This study addresses the comparative carbon emissions of different transportation modes within a unified evaluation framework,focusing on their carbon footprints from inception to disposal.Specifically,the entire life...This study addresses the comparative carbon emissions of different transportation modes within a unified evaluation framework,focusing on their carbon footprints from inception to disposal.Specifically,the entire life cycle carbon emissions of High-Speed Rail(HSR),battery electric vehicles,conventional internal combustion engine vehicles,battery electric buses,and conventional internal combustion engine buses are analyzed.The life cycle is segmented into vehicle manufacturing,fuel or electricity production,operational,and dismantlingrecycling stages.This analysis is applied to the Beijing-Tianjin intercity transportation system to explore emission reduction strategies.Results indicate that HSR demonstrates significant carbon emission reduction,with an intensity of only 24%-32% compared to private vehicles and 47%-89% compared to buses.Notably,HSR travel for Beijing-Tianjin intercity emits only 24% of private vehicle emissions,demonstrating the emission reduction benefits of transportation structure optimization.Additionally,predictive modeling reveals the potential for carbon emission reduction through energy structure optimization,providing a guideline for the development of effective transportation management systems.展开更多
Carbon capture, utilization, and storage (CCUS) have garnered extensive attention as a target of carbon neutrality in China. The development trend of international CCUS projects indicates that the cluster construction...Carbon capture, utilization, and storage (CCUS) have garnered extensive attention as a target of carbon neutrality in China. The development trend of international CCUS projects indicates that the cluster construction of CCUS projects is the main direction of future development. The cost reduction potential of CCUS cluster projects has become a significant issue for CCUS stakeholders. To assess the cost reduction potential of CCUS cluster projects, we selected three coal-fired power plants in the coastal area of Guangdong as research targets. We initially assessed the costs of building individual CCUS projects for each plant and subsequently designed a CCUS cluster project for these plants. By comparing individual costs and CCUS cluster project costs, we assessed the cost reduction potential of CCUS cluster projects. The results show that the unit emission reduction cost for each plant with a capacity of 300 million tonnes per year is 392.34, 336.09, and 334.92 CNY/tCO_(2). By building CCUS cluster project, it could save 56.43 CNY/tCO_(2) over the average cost of individual projects (354.45 CNY/tCO_(2)) when the total capture capacity is 9 million tonnes per year (by 15.92%). Furthermore, we conducted a simulation for the scenario of a smaller designed capture capacity for each plant. We found that as the capture scale increases, the cost reduction potential is higher in the future.展开更多
The influences of the time, temperature and atmosphere on the reduction swelling of oxidized pellets were investigated by single factor experiments. The mechanisms of reduction swelling of oxidized pellets were analyz...The influences of the time, temperature and atmosphere on the reduction swelling of oxidized pellets were investigated by single factor experiments. The mechanisms of reduction swelling of oxidized pellets were analyzed and investigated by SEM (scanning electron microscopy) and XRD (X-ray diffractometer) analysis. The results show that the change rules of reduction swelling index of oxidized pellets in different reduction atmospheres are very similar. With the increase of reduction time, the reduction swelling index moves up firstly and then down. When the reduction temperature is above 900 ℃, α-quartz turns into α-tridymite, and the transition generates additional volume expansion effect. The reduction swelling index changes faster in H2 atmosphere than in CO atmosphere. Increasing Ha content in the reduction atmosphere is useful to decrease the reduction swelling index, but it is also easy to cause oxidized pellets cracking.展开更多
This study compared effects of three different valent iron(Fe^(0),Fe(II)and Fe(III))on enhanced anaerobic sludge digestion,focusing on the changes of oxidation reduction potential(ORP),dissolved organic nitrogen(DON),...This study compared effects of three different valent iron(Fe^(0),Fe(II)and Fe(III))on enhanced anaerobic sludge digestion,focusing on the changes of oxidation reduction potential(ORP),dissolved organic nitrogen(DON),and microbial community.Under the same iron dose in range of 0−160 mg/L after an incubation period of 30 days(d),the maximum methane production rate of sludge samples dosed with respective Fe^(0),Fe(II)and Fe(III)at the same concentration showed indiscernible differences at each iron dose,regardless of the different iron valence.Moreover,their behavior in changes of ORP,DON and microbial community was different:(1)the addition of Fe^(0) made the ORP of sludge more negative,and the addition of Fe(II)and Fe(III)made the ORP of sludge less negative.However,whether being more or less negative,the changes of ORP may show unobservable effects on methane yield when it ranged from−278.71 to−379.80 mV;(2)the degradation of dissolved organic nitrogen,particularly proteins,was less efficient in sludge samples dosed with Fe^(0) compared with those dosed with Fe(II)and Fe(III)after an incubation period of 30 d.At the same dose of 160 mg/L iron,more cysteine was noted in sludge samples dosed with Fe(II)(30.74 mg/L)and Fe(III)(27.92 mg/L)compared with that dosed with Fe^(0)(21.75 mg/L);(3)Fe^(0) particularly promoted the enrichment of Geobacter,and it was 6 times higher than those in sludge samples dosed with Fe(II)and Fe(III)at the same dose of 160 mg/L iron.展开更多
Coal-based olefin(CTO)industry as a complement of traditional petrochemical industry plays vital role in China’s national economic development.However,high CO2 emission in CTO industry is one of the fatal problems to...Coal-based olefin(CTO)industry as a complement of traditional petrochemical industry plays vital role in China’s national economic development.However,high CO2 emission in CTO industry is one of the fatal problems to hinder its development.In this work,the carbon emission and mitigation potentials by different reduction pathways are evaluated.The economic cost is analyzed and compared as well.According to the industry development plan,the carbon emissions from China’s CTO industry will attain 189.43 million ton C02(MtC02)and 314.11 MtC02 in 2020 and 2030,respectively.With the advanced technology level,the maximal carbon mitigation potential could be attained to 15.3%and 21.9%in 2020 and 2030.If the other optional mitigation ways are combined together,the carbon emission could further reduce to some extent.In general,the order of mitigation potential is followed as:feedstock alteration by natural gas>C02 hydrogenation with renewable electricity applied>CCS technology.The mitigation cost analysis indicates that on the basis of 2015 situation,the economic penalty for feedstock alteration is the lowest,ranged between 186 and 451 CNY/tCO2,and the cost from CCS technology is ranged between 404 and 562 CNY/tC02,which is acceptable if the C02 enhanced oil recovery and carbon tax are considered.However,for the C02 hydrogenation technology,the cost is extremely high and there is almost no application possibility at present.展开更多
