Physical simulation test of soil-rock mixture from synthetic transparent soil

The waste dump of open-pit coal mine is remade of soil-rock mixture under the action of gravity,dynamic load of transportation equipment and earthquake,etc.By using artificial synthetic transparent soil,the developing process and migration law for soil-rock mixture are observed in the remade process.The mixture of fused quartz sand,liquid paraffin and n-tridecane is chosen as the material for synthetic transparent soil which is mixed with liquid paraffin and n-tridecane at a mass ratio of4.4at room temperature of17℃.Physical and mechanical properties of transparent soil are determined by physical test and compared with those in natural sandy soil.The results show that transparent soil and sandy soil have high similarity,in other words,transparent soil can be used for similar simulation experiments of soil-rock mixture.

Natural vegetation recovery on waste dump in opencast coalmine area

The changes of vegetation compositions, plant species diversity, species important value and succession of plant community were studied on waste dumps in Haizhou opencast coalmine which is located in the west of Liaoning Province, China (41°41(-42°56( N, 121°1(-122°56(E). Four kinds of terraces with different ages (5, 10, 20 and 40 years) were selected for investigation of plants. Total of 63 species of natural colonized plants were recorded on the waste dump and they belong to 23 families. The main families were Compositae (15 species), Fabaceae (11 species) and Leguminosae (8 species), which accounted for 54.0% of total species and play an important role in natural vegetation recovery in waste dump area. The dominant species on 5-, 10-, 20-, 40-year-old terraces were Tribulus terrestris + Echinochloa hispidula + Salsola collina, Echinochloa hispidula + Artemisia sieversiana + Artemisia scoparia, Echinochloa hispidula + Clinelymus dahuricus + Artemisia scoparia + Artemisia sieversiana + Melilotus officinalis, Clinelymus dahuricus+Phragmites communis + Echinochloa hispidula+ Setaria viridis, respectively. According to the important value of species calculated. It is determined that Tribulus terrestris can act as pioneer species on waste dump and Clinelymus dahuricus, Phragmites communis and Echinochloah hispidula are important dominant species in vegetation restoration in Haizhou opencast coalmine. The study results can provide scientific basis for selecting and disposing appropriately plant species and rehabilitating vegetation on waste dumps of coalmine.

Discrete element approach for mine dump stability analysis

Mine overburden dumps have posed significant safety issues in the operations of various unit operations of open pit min-ing especially the external dumps. The external dumps are composed of a mixture of fragmented rocks and loose soil. Their charac-teristic is comparable to heavily discontinuous solid mass. The conventional approach of limit equilibrium methods provide safety factors for the slope but nothing about the stress-strain characteristics of the large dump mass. The designs of dump location and their respective geometry are integrated for the know-how of the stability characteristics of these dumps. The discrete element method uses a circular disk to represent the granular solid mass and their interactions are described by the Newton’s third law of motion. The displacement is described by the sliding of the circular disk. This work is focused on the modeling efficiency of the discrete element methods to represent the behaviour of mine dump masses with the specified joint plane for the limit equilibrium method. The advantage of the work lies on the ease of information retrieval at any point at the dump mass concerning the stress and strain histories, displacement, failures etc. which when integrated produces a better understanding of the stability of the dump masses.

Experimental study on preferential solution flow during dump leaching of low-grade ores

The phenomenon of preferential solution flow during dump leaching of low-grade ores was studied.The formative mechanism of preferential solution flow was investigated through analyzing the relationship between permeability and ore diameter,and the relationship between surface tension and ore diameter.The preferential solution flow happened within the fine ore area when the dump was unsaturated.And it could happen within the coarse ore area when the dump became saturated.The results of experiment show that the outflow of coarse ore area increases sharply with higher applied rate.The outflow of fine ore area is greater than that of coarse ore area when the applied rate is below 3.2 L/min,and the preferential solution flow happens in fine ore area.But the preferential solution flow happens in coarse ore area when the applied rate is higher than 3.2 L/min.The result of the experiment is consistent with the mechanism analyzing.

