非对称性. 全球热散失量的计算得出,南半球高出北半球33髎;南半球地幔热散失量是北半球的2倍. 比较南北半球S波速度分布,得出南半球的上地幔为低速、高温,北半球的上地幔为高速、低温. 计算地幔各层的质心位置发现,地球的质心偏于北半球. 计算地球经、纬圈长度的年变化率表明,南半球在扩张,北半球在收缩. 用空间大地测量数据的检测结果证实,南半球处于扩张状态,北半球处于压缩状态. 对地球的非对称性作了初步的动力学解释.     

Antioxidant response of the seagrass Posidonia oceanica when epiphytized by the invasive macroalgae Lophocladia lallemandii

The aim was to evaluate the antioxidant defences and the occurrence of oxidative damage in Posidonia oceanica under a stress situation due to the epiphytism of the invasive macroalgae Lophocladia lallemandii. P. oceanica leaves were collected in the absence (control station) and in the presence of the epiphytic algae L. lallemandii and the antioxidant enzyme activities, markers of oxidative damage, and hydrogen peroxide production were determined. Antioxidant enzyme - catalase, glutathione peroxidase and superoxide dismutase - activities were significantly higher in Posidonia epiphytized by L. lallemandii. Malondialdehyde, protein carbonyl derivates, and glutathione levels were also higher in L. lallemandii epiphytized P. oceanica leaves compared to control samples. The production of hydrogen peroxide was also significantly increased when Posidonia was epiphytized by L. lallemandii. The invasion of P. oceanica meadows by L. lallemandii appeared to induce oxidative stress in the seagrass as evidenced by increased levels of oxidative stress markers and antioxidant defences.