Numerical Modeling of Wave-Enhanced Turbulence in the Oceanic Upper Layer

A coupled model of air-wave-sea interaction is modified based on a new roughness formulation and the latest data. The model parameters for aerodynamic roughness from below (ARB) and wave-dependent roughness from above (ARA, z _0a ) are assumed equal. The combined roughness is assumed to be a function of friction velocity, gravity, air and seawater densities, and wave age (c _w ). The model is used in a study of wave-enhanced turbulence under breaking waves to predict turbulent dissipation (), ARA, and drag coefficient (C _d ). Both waves and shear production are considered as sources of ocean turbulent energy. The atmospheric part of the model is used only to specify a correct condition at the interface. Numerical experiments are performed to study the -distribution, z _0a and C _d , and to compare with data. The major achievement is model verification using all available data. The first full application of this model is in conjunction with an ocean circulation model in a coupled circulation-wave system. Simulations show that the -distribution is strongly dependent on local wind-forced wave heights. For each wind and wave state there is a particular wave-dependent depth that is verified by data. The comparison shows that the model predicted agrees well with the observed of the z ^–4 law distribution of Gargett (1989). Simulations also show that waves have an important role in causing to differ from the classical wall-layer theory and z _0a , with a value of 0.30 for the empirical constant a _a . The model-predicted , z _0a , C _d and C _gd agree well with data.     

Horizontal Pressure Gradient Errors of the Monterey Bay Sigma Coordinate Ocean Model with Various Grids

A coastal ocean -coordinate model of Monterey Bay (MOB) with realistic bottom topography and coastlines is developed using the Princeton Ocean Model (POM) and grid generation technique (GGT) to study the horizontal pressure gradient errors associated with the MOB steep topography. The submarine canyon in MOB features some of the steepest topography encountered anywhere in the world oceans. The MOB grids are designed using the EAGEAL View and GENIE⁺⁺ grid generation systems. A grid package developed by Ly and Luong (1993) is used in this study to couple grids to the model. The MOB model is tested with both orthogonal and curvilinear nearly-orthogonal (CNO) grids. The CNO grid has horizontal resolution which varies from 300 m to 2 km, while the resolution of the orthogonal grid is uniform with x = 1.25 km and y = 1.38 km. These grids cover a domain of 180 × 160 km with the same number of grid points of 131 × 131. Vertical resolutions of 25, 35 and 45 vertical sigma levels are tested. The error in the MOB are evaluated in terms of mean kinetic energy and velocity against various grids, vertical, horizontal resolution and distributions, and bottom topography smoothing. Simulations with various grids show that GGT can be used as another tool in reducing -coordinate errors in coastal ocean modeling besides increasing resolution and smoothing bottom topography. Topographical smoothing not only reduces topographic slope, but changes realistic topography. A CNO grid with a high grid density packed along steep slopes and Monterey Submarine Canyon reduces the errors by 40% compared to a rectangular grid with the same number of grid points. The CNO grid is more efficient than the rectangular grid, since it has most of its grids over water. The simulations show that the presented MOB -coordinate model can be used with a confidence regarding horizontal pressure gradient error.     

Marine and Brackish Ecosystems of South Brittany (Lorient and Vilaine Bays) with Particular Reference to the Effect of the Turbidity Maxima

The south Brittany coast of France offers considerable opportunities to study the transition between estuaries and the sea. The sea coast is semi-enclosed, due to the local geomorphology, with sheltered conditions. The infaunal macrobenthic communities have been identified and characterized by species richness (S), abundance (A) and biomass (B), related to environmental factors. The spatial succession of infauna along the estuarine gradient shows the presence of an area with a much reduced fauna, and an oligobiotic area with low values of S, A and B. In these strongly stratified estuaries, concentration of organic matter and sediment can result in oxygen depletion, which is not favourable for survival of the infauna. The oligobiotic area seems to be related to the presence of the turbidity maximum, the location and importance of which are functions of river discharge and hydrodynamic mixing. The turbidity maximum which causes these conditions is shown to be at a higher salinity than has previously been described for this phenomenon, and is shown to break the spatial gradient of marine to brackish communities which has been described in larger estuaries.     