Accurate estimation of the postmortem interval(PMI)is an important task in forensic practice.In the last half-century,the use of postmortem biochemistry has become an important ancillary method in determining the time...Accurate estimation of the postmortem interval(PMI)is an important task in forensic practice.In the last half-century,the use of postmortem biochemistry has become an important ancillary method in determining the time of death.The present study was carried out to determine the correlation between blood oxidation-reduction potential(ORP)values and PMIs,and to develop a three-dimensional surface equation to estimate the PMI under various temperature conditions.A total of 48 rabbits were placed into six groups and sacrificed by air embolism.Blood was obtained from the right ventricle of each rabbit,and specimens were stored at 10℃,15℃,20℃,25℃,30℃,and 35℃.At different PMIs(once every 4 h),the blood ORP values were measured using a PB-21 electrochemical analyzer.Statistical analysis and curve fitting of the data yielded cubic polynomial regression equations and a surface equation at different temperatures.Result:The results showed that there was a strong positive correlation between the blood ORP values at different temperatures and the PMI.This study provides another example of using a three-dimensional surface equation as a tool to estimate the PMI at various temperature conditions.展开更多
A potential reduction algorithm is proposed for optimization of a convex function subject to linear constraints.At each step of the algorithm,a system of linear equations is solved to get a search direction and the Ar...A potential reduction algorithm is proposed for optimization of a convex function subject to linear constraints.At each step of the algorithm,a system of linear equations is solved to get a search direction and the Armijo's rule is used to determine a stepsize.It is proved that the algorithm is globally convergent.Computational results are reported.展开更多
Potential field due to line sources residing on slender heterogeneities is involved in various areas,such as heat conduction,potential flow,and electrostatics.Often dipolar line sources are either prescribed or induce...Potential field due to line sources residing on slender heterogeneities is involved in various areas,such as heat conduction,potential flow,and electrostatics.Often dipolar line sources are either prescribed or induced due to close interaction with other objects.Its calculation requires a higher-order scheme to take into account the dipolar effect as well as net source effect.In the present work,we apply such a higher-order line element method to analyze the potential field with cylindrical slender heterogeneities.In a benchmark example of two parallel rods,we compare the line element solution with the boundary element solution to show the accuracy as a function in terms of rods distance.Furthermore,we use more complicated examples to demonstrate the capability of the line element technique.展开更多
The solution purification process is an essential step in zinc hydrometallurgy. The performance of solution purification directly affects the normal functioning and economical benefits of zinc hydrometallurgy. This pa...The solution purification process is an essential step in zinc hydrometallurgy. The performance of solution purification directly affects the normal functioning and economical benefits of zinc hydrometallurgy. This paper summarizes the authors' recent work on the modeling, optimization, and control of solution purification process. The online measurable property of the oxidation reduction potential(ORP) and the multiple reactors, multiple running statuses characteristic of the solution purification process are extensively utilized in this research. The absence of reliable online equipment for detecting the impurity ion concentration is circumvented by introducing the oxidationreduction potential into the kinetic model. A steady-state multiple reactors gradient optimization, unsteady-state operationalpattern adjustment strategy, and a process evaluation strategy based on the oxidation-reduction potential are proposed. The effectiveness of the proposed research is demonstrated by its industrial experiment.展开更多
The effects of cathode potentials and initial nitrate concentrations on nitrate reduction in bio- electrochemical systems (BESs) were reported. These factors could partition nitrate reduction between denitrification...The effects of cathode potentials and initial nitrate concentrations on nitrate reduction in bio- electrochemical systems (BESs) were reported. These factors could partition nitrate reduction between denitrification and dissimilatory nitrate reduction to ammonium (DNRA). Pseudomonas alcaliphilastrain MBR utilized an electrode as the sole electron donor and nitrate as the sole electron acceptor. When the cathode potential was set from -0.3 to -I.1 V (vs. Ag/AgC1) at an initial nitrate concentration of 100 mg NO^-N/L, the DNRA electron recovery increased from (10.76 ± 1.6)% to (35.06 ± 0.99)%; the denitrification electron recovery decreased from (63.42 ± 1,32)% to (44.33 ± 1.92)%. When the initial nitrate concentration increased from (29.09 ± 0.24) to (490.97 ± 3.49) mg NO3-N/L at the same potential (-0.9 V), denitrification electron recovery increased from (5.88 ± 1.08)% to (50.19 ±2.59)%; the DNRA electron recovery declined from (48.79 ±1.32)% to (16.02 ± 1.41)%. The prevalence of DNRA occurred at high ratios of electron donors to acceptors in the BESs and denitrification prevailed against DNRA under a lower ratio of electron donors to acceptors. These results had a potential application value of regulating the transformation of nitrate to N2 or ammonium in BESs for nitrate removal.展开更多
In this paper we introduce a primal-dual potential reduction algorithm for positive semi-definite programming. Using the symetric preserving scalings for both primal and dual interior matrices, we can construct an alg...In this paper we introduce a primal-dual potential reduction algorithm for positive semi-definite programming. Using the symetric preserving scalings for both primal and dual interior matrices, we can construct an algorithm which is very similar to the primal-dual potential reduction algorithm of Huang and Kortanek [6] for linear programming. The complexity of the algorithm is either O(nlog(X0 · S0/ε) or O(nlog(X0· S0/ε) depends on the value of ρ in the primal-dual potential function, where X0 and S0 is the initial interior matrices of the positive semi-definite programming.展开更多
