The Namibian Electrical Energy Mix and Its Implications for Air Quality and Climate Variability

The urgent need for sustainable energy choices, local sustainable value creation, and reduction of import dependencies and non-sustainable resource use in Namibia cannot be over emphasised. This study was conducted with the ultimate goal to provide the basis for accurate energy fuel mix and climate change monitoring, and reporting and planning for addressing a global problem at local/domestic level. The energy consumption and production data for the country were used with International Panel on Climate Change (IPCC) and International Energy Agency (IEA) conversions, and carbon footprint calculation tools to determine the GHG emissions and air pollutants per type of energy fuel;and the carbon footprint associated with each energy fuel option for the country. The study showed that: 1) there is no single energy fuel which is not associated with GHG emissions and/or other environmental implications;2) increase in population and energy consumption and production yields increase in GHGs and other major pollutants (SOx, NOx, Particulate Matter);and 3) the choice of fuel mix determines the success of GHG emissions reduction. A future energy mix dominated by renewable energy technologies;and a balanced view of the actual benefits of the Namibian energy supply choices was also recommended.

Changes in China--Beijing is seeking less energy-intensive economic growth ＆ a less carbon-intensive energy mix and its impact over oil ＆ gas supply

Having experienced over 30 years of rapid growth,China’s economic development is entering a new normal featured by an ever optimizing economic structure shifting from high-speed to medium-high speed growth,and from factor-driven to innovation-driven pattern.In adapting

Renewable Energy Development in OAPEC Countries: History, Current Status, and Outlook

The renewable energy industry has grown its contribution to the global energy mix, particularly in terms of electricity generation. This study investigates the implications of an increasing renewable energy share on OAPEC countries and proposes a comprehensible policy strategy for the region. Four main topics are discussed: scientific and engineering principles of renewable energy utilization, current strategies for electricity generation in each OAPEC member country, economic and environmental implications of the energy transition under two future scenarios, as well as political interactions between oil-consuming and oil-producing countries. Based on this study, realistic and cost-effective strategies are proposed for OAPEC countries to better leverage their significant renewable energy resources while stabilizing fossil fuel supplies and strengthening their position in the global energy market. To mitigate the negative impacts of the energy transition, OAPEC countries are encouraged to take the following steps: 1) Developing renewable energy in conjunction with fossil fuel resources to reduce local demand for fossil fuel and increase the supply for exportation;2) Reviewing economic policies, environmental regulations, and carbon taxes imposed by oil-consuming countries;3) Increasing investment in renewable energy infrastructure;4) Cooperating to achieve a balance between economic development and environmental protection.

Morphodynamic evolution of the Xiaoqing River mouth:a Huanghe River-derived mixed energy estuary

In an estuary,tidal,wave and other marine powers interact with the coast in different ways and affect estuary morphology as well as its evolution.In the Huanghe(Yellow) River estuaries and nearby delta,there are many small sediment-affected estuaries with a unique morphology,such as the Xiaoqing River estuary.In this study,we investigated the special evolution and genetic mechanism of the Xiaoqing River estuary by analyzing graphic and image data with a numerical simulation method.The results show that NE and NE-E tide waves are the main driving force for sandbar formation.Sediment shoals have originated from huge amounts of sediment from the Huanghe River,with consequent deposition at the Xiaoqing River mouth.The lateral suspended sediments beyond the river mouth move landward.Siltation takes place on the northern shoreline near the river mouth whereas erosion occurs in the south.The deposits come mainly from scouring of the shallow seabed on the northern side of the estuary.Storm surges speed up deposition in the estuary.Development of the sediment shoals has occurred in two steps involving the processes of growth and further southward extension.Although the southward shift increases the river curvature and length,the general eastward orientation of the estuary is unlikely to change.Processes on the adjacent shorelines do not affect the development of the sediment shoals.The study presents a morphodynamic evolutionary model for the Xiaoqing River estuary,with a long-term series cycle,within which a relatively short cycle occurs.

MIXED ENERGY METHOD FOR SOLUTION OF QUADRATIC PROGRAMMING PROBLEMS AND ELASTIC-PLASTIC ANALYSIS OF TRUSS STRUCTURES

A new algorithm for the solution of quadratic programming problemsis put forward in terms of the mixed energy theory and is furtherused for the incremental solution of elastic-plastic trussstructures. The method proposed is different from the traditionalone, for which the unknown variables are selected just in one classsuch as displacements or stresses. The present method selects thevariables in the mixed form with both displacement and stress. As themethod is established in the hybrid space, the information found inthe previous incremental step can be used for the solution of thepresent step, making the algorithm highly effi- cient in thenumerical solution process of quadratic programming problems. Theresults obtained in the exm- ples of the elastic-plastic solution ofthe truss structures verify what has been predicted in thetheoretical anal- ysis.