A Novel Hunger Games Search Optimization-Based Artificial Neural Network for Predicting Ground Vibration Intensity Induced by Mine Blasting

Innovation efforts in developing soft computing models (SCMs) of researchers and scholars are significant in recent years, especially for problems in the mining industry. So far, many SCMs have been proposed and applied to practical engineering to predict ground vibration intensity (BIGV) induced by mine blasting with high accuracy and reliability. These models significantly contributed to mitigate the adverse effects of blasting operations in mines. Despite the fact that many SCMs have been introduced with promising results, but ambitious goals of researchers are still novel SCMs with the accuracy improved. They aim to prevent the damages caused by blasting operations to the surrounding environment. This study, therefore, proposed a novel SCM based on a robust meta-heuristic algorithm, namely Hunger Games Search (HGS) and artificial neural network (ANN), abbreviated as HGS–ANN model, for predicting BIGV. Three benchmark models based on three other meta-heuristic algorithms (i.e., particle swarm optimization (PSO), firefly algorithm (FFA), and grasshopper optimization algorithm (GOA)) and ANN, named as PSO–ANN, FFA–ANN, and GOA–ANN, were also examined to have a comprehensive evaluation of the HGS–ANN model. A set of data with 252 blasting operations was collected to evaluate the effects of BIGV through the mentioned models. The data were then preprocessed and normalized before splitting into individual parts for training and validating the models. In the training phase, the HGS algorithm with the optimal parameters was fine-tuned to train the ANN model to optimize the ANN model's weights. Based on the statistical criteria, the HGS–ANN model showed its best performance with an MAE of 1.153, RMSE of 1.761, R² of 0.922, and MAPE of 0.156, followed by the GOA–ANN, FFA–ANN and PSO–ANN models with the lower performances (i.e., MAE?=?1.186, 1.528, 1.505; RMSE?=?1.772, 2.085, 2.153; R²?=?0.921, 0.899, 0.893; MAPE?=?0.231, 0.215, 0.225, respectively). Based on the outstanding performance, the HGS–ANN model should be applied broadly and across a swath of open-pit mines to predict BIGV, aiming to optimize blast patterns and reduce the environmental effects.

     

Estimation of Ground Vibration Intensity Induced by Mine Blasting using a State-of-the-Art Hybrid Autoencoder Neural Network and Support Vector Regression Model

Natural Resources Research - In surface mining, blasting is an indispensable method for fragmenting rock masses. Nevertheless, it can inherently induce many side effects like ground vibrations. At...     

Predicting Blast-induced Ground Vibration in Quarries Using Adaptive Fuzzy Inference Neural Network and Moth–Flame Optimization

Natural Resources Research - Blasting is a first preparatory stage that plays a fundamental role in the subsequent operations of an open pit mine. However, its adverse effects can seriously affect...     

A New Species of Amsassia from the Ordovician of Korea and South China: Paleobiological and Paleogeographical Significance

A new species of the probable calcareous alga Amsassia, A. koreanensis, is recognized from the Duwibong Formation (Middle Ordovician, Darriwilian) of the Taebaeksan Basin in mid-eastern Korea. This is the first report of the genus from the Korean Peninsula, expanding its geographical range to the eastern Sino-Korean Block. The new species also occurs in the Xiazhen Formation (Upper Ordovician, Katian) at Zhuzhai in the South China Block. Amsassia koreanensis is the smallest species of this modular genus, having a maximum module diameter of 0.28 mm. Module increase is by bipartite, tripartite and quadripartite types of longitudinal axial fission, but unlike other species of the genus, quadripartite fission is common. The types of fission are comparable to those in some Tetradiida (now Prismostylales, florideophycean rhodophyte algae), although the processes of fission are different. The distribution of A. koreanensis further strengthens the biogeographical connection between the Sino-Korean and South China blocks, suggesting that these two paleocontinents were located closer together during the Middle to Late Ordovician than previously speculated.     