Presents a regular splitting and potential reduction method for solving a quadratic programming problem with box constraints. Discussion on the regular splitting and potential reduction algorithm; Complexity analysis ...Presents a regular splitting and potential reduction method for solving a quadratic programming problem with box constraints. Discussion on the regular splitting and potential reduction algorithm; Complexity analysis of the algorithm; Analysis of the complexity bound on obtaining an approximate solution.展开更多
With the Kigali Amendment(KA)coming into effect in China,the control of hydrofuorocarbons(HFCs)emissions has become more imperative.The mobile air-conditioning(MAC)sector is one of the important HFCs consumer sectors,...With the Kigali Amendment(KA)coming into effect in China,the control of hydrofuorocarbons(HFCs)emissions has become more imperative.The mobile air-conditioning(MAC)sector is one of the important HFCs consumer sectors,and therefore studying its feasible mitigation paths and costs is of great significance to Chinas successful implementation of KA.This study used the bottom-up method with updated emission factors to re-evaluate the emission inventory of HFCs from the MAC sector in China from 2005 to 2020.The average annual growth rate of HFCs consumption in the MAC sector is 9.8%,and HFCs emissions have increased from 5.8(5.3-6.2)kt in 2005 to 22.2(20.6-23.8)kt in 2020,with an average annual growth rate of 8.8%.Using the Gompertz model combined with the Weibull function of vehicle survival rate,the ownership and new registrations of internal combustion engine vehicles(ICEVs)and electric vehicles(EVs)in China are predicted.The ownership of ICEVs and EVs is projected to be 310 million and 91 million in 2030,respectively and 2 million and 641 million in 2060,respectively.HFCs emissions in the MAC sector would reach 59.8(55.3-64.3)kt(80.093.0 Mt CO_(2-eq))in 2060 if without any control measure.To implement the KA,the cumulative of 1.6 Gt CO_(2-eq) emissions would be reduced.Under the other two accelerated mitigation scenarios,the MAC sector's HFCs will reach their emissions peak in 2028 and 2025 and achieve zero emissions in 2050 and 2046,respectively.Under the accelerated mitigation with recovery scenario,the cumulative emissions are only 15.0%of the business as usual(BAU)scenario.Using HFO-1234yf as the substitute,the unit abatement cost of the MAC sector is 27.3-37.4 USD _(t)^(-1)CO_(2-eq).展开更多
Permeable reactive barriers(PRBs)are used for groundwater remediation at contaminated sites worldwide.This technology has been efficient at appropriate sites for treating organic and inorganic contaminants using zero-...Permeable reactive barriers(PRBs)are used for groundwater remediation at contaminated sites worldwide.This technology has been efficient at appropriate sites for treating organic and inorganic contaminants using zero-valent iron(ZVI)as a reductant and as a reactive material.Continued development of the technology over the years suggests that a robust understanding of PRB performance and the mechanisms involved is still lacking.Conflicting information in the scientific literature downplays the critical role of ZVI corrosion in the remediation of various organic and inorganic pollutants.Additionally,there is a lack of information on how different mechanisms act in tandem to affect ZVI-groundwater systems through time.In this review paper,we describe the underlying mechanisms of PRB performance and remove isolated misconceptions.We discuss the primary mechanisms of ZVI transformation and aging in PRBs and the role of iron corrosion products.We review numerous sites to reinforce our understanding of the interactions between groundwater contaminants and ZVI and the authigenic minerals that form within PRBs.Our findings show that ZVI corrosion products and mineral precipitates play critical roles in the long-term performance of PRBs by influencing the reactivity of ZVI.Pore occlusion by mineral precipitates occurs at the influent side of PRBs and is enhanced by dissolved oxygen and groundwater rich in dissolved solids and high alkalinity,which negatively impacts hydraulic conductivity,allowing contaminants to potentially bypass the treatment zone.Further development of site characterization tools and models is needed to support effective PRB designs for groundwater remediation.展开更多
Although gold nanorods(GNRs)have been produced with different dimensions and aspect ratios,the current synthesis methods through seed-mediated growth are far from ideal,for instance,the quality(rod yield)and the quant...Although gold nanorods(GNRs)have been produced with different dimensions and aspect ratios,the current synthesis methods through seed-mediated growth are far from ideal,for instance,the quality(rod yield)and the quantity(gold conversion)cannot be simultaneously satisfied.More critically,there is no molecular level understanding of the growth mechanism.Here,we solved the problem by employing the stoichiometric ratio of reactants and tuning the reactivity of the reductant through adjusting the initial pH value of the growth solution to achieve both good quality and high quantity simultaneously.We also extended our strategy to other enols besides ascorbic acid,such as phenolic compounds,and found that the optimal pH for GNRs synthesis depends on the structure of the individual compound.The mechanistic insight greatly enriches the toolbox of reductants for GNRs growth and makes it possible to synthesize GNRs at both acidic and basic conditions.An interesting phenomenon is that for most of the phenolic compounds we tested,the morphology of the final products follows the same sphere-rod-sphere trend as the initial pH value of the reaction increases,whether it is under acidic or basic conditions,which cannot be explained by any previously proposed mechanism.The effect of pH is mainly attributed to the regulation of the reduction potential of the reductants,and thus the reaction rate.A model has been proposed to explain the dependence of anisotropic growth of GNRs on the concentration gradient of reactants around the seeds,which is decided by both the reaction rate and diffusion rate.展开更多
The succession of fungal community,trophic mode and metabolic characteristics were evaluated in 60 days composting of swine manure by high-throughput sequencing,FUNGuild and Biolog method,respectively.The result showe...The succession of fungal community,trophic mode and metabolic characteristics were evaluated in 60 days composting of swine manure by high-throughput sequencing,FUNGuild and Biolog method,respectively.The result showed that the ftingal community diversity reached to the highest level(76 OTUs)in the thermophilic phase of composting,then sustained decline to 15 OTUs after incubation.There were 10 fungal function groups in the raw swine manure.Pathotroph-saprotroph fungi reached to 15.91%on Day-10but disappeared on Day-60.Dung saprotroph-undefined saprotroph fungi grown from 0.19%to 52.39%during the treatment.The ftmgal community had more functional groups but the lower substrate degradation rates in the thermophilic phase.The fungal communities on Day-0 and Day-60 had the highest degradation rates of amino acids and polymers,respectively.Redundancy analysis showed that ORP(49.6%),VS/Ash(45.3%)and moisture(39.2%)were the main influence factors on the succession of fungal community in the swine manure composting process.展开更多
