Distribution characteristics of seamount cobalt-rich ferromanganese crusts and the determination of the size of areas for exploration and exploitation

In 2001, the International Seabed Authority （ISBA） initiated the consideration relating to the Regulations for Prospecting and Exploration for Hydrothermal Polymetallic Sulphides and Cobalt-rich Ferromanganese Crusts in the Area at its 7th session. Since then, the consideration of the Regulations has been mainly focused on the size of areas to be allocated for exploration and exploitation of the crusts. This paper, based on the investigation data and the analysis of the distribution characteristics of the crusts, suggests a model for determining the size of areas for exploration and exploitation of the crusts, taking into account various factors such as production scale, crust thickness and grade, mineable area proportion, recovery efficiency, exploration venture, and so on. Through the modeling, the paper suggests that the exploration area （the area covered by each application for approval of a plan of work for exploration of cobalt-rich crusts） shall be 4 856 km2 and the exploitation area （the mine site area） shall be 1 214 km2, for 20 years of 1 million wet tonnes annual production.

The eco-innovation mode in China and its impact on carbon emissions:From the exploration/exploitation perspective

The exploration/exploitation perspective is a well-known concept in the strategic management field;however,it has seldom been used to explore and analyze strategy at a national level.This study utilizes this perspective to analyze China's eco-innovation mode in response to climate change.By categorizing eco-innovation into radical and incremental eco-innovation,we examine the relationship between these concepts using Y02 patents as a proxy and panel data from 30 Chinese provinces from 2004 to 2015.The results show that eco-innovation as a whole as well as both radical and incremental innovations are drivers for reducing carbon emissions.Furthermore,contradictory to most previous empirical results related to the complementarity hypothesis,we find a complementary relationship between radical and incremental eco-innovation.These results collectively represent China's unique eco-innovation mode,confirming the assumed diversity of eco-innovation models in different contexts.The results also show the significant positive effects of economic development,urbanization level,industrial structure,and China's opening up on carbon emissions,indicating that economic and social development have not yet been completely dissociated from carbon emissions in China.

Comparative Analysis for Evaluating Wind Energy Resources Using Intelligent Optimization Algorithms and Numerical Methods

Statistical distributions are used to model wind speed,and the twoparameters Weibull distribution has proven its effectiveness at characterizing wind speed.Accurate estimation of Weibull parameters,the scale(c)and shape(k),is crucial in describing the actual wind speed data and evaluating the wind energy potential.Therefore,this study compares the most common conventional numerical(CN)estimation methods and the recent intelligent optimization algorithms(IOA)to show how precise estimation of c and k affects the wind energy resource assessments.In addition,this study conducts technical and economic feasibility studies for five sites in the northern part of Saudi Arabia,namely Aljouf,Rafha,Tabuk,Turaif,and Yanbo.Results exhibit that IOAs have better performance in attaining optimal Weibull parameters and provided an adequate description of the observed wind speed data.Also,with six wind turbine technologies rating between 1 and 3MW,the technical and economic assessment results reveal that the CN methods tend to overestimate the energy output and underestimate the cost of energy($/kWh)compared to the assessments by IOAs.The energy cost analyses show that Turaif is the windiest site,with an electricity cost of$0.016906/kWh.The highest wind energy output is obtained with the wind turbine having a rated power of 2.5 MW at all considered sites with electricity costs not exceeding$0.02739/kWh.Finally,the outcomes of this study exhibit the potential of wind energy in Saudi Arabia,and its environmental goals can be acquired by harvesting wind energy.

Progress in Research of Gas Hydrate

It is of great significance to study gas hydrate because of following reasons. （1） Most organic carbon in the earth reserves in the form of natural gas hydrate, which is considered as a potential energy resource for the survival of human being in the future. （2） A series of novel technologies are based on gas hydrate. （3） Gas hydrate may lead to many hazards including plugging of oil/gas pipelines, accelerating global warming up, etc. In this paper, the latest progresses in exploration and exploitation of natural gas hydrate, the development of hydrate-based technologies including gas separation, gas storage, CO2 sequestration via forming hydrate, as well as the prevention of hydrate hazards are reviewed. Additionally, the progresses in the fundamental study of gas hydrate, including the thermodynamics and kinetics are also reviewed. A prospect to the future of gas hydrate research and application is given.

