An Experimental Study on A Trapezoidal Pendulum Wave Energy Converter in Regular Waves     

王冬姣  邱守强  叶家玮 《海洋工程》2015,29(4):623-632

Experimental studies were conducted on a trapezoidal pendulum wave energy converter in regular waves. To obtain the incident wave height, the analytical method (AM) was used to separate the incident and reflected waves propagating in a wave flume by analysing wave records measured at two locations. The response amplitude operator (RAO), primary conversion efficiency and the total conversion efficiency of the wave energy converter were studied; furthermore, the power take-off damping coefficients corresponding to the load resistances in the experiment were also obtained. The findings demonstrate that the natural period for a pendulum wave energy converter is relatively large. A lower load resistance gives rise to a larger damping coefficient. The model shows relatively higher wave energy conversion efficiency in the range of 1.0?1.2 s for the incident wave period. The maximum primary conversion efficiency achieved was 55.5%, and the maximum overall conversion efficiency was 39.4%.  相似文献   

轨道交通整体床道测量     

管鑫 《测绘与空间地理信息》2015,(2):202-203,206

本文从地铁床道测量的意义出发,结合轨道交通八号线二期工程,介绍了轨道交通整体床道测量技术设计、作业方法、数据采集、成果分析,以及在作业过程中的注意事项.  相似文献   

AutoCAD自动加载VBA程序研究     

魏磊  田磊 《测绘与空间地理信息》2015,(9)

VBA语言是进行AutoCAD二次开发的重要手段之一。本文主要探讨了AutoCAD平台下如何自动加载VBA程序,详细介绍了当前常用的自动加载VBA程序的方法,对这些方法在使用过程中的优点和局限性进行了对比分析,最后引入了使用代码操作注册表加载VBA程序的方法。  相似文献   

深部盐岩层绳索取心钻井液技术研究与应用   总被引：1，自引：0，他引：1  

郑文龙 《地质与勘探》2015,51(5):977-983

由于次生应力场的作用以及盐岩易溶于水的特性,深部盐岩层钻进存在岩层蠕动、钻井液易遭受盐钙侵等问题;钻进参数选择不合理易导致盐岩层取心效率低、岩心冲蚀严重。本文以河南省叶舞凹陷ZK3井为例,采用石油钻井与绳索取心相结合的措施,解决了普通固体矿产钻探设备在深部地层取心中效力不足的问题;通过阳离子交换容量测定、矿物组分鉴定、钻井液体系优选及性能测试等试验,确定了针对上部泥岩地层的聚合物钻井液体系,中部含膏泥岩的欠饱和盐水钻井液体系,下部盐岩层取心段的饱和盐水钻井液体系。通过确定合适的钻井液密度与临界环空返速,可以有效控制深部盐岩层蠕变与井壁冲蚀,适度提高排量以成倍提高钻进速度。钻进过程中钻井液性能稳定,体系转换顺利且性能易于调整,为取心任务的顺利完成提供了有力保证。  相似文献   

均质土岸坡崩塌与河床冲淤交互过程试验     

李国敏  余明辉  陈曦  胡呈维 《水科学进展》2015,26(1):66-73

在弯道水槽中展开系列试验,研究水力冲刷过程中均质土岸坡冲刷崩塌输移与河床冲淤过程及其影响因素。该过程及变化特征可描述为:水下坡面侵蚀及坡脚淘刷导致岸坡失稳崩塌;暂时堆积在凹岸坡脚处的崩塌体加剧附近水流紊动程度利于其输运与分解;分解后较粗的颗粒随弯道螺旋流以推移质形式被输移至下游凸岸落淤,较细的颗粒大部分都随水流以悬移质形式被携带至下游出口;水流结构随岸坡及河床变形而调整;如此循环往复。试验成果进一步表明:冲刷状态下,试验材料黏性越小、近岸流速越大、作用时间越长,岸坡冲刷崩塌量及河床冲刷量都越大;同条件下岸坡冲刷崩塌总量大于河床冲刷总量,且河床相对冲刷率随岸坡冲刷崩塌量的增大而减小,数值范围为0.40~0.92。  相似文献   

黄河内蒙古河段输沙量与淤积量计算方法   总被引：2，自引：0，他引：2       下载免费PDF全文

吴保生  刘可晶  申红彬  周丽艳 《水科学进展》2015,26(3):311-321

基于多沙河流"多来多排"输沙基本公式,建立了考虑上站来沙量、前期累计淤积量、临界输沙水量及干支流泥沙粒径影响的输沙量一般表达式。进而根据黄河内蒙古河段1953—2010年实测水沙资料,得到了内蒙古巴彦高勒—头道拐全河段及巴彦高勒—三湖河口和三湖河口—头道拐分河段的年输沙量公式,并根据输沙率法采用建立的输沙量公式计算了各河段1953—2010年的逐年冲淤量。选取三湖河口—头道拐河段的计算结果分析表明,在输沙基本公式基础上增加前期累计淤积量、临界输沙水量及干支流泥沙粒径参数,所得公式计算的年冲淤量与实测值之间的相关系数R2由基本公式的0.41依次提高到0.50、0.75和0.80,说明在基本公式基础上进一步考虑这些参数的必要性。此外,全河及分河段输沙公式计算所得输沙量及各河段冲淤量和累计淤积量与实测值的符合程度均较好,表明建立的输沙公式能够用于不同水沙条件下的输沙量和冲淤量计算,可为分析内蒙古河段的输沙特性和长期淤积趋势提供参考。  相似文献   