Electric field distribution in 75 kA drained aluminum reduction cell

Current distribution in a drained aluminum reduction cell is critical due to its influence on the current efficiency, electrolysis stability, anodes and cathodes integrity. A finite element model was developed to simulate the electric field in a 75 kA drained aluminum reduction cell. The current distribution and influences of the cathode inclination angle and anode-cathode distance (ACD) were studied. The results show that relatively large horizontal current density appears in the aluminum film, and the maximum value reaches 600 kA/m2. As the cathode inclination angle increases from 2° to 15°, the maximum current density of the metal pad increases by 15%, while the maximum current density of the aluminum-wettable coating layer decreases by 27%. The influence of the ACD on the current distribution is not obvious.

Numerical simulation of vegetated mine dump slope with reference to small plants

The present paper discusses the effects of small plants on the dump mass reinforcement and slope stability.The roots of smaller plants(such as grasses and shrubs)do not go deep.However,they stabilize the slope by binding the upper layer of dump slope.Shear strength of the dump mass with and without root reinforcement is determined by laboratory shear box instrument.The increased cohesion(apparent cohesion)of upper layer of the dump mass due to plants is determined by fabricated shear box.The kinetic behavior of the dump has been investigated using the FLAC software.The factor of safety has been calculated in order to determine the possible effect of small plants on the stability of the dump slope.It is observed that the small plants do not significantly improve the factor of safety(FOS)of slope.However,it could be useful for early stabilization.The grasses quickly bind the upper surface,whereas shrubs too immensely strengthen the stability of the dump in the initial stage.

Enhanced Field Emission from Printed Carbon Nanotubes by Hard Hairbrush

A method, the morphology of screen printed carbon nanotube pastes is modified using a hard hairbrush, is presented. In this way, the organic matrix material is preferentially removed. Compared to those untreated films, the turn-on electric field of the treated film decreases from 2.2V/μm to 1.6V/μm, while the total emission current of the treated increases from 0.6mA/cm2 to 3mA/cm2, and uniform emission site density image has also been observed.

Thermal conductivity of PVDF/PANI-nanofiber composite membrane aligned in an electric field

Poly(vinylidene fluoride)(PVDF) is a semi-crystalline thermoplastic polymer with excellent thermal stability,electrochemical stability and corrosion resistance, which has been widely studied and applied in industrial nonmetallic heat exchanger and piezoelectric-film sensor. In this study, polyaniline(PANI) nanofibers were synthesized using dodecylbenzene sulfonic acid as the surfactant. The obtained PANI nanofibers were blended in PVDF matrix to enhance thermal conductivity and tensile strength of composite materials. Electric field was applied for the orientation of membrane structure during membrane formation. Scanning electron microscope(SEM) images exhibited that the PANI nanofibers were well-dispersed in the composite membranes. The structure of composite membranes was more orderly after alignment. X-ray diffraction(XRD) and differential scanning calorimetry(DSC) indicated that the content of PANI nanofibers contributed to the transformation of PVDF from α-phase to β-phase. Both the tensile strength and thermal conductivity of composite membranes were significantly improved. This tendency was further enhanced by the application of electric field. The maximum tensile strength was obtained when the content of PANI nanofibers was 3 wt%, which was 46.44% higher than that of pure PVDF membrane. The maximum thermal conductivity of composite membranes after alignment was 84.5% greater than that of pure PVDF membrane when the content of PANI nanofibers was 50 wt%. The composite membrane is a promising new potential material in heat transfer field and the mechanism explored in this study would be informative for further development of similar thermal conductive polymeric materials.

