Experimental characterization,design and modelling of the RBRL seismic‐isolation system for lightweight structures

The Rolling‐Ball Rubber‐Layer (RBRL) system was developed to enable seismic isolation of lightweight structures, such as special equipment or works of art, and is very versatile, a great range of equivalent natural frequencies and coefficients of damping being achievable through choice of the system parameters. The necessity to have a simple and effective design procedure has led to a new parametric experimentation at Tun Abdul Razak Research Centre (TARRC) on the rolling behaviour of the RBRL system and load–deflection behaviour of the recentering springs. The experimental results, together with theories for the rolling resistance of a loaded steel ball on a thin rubber layer and the lateral load–deflection behaviour of cylindrical rubber springs, are used to develop a general design method for the RBRL system, which allows the system to be tailored to the specific application. Sinusoidal test results are presented for the small‐deflection behaviour of the system, influenced by the presence of a viscoelastic depression on the rubber tracks beneath each ball, and an amplitude‐dependent time‐domain model is proposed, based on these results and on the steady‐state behaviour of the system. The model is validated through comparison with previously performed shaking‐table tests. Attention is here restricted to uniaxial behaviour. Copyright © 2016 John Wiley & Sons, Ltd.     

石花形恐龙幻迹：中国重庆綦江区下白垩统夹关组的罕见遗迹化石

在中国重庆綦江区虎山足迹点发现了2个大型恐龙天然足模化石,化石赋存于砂质富集的夹关组的一悬崖底面。它们属于罕见的幻迹,同类足迹也发现于韩国和北美白垩系足迹点。放射状、同心及半脆性形变使这些幻迹具有切断状或网状外观,有时呈现出类似裂断花或菜花的形态。这正是当地“石头开花”民间传说的来源。这些特征表明,造迹者必然是恐龙,同时也清晰地展现了其外形态学特征。     

An Important Ornithischian Tracksite in the Early Jurassic of the Shenmu Region,Shaanxi, China

A large track site with multiple,well-preserved trackways of an Early Jurassic quadrupedal ornithischian dinosaur is the first report of Moyenisauripus-like trackways from Asia,herein named Shenmuichnu...     

我国沙尘暴的时空分布规律及其源地和移动路径

利用1971-1996年的地面气象记录月报和地面天气图资料，系统分析了我国沙尘暴的年际变化趋势及其时空分布规律，研究了沙尘暴的移动路径和源地，结果表明：1971-1996年，除青海、内蒙古的部分地区及北京等地外，我国各地沙尘暴发生的总次数呈现明显的下降趋势；根据沙尘暴的起源，可将发生在我国的沙尘暴天气过程分为外源型和内源型沙尘暴2类；外源型沙尘暴的移动路径主要包括北路和西路2条，其中北路沙尘暴侵我国的范围在西起新疆东部的哈密，东至内蒙古锡林郭勒盟的中蒙边境，西部沙尘暴入侵我国的范围在南疆和北疆的部分地区；我国沙尘暴源地主要集中在南疆和北疆的沙漠及其周边地区，甘肃河西走廓和内蒙古干燥沙漠及青海柴达木盆地等地。     

Catchment‐scale contribution of forest roads to stream exports of sediment,phosphorus and nitrogen

The relative contribution of forest roads to total catchment exports of suspended sediment, phosphorus, and nitrogen was estimated for a 13 451 ha forested catchment in southeastern Australia. Instrumentation was installed for 1 year to quantify total in‐stream exports of suspended sediment, phosphorus, and nitrogen. In addition, a total of 101 road–stream crossings were mapped and characterized in detail within the catchment to identify the properties of the road section where the road network and the stream network intersect. Sediment and nutrient generation rates from different forest road types within the catchment were quantified using permanent instrumentation and rainfall simulation. Sediment and nutrient generation rates, mapped stream crossing information, traffic data and annual rainfall data were used to estimate annual loads of sediment, phosphorus, and nitrogen from each stream crossing in the catchment. The annual sum of these loads was compared with the measured total catchment exports to estimate the proportional contribution of loads from roads within the catchment. The results indicated that 3·15 ha of near‐stream unsealed road surface with an average slope of 8·4% delivered an estimated 50 t of the 1142 t of total suspended sediment exported from the catchment, or about 4·4% of the total sediment load from the forest. Stream discharge over this period was 69 573 Ml. The unsealed road network delivered an estimated maximum of 22 kg of the 1244 kg of total phosphorus from the catchment, or less than 1·8% of the total load from the forest. The average sediment and phosphorous load per crossing was estimated at 0·5 t (standard deviation 1·0 t) and 0·22 kg (standard deviation 0·30 kg) respectively. The lower proportional contribution of total phosphorus resulted from a low ratio of total phosphorus to total suspended sediment for the road‐derived sediment. The unsealed road network delivered approximately 33 kg of the 20 163 kg of total nitrogen, about 0·16% of the total load of nitrogen from the forest. The data indicate that, in this catchment, improvement of stream crossings would yield only small benefits in terms of net catchment exports of total suspended sediment and total phosphorus, and no benefit in terms of total nitrogen. These results are for a catchment with minimal road‐related mass movement, and extrapolation of these findings to the broader forested estate requires further research. Copyright © 2007 John Wiley & Sons, Ltd.     

Dinosaur tracks in the Kokorkom Desert,Candeleros Formation (Cenomanian,Upper Cretaceous), Patagonia Argentina: Implications for deformation structures in dune fields

The Kokorkom desert extended over an area of 826 km² in the central-west sector of Neuquén and Río Negro provinces along the area of the backbulge basin within the Andean Foreland basin in the Neuquén Basin. Its deposits constitute the middle-upper section of the Candeleros Formation (Cenomanian) and reach approximately 130 m thick. Tracks are found on wet and dry interdune and within draa slipface deposits. They constitute biogenic deformation structures characterized by folded-up and/or brecciated sandstone levels formed under dry and/or wet substrate conditions with passive filling. The degree of preservation varies, but the identification of digit impression suggests that they were produced by theropods or iguanodontians.     

试用新"回归系数估计"法制作南海责任区的热带气旋路径集成预报

在正确评估我国各种客观预报方法性能的基础上,应用新“回归系数估计”方法,将几种预报效果较好、操作方便的模式作为子方法加以集成,建立一个包括数值预报产品在内的优化的客观预报集成模式,经用１９９３年热带气旋样本试报及１９９４年台汛期实例试验,模式的性能稳定,预报精度进一步提高。     

Seasonal Variation Features of Western North Pacific Tropical Cyclone Tracks with Their Predictability

Analysis is done of monthly and seasonal variations as climatic features of the tracks from 1196 tropical cyclones originating in the western North Pacific over the period 1949 to 1980, followed by the investigation of 301 onland cyclone tracks over China mainland in terms of methodology for nonlinear system. Obtained by computing the accumulated distance distribution function of the tracks Cm (l) is the characteristic chaos quantity for the related dynamic systems and then the fractual dimensionality d = 4.86 and Kolmogorov entropy approximation K2 = 0.0164, thereby leading to the predictability time scale = 2.54 days. It is found that the reference path among the onland typhoon No.23 of 1971, or Bess in the international nomenclature. Our results could be of operational use as a kind of reference.