The cruise observation of turbulent mixing in the upwelling region east of Hainan Island in the summer of 2012

The turbulent mixing in the upwelling region east of Hainan Island in the South China Sea is analyzed based on in situ microstructure observations made in July 2012. During the observation, strong upwelling appears in the coastal waters, which are 3℃ cooler than the offshore waters and have a salinity 1.0 greater than that of the offshore waters. The magnitude of the dissipation rate of turbulent kinetic energy ε in the upwelling region is O（10–9 W/kg）, which is comparable to the general oceanic dissipation. The inferred eddy diffusivity Kρ is O（10–6 m2/s）, which is one order of magnitude lower than that in the open ocean. The values are elevated to Kρ≈O（10–4 m2/s） near the boundaries. Weak mixing in the upwelling region is consistent with weak instability as a result of moderate shears versus strong stratifications by the joint influence of surface heating and upwelling of cold water.The validity of two fine-scale structure mixing parameterization models are tested by comparison with the observed dissipation rates. The results indicate that the model developed by Mac Kinnon and Gregg in 2003 provides relatively better estimates with magnitudes close to the observations. Mixing parameterization models need to be further improved in the coastal upwelling region.

Solution for Energies and Mixing of Two 0^+ States in ^(10)He

Using results from various reactions that populate 10He, I conclude that the ground state has E2n = 1.07（7） MeV and the excited 0＋ state is in the region of 2.1-3.1 MeV. The amount of the （sd）2 component in the ground state is less than about 0.075.

Forecast of natural gas supply and demand in China under the background of “Dual Carbon Targets”

As a kind of clean energy which creates little carbon dioxide, natural gas will play a key role in the process of achieving “Peak Carbon Dioxide Emission” and “Carbon Neutrality”. The Long-range Energy Alternatives Planning System(LEAP) model was improved by using new parameters including comprehensive energy efficiency and terminal effective energy consumption. The Back Propagation(BP) Neural Network–LEAP model was proposed to predict key data such as total primary energy consumption, energy mix, carbon emissions from energy consumption, and natural gas consumption in China. Moreover, natural gas production in China was forecasted by the production composition method. Finally, based on the forecast results of natural gas supply and demand, suggestions were put forward on the development of China’s natural gas industry under the background of “Dual Carbon Targets”. The research results indicate that under the background of carbon peak and carbon neutrality, China’s primary energy consumption will peak(59.4×10^(8)tce) around 2035, carbon emissions from energy consumption will peak(103.4×10^(8)t) by 2025, and natural gas consumption will peak(6100×10^(8)m^(3)) around 2040, of which the largest increase will be contributed by the power sector and industrial sector. China’s peak natural gas production is about(2800–3400)×10^(8)m^(3), including(2100–2300)×10^(8)m^(3)conventional gas(including tight gas),(600–1050)×10^(8)m^(3)shale gas, and(150–220)×10^(8)m^(3)coalbed methane. Under the background of carbon peak and carbon neutrality, the natural gas consumption and production of China will further increase, showing a great potential of the natural gas industry.

A Spatial Econometric Approach to Studying Regional Air Pollution in China

Using spatial econometric method,this paper investigates the mutual influence of air pollution among 31 Chinese provincial regions,together with the effects of energy mix and economic variations.Global spatial autocorrelation analysis reveals that significant positive spatial correlation exists for air pollution;Local spatial autocorrelation analysis indicates that pollution aggregation hot spots are concentrated in Beijing-Tianjin-Hebei region,the Yangtze River Delta and part of the central region between these two economic growth poles.This paper believes that industrial relocation is a major reason behind such distribution of air pollution in China as it has deepened the spatial correlation between interregional economy and pollution,which will further give rise to the spatial spillover effect of pollution.With the creation of the regression model of spatial and Environmental Kuznets Curve,the authors discovered that the level of pollution is closely related to energy mix and industrial structure.In addition,the inverted U-shape relationship between air pollution and economic development as demonstrated by previous studies does not exist or is yet to appear in China,where continuous growth of per capita GDP is accompanied by an increasing level of pollution.According to empirical analysis,the improvement of environmental quality at the expense of industrial relocation to neighboring regions is temporary.Due to the existence of spillover effect of pollution,regions that have enforced tighter environmental regulation such as Beijing and Tianjin are unable to acquire all benefits from such regulation.Treatment of air pollution necessitates interregional joint prevention and control.In the long run,adjusting energy mix and optimizing industrial structure are the key to fighting air pollution.But in the short run,reducing the consumption of inferior coal is the most effective option for China,which has seen multiple-fold increase in imports of inferior coal each year.

