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Sediment Sampling, Mapping, and Data Analysis
Published in Renato Baudo, John P. Giesy, Herbert Muntau, Sediments:, 2020
The second type, the grab, is the favorite one for biologists (Dall 1981), since it produces large samples of known surface from the top layers of sediment, which are the ones that are more likely to be inhabited by the bottom flora and fauna. Grabs are usually composed of two metallic jaws that can be closed, after the grab reaches the bottom, either automatically or by sending a mechanical, acoustical, or electric signal from the surface. Examples of these grabs are shown in Figure 2. The drawbacks of these devices are the unpredictable penetration, which depends on the density of the sediment and on the weight and speed of the grab when it hits the bottom, and the more or less pronounced perturbations of the interface due to both the impact and the subsequent opening of the grab for removing the sample.
Intelligent scheduling of double-deck traversable cranes based on deep reinforcement learning
Published in Engineering Optimization, 2022
Zhenyu Xu, Daofang Chang, Tian Luo, Yinping Gao
Considering safety factors, the gantry, trolley and claw of the crane are not allowed to move concurrently; thus, the movement of the crane in all directions must be performed in a step-by-step manner.The speed of the crane does not change during transportation, and the parameters of the upper and the lower cranes are the same.When a crane is moving a job, it is not allowed to transport other jobs halfway.Each crane can reach above any machine to grab or place jobs.Unexpected factors such as crane or machine failure are not considered.
Concentrations, Sources and Ecological Risk of Organochlorine Pesticides in Urban Stream Sediments of Suzhou Industrial Park, China
Published in Soil and Sediment Contamination: An International Journal, 2022
Xiaoguo Wu, Qing Wang, Zijiao Yuan, Binbin He, Houqi Liu, Shanshan Wang
Surface sediment samples (n = 26) were collected from urban steams of the SIP in Nov. of 2018, detailed latitude and longitude of the sampling sites can be found in the supplementary material (SM, Table S1). The land of SIP is relatively flat. Thus, the urban streams of the SIP take no definite course. The velocity and direction of the flow were controlled by the dams and pump stations of the northern Yangchen Lake and southern Wusong River (Figure 1). Geographically, streams of the SIP belong to the Yangcheng-Dianmao water system, which is a part of the Taihu Lake water system. At a specific sampling site, triplicated sediment samples were collected from 0–10 cm depth using a grab bucket and mixed as a composite sample. All the collected sediments were stored in a refrigerator (−20°C) for further treatment.
Artificial neural network modeling of cross-shore profile on sand beaches: The coast of the province of Valencia (Spain)
Published in Marine Georesources & Geotechnology, 2018
Isabel López, L. Aragonés, Y. Villacampa, P. Compañ
The sample extraction was performed using the following procedure: using a Van Veen’s grab, the sample is extracted and saved in a bucket to be labeled. After being packed into bags, the samples were transported in an icebox to the laboratory. The median sediment size (D50), real sample density (ρm), the material density (ρs), and the porosity (p) for each of the dry beach samples, and the median sediment size (D50) of the sample obtained at the DoC (Birkemeier 1985) were obtained following the UNE 103 101 1995, the UNE 7050-2 1997, and the UNE 103 100 1995. Also, the following scientific literature was taken into account: Román-Sierra, Muñoz-perez, and Navarro-Pons (2013); Syvitski (2007). For the characterization of the cross-shore profiles, the data obtained from the nearest sample to each profile were used.