The effect of cement material properties on the fracture patterns developing within cement-covered brittle sphere under impact

Acta Geotechnica - Dynamic loading experiments of single glass bead cement-covered by epoxy resins of different compositions demonstrate the existence of diverse fracture patterns under similar...     

Impact of different sampling rates on precise point positioning performance using online processing service

In this study, the effect of different sampling rates (i.e. observation recording interval) on the Precise Point Positioning (PPP) solutions in terms of accurac...     

Enzymatic activity in the rhizosphere of Spartina maritima: potential contribution for phytoremediation of metals

Extracellular enzymatic activity (EEA) of five enzymes (peroxidase, phenol oxidase, beta-glucosidase, beta-N-acetylglucosaminidase and acid phosphatase) was analysed in sediments colonised by Spartina maritima in two salt marshes (Rosário and Pancas) of the Tagus estuary (Portugal) with different characteristics such as sediment parameters and metal contaminant levels. Our aim was a better understanding of the influence of the halophyte on microbial activity in the rhizosphere under different site conditions, and its potential consequences for metal cycling and phytoremediation in salt marshes. Acid phosphatase and beta-N-acetylglucosaminidase presented significantly higher EEA in Rosário than in Pancas, whereas the opposite occurred for peroxidase. This was mainly attributed to differences in organic matter between the two sites. A positive correlation between root biomass and EEA of hydrolases (beta-glucosidase, beta-N-acetylglucosaminidase and acid phosphatase) was found, indicating a possible influence of the halophyte in sediment microbial function. This would potentially affect metal cycling in the rhizosphere through microbial reactions.     

A case study of sewage discharge in the shallow coastal area of the Northern Adriatic Sea (Gulf of Trieste)

A case study was carried out in 2000 in the shallow coastal area of the Northern Adriatic Sea (Gulf of Trieste) where untreated domestic sewage and industrial wastes are discharged at rate of 5500 m³·day^?1. The sewage plume above the outfall was followed using faecal coliforms (FC) and overturning length scale (l_T). The latter was rejected as a marker as the discharge conditions prohibit following the turbulence of sewage water. Intermittent sewage discharge is reflected in the minimal effect of eutrophication. Increase of phytoplankton biomass is thus only minor compared with the unpolluted area regardless of elevated concentrations of sewage‐derived nutrients (confirmed by correlation coefficients between FC and NH₄⁺, TP, PO₄^3?: 0.78, 0.71 and 0.67, respectively). Deteriorated trophic status, determined by the TRIX index, was observed only in the surface layer (average TRIX: 5.67). High FC content well above the regulation limit (up to 2.6 × 10⁵ FC·100 ml^?1) represents, therefore, the major negative impact of the improperly treated waste for the risk to human health.     

Studying Resource-Dependent Communities Through a Social-Ecological Lens? Examining Complementarity with Existing Research Traditions in Canada

This article explores the suitability of Ostrom and colleagues' social-ecological systems framework (SESF) for the study of resource-dependent communities in Canada. Through a broad literature about resource-dependent communities in Canada, three main approaches are identified, named staples research, rural development, and sustainability studies. Each of these research traditions is analyzed with regards to a common set of criteria – focus, scale, methods, treatment of institutions, and treatment of environmental dimensions. Research in each category is compared and contrasted with the SESF approach, to identify areas of overlap and divergence. Results indicate that the SESF is unlikely to provide additional benefit in terms of in-depth of social analysis, however, it does provide a unique contribution in terms of its coupled approach to conceiving social and ecological systems and its ability to operationalize these relationships through structured variables.     

Use of genetic algorithm in new approach to modeling of flood routing

Journal of Oceanology and Limnology - The hydrological models and simplified methods of Saint-venant equations are used extensively in hydrological modeling, in particular for the simulation of the...     

Integration of Electrofacies and Hydraulic Flow Units to Delineate Reservoir Quality in Uncored Reservoirs: A Case Study,Nubia Sandstone Reservoir,Gulf of Suez,Egypt

Natural Resources Research - Recognition of reservoir quality is an important objective in reservoir characterization process. By definition, the quality of a reservoir is described by its...     

A literature synthesis of LiDAR applications in transportation: feature extraction and geometric assessments of highways

Interest in using Light Detection and Ranging (LiDAR) technology in Transportation Engineering has grown over the past decade. The high accuracy of LiDAR datasets and the efficiency by which they can be collected has led many transportation agencies to consider mobile LiDAR as an alternative to conventional tools when surveying roadway infrastructure. Nonetheless, extracting semantic information from LiDAR datasets can be extremely challenging. Although extracting roadway features from LiDAR has been considered in previous research, the extraction of some features has received more attention than others. In fact, for some roadway design elements, attempts to extract those elements from LiDAR have been extremely scarce. To document the research that has been done in this area, this paper conducts a thorough review of existing studies while also highlighting areas where more research is required. Unlike previous research, this paper includes a thorough review of the previous attempts at data extraction from LiDAR while summarizing the detailed steps of the extraction procedure proposed in each study. Moreover, the paper also identifies common tools and techniques used to extract information from LiDAR for transportation applications. The paper also highlights common limitations in existing algorithms that could be improved in future research. This paper represents a valuable resource for researchers and practitioners interested in knowing the current state of research on the applications of LiDAR in the field of Transportation Engineering while also understanding the opportunities and challenges that lie ahead.     

Geological and geophysical studies of the Agoudal impact structure (Central High Atlas,Morocco): New evidence for crater size and age

Since the discovery of shatter cones (SCs) near the village of Agoudal (Morocco, Central High Atlas Mountains) in 2013, the absence of one or several associated circular structures led to speculation about the age of the impact event, the number, and the size of the impact crater or craters. Additional constraints on the crater size, age, and erosion rates are obtained here from geological, structural, and geophysical mapping and from cosmogenic nuclide data. Our geological maps of the Agoudal impact site at the scales of 1:30,000 (6 km²) and 1:15,000 (2.25 km²) include all known occurrences of SCs in target rocks, breccias, and vertical to overturned strata. Considering that strata surrounding the impact site are subhorizontal, we argue that disturbed strata are related to the impact event. Three types of breccias have been observed. Two of them (br1‐2 and br2) could be produced by erosion–sedimentation–consolidation processes, with no evidence for impact breccias, while breccia (br1) might be impact related. The most probable center of the structure is estimated at 31°59′13.73?N, 5°30′55.14?W using the concentric deviation method applied to the orientation of strata over the disturbed area. Despite the absence of a morphological expression, the ground magnetic and electromagnetic surveys reveal anomalies spatially associated with disturbed strata and SC occurrences. The geophysical data, the structural observations, and the area of occurrence of SCs in target rocks are all consistent with an original size of 1.4–4.2 km in diameter. Cosmogenic nuclide data (³⁶Cl) constrain the local erosion rates between 220 ± 22 m Ma^?1 and 430 ± 43 m Ma^?1. These erosion rates may remove the topographic expression of such a crater and its ejecta in a time period of about 0.3–1.9 Ma. This age is older than the Agoudal iron meteorite age (105 ± 40 kyr). This new age constraint excludes the possibility of a genetic relationship between the Agoudal iron meteorite fall and the formation of the Agoudal impact site. A chronolgy chart including the Atlas orogeny, the alternation of sedimentation and erosion periods, and the meteoritic impacts is presented based on all obtained and combined data.