First genetically verified occurrence of Ligula pavlovskii outside its native range and characteristics of its infection in Neogobius fluviatilis

In this study, we provide the first genetically verified distribution record beyond its native range of Ligula pavlovskii, a high-impact endoparasite of Ponto-Caspian gobies. According to parasitological surveys, ligulosis was detected for the first time in monkey goby individuals collected from Lake Balaton in 2004, 34 years after the first record of monkey goby in the lake. During a Lake Balaton survey in 2018, we detected tapeworms in 44.4% of the sampled monkey gobies. This prevalence is about two to ten times higher than it was reported from within the native range of the fish hosts. The same survey revealed an uneven spatial distribution of the ligulosis in the monkey gobies inhabiting different shoreline sections of the lake. We assume that the occurrence and recent distribution data of this high-impact endoparasite may provide useful information for potential biocontrol measures of invasive Ponto-Caspian gobies in the future.     

中国石化流程模拟技术应用对盐湖化工的启示

通过对中国石化系统推广应用流程模拟技术历程回顾,简述了其具体实施方法和在生产企业所起到的作用、取得的经验,对盐湖化工推广应用流程模拟技术,促进工业化和信息化深度融合具有启示。     

AMIDA浅层介质过滤器在循环水旁滤系统中的应用

通过对AMIDA浅层介质过滤器工作原理、过滤过程、反冲洗过程的介绍,以及与传统重力式无阀过滤器的比较,阐述了AMIDA浅层介质过滤器在循环水旁滤系统应用中的优越性。     

The ultimate bearing capacity of shallow strip footings using slip-line method

Based on the limit equilibrium theory, an accurate approach is proposed to solve the ultimate bearing capacity of shallow strip footings under general conditions. The foundation soil is considered to be an ideal elastic-plastic material, which obeys the Mohr-Coulomb yield criterion, and is assumed to be an ideal continuous medium which is isotropic, homogeneous and incompressible or non-expansive. Through analyzing the relative motion and interaction between the footing and soil, the problem of the ultimate bearing capacity of shallow strip footings is divided into two categories. A minimum model with the total vertical ultimate bearing capacity as its objective function is established to solve the ultimate bearing capacity using the slip-line method with no need to make any assumptions on the plastic zone and non-plastic wedge in advance. A convenient and practical simplified method is also proposed for practical engineering purposes. Furthermore, the first category of the problem in the case of the same uniform surcharges on both sides of footings is the focus of the study: the applicable conditions of Terzaghi’s ultimate bearing capacity equation as well as the theoretical exact solutions to its three bearing capacity factors are derived, and a new bearing capacity equation is put forward as a replacement for Terzaghi’s equation. The geometric and mechanical similarity principle is proposed by a dimensionless analysis. The results show that for perfectly smooth footings, the total vertical ultimate bearing capacity obtained by the present method is in good agreement with those by existing methods, whereas the existing methods underestimate the ultimate bearing capacity in the case of perfectly rough footings. The classic Prandtl mechanism is not the plastic failure mechanism of the ultimate bearing capacity problem of perfectly smooth footings on weightless soil.     

Centrifuge modeling of hybrid foundation to mitigate liquefaction-induced effects on shallow foundation resting on liquefiable ground

A hybrid foundation is developed in this study to mitigate the liquefaction-induced effects on shallow foundations. The proposed hybrid foundation is a combination of a gravel drainage system and friction steel piles with spiral blades, framed under the footing. The motivation behind having a gravel drainage system, as an integral part of the hybrid foundation, is its ability to improve the liquefaction resistance of the ground in the most economical way. However, case histories and the development of recent research have highlighted that gravel drainage systems have exhibited poor performances and could not prevent ground liquefaction during strong ground motion. To counteract these shortcomings, friction steel piles are provided which are supposed to yield frictional resistance during earthquakes and are presumed to minimize the rocking/tilting behavior of the foundation-structure system even if the ground undergoes liquefaction. The evolution of excess pore water pressure, specifically in the vicinity of the foundation-structure system, dominatingly influences the settlement mechanism of shallow foundations. Centrifuge test results show that the presence of gravel drainage can minimize the post-liquefaction settlement of shallow foundations through the rapid dissipation of excess pore water pressure. Moreover, friction piles are able to minimize the tilting/differential settlement of shallow foundations. It is found that the proposed hybrid foundation provides the desired function of reducing the overall liquefaction-induced effects on shallow foundations resting on liquefiable grounds.     

高强和高性能混凝土在青海盐湖卤水中的抗腐蚀性

针对青海盐湖地区特定的自然环境，配制了普通、高强和高性能混凝土，同时进行了不同混凝土的卤水腐蚀单因素试验和卤水腐蚀－－干湿循环双因素试验。结果表明，普通混凝土的耐久性很差，高强混凝土的抗腐蚀性不尽人意，高性能混凝土具有优良的抗腐蚀性能，钢纤维和高强高弹模聚乙烯纤维增强高性能混凝土在双因素作用下抗腐蚀性更好。     

利用东湖淤泥制备超轻陶粒的研究

利用东湖淤泥为主要原材料,进行堆积密度小于500kg/m3超轻陶粒研制。结果表明:按照发泡组分与东湖淤泥比例为20%∶80%,600℃预烧15min,1180℃焙烧12min,制备出了筒压强度1.7MPa、吸水率13.4%、堆积密度为485 kg/m3超轻陶粒。     

实现人工湖污染治理与景观建设的结合：谈深圳东湖公园人工湖污染治理与景观建设

为解决市政公园人工湖污染的问题,介绍了深圳东湖公园人工湖污染治理与景观建设,阐述如何实现两者的结合。     

工程勘察在地源热泵系统工程中的重要性

地源热泵系统所利用的热源主要位于地层浅部。它的存在具有普遍性的同时又具有隐蔽性和复杂性,从而决定了地源热泵系统进行工程勘察的必要性,本文从浅层地热能的赋存特征入手阐述工程勘察的必要性,并就工程勘察的程序及注意事项等问题进行了讨论,以希望有关勘察部门在进行地源热泵系统勘察和施工中有所借鉴。     

Nitrogen gas supersaturation in the recent sediments of lake erie and two polluted harbors

Nitrogen gas distributions in sediment pore water were determined for cores collected in Lake Erie and two nearby harbors. Concentrations of N₂ gas ranged from 11.9 to 37.0 ml l⁻¹ and from 8.9 to 58.3 ml l⁻¹ for open lake and polluted harbor sediments, respectively. Maximum concentrations in the harbor sediments were as high as 3.5 times N₂ saturation calculated for the overlying water. Indirect diffusive flux estimates for nitrogen gas ranged from 20 to 32% of the particulate nitrogen sedimentation rate in Lake Erie. At one location, the amount of nitrogen gas lost by diffusion was calculated to be greater than the nitrogen deposited to the sediments. Nitrogen gas production and diffusive loss from surficial sediments probably represents a major pathway for nitrogen removal from Lake Erie.