DEM simulation of influence of parameters on energy and degree of mixing

Powder mixing is being modeled using a simulation based on Newtonian mechanics. Variables under consideration include particle friction and the amplitude, frequency, and direction of shaking. Trajectories for each particle were recorded, and a mixing degree was calculated for each simulation, for which the average energy transferred into the powder system was recorded and compared to the resulting mixing degree. Mixing of particles originally located near the bottom was studied separately, as was the mixing of particles near the surface. This study shows that choosing the proper mixing parameters not only enhances the final result of mixing, but also yields good results with less strain on the material mixed and on the mixing device.

Study on the flotation technology and adsorption mechanism of galena–jamesonite separation

In order to further separate the concentrate containing galena and jamesonite before undergoing hydrometallurgical process, flotation experiment was performed on the basis of mineralogical analysis.And the adsorption mechanisms of collector H on galena and jamesonite were also studied by FT-IR spectra analysis and molecular dynamics(MD) simulation. The flotation result shows that the efficient separation can be achieved with H as selective collector. Galena concentrated with Pb grade of 72.09%and Pb recovery of 50.96% was obtained, and jamesonite concentrated with Sb grade and recovery of10.89% and 76.67% respectively was obtained as well. Infrared spectrum analysis indicates that collector H can adsorb on the surface of galena and react with Pb2+to generate hydrophobic salt, while no evident adsorption phenomenon was observed on the surface of jamesonite. The MD simulation and calculation results demonstrate that adsorption energy of collector H on galena and jamesonite surface is à872.74 k J/mol and à500.538 k J/mol, respectively, which means collector H is easier to adsorb on the surface of galena than that of jamesonite.

Diagnostic Study of Global Energy Cycle of the GRAPES Global Model in the Mixed Space-Time Domain

Some important diagnostic characteristics for a model’s physical background are reflected in the model’s energy transport, conversion, and cycle. Diagnosing the atmospheric energy cycle is a suitable way towards understanding and improving numerical models. In this study, formulations of the “Mixed Space-Time Domain”energy cycle are calculated and the roles of stationary and transient waves within the atmospheric energy cycle of the Global-Regional Assimilation and Prediction System （GRAPES） model are diagnosed and compared with the NCEP analysis data for July 2011. Contributions of the zonal-mean components of the energy cycle are investigated to explain the performance of numerical models. The results show that the GRAPES model has the capability to reproduce the main features of the global energy cycle as compared with the NCEP analysis. Zonal available potential energy （AZ） is converted into stationary eddy available potential energy （ASE） and transient eddy available potential energy （ATE）, and ASE and ATE have similar values. The nonlinear conversion between the two eddy energy terms is directed from the stationary to the transient. AZ becomes larger with increased forecast lead time, reflecting an enhancement of the meridional temperature gradient, which strengthens the zonal baroclinic processes and makes the conversion from AZ to eddy potential energy larger, especially for CAT （conversion from AZ to ATE）. The zonal kinetic energy （KZ） has a similar value to the sum of the stationary and transient eddy kinetic energy. Barotropic conversions are directed from eddy to zonal kinetic energy. The zonal conversion from AZ to KZ in GRAPES is around 1.5 times larger than in the NCEP analysis. The contributions of zonal energy cycle components show that transient eddy kinetic energy （KTE） is associated with the Southern Hemisphere subtropical jet and the conversion from KZ to KTE reduces in the upper tropopause near 30？S. The nonlinear barotropic conversion between stationary and transient kinetic energy terms （CKTE） is reduced predominantly by the weaker KTE.

A new approach to quantifying vehicle induced turbulence for complex traffic scenarios

Traffic-related pollutants adversely affect air quality, especially in regions near major roadways. The vehicleinduced turbulence(VIT) is a significant factor that controls the initial dilution, dispersion, and ultimately the chemical and physical fate of pollutants by altering the conditions in the microenvironment. This study used a computational fluid dynamics(CFD) software FLUENT to model the vehicle-induced turbulence(VIT) generated on roadways, with a focus on impact of vehicle-vehicle interactions, traffic density and vehicle composition on turbulent kinetic energy(TKE). We show, for the first time, that the overall TKE from multiple vehicles traveling in series can be estimated by superimposing the TKE of each vehicle, without considering the distance between them while the distance is greater than one vehicle length. This finding is particularly significant since it enables a new approach to VIT simulations where the overall TKE is calculated as a function of number of vehicles. We found that the interactions between vehicles traveling next to each other in adjacent lanes are insignificant,regardless the directions of the traffic flow. Consequently, simulations of different traffic scenarios can be substantially simplified by treating two-way traffic as one-way traffic, with less than 5% difference in the overall volume-averaged TKE. We also developed equations that allow the estimation of the overall volume-averaged TKE as a function of the number and the type of vehicles.

