Characterizing seabed sediments at contrasting offshore renewable energy sites

Due to the impacts of climate change, there is an urgent need to scale up existing, and develop novel, renewable energy technologies. Although there are many types of renewable energy technology, ocean renewable energy, including established offshore wind, and novel wave and tidal energy converters, offers many opportunities due to the abundance of the resource, availability of sea space, and (for tidal) predictability. However, the extraction of energy from the ocean environment will influence sediment dynamics and morphodynamics at various temporal and spatial scales. Detailed knowledge of seabed properties is also important for device installation, affecting foundation design and cabling. In this study, 36 seabed sediment samples were collected across a region of the Irish Sea extending from the west of Anglesey into Liverpool Bay up to a maximum distance of around 35 km offshore – a region where there are many existing and planned ocean renewable energy projects. Particle size analysis at quarter phi intervals was used to calculate the statistical properties of the seabed sediment samples, including Mean grain size, Sorting, Skewness and Kurtosis. These properties were compared against the outputs of wave (SWAN) and tidal (TELEMAC) models of the region to investigate the relationship between environmental variables and sediment characteristics, and to determine the impact and challenges of renewable energy technologies deployed in the region. Most of the sediments in the study area are medium sand, polymodal, very poorly sorted, coarse skewed, and very platykurtic. We found that mean water depth and peak current speed have the largest influence on Median grain size, and Sorting can be affected by tidal range, in addition to water depth and peak current speed. Moreover, minimal influence of wave climate was found on the sediments. A thorough discussion based on a literature review of the environmental issues of various energy converters (tidal energy converter (both individual and arrays), tidal barrage/lagoons, and wind turbines) was used to determine how devices in the study region, and at other sites throughout the world, would interact with sediment dynamics. We make recommendations on ways to minimize environmental impacts of ocean energy technologies

Factors affecting the severity of pedestrian traffic crashes

Background: Considering the importance of pedestrian traffic crashes and the role of environmental and demographic factors in the severity of these crashes, this article aimed to review the published evidence and synthesize the results of related studies to determine any associations between demographic and environmental factors and the severity of pedestrian-vehicle crashes. Methods: All epidemiological studies published from 1970 to 2019 were searched in international electronic databases (PubMed Medline, Scopus, Web of Science, Embase, ScienceDirect, and Ovid) and reference lists of the identified articles were also searched. Studies were included if they investigated the severity of pedestrian-vehicle crashes as outcome, measured any environmental and demographic factors for pedestrian-vehicular crashes as exposure, designed observational, and if they were written in all languages. Quality of included studies was evaluated using the strengthening the reporting of observational studies in epidemiology checklist for observational studies. Results: We found 3126 references among which 24 studies were included in this review. All retrieved studies were conducted between 1990 and 2019 and had a cross-sectional design. In most of these studies, the associations between environmental and demographic variables such as vehicle speed or speed limits, pedestrian age, lighting, type of road, type of vehicle, and alcohol intake with the severity of pedestrian traffic crashes were examined. Conclusion: This study showed that few studies were conducted in this area; in fact, most of the studies were carried out in metropolises of developed countries. As a result, studies which provide strong causal inferences by focusing on high-risk groups and a higher level of evidence such as cohort and case-control ones are needed in developing countries