Modeling of Multi-Freedom Ship Motions in Irregular Waves with Fuzzy Neural Networks

1 .IntroductionAshiptravelingatseaundergoesundesirablewave inducedmotions ,namely ,surge ,sway ,heav ing ,rolling ,pitchingandyaw .Thesemotionsoftencauseproblemstothecrew ,theonboardequip mentand ,intheworstcase ,thesafetyofthevessel.Tominimizethewave inducedshipmotions ,controlsystemsmaybeapplied .Theaccuratemodelingofshipmotionsisthereforeveryimportantforshipdesignanddesignofmotioncontrolsystems .Manyresearchershavedevelopedshipmotionpredictionmethodsbasedonthepotentialflowtheo ries (Dong ,…     

1999年以来台湾及邻近海域7.5级以上强震前的条带现象

中国台湾地区地处欧亚板块与菲律宾海板块之间,地震活动频繁．本文报道了 我国台湾地区及其邻近海域1985～2002年间5．5级以上地震的条带内外频度比分 布,并着重研究了1999—2002年中发生的3次7．5级以上地震前的条带现象．其结 果表明:台湾地区近期发生的3次7．5级以上大地震前,5．5级以上地震呈条带分 布．这些条带符合条带内地震个数Nin≥6的条件,符合条带内、外频度比Nin／(Nin Nout)≥75％的条件,也符合条带长宽比大于5的要求,只是与板内地震条带相比,条 带的长度较短．     

广饶县河流污染带地下水水质现状评价与污染分析

多年来由于接纳上游和境内工业、生活污废水,淄河、阳河、织女河三条河流大部分时间水质为劣V类,沿河两测形成2km左右的浅层地下水污染带。对污染带内地下水水质现状进行评价与分析、应用模糊综合评价法进行污染程度评价。得出的结论是河流两岸浅层地下水水质由以优良或良好为主变为以较差或极差为主,污染和微污染的地下水井占81．2％,石油类、亚硝酸盐氮、氨氮、挥发酚、硝酸盐氮、高锰酸盐指数等主要污染参数超标率均在30％以上。     

Spatial assessment and redesign of a groundwater quality monitoring network using entropy theory, Gaza Strip, Palestine

Using entropy theory, a methodology was developed for the evaluation and redesign of groundwater quality monitoring wells in the Gaza Strip in Palestine. Essential to the methodology is the development of a Transinformation Model (TM) which yields the amount of information transfer and the dependency between the wells as a function of distance. The TM parameters, such as the minimum transinformation and the range, were employed for evaluating the network which revealed that most of the distances between wells were less than the range. It also indicated that a high percentage of redundant information existed in the network. Therefore, the network was reduced by superimposing a square pattern over the monitored area and selecting one well per square block in a stratified pattern. The methodology was tested using the chloride data collected from 1972–2000 from 417 groundwater quality monitoring wells in the Gaza Strip. The number of the groundwater quality monitoring wells in the Gaza Strip was reduced by 53%, while there was 26% redundant information based on the minimum existing distance between wells. This methodology is meant to help monitor the groundwater quality (salinity) in the Gaza Strip.     

CELLULOSE DECOMPOSTION IN TROPICAL PEAT SWAMPS

Given that organic soil is a complex substrate and there are many environmental factors which directly or indirectly control its decomposition processes, the use of standard substrate simplify the system in that the effect of substrate quality could be eliminated and influence of certain environmental conditions such as edaphic factors, acidity and moisture could be focused on. In addition to the forest floor, decomposition potential down the peat profile can also be examined. Cotton strip assay was used to estimate decomposition potentials in tropical peat swamp occupied by different Shorea Albida peat swamp forest communities, The 'Alan Batu' , the ' Alan Bunga' , the 'Alan Padang' and the ' mixed Alan' forest communities.Greatest decay rates on the peat surface took place during the wet period. The moist condition of the wet months appeared to favour the growth and stimulate activities of decomposer population and soil invertebrates. Generally, 50% of cotton tensile loss is achieved after four weeks     

