Cause Of Emissions Research Articles

Potential option for mitigating methane emission from tropical paddy rice through selection of suitable rice varieties

Cultivation of rice, a globally important cereal crop, is a major cause of emission of the greenhouse gas (GHG) methane (CH4), giving rise to global warming. Physiological and anatomical characteristics of rice plants associated with CH4 emission were studied in six high-yielding rice varieties, Dikhow, Dishang, Jaya, Kolong, Kopilee and Lachit, during the pre-monsoon season (April–August) for 2 years (2013 and 2014) in a tropical climate in India. Significant differences (P < 0.001) in photosynthetic rate among the rice varieties were recorded and were found to influence CH4 emission from the ecosystem. Rate of CH4 emission was found correlated (r = 0.942) with size of the xylem vessels of the node of the varieties. Kolong, Lachit and Dikhow were identified as low CH4 emitters with smaller xylem vessels. The recorded GHG intensity (GHGI) revealed rice varieties as a source of GHGs, and among the varieties, Kopilee as a major source of CH4, with GHGI of 0.083 and 0.093 during 2013 and 2014, respectively. Results suggest that selection of suitable rice varieties with high grain yield accompanied by lower rate of CH4 emission can be a viable option for reduction of CH4 emissions from rice agriculture.

OUP accepted manuscript

Because carbon taxes can lead to loss of competitiveness, applying tariffs on imports from non-carbon-restricting countries helps address the cost disadvantage faced by producers in carbon-restricting countries. Such tariffs, known as border carbon adjustments (BCAs), can also help reduce possible carbon “leakage,” or the growth in foreign emissions due to increased production of carbon-intensive goods in non-carbon-restricting countries. We demonstrate that BCAs that do not exceed the burdens imposed by carbon taxation on domestic like products could be consistent with World Trade Organization (WTO) rules. However, “neutral” (i.e., nondiscriminatory) BCAs might still be inefficiently high from a global welfare perspective. This stems from the misaligned focus of BCAs on imports rather than production—the real cause of emissions. The discrepancy between neutrality and efficiency enables carbon-restricted industries to seek inefficiently high BCAs. Recognition of this discrepancy strengthens the case for multilateral alternatives that curb global carbon emissions.

An assessment for leakage reduction methods of reservoir embankments through estimation of CO2 emissions during the construction process

Abstract Many stability issues may occur as agricultural reservoir embankments become superannuated in South Korea. Reinforcement of reservoir embankments is necessary because of the potential for the loss of lives and property damage can occur, if an embankment is failed due to its faults. However, construction activities that are associated with repairing reservoir embankments are not recognized as environmentally friendly, although the importance of reservoirs is increasing. Therefore, the objective of this research was to assess the environmental effect for leakage reduction methods of reservoir embankments through estimation of CO 2 emissions during the construction using hybrid method for a rational selection considering economic and environmental characteristics. Based on an estimate of the construction cost and CO 2 emissions at the scale assumed, the Jumbo Special Pattern (JSP) method had the highest cost and emissions and the surface impermeable wall method had the lowest cost and emissions. However CO 2 emissions for the sheet pile method were relatively low compared to the total construction cost due to use of steel sheets, which have a high unit price but low basic unit of CO 2 emissions. Among the causes of emissions, material division is the largest contributor to total emissions for all of the methods. The suggested process of estimating CO 2 emissions is applied to the targeted reservoir where curtain grouting was applied. For both the total construction cost and CO 2 emissions, results were similar to those of the scale that was assumed. The total CO 2 emissions for most of the methods were smaller than that of the curtain method that was installed in the study area, except for the JSP method. Thus, the method for estimating CO 2 emissions for leakage reduction methods properly described the characteristics of each of the methods proposed in this study, and may provide a basis for establishing a policy to reduce CO 2 emissions in the selection of repair methods.

Combined Life Cycle Environmental and Exergetic Assessment of Four Typical Sewage Sludge Treatment Techniques in China

Four commonly used sewage sludge treatment techniques in China are compared, each with and without the combination of anaerobic digestion: composting, co-combustion in power plant, thermal drying-incineration, and cement manufacturing. Life cycle assessment (LCA) is used to quantify the environmental burden, while exergetic life cycle assessment (ELCA) is supplemented to measure the resources conversion efficiency. Afterward, abatement exergy is adopted to determine their degree of environmental sustainability, so that all environmental issues associated with resource use and environmental emissions can be solved simultaneously. Results show that anaerobic digestion is an effective pretreatment approach to reduce environmental burden. Thermal drying-incineration is preferable to co-combustion and cement production, since fossil fuel combustion is the dominant cause of emissions. Composting poses a positive effect to mitigate global warming, but it introduces high heavy metals to the soil. Results from ELCA reveal that thermal techniques present higher resources conversion efficiency than a biological system. Adopting anaerobic digestion obviously improves the performance of composting, but it has reduced the total energy recovered in thermal techniques. For process improvements, an efficient sludge predrying is important; and the use of a combined heat and power system can also provide more effective recovery of energy.