Improving fisheries management in New Zealand: Developing dialogue between fisheries science and management (FSM) and ecosystem science and management (ESM)

This paper attempts to overcome the dichotomy between the broadly different and largely separate fisheries science and management (FSM) and ecosystem science and management (ESM) knowledge systems that characterise the international literature and are found in fisheries management practice in different countries. The paper argues that the construction of a heuristic we term the fisheries problematic, around issues and contexts, reveals the breadth of international fisheries management concerns and the variety of contexts in which these concerns are being faced. Adopting a political economy informed nature-society approach the paper considers ecological and socio-economic processes in their institutional settings in an attempt to shift from the either/or arguments around fish or ecosystems found in the FSM or ESM literatures to investigation that is grounded in understandings of the historically and geographically specific trajectories of fisheries related interactions and understandings of how knowledge about the trajectories and their interactions is fashioned. Drawing on recent conceptual innovations in the field, the paper develops a matrix-centred approach to explore ecological, industry, community and policy domains in New Zealand’s Quota Management System (QMS) and Individual Transferable Quota (ITQ) fisheries management regime. The extended framework prioritises scrutiny of the interaction amongst the four domains, as a strategy to help develop institutional frameworks that facilitate behaviours that are societally inclusive. The paper offers three conclusions. First, the landscape of New Zealand fisheries issues is very much a product of the contingent interaction of the QMS, a management regime designed around the principles of a FSM approach and laid down in a neo-liberal political environment and Maori aspirations encompassing the fisheries sector. Second, the conceptual mapping of FSM and ESM perspectives over New Zealand’s fisheries management experience highlights that a number of management issues have been down played by the commitment to FSM, a situation that has led to on-going tensions between commercial, recreational and customary stakeholders regarding fisheries management. Put another way, there is more to running a sustainable fishery (as defined in the Fisheries Act 1996) than QMS and other tools and dialogue about the development of these should be a priority. Third and more generally, improved dialogue on fisheries questions is likely to be most expeditiously advanced by studies that explicitly conceptualise and contextualise ecological and socio-economic processes and their institutional arrangements.     

Rift propagation at craton margin.: Distribution of faulting and volcanism in the North Tanzanian Divergence (East Africa) during Neogene times

A revised kinematic model is proposed for the Neogene tectono-magmatic development of the North Tanzanian Divergence where the axial valley in S Kenya splits southwards into a wide diverging pattern of block faulting in association with the disappearance of volcanism. Propagation of rifting along the S Kenya proto-rift during the last 8 Ma is first assumed to have operated by linkage of discrete magmatic cells as far S as the Ngorongoro–Kilimanjaro transverse volcanic belt that follows the margin of cratonic blocks in N Tanzania. Strain is believed to have nucleated throughout the thermally-weakened lithosphere in the transverse volcanic belt that might have later linked the S Kenya and N Tanzania rift segments with marked structural changes along-strike. The North Tanzanian Divergence is now regarded as a two-armed rift pattern involving: (1) a wide domain of tilted fault blocks to the W (Mbulu) that encompasses the Eyasi and Manyara fault systems, in direct continuation with the Natron northern trough. The reactivation of basement fabrics in the cold and intact Precambrian lithosphere in the Mbulu domain resulted in an oblique rift pattern that contrasts with the orthogonal extension that prevailed in the Magadi–Natron trough above a more attenuated lithosphere. (2) To the E, the Pangani horst-like range is thought to be a younger (< 1 Ma) structure that formed in response to the relocation of extension S of the Kilimanjaro magmatic center. A significant contrast in the mechanical behaviour of the stretched lithosphere in the North Tanzanian diverging rift is assumed to have occurred on both sides of the Masai cratonic block with a mid-crustal decoupling level to the W where asymmetrical fault-basin patterns are dominant (Magadi–Natron and Mbulu), whereas a component of dynamical uplift is suspected to have caused the topographic elevation of the Pangani range in relation with possible far-travelled mantle melts produced at depth further N.