Electromagnetic emanation exploration in FPGA-based digital design

As semiconductor technologies have been shrinking,the speed of circuits,integration density,and the number of I/O interfaces have been significantly increasing.As a consequence,electromagnetic emanation(EME)becomes a critical issue in digital system designs.Electronic devices must meet electromagnetic compatibility(EMC)requirements to ensure that they operate properly,and safely without interference.I/O buffers consume high currents when they operate.The bonding wires,and lead frames are long enough to play as efficient antennas to radiate electromagnetic interference(EMI).Therefore,I/O switching activities significantly contribute to the EMI.In this paper,we evaluate and analyze the impact of I/O switching activities on the EME.We will change the circuit configurations such as the supply voltage for I/O banks,their switching frequency,driving current,and slew rate.Additionally,a trade-off between the switching frequencies and the number of simultaneous switching outputs(SSOs)is also considered in terms of EME.Moreover,we evaluate the electromagnetic emissions that are associated with the different I/O switching patterns.The results show that the electromagnetic emissions associated I/O switching activities depend strongly on their operating parameters and configurations.All the circuit implementations and measurements are carried out on a Xilinx Spartan-3 FPGA.

2D finite element analysis of thermal balance for drained aluminum reduction cells

Based on the principle of energy conservation,the applicable technique for drained cell retrofitted from conventional one was analyzed with 2D finite element model. The model employed a 1D heat transfer scheme to compute iteratively the freeze profile until the thickness variable reached the terminating requirement. The calculated 2D heat dissipation from the cell surfaces was converted into the overall 3D heat loss. The potential drop of the system, freeze profile and heat balance were analyzed to evaluate their variation with technical parameters when designing the 150 kA conventional cell based drained cell. The simulation results show that the retrofitted drained cell is able to keep thermal balance under the conditions that the current is 190 kA, the anodic current density is 0.96 A/cm2, the anode-cathode distance is 2.5 cm, the alumina cover is 16 cm thick with a thermal conductivity of 0.20 W/(m·℃ ) and the electrolysis temperature is 946 ℃ .

A study of legal attributes of carbon emission rights in carbon trading

Clean Development Mechanism (CDM) has given birth to an international carbon trading market prosperity, which provides developing countries with valuable opportunity to address climate change issues right along with economic development and environmental improvement to achieve sustainable development. However, most studies of CDM focus on economics, and few on its legal problems. CDM involves too many aspects. And the clear legal attribute of trading object is the basis of progress of the transaction and also the start point of legal protection. Therefore, this paper in accordance with the inherent principle of property rights economics, and environmental economics in CDM, only discusses CDM carbon emission right legal interpretation and its attribution. The paper recommends that in order to ensure and promote the carbon emission right trading, carbon emission right should be attributed into the system of real rights to be regulated by Real Right Law. In this way, carbon emission right can gain exclusive power of possession and use, which can achieve a clear right def inition of environmental goods in line with Coase's theory to protect Chinese prof it in carbon trading market and promote the development of the carbon trading market further.

Policy Implications for Carbon Trading Market Establishment in China in the 12th Five-Year Period

Based on the survey of international emissions trading system （ETS） and quantitative analysis, policy suggestions on establishing a carbon ETS in China are presented in this study. Sectors sensitive to carbon prices, e.g., the power generation sector and the iron and steel industry, are given priority to be covered by the ETS. Interregional carbon trading should be carried out as early as possible. The cap of the ETS should be based on China＇s carbon intensity reduction target with the floor carbon price for the market being set in the beginning. Suggestions on the infrastructure of ETS are also proposed, including the national wide carbon measuring, reporting, verification system building. account registration system and the legislation to national

Study on comprehensive gas control techniques and practice in coal mines

The origins and main control methods of gas in coal seams were introduced cursorily, and the processes that need to be done in controlling gas, which includes prediction of gas emissions, drainage systems, the means of prevention of gas outbursts, and some suggestions were put forward. The characteristic of different gas emissions and the corresponding counter measures were presented, and ＆ case study of simultaneous extraction of coal and gas in Xieyi Coal Mine was carried out by coal mining and gas extraction without coal-pillar. The field application shows that gas drainage ratio in panel 5121（0） averages about 90% and reaches as high as 95~/0, which will give beneficial references to gas control in coal mines.