Mechanism of radiation pulse shortening in plasma relativistic microwave generator

The causes of emission quenching in the plasma relativistic microwave generator are studied by numerical calculations using the particle-in-cell method. The process mechanism in which the plasma boundary moves from the coaxial collector edge with a velocity above 107 cm/s is found. An electron flux with an energy of ∼105 eV and a current of ∼103 A is generated from the collector in the formed gap, which heats plasma and increases its potential. Microwave generation stops due to a multiple decrease in the wave reflectance from the collector. The use of the hollow collector is presumably a method for preventing microwave generation quenching.

A comparison of the GHG emissions caused by manufacturing tissue paper from virgin pulp or recycled waste paper

Purpose The aim of this work is to compare greenhouse gas (GHG) emissions from producing tissue paper from virgin pulp (VP) or recycled waste paper (RWP). In doing so, the study aims to inform decision makers at both company and national levels which are the main causes of emissions and to suggest the actions required to reduce pollution.

Methane emissions from gas engines driving combined heat and power installations

In the Netherlands, wide-scale implementation of cogeneration of electricity and heat substantially reduces primary energy use and CO2 emissions. However, gas engines of cogeneration installations in the greenhouse horticultural sector alone are already responsible for a methane emission of roughly 1 Megatonne of CO2-equivalents. This amount has been determined by a series of measurement programmes as ordered by the Dutch Ministry of Infrastructure and Environment. This Ministry aims at reducing that methane slip, amongst others by setting legal emission limit values and stimulating engine innovations. However, the data from those measurement studies neglect important underlying causes of the emissions. Therefore, they are likely to be insufficiently conclusive for policy-making. In this paper, the most important causes of hydrocarbon emissions of combined heat and power (CHP) engines in relation to their design and process conditions have been assessed. An important finding is that a simple approach of just registering the output of measurement instruments and reporting these holds a high risk of methodological errors and neglected causes leading to inappropriate conclusions and subsequently inadequate policies. Overall, the paper not only contributes to the academic understanding of the qualifications and quantifications of these emissions, but also to the relevant policy-making in this field.

Carbon and Materials Embodied in the International Trade of Emerging Economies

SummaryProduction in emerging economies, such as Brazil, Russia, India, China, South Africa, and Argentina (BRICSA), increased substantially over the past two decades. This is, on the one hand, due to growing domestic demand within these countries, and, on the other hand, due to a deepened international division of work. Global trade linkages have become denser and production chains are no longer restricted to only one or two countries. The volume of international trade in intermediate inputs as well as final consumption goods has tripled in the past two decades. With this, carbon dioxide (CO2) emissions and materials embodied in traded goods have increased, making it increasingly difficult to identify the actual causes of emissions and material extractions, as producing and extracting countries are not necessarily consuming the resulting goods. Using the multiregional input‐output Global Resource Accounting Model (GRAM), this article shows how global carbon emissions and materials requirements are allocated from producing/extracting countries to consuming countries. It thereby contributes to the rapidly growing body of literature on environmental factors embodied in international trade by bringing two key environmental categories—CO2 emissions and materials—into one consistent and global framework of analysis for the first time. The results show that part of the increase in carbon emissions and materials extraction in BRICSA is caused by increasing amounts of trade with countries in the Organisation for Economic Co‐operation and Development as well as a growing demand for goods and services produced within BRICSA.

Deciphering mechanism of aggregation-induced emission (AIE): Is E–Zisomerisation involved in an AIE process?

In this work, we address a mechanistic issue on AIE process and correct a long-held misconception on stilbene photoluminescence. E–Zisomerisation has been generally recognized as the cause of emission quenching in stilbene solutions. A natural question arisen from this common belief is whether suppression of E–Zisomerisation by aggregate formation in a stilbenic fluorogen system is responsible for its AIE phenomenon. Monitoring of the structural change of a stilbene derivative named 1,2-diphenyl-1,2-di(p-tolyl)ethene by NMR during UV irradiation reveals that the E–Zisomerisation is not involved in its AIE process under the normal photoluminescence spectral measurement conditions.