三峡水库运行初期的泥沙淤积特点   总被引：3，自引：0，他引：3       下载免费PDF全文

李文杰  杨胜发  付旭辉  肖毅 《水科学进展》2015,26(5):676-685

针对三峡蓄水运行后的泥沙淤积问题,基于实测资料,采用输沙率法和断面法分析了三峡水库运行初期的泥沙淤积特点.结果表明:三峡水库2003—2013年泥沙淤积总量为15.31亿t,平均排沙比为24.5%,均较论证阶段降低;库区泥沙淤积主要分布在常年回水区的宽谷和弯道河段,宽谷段全断面发生淤积、弯道断面流速较小一侧淤积、峡谷无累积性淤积;常年库区近坝段泥沙淤积速度逐年减小,而上段泥沙淤积速度则呈增大趋势;淤积物粒径沿程分选不明显,常年回水区淤积物中值粒径多在0.01 mm以下.库区峡谷段深泓线无明显变化、尚未出现泥沙淤积三角洲、库尾泥沙淤积上延和尾水抬高不明显,据此初步推断峡谷河段存在富余挟沙力而成为局部侵蚀基准面,整个库区将无统一平衡比降的趋势.  相似文献   

竖向高荷载作用下大直径超长钻孔灌注桩承载性能试验     

桑伟锋 《世界地质》2020,39(1):127-134

通过机场—西华高速大直径超长钻孔灌注桩大吨位竖向单桩静载试验,分析了该地区大直径超长钻孔灌注桩的承载性状以及荷载传递机理。试验结果表明:试桩的Q-S曲线呈缓变型,桩端承载力占总荷载的比例均<10%,即均表现为摩擦桩特性;试桩的侧摩阻力自上而下逐步发挥,侧摩阻力和桩端阻力异步发挥且互相耦合;大直径超长钻孔灌注桩桩侧摩阻力的发挥与土层性质、土层埋深及桩顶荷载水平有关;在高荷载作用下桩侧上部土层摩阻力具有不同程度的软化现象,而中下部土层侧摩阻力具有不同程度的强化现象,甚至即使在最大加载情况下,桩身下部土层的侧摩阻力也并未完全发挥,因此在根据规范计算超长桩承载力时,不同深度土层的侧摩阻力应乘以相应不同的修正系数。  相似文献   

Evaluation of Sludge Digester Effluent as Feeding Solution for the Enrichment of Anammox Bacteria     

&#x;pek elen‐Erdem 《洁净——土壤、空气、水》2020,48(3)

The aim of this study is to evaluate the feasibility of sludge digester effluent as feeding solution to enrich anaerobic ammonium oxidation (anammox) bacteria. The performance of the two parallel pilot scale‐upflow packed bed anammox reactors (UPBAn1 and UPBAn2) are examined in terms of the enrichment of anammox bacteria. The control experiment is set up conducting synthetic wastewater as feeding solution in the UPBAn1 reactor whereas, the sludge digester effluent is fed to the nitritation reactor and then the partially nitrated digester effluent to the UPBAn2 reactor. Anammox activities are evaluated by mass balances based on ammonium (NH₄⁺), nitrite (NO₂^?), and nitrate (NO₃^?) analysis and NRR. Microbial community of anammox bacteria is analyzed using real‐time polymerase chain reaction (PCR). The results demonstrate that UPBAn 1 and UPBAn2 reactors are successfully enriched on days 64 and 40 with NRRs of 19.54 and 19.43 g N m^?3 per day, respectively. This study reveals that both synthetic wastewater and digester effluent are suitable for the enrichment of anammox bacteria; however, digester effluent as feeding solution for enrichment of anammox bacteria based on the ease of process control and process stability is more advisable.  相似文献   

Effects of long-term cyclic horizontal loading on bucket foundations in saturated loose sand     

《Applied Ocean Research》2019

A 1-g model experimental study was conducted to investigate the accumulated rotations and unloading stiffness of bucket foundations in saturated loose sand. One-way horizontal cyclic loading was applied to model bucket foundations with embedment ratios 0.5 and 1.0. Up to 10⁴ cycles of loading were applied at a frequency of 0.2 Hz varying load amplitudes. The accumulated rotation of the bucket foundations increased with the number of cycles and the load amplitudes. Empirical equations were proposed to describe the accumulated rotation of the foundations. The unloading stiffness of foundations increased with the number of cycles but decreased with an increase in load amplitude. The initial unloading stiffness of L/D = 1.0 (L is skirt length; D is foundation diameter) was approximately twice that of L/D = 0.5. Excess pore water pressure difference of 50% was observed between L/D = 0.5 and 1.0. The suction and static capacity of the bucket increased with increase of bucket embedment ratio with a difference of 69.5% and 73.6% respectively between L/D = 0.5 and 1.0.  相似文献