Canopy Carbon Exchange on a Coarse-Sand-Field, No-tillage Peach Orchard

Plant carbon sequestration is an effective way to abate the global warming. However, the field-scale carbon exchange on a peach orchard remains unclear. Here, using an eddy covariance technique, the net ecosystem carbon dioxide exchange and energy balance were analyzed on a coarse-sand-field, no-tillage, 12-year-old-peach orchard. The results showed that during full flowering, the ability to sequestrate carbon was significant, it reached on the peak of-0.33 mg （CO2） m^-2 s^-1. During rapid growth, the Bowen ratio was under 0.3 and daily net carbon sequestration reached on the peak of-25.1 g （CO2） m^-2 d^-1. During the leaf fall stage, there is a great deal of CO2 emissions, the peak value of carbon sequestration reached ＋0.60 mg （CO2） m^-2 s^-1. During monitoring period, the daily average of net carbon sequestration and Bowen ratio was 1.22 ± 1.56 and -2.90 ± 6.63 g （CO2） m^-2 d^-1, respectively. The net carbon sequestration could reach -1,052 g （CO2） m^-2 in a year. These results reveal that there is high carbon sequestration on a coarse-sand-field, no-tillage peach orchard.

Analysis of interprovincial trade embodied carbon emissions in Beijing-Tianjin-Hebei and surrounding provinces: based on constructed MRIO Model

The interprovincial trade embodied carbon emissions plays an important role in the national emission reduction target among China's provinces. Furthermore, it will affect the smooth start-up of the national carbon trade market as well as the implementation of targets in 2030 for dealing with the climate change. Based on constructed MRIO model, this paper analyzes the embodied carbon emission trade flows among Beijing, Tianjin, Hebei and surrounding regions such as Shanxi, Shaanxi, and Inner Mongolia. The results indicate that six provinces have formed different patterns of carbon trade balance, where Beijing, Tianjin, and Hebei provinces are in a deficit position, while the other three provinces are in a surplus position.Beijing, Tianjin, and Hebei have transferred part of the carbon emissions to the other three provinces, which shows greater heterogeneity among various provinces and provincial different sectors. On basis of the conclusions, this paper puts forward some suggestions on provincial decomposition, responsibility distribution, and provincial collaborative reduction for national emission reduction targets.

Explanation of Tautomerism and Isomerization in Terms of the Magnetic Field

A study of the influence of magnetic field on the tautomerism, the authors proposed a new method for predicting possible new intra- and intermolecular rearrangements due to tautomerism. The authors have proposed a general mechanism of possible rearrangements and tautomerism.

Study on carbon intensity trading market based on carbon finance mechanism

As the largest developing country in the world, China has not be involved in the obligation of emissions reduction in the （〈Kyoto Protocol）） . But it has become the largest CO2 emissions countries in the world. This makes China confronted with more pressure of carbon emissions reduction in the post-Kyoto era, and face great challenges in response to climate change issues. On one hand, China＇ s economic growth stage has decided that the situation of more energy consumption and increased carbon emissions is diffficult to reverse in the short term; On the other hand, the traditional policy under the control of total amount of carbon emission has largely restricted economic development. If a developing country in economic transition is carried out compulsory absolute amount of carbon reduction policies, its economic activity and social consumption will be imposed additional constraints inevitably, which will eventually lead to lower economic competitiveness and decline in social standards of living. Ultimately it will affect the good effects of carbon emissions reduction, so the policy can not achieve a satisfactory result. This paper introduces the financial mechanism into the carbon market model, extends the time of model from one phase to multi-phase. And this paper tries to establish a cross-time carbon credits trade system, and the current strength of the traditional carbon emission market trade model is extended. The paper designs two type of option mechanism model--call options trade carbon emissions model and put options carbon emissions model. Models＇ results show that choosing options tool to extend our traditional carbon market model can bring following impacts on carbon market development： trade costs have fallen, the carbon intensity also has descended, and has realized the flow of carbon intensity in diffident time; it enables manufacturers to effectively avoid the risk of carbon emissions trade; it increases the flexibility and maneuverability of the carbon trade market. Finally, the policy recommendations in the financial mechanisms carbon market trade are put forward.