The feasibility of pH and oxidation reduction potential(ORP)as on-line control parameters to advance nitrogen removal in pulsed sequencing batch reactors(SBR)was evaluated.The pulsed SBR,a novel operational mode of SB...The feasibility of pH and oxidation reduction potential(ORP)as on-line control parameters to advance nitrogen removal in pulsed sequencing batch reactors(SBR)was evaluated.The pulsed SBR,a novel operational mode of SBR,was utilized to treat real municipal wastewater accompanied with adding ethanol as external carbon source.It was observed that the bending-point(apex and knee)of pH and ORP profiles can be used to control denitrification process at a low influent C/N ratio while dpH/dt can be used to control the nitrification and denitrification process at a high influent C/N ratio.The experimental results demon-strated that the effluent total nitrogen can be reduced to lower than 2 mg/L,and the average total nitrogen(TN)removal effici ency was higher than 98%by using real-time controll strategy.展开更多
Carbon emission is inevitable,and changes with energy consumption and economic development,presents policy options toward sustainable development path.Currently,there is little assurance from policymakers in committin...Carbon emission is inevitable,and changes with energy consumption and economic development,presents policy options toward sustainable development path.Currently,there is little assurance from policymakers in committing to climate change pledges:taking the Middle-East and North African(MENA)region as a specific case with using 2019 as a cut-off period.We conducted an interim assessment of the Paris Agreement to ascertain whether climate actions are in tandem with emissions reduction targets.Making use of difference-in-difference technique as a quasiexperiment supported by fixed-effects and placebo treatment models,the results point to evidence of less than 1%effective CO_(2) emissions reduction as of 2019 compared to the 2015 level.The current carbon emissions reduction commitment level is far-reaching contrary to the Nationally Determined Contributions(NDCs)pledged(16.43%on average by 2030 compared to the 2015 level).The analysis suggests that achieving NDCs commitments are currently major burden on policymakers since the economic development is highly linked with nonrenewable energy consumption.Furthermore,a more comprehensive framework when accounting for all available renewable and clean energy projects shows reduction levels in the range of 30%-40%from 2020 to 2030.These results suggest that the Paris Agreement in MENA countries may be more effective from 2020,thus underscore the importance of capturing ongoing projects(involving renewable and clean energy technologies)into interim policy assessment.The shared implication is that greater efforts are demanded from the region and at country levels to further decrease emissions through the use of negative emissions technologies particularly in the electricity generation sector.展开更多
This paper investigated aqueous chemistry for two geothermal spring groups responsive and sensitive to flow fluctuations induced by earthquakes. Quake monitorings are favored for their being in residential areas with ...This paper investigated aqueous chemistry for two geothermal spring groups responsive and sensitive to flow fluctuations induced by earthquakes. Quake monitorings are favored for their being in residential areas with well-preserved natural flow systems in Xinyi City's Xijiang Hot Springs and Fengshun County's Shihu Hot Spring. The hot springs are typical in temperatures and flow rates in southern China's Guangdong Province. Physical and chemical conditions deep down in the heat sources are important constraints on earthquake, fluid flow, reactive solute transport and heat transfer, but remain challenging to address via field observations and numerical experiments. In this paper, we made daily and annual observations on flow rates, temperature, and/or aqueous chemistry. We employed strontium isotopes as tracers for the water sources, equilibrium phase diagram for K-feldspar and albite stability, and Na-K-Mg diagram for heat reservoir temperatures. The abundant sulfite content in Xi- jiang Hot Springs is discussed. Our main finding are that the deep fault springs are characterized by low reduction-oxidation potential at around -200- -150 mV and relatively large daily flow variations. The resuits provide scientific background features on the field sites regarding earthquake monitoring and predictions and geothermal reservoir.展开更多
Pulse-width modulation(PWM)sprays can improve flow accuracy by adjusting duty cycle and frequency signal which accurately controls the relative proportion of opening time of solenoid valve.The objective of this resear...Pulse-width modulation(PWM)sprays can improve flow accuracy by adjusting duty cycle and frequency signal which accurately controls the relative proportion of opening time of solenoid valve.The objective of this research was to determine the impacts of PWM duty cycle and frequency on spray drift characteristic.Spray tests were conducted in a wind tunnel with a PWM variable-rate spraying system.The airborne drift and sediment drift were determined with tracer method,and the drift potential reduction(DPR)compared with reference condition of 100%duty cycle at vertical profile and horizontal planes were calculated,respectively.The results show that,at a given frequency,droplet size decreases with the increase of duty cycle,the main reason is that the liquid does not reach full pattern development at lower duty cycle.Duty cycle has a greater impact than the frequency on spray drift,the influence weights of duty cycle on airborne drift and sediment drift were 88.32%and 77.89%,respectively.At a lower PWM frequency,in addition to the droplet size,the spray drift may be affected by the pulsed spray pattern.From the perspective of reducing spray drift,it is recommended that the PWM duty cycle should be set in the range of 20%-70%to reduce the potential drift in PWM sprays.This research provides a pesticide drift reduction scheme for variable spraying technology,which can serve as a theoretical basis for PWM parameter selection.展开更多
基金the financial support of the National Natural Science Foundation of China(U2268208)Science and Technology Program of China National Railway Group Co.,Ltd.(N2022×037).