露天铁矿禀赋优势等级划分和合理矿业税费的研究

利用自组织神经网络，对我国主要露天铁矿进行了禀赋优势等级划分。权利金大小的确定，应以铁矿资源的资产评估为基础，资产评估时合理成本的取值应是评估矿山所在同一等级矿山的平均成本。矿产资源的原有价值是权利金征收的对象。最后以歪头山为实例，计算了铁矿资源的原有价值和权利金。结果表明，目前对歪头山铁矿征收的税费仍然偏高。     

Optimization of the Sampling Technique for the Determination of Dissolved Hydrogen in Groundwater

In this study a field‐sampling technique for dissolved hydrogen (H₂) in groundwater will be presented which allows the transport of gaseous samples into the laboratory for further analysis. The method consists of transferring the headspace trapped in a gas‐sampling bulb which is continuously purged by groundwater into previously evacuated vials using a gas‐tight syringe. Three transfer steps with preceding evacuation of the vial led to a H₂‐recovery of 100 % in laboratory experiments. The method has been applied to determine H₂ concentrations in an aquifer contaminated with chlorinated solvents. Tests concerning the effect of different pumping techniques on H₂ concentrations revealed that most reliable values were obtained with a bladder pump, while an electrically driven submersible pump generated considerable amounts of hydrogen due to electrochemical interactions with the sampled water. Concentrations of dissolved hydrogen in field and laboratory samples were about two orders of magnitude higher when sampling was performed with the electrically driven submersible pump compared to sampling with the bladder pump and a peristaltic pump. Lab experiments with a Plexiglas reservoir to produce H₂‐enriched water were used to study the effect of two tubing materials (PVC, polyamide) on H₂ losses. PVC tubing turned out to allow transfer of H₂‐enriched water over 25 m without significant losses, while PA‐tubing was not suitable for sampling of H₂.     

Vertical vibration of a rigid strip footing on viscoelastic half-space

This paper presents an analytical method for modeling the dynamic response of a rigid strip footing subjected to vertical-only loads. The footing is assumed to rest on the surface of a viscoelastic half-space; therefore, effects of hysteretic soil damping on the impedance of the foundation and the generated ground vibrations are considered in the solution. To solve the mixed boundary value problem, we use the Fourier transform to cast a pair of dual integral equations providing contact stresses, which are solved by means of Jacobi orthogonal polynomials. The resulting soil and footing displacements and stresses are obtained by means of the Fourier inverse transform. The solution provides more realistic estimates of footing impedance, compared to existing solutions for elastic soil, as well as of the attenuation of ground vibrations with distance of the footing. The latter is important for the estimation of machine vibration effects on nearby structures and installations.     

架子台沟低品位铅锌矿原生晕地球化学特征及深部矿产预测

对架子台沟一带1:50 000化探异常检查中,地表发现有铅锌矿化显示,经对激电测深异常深部钻探验证发现有低品位锌矿(化)体。通过系统采集0号勘探线上的2个钻孔中岩石、矿石样品,进行原生晕特征研究分析表明:矿体近矿元素为Ag、Pb、Zn、Cd,尾矿元素为W、Sn、Bi;轴向分带序列由上至下为:Pb-Au-Ag-Mo-Bi-Sn-Cu-Cd-W-Zn。对成矿元素与相关金属元素进行聚类分析、因子分析,并结合激电测深结果,认为在矿体的侧部、深部仍可能有盲矿体。     

Analytic element modelling for strip aquifers

The Analytic Element Method (AEM) provides a convenient tool for groundwater flow analysis in unbounded continuous domains. The AEM is based on the superposition of analytic functions, known as elements, useful at both regional and local scales. In this study, analytic elements for strip aquifers are presented. Such aquifers occur in riverine or coastal deposits and in outcrop zones of confined aquifers. Local flow field is modelled indirectly, using a reference plane related to the aquifer domain through the Schwarz‐Christoffel transform. The regional flow is obtained as a solution of the one‐dimensional flow equation. The proposed methodology was tested by modelling two hypothetical situations, which were compared to exact solutions. It is shown that regional boundaries can be reproduced exactly while local fields are adequately reproduced with analytic elements. The developed elements are applied to simulate a real flow field in northeastern Brazil showing good agreement with measured water levels. Copyright © 2011 John Wiley & Sons, Ltd.