Regional Allocation of CO_2 Intensity Reduction Targets Based on Cluster Analysis

To meet China＇s CO2 intensity target of 40%-45% reduction by 2020 based on the 2005 level, a regional allocation method based on cluster analysis is developed. Thirty Chinese provinces are classified into six groups based on economy, emissions, and reduction potential indicators. Under the equity principle, the two most developed groups axe assigned the highest reduction targets （55% and 65%, respectively）. However, their reduction potent!al is limited. Under the efficiency principle, the two groups with the highest reduction potential take the highest targets （48% and 61%, respectively）, but their economy is relatively backward. When equity and efficiency are equally weighted, the 5th group with a prominent reduction potential takes the highest target （54%）, and the 2nd and the 3rd groups with large industry scales take the second highest target （49%）. However, under all the three allocation schemes, the targets are not greater than 40% for the 4th and the 6th groups, which have a relatively low economic ability, emissions, and reduction potential. Due to inconsistency between economic and reduction potential, corresponding market mechanisms and policy instruments should be established to ensure equity and efficiency of regional target allocation.

Inspection of pipeline girth welds with ultrasonic phased array technique

A novel automatic ultrasonic system used for the inspection of pipeline girth welds is developed, in which a linear phased array transducer using electronic scan is adopted. Optimal array parameters are determined based on a mathematical model of acoustic field for linear phased army derived from Huygens＇ principle. The testing method and the system structure are introduced. The experimental results show that the phased array transducer system has the same detectability as that of conventional ultrasonic transducer system, but the system architecture can be simplified greatly, and the testing flexibility and the testing speed can be improved greatly.

A Comparative Analysis of Emission of Methane from Livestock Farms in Enugu, Eastern Nigeria

This study compares CH4 emissions from different livestock farms （poultry, cattle and swine farms） in Enugu, Eastern Nigeria. Data on animal type, number and age were obtained by direct observations while the concentrations of CH4 in the livestock farms were measured with the Gasman Crowcrown Gas Monitor. Daily ambient air temperature and rainfall data were obtained from the Nigerian Meteorological Agency （NIMET） Enugu. Regression analysis was used to determine possible relationships existing between weather parameters and CH4 emissions while the One-Way ANOVA was used to determine variance equality in means of greenhouse gas emission spatially at P 〈 0.05. Minimum and maximum temperatures ranged between 21.9 and 22.7 ℃ and 26.2 and 30.6 ℃ respectively, with rainfall ranging between 0.0 and 12.5 mm during the study period. Of the livestock farms sampled, swine farm emitted the highest concentrations of the greenhouse gas at both the livestock house （2.88 ± 0.28 ppm） and feaces decomposition site （2.30 ±0.30 ppm）, while poultry emitted the least concentrations of 1.96 ± 0.23 and 1.92 ± 0.10 ppm in the livestock house and faeces decomposition locations respectively. Age and number of livestock did not affect emissions of greenhouse gas. Though the prevailing weather parameters measured （temperature and rainfall） did not exert significant influences on greenhouse gas emissions, significant spatial variations in emissions in the feaces decomposition sites of the farmhouses was observed at P 〈 0.05. CH4emission in cattle farmhouse （2.80 ± 0.46 ppm） and swine farmhouse （2.88 ± 0.28 ppm） as well as those measured in the faeces decomposition locations of swine farmhouse （2.30 ± 0.30 ppm） exceeded the CH4 concentration level of 2.0 ppm measured in dry air at sea level. There is need for a further research on the effects of animal age, growth rate and biochemistry on CH4 emissions at the farmhouses.