文摘This study addresses the comparative carbon emissions of different transportation modes within a unified evaluation framework,focusing on their carbon footprints from inception to disposal.Specifically,the entire life cycle carbon emissions of High-Speed Rail(HSR),battery electric vehicles,conventional internal combustion engine vehicles,battery electric buses,and conventional internal combustion engine buses are analyzed.The life cycle is segmented into vehicle manufacturing,fuel or electricity production,operational,and dismantlingrecycling stages.This analysis is applied to the Beijing-Tianjin intercity transportation system to explore emission reduction strategies.Results indicate that HSR demonstrates significant carbon emission reduction,with an intensity of only 24%-32% compared to private vehicles and 47%-89% compared to buses.Notably,HSR travel for Beijing-Tianjin intercity emits only 24% of private vehicle emissions,demonstrating the emission reduction benefits of transportation structure optimization.Additionally,predictive modeling reveals the potential for carbon emission reduction through energy structure optimization,providing a guideline for the development of effective transportation management systems.
基金the Department of Education of Guangdong Province(No.2021KQNCX143)the National Social Science Foundation of China(Grant No.21AGJ009)the Research Base of Carbon Neutral Finance for Guangdong-Hong Kong-Macao(No.22ATJR03).
文摘Carbon capture, utilization, and storage (CCUS) have garnered extensive attention as a target of carbon neutrality in China. The development trend of international CCUS projects indicates that the cluster construction of CCUS projects is the main direction of future development. The cost reduction potential of CCUS cluster projects has become a significant issue for CCUS stakeholders. To assess the cost reduction potential of CCUS cluster projects, we selected three coal-fired power plants in the coastal area of Guangdong as research targets. We initially assessed the costs of building individual CCUS projects for each plant and subsequently designed a CCUS cluster project for these plants. By comparing individual costs and CCUS cluster project costs, we assessed the cost reduction potential of CCUS cluster projects. The results show that the unit emission reduction cost for each plant with a capacity of 300 million tonnes per year is 392.34, 336.09, and 334.92 CNY/tCO_(2). By building CCUS cluster project, it could save 56.43 CNY/tCO_(2) over the average cost of individual projects (354.45 CNY/tCO_(2)) when the total capture capacity is 9 million tonnes per year (by 15.92%). Furthermore, we conducted a simulation for the scenario of a smaller designed capture capacity for each plant. We found that as the capture scale increases, the cost reduction potential is higher in the future.
基金Sponsored by National Natural Science Foundation of China(51104014)National Natural Science Foundation of China and Baosteel(51134008)National Basic Research Program(973Program)of China(2012CB720401)
文摘The influences of the time, temperature and atmosphere on the reduction swelling of oxidized pellets were investigated by single factor experiments. The mechanisms of reduction swelling of oxidized pellets were analyzed and investigated by SEM (scanning electron microscopy) and XRD (X-ray diffractometer) analysis. The results show that the change rules of reduction swelling index of oxidized pellets in different reduction atmospheres are very similar. With the increase of reduction time, the reduction swelling index moves up firstly and then down. When the reduction temperature is above 900 ℃, α-quartz turns into α-tridymite, and the transition generates additional volume expansion effect. The reduction swelling index changes faster in H2 atmosphere than in CO atmosphere. Increasing Ha content in the reduction atmosphere is useful to decrease the reduction swelling index, but it is also easy to cause oxidized pellets cracking.
基金funded by the National Natural Science Foundation of China(Grant Nos.52170133,U1901216,51708239)the Natural Science Foundation of Hubei Province(No.2020CFA042)Applied Basic Research Program of Wuhan(No.2020020601012277),and Program for HUST Academic Frontier Youth Team.
文摘This study compared effects of three different valent iron(Fe^(0),Fe(II)and Fe(III))on enhanced anaerobic sludge digestion,focusing on the changes of oxidation reduction potential(ORP),dissolved organic nitrogen(DON),and microbial community.Under the same iron dose in range of 0−160 mg/L after an incubation period of 30 days(d),the maximum methane production rate of sludge samples dosed with respective Fe^(0),Fe(II)and Fe(III)at the same concentration showed indiscernible differences at each iron dose,regardless of the different iron valence.Moreover,their behavior in changes of ORP,DON and microbial community was different:(1)the addition of Fe^(0) made the ORP of sludge more negative,and the addition of Fe(II)and Fe(III)made the ORP of sludge less negative.However,whether being more or less negative,the changes of ORP may show unobservable effects on methane yield when it ranged from−278.71 to−379.80 mV;(2)the degradation of dissolved organic nitrogen,particularly proteins,was less efficient in sludge samples dosed with Fe^(0) compared with those dosed with Fe(II)and Fe(III)after an incubation period of 30 d.At the same dose of 160 mg/L iron,more cysteine was noted in sludge samples dosed with Fe(II)(30.74 mg/L)and Fe(III)(27.92 mg/L)compared with that dosed with Fe^(0)(21.75 mg/L);(3)Fe^(0) particularly promoted the enrichment of Geobacter,and it was 6 times higher than those in sludge samples dosed with Fe(II)and Fe(III)at the same dose of 160 mg/L iron.