Market-based control strategy for long-span structures considering the multi-time delay issue

To solve the different time delays that exist in the control device installed on spatial structures, in this study, discrete analysis using a 2N precise algorithm was selected to solve the multi-time-delay issue for long-span structures based on the market-based control （MBC） method. The concept of interval mixed energy was introduced from computational structural mechanics and optimal control research areas, and it translates the design of the MBC multi-time-delay controller into a solution for the segment matrix. This approach transforms the serial algorithm in time to parallel computing in space, greatly improving the solving efficiency and numerical stability. The designed controller is able to consider the issue of time delay with a linear controlling force combination and is especially effective for large time-delay conditions. A numerical example of a long-span structure was selected to demonstrate the effectiveness of the presented controller, and the time delay was found to have a significant impact on the results.

Numerical solutions of linear quadratic control for time-varying systems via symplectic conservative perturbation

Optimal control system of state space is a conservative system, whose approximate method should be symplectic conservation. Based on the precise integration method, an algorithm of symplectic conservative perturbation is presented. It gives a uniform way to solve the linear quadratic control （LQ control） problems for linear timevarying systems accurately and efficiently, whose key points are solutions of differential Riccati equation （DRE） with variable coefficients and the state feedback equation. The method is symplectic conservative and has a good numerical stability and high precision. Numerical examples demonstrate the effectiveness of the proposed method.

Design factors affecting the dynamic performance of soil suspension in an agitated, baffled tank

The effects of particle size, impeller clearance and impeller speed are assessed to show how condition variations influence power consumption in the water-solid slurry suspension in an agitated tank. The energy efficiency of slurry height variation, impeller type and diameter, and solid movement speed has been investigated with six soil series stirred in a soil-water slurry. Coarser sand particles are observed to significantly increase power consumption, while finer particles, for instance clay, decrease the stirring power requirement. The 3-blade HR100 SUPERMIX? impeller manufactured by SATAKE generally performs more efficiently than a conventional4-pitched blade turbine. The impeller's geometric design, including diameter and number of blades influences the impeller's energy efficiency, and HR100 impellers with greater diameters remarkably reduce power consumption. The tests demonstrated that the power required to provide off-bottom solid suspension and solid dispersion can be reduced dramatically by increasing the slurry height rather than by accelerating the impeller, if this option is possible.

100% renewable energy with pumped-hydro-energy storage in Nepal

A radical transformation of the global energy system is underway.Solar photovoltaics and wind now comprise three-quarters of the global net new electricity-generation-capacity additions because they are cheap.The deep renewable electrification of energy services including transport,heating and industry will allow solar and wind to largely eliminate fossil fuels over the next few decades.This paper demonstrates that Nepal will be able to achieve energy self-sufficiency during the twenty-first century.Nepal has good solar and moderate hydroelectric potential but has negligible wind-and fossil-energy resources.The solar potential is about 100 times larger than that required to support a 100%solar-energy system in which all Nepalese citizens enjoy a similar per-person energy consumption to developed countries,without the use of fossil fuels and without the environmental degradation resulting from damming Nepal’s Himalayan rivers.Nepal has vast low-cost off-river pumped hydro-energy-storage potential,thus eliminating the need for on-river hydro storage and moderating the need for large-scale batteries.Solar,with support from hydro and battery storage,is likely to be the primary route for renewable electrification and rapid growth of the Nepalese energy system.

Real prospects for the development of power technologies based on renewable energy sources in Poland

In Poland more than 40% of the power units have been operating for over 40 years now and more than 10% are over 50 years old, which indicates a high degree of decrease in the value of the energy sector. An analysis of the energy market shows that every year a new power plant should be built with a capacity of 1000 MW to ensure the national energy security. An energy market research indicates that in Poland the structure of energy production is changing in recent years-the share of fossil (solid) fuels in electricity and heat production was approximately 88% in 2009, while in 2004 it reached 93%. According to the analysis of the market, it can be seen that conventional energy, mainly based on coal and lignite, has been the most important segment of the sector for a long time. In this paper the prospects for the development of power technologies based on renewable energy sources (RES) in Poland are presented.

Feature of thermohaline circulation in two-layer conceptual model based on energy constraint

The assertion that the thermohaline circulation(THC)is driven and sustained by mechanical energy has been increasingly accepted.The simplest conceptual model describing the THC is the Stommel two-box model.Given the vertical stratification in the real ocean,layered models were designed and used.In this research,using a two-layer conceptual model based on energy constraint,we studied basic features of thermal-mode and saline-mode circulations.We focused on the effects of freshwater flux and mixing energy on the intensity and multiple equilibrium states of the THC.The results show that more important than affecting the THC intensity,both the decrease of freshwater flux and increase of mixing energy can lead to an"abrupt transition"in the THC from a stable saline to a stable thermal mode,which further develops the THC energy theory.