Socio-economic implications of the KwaZulu-Natal sardine run for local indigenous communities

The economic and social effects of the annual sardine run on the indigenous community on the south coast of KwaZulu-Natal, South Africa, were assessed using data gathered from questionnaires and personal interviews with 329 members of the community. Their knowledge, perceptions and attitudes about the sardine run, as well as their level of involvement in, and the financial benefits accrued from it, were also assessed. Although around two-thirds of those interviewed were aware of the sardine run and just over half participated in it, only some 17% benefited financially from it. However, despite this low level of participation, the financial benefit to the community could amount to R17–18 million, and as much as R34–54 million if a multiplier effect of 2–3 is applied. There was a high level (over 70%) of willingness to learn more about the event, and to become more involved in training exercises that would allow local people to take advantage of opportunities arising from the sardine run. It is recommended that management strategies and development plans should be implemented towards assisting the indigenous communities to become more involved in the sardine run.     

Power aspects of a horizontal ring mill pulverizer under continuous comminution of olivine

The work presents a theoretical and experimental assessment of the mechanical power absorption by a prototype horizontal ring mill, during the continuous comminution of olivine with feed rates for a wide range of operating conditions. The forces acting on a ring element of a prototype ring mill under continuous operating conditions have been theoretically calculated and it has been experimentally confirmed that they are proportional to the square of the rotational speed. A linear variation of power with feed rate has been established and a functional relationship between consumed power and rotational speed is also proposed. Results demonstrate that there exists a feed rate for which the value of the friction coefficient between the rings and the powdered material is minimized, independently of the rotational speed. It was further found that the product size depends on the absorbed mechanical power and it decreases with increasing power values.     

Robust Statistical Methods to Discriminate Extreme Events in Geoelectrical Precursory Signals: Implications with Earthquake Prediction

In this study, we propose a robuststatistical method to discern anomalous patternsin geoelectrical time series measured in a seismicarea of the Southern Apennine chain. First, a filteringprocedure to remove seasonal effects related tometeo-climatic fluctuations was carried out.Then, we selected an autoregressive model able todescribe the time fluctuations of geoelectricalsignals and propose a method to obtain an objectiveestimate of probability of occurrence for each extremeevent detected in the time series. Our applications inSouthern Italy allow us to hypothesize that theambiguity of short-term prediction is within thecomplicated dynamics of the physical processresponsible for electrical anomalies observed on theearth's surface.     

Introducing run-size driven fisheries management for the coastal fishery of Atlantic salmon: Preseason forecasts for policy makers

The Finnish coastal fishery of Atlantic salmon (Salmo salar) in the northern Baltic Sea is regulated using multi-annual, pre-fixed, opening dates of harvests that aim to enhance spawning escapement of early migrating wild salmon. Such an inflexible management regime does not set regulations that track varying run sizes of salmon. We introduce an array of computational intelligence techniques to estimate and forecast coastal run size and escapement of salmon into three spawning rivers in the northern Baltic Sea. Our results indicated that the present management pattern, driven largely by regional fisheries policy, contrasts greatly with a “run-size driven” (i.e. abundance-based) management approach. Introducing run-size driven management, i.e. setting regulations annually by tracking preseason forecasts, would better ensure adequate escapement and at the same time allow the maintenance of coastal catch at sustainable level. Setting regulations annually would allow effective harvesting in years when the run is high, and would effectively restrict harvests when the run is low.     

Relevance of Bathymetry for Tsunami Run‐up Modeling

Abstract

Marine positioning is relevant for several aspects of tsunami research, observation, and prediction. These include accurate positioning of instruments on the ocean bottom for determining the deep‐water signature of the tsunami, seismic observational setups to measure the earthquake parameters, equipment to determine the tsunami characteristics during the propagation phase, and instruments to map the vertical uplift and subsidence that occurs during a dip‐slip earthquake.

In the accurate calculation of coastal tsunami run‐up through numerical models, accurate bathymetry is needed, not only near the coast (for tsunami run‐up) but also in the deep ocean (for tsunami generation and propagation). If the bathymetry is wrong in the source region, errors will accumulate and will render the numerical calculations inaccurate. Without correct and detailed run‐up values on the various coastlines, tsunami prediction for actual events will lead to false alarms and loss of public confidence.     