基金sponsored by the National Key Research and Development Program(No.2016YFA0602603,No.2016YFA0602602)Chinese Academy of Sciences Youth Innovation Promotion Association FundingShanghai Natural Science Foundation(No.18ZR1444200)
文摘Coal-based olefin(CTO)industry as a complement of traditional petrochemical industry plays vital role in China’s national economic development.However,high CO2 emission in CTO industry is one of the fatal problems to hinder its development.In this work,the carbon emission and mitigation potentials by different reduction pathways are evaluated.The economic cost is analyzed and compared as well.According to the industry development plan,the carbon emissions from China’s CTO industry will attain 189.43 million ton C02(MtC02)and 314.11 MtC02 in 2020 and 2030,respectively.With the advanced technology level,the maximal carbon mitigation potential could be attained to 15.3%and 21.9%in 2020 and 2030.If the other optional mitigation ways are combined together,the carbon emission could further reduce to some extent.In general,the order of mitigation potential is followed as:feedstock alteration by natural gas>C02 hydrogenation with renewable electricity applied>CCS technology.The mitigation cost analysis indicates that on the basis of 2015 situation,the economic penalty for feedstock alteration is the lowest,ranged between 186 and 451 CNY/tCO2,and the cost from CCS technology is ranged between 404 and 562 CNY/tC02,which is acceptable if the C02 enhanced oil recovery and carbon tax are considered.However,for the C02 hydrogenation technology,the cost is extremely high and there is almost no application possibility at present.
基金This study was supported by the Key Projects in the National Science and Technology Pillar Program during the Eleventh Five‑year Plan Period(2012BAK16B02)the Scientific Research Foundation for the Returned Overseas Chinese Scholars,the State Education Ministry[(2013)1792]+2 种基金the Training Programmers Foundation for the Beijing Talents(2013D002023000002)the Beijing Planning Project of Philosophy and Social Science(13FXC032)the Project of Young Teachers’Academic Innovation Team by China University of Political Science and Law(2014CXTD04).
文摘Accurate estimation of the postmortem interval(PMI)is an important task in forensic practice.In the last half-century,the use of postmortem biochemistry has become an important ancillary method in determining the time of death.The present study was carried out to determine the correlation between blood oxidation-reduction potential(ORP)values and PMIs,and to develop a three-dimensional surface equation to estimate the PMI under various temperature conditions.A total of 48 rabbits were placed into six groups and sacrificed by air embolism.Blood was obtained from the right ventricle of each rabbit,and specimens were stored at 10℃,15℃,20℃,25℃,30℃,and 35℃.At different PMIs(once every 4 h),the blood ORP values were measured using a PB-21 electrochemical analyzer.Statistical analysis and curve fitting of the data yielded cubic polynomial regression equations and a surface equation at different temperatures.Result:The results showed that there was a strong positive correlation between the blood ORP values at different temperatures and the PMI.This study provides another example of using a three-dimensional surface equation as a tool to estimate the PMI at various temperature conditions.
文摘A potential reduction algorithm is proposed for optimization of a convex function subject to linear constraints.At each step of the algorithm,a system of linear equations is solved to get a search direction and the Armijo's rule is used to determine a stepsize.It is proved that the algorithm is globally convergent.Computational results are reported.
文摘Potential field due to line sources residing on slender heterogeneities is involved in various areas,such as heat conduction,potential flow,and electrostatics.Often dipolar line sources are either prescribed or induced due to close interaction with other objects.Its calculation requires a higher-order scheme to take into account the dipolar effect as well as net source effect.In the present work,we apply such a higher-order line element method to analyze the potential field with cylindrical slender heterogeneities.In a benchmark example of two parallel rods,we compare the line element solution with the boundary element solution to show the accuracy as a function in terms of rods distance.Furthermore,we use more complicated examples to demonstrate the capability of the line element technique.
基金supported by the National Natural Science Foundation of China(61603418,61673400,61273185)the Foundation for Innovative Research Groups of the National Natural Science Foundation of China(61621062)the Innovation-driven Plan in Central South University(2015cx007)
文摘The solution purification process is an essential step in zinc hydrometallurgy. The performance of solution purification directly affects the normal functioning and economical benefits of zinc hydrometallurgy. This paper summarizes the authors' recent work on the modeling, optimization, and control of solution purification process. The online measurable property of the oxidation reduction potential(ORP) and the multiple reactors, multiple running statuses characteristic of the solution purification process are extensively utilized in this research. The absence of reliable online equipment for detecting the impurity ion concentration is circumvented by introducing the oxidationreduction potential into the kinetic model. A steady-state multiple reactors gradient optimization, unsteady-state operationalpattern adjustment strategy, and a process evaluation strategy based on the oxidation-reduction potential are proposed. The effectiveness of the proposed research is demonstrated by its industrial experiment.
基金supported by the National Natural Science Foundation of China(No.51074149,31270166,31270531 and 31000070)the West Light Foundation of the Chinese Academy of Sciences
文摘The effects of cathode potentials and initial nitrate concentrations on nitrate reduction in bio- electrochemical systems (BESs) were reported. These factors could partition nitrate reduction between denitrification and dissimilatory nitrate reduction to ammonium (DNRA). Pseudomonas alcaliphilastrain MBR utilized an electrode as the sole electron donor and nitrate as the sole electron acceptor. When the cathode potential was set from -0.3 to -I.1 V (vs. Ag/AgC1) at an initial nitrate concentration of 100 mg NO^-N/L, the DNRA electron recovery increased from (10.76 ± 1.6)% to (35.06 ± 0.99)%; the denitrification electron recovery decreased from (63.42 ± 1,32)% to (44.33 ± 1.92)%. When the initial nitrate concentration increased from (29.09 ± 0.24) to (490.97 ± 3.49) mg NO3-N/L at the same potential (-0.9 V), denitrification electron recovery increased from (5.88 ± 1.08)% to (50.19 ±2.59)%; the DNRA electron recovery declined from (48.79 ±1.32)% to (16.02 ± 1.41)%. The prevalence of DNRA occurred at high ratios of electron donors to acceptors in the BESs and denitrification prevailed against DNRA under a lower ratio of electron donors to acceptors. These results had a potential application value of regulating the transformation of nitrate to N2 or ammonium in BESs for nitrate removal.