A review: Enhanced recovery of natural gas hydrate reservoirs

Natural gas hydrate(NGH)is a highly efficient and clean energy,with huge reserves and widespread distribution in permafrost and marine areas.Researches all over the world are committed to developing an effective exploring technology for NGH reservoirs.In this paper,four conventional in-situ hydrate production methods,such as depressurization,thermal stimulation,inhibitor injection and CO2 replacement,are briefly introduced.Due to the limitations of each method,there has been no significantly breakthrough in hydrate exploring technology.Inspired by the development of unconventional oil and gas fields,researchers have put forward some new hydrate production methods.We summarize the enhanced hydrate exploiting methods,such as CO2/N2–CH4 replacement,CO2/H2–CH4 replacement,hydraulic fracturing treatment,and solid exploration;and potential hydrate mining techniques,such as self-generating heat fluid injection,geothermal stimulation,the well pattern optimization of hydrate exploring.The importance of reservoir stimulation technology for hydrate exploitation is emphasized,and it is believed that hydrate reservoir modification technology is a key to open hydrate resources exploitation,and the major challenges in the process of hydrate exploitation are pointed out.The combination of multiple hydrate exploring technologies and their complementary advantages will be the development trend in the future so as to promote the process of hydrate industrialization.

A Multi-Layered Gravitational Search Algorithm for Function Optimization and Real-World Problems

A gravitational search algorithm(GSA)uses gravitational force among individuals to evolve population.Though GSA is an effective population-based algorithm,it exhibits low search performance and premature convergence.To ameliorate these issues,this work proposes a multi-layered GSA called MLGSA.Inspired by the two-layered structure of GSA,four layers consisting of population,iteration-best,personal-best and global-best layers are constructed.Hierarchical interactions among four layers are dynamically implemented in different search stages to greatly improve both exploration and exploitation abilities of population.Performance comparison between MLGSA and nine existing GSA variants on twenty-nine CEC2017 test functions with low,medium and high dimensions demonstrates that MLGSA is the most competitive one.It is also compared with four particle swarm optimization variants to verify its excellent performance.Moreover,the analysis of hierarchical interactions is discussed to illustrate the influence of a complete hierarchy on its performance.The relationship between its population diversity and fitness diversity is analyzed to clarify its search performance.Its computational complexity is given to show its efficiency.Finally,it is applied to twenty-two CEC2011 real-world optimization problems to show its practicality.

Current Status of the Research on Coal Geology in China

Coal is the main energy in China, which has already played and will continue to play an important role in the national economy. Coal geology, as a practical science, has an access to gradual development with the growth and prosperity of China. From the meaning of the coalfield geology, this paper introduces the research progress and status of coalfield geology, including the research on coal basin, stratigraphy of coal-bearing stratigraphic sequences, coal-forming process, structural geology of coalfields, and exploration and development status of coal resources. The paper specially focuses on coal-forming process, including coal formation in terrestrial facies and transgressive / regression events, and introduces new technology which has been applied to research progress in structural geology of coalfield. This paper puts forward a new comprehensive exploration system for coal exploration and reviews regional coal geological exploration results in recent years, such as coal-poor regions of seven provinces in southern China and the coal resources area in northwest China, which will be an important coal-producing area in the future .

EXPLORATION/EXPLOITATION TRADEOFF WITH CELL-SHIFT AND HEURISTIC CROSSOVER FOR EVOLUTIONARY ALGORITHMS

In order to tradeoff exploration/exploitation and inspired by cell genetic algorithm a cellshift crossover operator for evolutionary algorithm （EA） is proposed in this paper. The definition domain is divided into n-dimension cubic sub-domains （cell） and each individual locates at an ndimensional cube. Cell-shift crossover first exchanges the cell numbers of the crossover pair if they are in the different cells （exploration） and subsequently shift the first individual from its initial place to the other individual＇s cell place. If they are already in the same cell heuristic crossover （exploitation） is used. Cell-shift/heuristic crossover adaptively executes exploration/exploitation search with the vary of genetic diversity. The cell-shift EA has excellent performance in terms of efficiency and efficacy on ten usually used optimization benchmarks when comparing with the recent well-known FEP evolutionary algorithm.

Exploring and exploiting unique properties of the hippocampal dentate gyrus for post-stroke therapy:astrocytes link ischemic resistance with neurogenic potential

Acute cerebral ischemia can occur secondary to embolism, cardiac arrest, hemorrhage, traumatic brain injury, edema, vascular compression, or any physiologic condition resulting in low cardiac output state. Survivors of cerebral ischemic events frequently suffer from profound disability,