超深涌水水平孔绳索取心钻具投送和打捞技术

为了精准查明拟建隧道沿线地质情况,通常采用水平孔绳索取心钻探技术。在超深涌水水平孔绳索取心钻进中,投放、打捞内管总成钻具和打捞器是施工中的难题。因此从研制专用水平钻机、选择大功率泥浆泵、封隔分流涌水、设计绳索取心钻具送绳器、定制专用内平绳索取心钻杆等几方面开展研究。全面分析了泥浆泵压力、钻杆内径大小、钻孔深度、钻杆的密封性、钻孔涌水量、涌水压力、孔壁间隙等因素对投送内管总成钻具和打捞器速度的影响,实现了高效、低成本、绿色钻探技术集成。经过精心组织,成功完成了千米级的大涌水水平孔绳索取心钻探施工,精准查明了隧道洞身段工程地质条件,取得了满意的技术效果,为隧道设计和施工提供了安全保障,也为超深涌水水平孔钻探提供了经验。     

风浪波群中波高分布研究

在实验室风浪槽中观测风浪,发现波群连长是影响波群中波高分布的重要因素,随着波群连长增大,波群中波高分布信息熵增大。当以平均波高无因次化,连长较大时波群中波高累积概率明显大于连长较小时情形。波群中波高分布受谱宽度影响。当谱宽度增大,波群中波高累积概率降低。谱宽度和波群连长对波群中波高累积概率的影响相当。引进体现波群特性的1个无因次化波高参量研究波群中波高累积概率。     

Sedimentation limits the erosion rate of a bioeroding sponge

Coral reefs are increasingly threatened by anthropogenic disturbances and consequently coral cover and complexity are declining globally. However, bioeroding sponges, which are the principal agents of internal bioerosion on many coral reefs, are increasing in abundance on some degraded reefs, tipping them towards net carbonate erosion. The aim of this study was to identify the environmental factors that drive the erosion rates of the common Indonesian bioeroding sponge Spheciospongia cf. vagabunda . Sponge explants were attached to limestone blocks and deployed across seven sites characterized by different environmental conditions in the UNESCO Wakatobi Biosphere Reserve in Indonesia. Average bioerosion rates were 12.0 kg m^?2 sponge tissue year^?1 (±0.87 SE ), and were negatively correlated with depth of settled sediment (r  = ?.717, p  < .01) and showed weak positive correlation with water movement (r  = .485, p  = .012). Our results suggest that although bioeroding sponges may generally benefit from coral reef degradation, bioerosion rates may be reduced on reefs that are impacted by high sedimentation, which is a common regional stressor in the South‐East Asian Indo‐Pacific.     

Microstructure characterization of mechanically activated hematite using XRD line broadening

The effect of dry milling in a vibratory mill on the structural changes and microstructural characteristics of hematite using different methods was investigated. We have described the line profile analysis (LPA) to extract the size of coherently diffracting domains and the lattice strain of activated hematite in a vibratory mill. The Warren–Averbach and Williamson–Hall methods were used as the main tools for characterization. The changes in the particle size, surface area and new phase formation of hematite concentrate were also investigated. It was concluded that the breakage and agglomeration of particles take place mainly at lower and higher levels of specific energy input, respectively. The pores in agglomerates remain accessible for the nitrogen gas. Milling of hematite increased specific surface area up to 18.4 m²/g. The hematite milled under various levels of specific energy input did not undergo a significant reaction or phase transformation during milling. The Williamson–Hall method confirms its merit for a rapid overview of the line broadening effects and possible understanding of the main causes. The anisotropic character of line broadening for deformed hematite as a function of specific energy input was revealed. Higher level of specific energy input favors the generation of small crystallite size, higher microstrain, BET surface area, amorphization and line breadth. The Warren–Averbach method suggested that the nanocrystalline hematite with grain sizes of 73.5–12.2 nm was formed by mechanical treatment using different milling intensities in the vibratory mill. The root mean square strain (RMSS) at L = 10 nm varies between 1.7 × 10^− 3 and 4.0 × 10^− 3 depending on the level of energy input. Limits in the applicability of Williamson–Hall method and reliability of the results are discussed in detail.