基金This research was partially supported by a fund from Chinese Academy of Science,and a fund from the Personal Department of the State Council.It is also sponsored by scientific research foundation for returned overseas Chinese Scholars,State Education
文摘In this paper we introduce a primal-dual potential reduction algorithm for positive semi-definite programming. Using the symetric preserving scalings for both primal and dual interior matrices, we can construct an algorithm which is very similar to the primal-dual potential reduction algorithm of Huang and Kortanek [6] for linear programming. The complexity of the algorithm is either O(nlog(X0 · S0/ε) or O(nlog(X0· S0/ε) depends on the value of ρ in the primal-dual potential function, where X0 and S0 is the initial interior matrices of the positive semi-definite programming.
基金This research supported partially by The National Natural Science Foundation of China-19771079 and 19601035State Key Laboratory of Scientific and Engineering Computing.
文摘Presents a regular splitting and potential reduction method for solving a quadratic programming problem with box constraints. Discussion on the regular splitting and potential reduction algorithm; Complexity analysis of the algorithm; Analysis of the complexity bound on obtaining an approximate solution.
基金supported by the National Key R&D Program of China(2019YFC0214500)and the Energy Foundation Beijing Representative Office in China。
文摘With the Kigali Amendment(KA)coming into effect in China,the control of hydrofuorocarbons(HFCs)emissions has become more imperative.The mobile air-conditioning(MAC)sector is one of the important HFCs consumer sectors,and therefore studying its feasible mitigation paths and costs is of great significance to Chinas successful implementation of KA.This study used the bottom-up method with updated emission factors to re-evaluate the emission inventory of HFCs from the MAC sector in China from 2005 to 2020.The average annual growth rate of HFCs consumption in the MAC sector is 9.8%,and HFCs emissions have increased from 5.8(5.3-6.2)kt in 2005 to 22.2(20.6-23.8)kt in 2020,with an average annual growth rate of 8.8%.Using the Gompertz model combined with the Weibull function of vehicle survival rate,the ownership and new registrations of internal combustion engine vehicles(ICEVs)and electric vehicles(EVs)in China are predicted.The ownership of ICEVs and EVs is projected to be 310 million and 91 million in 2030,respectively and 2 million and 641 million in 2060,respectively.HFCs emissions in the MAC sector would reach 59.8(55.3-64.3)kt(80.093.0 Mt CO_(2-eq))in 2060 if without any control measure.To implement the KA,the cumulative of 1.6 Gt CO_(2-eq) emissions would be reduced.Under the other two accelerated mitigation scenarios,the MAC sector's HFCs will reach their emissions peak in 2028 and 2025 and achieve zero emissions in 2050 and 2046,respectively.Under the accelerated mitigation with recovery scenario,the cumulative emissions are only 15.0%of the business as usual(BAU)scenario.Using HFO-1234yf as the substitute,the unit abatement cost of the MAC sector is 27.3-37.4 USD _(t)^(-1)CO_(2-eq).
文摘Permeable reactive barriers(PRBs)are used for groundwater remediation at contaminated sites worldwide.This technology has been efficient at appropriate sites for treating organic and inorganic contaminants using zero-valent iron(ZVI)as a reductant and as a reactive material.Continued development of the technology over the years suggests that a robust understanding of PRB performance and the mechanisms involved is still lacking.Conflicting information in the scientific literature downplays the critical role of ZVI corrosion in the remediation of various organic and inorganic pollutants.Additionally,there is a lack of information on how different mechanisms act in tandem to affect ZVI-groundwater systems through time.In this review paper,we describe the underlying mechanisms of PRB performance and remove isolated misconceptions.We discuss the primary mechanisms of ZVI transformation and aging in PRBs and the role of iron corrosion products.We review numerous sites to reinforce our understanding of the interactions between groundwater contaminants and ZVI and the authigenic minerals that form within PRBs.Our findings show that ZVI corrosion products and mineral precipitates play critical roles in the long-term performance of PRBs by influencing the reactivity of ZVI.Pore occlusion by mineral precipitates occurs at the influent side of PRBs and is enhanced by dissolved oxygen and groundwater rich in dissolved solids and high alkalinity,which negatively impacts hydraulic conductivity,allowing contaminants to potentially bypass the treatment zone.Further development of site characterization tools and models is needed to support effective PRB designs for groundwater remediation.
文摘Although gold nanorods(GNRs)have been produced with different dimensions and aspect ratios,the current synthesis methods through seed-mediated growth are far from ideal,for instance,the quality(rod yield)and the quantity(gold conversion)cannot be simultaneously satisfied.More critically,there is no molecular level understanding of the growth mechanism.Here,we solved the problem by employing the stoichiometric ratio of reactants and tuning the reactivity of the reductant through adjusting the initial pH value of the growth solution to achieve both good quality and high quantity simultaneously.We also extended our strategy to other enols besides ascorbic acid,such as phenolic compounds,and found that the optimal pH for GNRs synthesis depends on the structure of the individual compound.The mechanistic insight greatly enriches the toolbox of reductants for GNRs growth and makes it possible to synthesize GNRs at both acidic and basic conditions.An interesting phenomenon is that for most of the phenolic compounds we tested,the morphology of the final products follows the same sphere-rod-sphere trend as the initial pH value of the reaction increases,whether it is under acidic or basic conditions,which cannot be explained by any previously proposed mechanism.The effect of pH is mainly attributed to the regulation of the reduction potential of the reductants,and thus the reaction rate.A model has been proposed to explain the dependence of anisotropic growth of GNRs on the concentration gradient of reactants around the seeds,which is decided by both the reaction rate and diffusion rate.
基金This research was financially supported by the National Natural Science Foundation of China(Nos.51778180 and 51761145031)Fundamental Research Funds for the Central Universities(HIT.NSRIF.2017057)+1 种基金Postdoctoral Science Special Foundation of Heilongjiang(LBH-TZ0510)Heilongjiang Postdoctoral Funds for scientific research initiation(LBH-Q16110).
