Stochastic inversion for the roll gyradius second moment mass property in ships at full-scale and model-scale     

《Applied Ocean Research》2017

In current Naval Architecture practice, employing static considerations is an important and necessary step in assessing ship stability and seakeeping properties (e.g. inclining experiments, load line regulations, range of stability calculations). However, damaged vessels and vessels operating in heavy weather or in conditions where topside icing is a concern may require an additional assessment of stability that considers dynamic effects. Within such contexts, the actual (i.e. current) second moment properties of the vessel mass become very important in the associated equations of motion for a given ship. One such critical second mass moment property is the roll gyradius, as it is closely related to the occurrence of capsizing. The present paper furnishes a means for reckoning the actual roll gyradius of a given ship operating within a seaway. The approach hinges on the formulation and solution of a stochastic inverse problem that leverages existing seakeeping software against the shipboard inertial measurement unit (IMU) telemetry. The method is demonstrated at full-scale and validated at model scale.  相似文献   

贝叶斯准则在农牧交错带农业种植决策中的应用     

赵慧颖  刘斌  徐桂梅  赵恒和  田辉春 《气象科技》2007,35(5):703-707

为揭示呼伦贝尔市农牧交错带农业种植结构的实质,利用贝叶斯准则及该区气象资料,主要作物大豆、玉米和小麦的种植面积及产量资料进行了分析。结果表明:①该区种植作物的经济效益大小排序为:大豆>玉米>小麦;②如果预报有干旱发生,则作物种植比例大小排序为:玉米>大豆>小麦;如果预报有洪涝或低温冷害发生,则作物种植比例大小排序为:大豆>玉米>小麦;③设计了两种在干旱气候年型下的作物种植比例最优方案,产值可分别增加3%和5%以上。  相似文献   

井间地震在济南市小冶睦里煤矿采空区勘查中的应用          下载免费PDF全文

宋津宇  白新飞  张晓彤  张军  徐蒙  于超  张松林  翟立民 《山东国土资源》2022,38(12):36-41

以济南市章丘区小冶睦里地区石炭-二叠纪含煤地层采空区为研究对象,采取资料收集、井间地震、钻探验证等方法手段,分析井间地震层析成像技术对采空区解译推断的有效性。结果表明,井间地震层析成像速度反演结果体现为高速分布的区域,推断为基岩完整区域;速度反演结果体现为低速分布的区域,推断为采煤采空区域。经与钻探工程比对,井间地震层析成像技术推断的采空区位置与钻探揭露深度较为吻合,表明井间地震层析成像技术在济南市章丘区小冶睦里煤矿采空区勘查中具有较高的可行性和实用性,为该地区同类型的采空区勘查提供了参考依据。  相似文献   

Chronology of the Paleolithic site of Xibaimaying in the Nihewan Basin,North China,inferred from optical dating of fine-grained quartz     

《Quaternary Geochronology》2022

The Paleolithic site of Xibaimaying (XBMY), once considered the youngest flake tool site within the Nihewan Basin, North China, is an ideal archive to study the chronological relationship between flake tool and microblade industries in the Nihewan Basin during the Upper Palaeolithic, but the previous ages obtained for the site remain controversial. From 2015 to 2019, three areas at two archaeological localities (XBMY-I and XBMY-II) of the site were excavated, and well-preserved fossils and flake tools were unearthed. In this study, a total of 26 samples were collected from the three areas for optically stimulated luminescence (OSL) dating using a single-aliquot regenerative-dose (SAR) protocol on fine-grained quartz. A shared ‘Standardized growth curve’ (SGC) for a section was constructed to reduce the time required for D_e estimation. The long-term weighted average water contents of the samples during their burial period were estimated based on the in-situ water contents of continuous samples from a nearby borehole. All the OSL ages were modelled via Bayesian statistics using the OxCal software, modifying the OSL ages with stratigraphic constraints in each section. The results show that the cultural layer bearing flake tool assemblages falls within the period of 122–36 ka, indicating that the flake tool industry of the Xibaimaying site is comparable to that of the Youfangbei (108–86 ka), Banjingzi (∼86 ka) and Xinmiaozhuang (75–63 ka) sites, rather than the youngest one in the Nihewan basin, which explains why the Xibaimaying site is characterized as pure flake tool culture without any ‘advanced’ trait. The OSL dating results also shed new light on the study of sedimentary processes in the Xibaimaying site area. The different deposition rates (0.01–1.61 mm/a) for the sediments at the three newly excavated areas imply complex geomorphologic processes in the site area.  相似文献