文摘The succession of fungal community,trophic mode and metabolic characteristics were evaluated in 60 days composting of swine manure by high-throughput sequencing,FUNGuild and Biolog method,respectively.The result showed that the ftingal community diversity reached to the highest level(76 OTUs)in the thermophilic phase of composting,then sustained decline to 15 OTUs after incubation.There were 10 fungal function groups in the raw swine manure.Pathotroph-saprotroph fungi reached to 15.91%on Day-10but disappeared on Day-60.Dung saprotroph-undefined saprotroph fungi grown from 0.19%to 52.39%during the treatment.The ftmgal community had more functional groups but the lower substrate degradation rates in the thermophilic phase.The fungal communities on Day-0 and Day-60 had the highest degradation rates of amino acids and polymers,respectively.Redundancy analysis showed that ORP(49.6%),VS/Ash(45.3%)and moisture(39.2%)were the main influence factors on the succession of fungal community in the swine manure composting process.
基金The key international cooperation project was supported by the National Natural Science Foundation of China(Grant No.50521140075)the Project of Beijing Science and Technology Committee(Z0005186040421)the National Key Technologies R&D Program of China(2006BAC19B03)。
文摘The feasibility of pH and oxidation reduction potential(ORP)as on-line control parameters to advance nitrogen removal in pulsed sequencing batch reactors(SBR)was evaluated.The pulsed SBR,a novel operational mode of SBR,was utilized to treat real municipal wastewater accompanied with adding ethanol as external carbon source.It was observed that the bending-point(apex and knee)of pH and ORP profiles can be used to control denitrification process at a low influent C/N ratio while dpH/dt can be used to control the nitrification and denitrification process at a high influent C/N ratio.The experimental results demon-strated that the effluent total nitrogen can be reduced to lower than 2 mg/L,and the average total nitrogen(TN)removal effici ency was higher than 98%by using real-time controll strategy.
基金supported by the funding of Belt and Road Research Institute,Xiamen University(No:1500-X2101200)National Natural Science Foundation of China(Key Program,No 72133003).
文摘Carbon emission is inevitable,and changes with energy consumption and economic development,presents policy options toward sustainable development path.Currently,there is little assurance from policymakers in committing to climate change pledges:taking the Middle-East and North African(MENA)region as a specific case with using 2019 as a cut-off period.We conducted an interim assessment of the Paris Agreement to ascertain whether climate actions are in tandem with emissions reduction targets.Making use of difference-in-difference technique as a quasiexperiment supported by fixed-effects and placebo treatment models,the results point to evidence of less than 1%effective CO_(2) emissions reduction as of 2019 compared to the 2015 level.The current carbon emissions reduction commitment level is far-reaching contrary to the Nationally Determined Contributions(NDCs)pledged(16.43%on average by 2030 compared to the 2015 level).The analysis suggests that achieving NDCs commitments are currently major burden on policymakers since the economic development is highly linked with nonrenewable energy consumption.Furthermore,a more comprehensive framework when accounting for all available renewable and clean energy projects shows reduction levels in the range of 30%-40%from 2020 to 2030.These results suggest that the Paris Agreement in MENA countries may be more effective from 2020,thus underscore the importance of capturing ongoing projects(involving renewable and clean energy technologies)into interim policy assessment.The shared implication is that greater efforts are demanded from the region and at country levels to further decrease emissions through the use of negative emissions technologies particularly in the electricity generation sector.
基金supported in part by 211 startup fund to the first author by China University of Geosciences (Wuhan)
文摘This paper investigated aqueous chemistry for two geothermal spring groups responsive and sensitive to flow fluctuations induced by earthquakes. Quake monitorings are favored for their being in residential areas with well-preserved natural flow systems in Xinyi City's Xijiang Hot Springs and Fengshun County's Shihu Hot Spring. The hot springs are typical in temperatures and flow rates in southern China's Guangdong Province. Physical and chemical conditions deep down in the heat sources are important constraints on earthquake, fluid flow, reactive solute transport and heat transfer, but remain challenging to address via field observations and numerical experiments. In this paper, we made daily and annual observations on flow rates, temperature, and/or aqueous chemistry. We employed strontium isotopes as tracers for the water sources, equilibrium phase diagram for K-feldspar and albite stability, and Na-K-Mg diagram for heat reservoir temperatures. The abundant sulfite content in Xi- jiang Hot Springs is discussed. Our main finding are that the deep fault springs are characterized by low reduction-oxidation potential at around -200- -150 mV and relatively large daily flow variations. The resuits provide scientific background features on the field sites regarding earthquake monitoring and predictions and geothermal reservoir.
基金The authors acknowledge that this research was financially supported by National Key R&D Program of China(2019YFD1101102-3)National Natural Science Foundation of China(32071907)+1 种基金Outstanding Scientist Cultivation Project of Beijing Academy of Agriculture and Forestry Sciences(JKZX202205)Qingyuan Smart Agriculture Research Institute+New R&D Institutions Construction in North and West Guangdong(2019B090905006).
文摘Pulse-width modulation(PWM)sprays can improve flow accuracy by adjusting duty cycle and frequency signal which accurately controls the relative proportion of opening time of solenoid valve.The objective of this research was to determine the impacts of PWM duty cycle and frequency on spray drift characteristic.Spray tests were conducted in a wind tunnel with a PWM variable-rate spraying system.The airborne drift and sediment drift were determined with tracer method,and the drift potential reduction(DPR)compared with reference condition of 100%duty cycle at vertical profile and horizontal planes were calculated,respectively.The results show that,at a given frequency,droplet size decreases with the increase of duty cycle,the main reason is that the liquid does not reach full pattern development at lower duty cycle.Duty cycle has a greater impact than the frequency on spray drift,the influence weights of duty cycle on airborne drift and sediment drift were 88.32%and 77.89%,respectively.At a lower PWM frequency,in addition to the droplet size,the spray drift may be affected by the pulsed spray pattern.From the perspective of reducing spray drift,it is recommended that the PWM duty cycle should be set in the range of 20%-70%to reduce the potential drift in PWM sprays.This research provides a pesticide drift reduction scheme for variable spraying technology,which can serve as a theoretical basis for PWM parameter selection.