RENEWABLE ENERGY SOURCES, DRYING AND SUSTAINABLE DEVELOPMENT

Sustainable development, energy efficiency, use of renewable energy sources and protection of the environment are of greatest current interest at the start of this century. The first energy crisis in 1973 showed that conventional energy sources are limited. The knowledge that energy consumption is greatly the cause of emission of SO2, NOx and CO2 pollutants initiate worldwide investigation of technologies and production of systems using renewable energy sources representing ecologically clean energy sources with no pollutants and harmful influences. The most important role of renewable energy sources is reducing the greenhouse effect, increasing energy safety and the opportunity for opening of new work places in small and medium enterprises. In this paper a short review of alternative energy sources from the viewpoint of sustainable development, energy efficiency and protection of the environment is given including the role of the drying process technology in sustainable development through: reduction of energy “consumption”, drying source bio-fuel, solar drying, drying in order to prevent resource “losses”, drying to protect the environment etc.

Fine-grained barite in coal fly ash from the Upper Silesian Industrial Region

Barite nanocrystals are common and abundant in the troposphere over the Upper Silesian Industrial Region, Poland. The presence of barite nanocrystals is the result of burning Ba-enriched coals (up to 4,260 ppm Ba). ATEM, ASEM and EPMA analyses provided evidence of inefficient coal burning for domestic purposes at temperatures of 800–900 °C as the cause of emissions of barite, which survived unmelted. Much higher temperatures of coal burning for industrial purposes resulted in thermal decomposition of barite into BaO, which could react with airborne sulfuric acid to produce nanometre-sized secondary barite. Formation of both the secondary barite and gypsum in the troposphere contributes to the lowering of acidity of rain over Upper Silesia. Barite nanocrystals are often embedded in sheets of hydrocarbon materials with sizes in the range of respirable aerosols; therefore, they may enter the human respiratory system.

Cause and Remediation of Hydrogen Sulfide Emissions from a Sodium‐Based Flue Gas Desulfurization Sludge Disposal Pond

AbstractA flue gas desulfurization (FGD) sludge disposal pond with a history of H2S emissions to the atmosphere was studied to determine the cause of emissions and remediation strategies. The pond receives sludge and associated waters from a single‐pass Na2CO3 flue gas scrubber unit. The pond water is a sodic alkaline brine with large SO3 and S2O3 concentrations (>5000 mg L−1), and hence, an elevated chemical O2 demand. The pond water H2S concentrations are small as a result of periodic H2O2 additions. The sediments, however, have as much as 3500 mg L−1 H2S in the pore water. The production of H2S appeared to originate from the sediments and diffuses through the anoxic water column with little oxidation. Large concentrations of the reduced sulfur species SO3 and S2O3 were present as a result of the flue gas desulfurization process and incomplete oxidation of H2S. The pond was reconstructed to circulate the water through an air injection system that was designed to oxidize the SO3 and S2O3 to SO4, and thereby reduce the chemical O2 demand. After the installation of the air injection system, emissions of H2S ceased and the concentrations of SO3 and S2O3 were reduced by at least a factor of 10 within 3 to 4 wk. The production of H2S in the sediments, however, did not appear to be affected, nor did it appear that it will be reduced in the future by the air injection system.

The heliospheric boundary regions

Estimates of heliosphere size based on analysis of VLF emissions measured by Voyager spacecraft are discussed. Observed spectral frequency drift of ∼ 1 kHz/year, if interpreted in terms of a 1st order Fermi effect for radiations trapped in a cavity, leads to average heliopause radius L ≤ 100 AU and local interstellar plasma density of 0.15/cm3. The distance to the termination shock, found from the flight time across the heliosphere of three solar wind transients whose interaction with the shock is thought to be the cause of emissions, gives average shock distance R = 90 AU. Discussion of charge exchange processes in the shocked solar wind plasma (inner heliosheath) indicates that observable fluxes of suprathermal neutral hydrogen atoms should be emitted. Atoms with energies corresponding to anomalous cosmic rays energy range should come preferentially from the tail side of the heliosphere (effect of tailward convection of the cosmic ray particles). Plasma energy loss by energetic neutral atoms emission may cause a thermal collapse of the frontal heliosheath. Analysis of possible oscillations of the termination shock caused by varying solar wind is developed for small amplitude perturbations. Resulting shock displacements are < 1 AU for variations associated with typical solar rotation and may attain ∼ 10 AU for solar cycle time scale effects.

Visible Radiation from Metal Anodes Preceding Electrical Breakdown

Transmission radiation as possible cause for emission of blue light from localized spots on metal anode preceding breakdown

XXV. On the excitation of the spectra of carbon, titanium, and vanadium by thermelectronic currents. With special reference to the cause of emission of light radiations by luminous vapours in the carbon tube resistance furnace

XXV. <i>On the excitation of the spectra of carbon, titanium, and vanadium by thermelectronic currents. With special reference to the cause of emission of light radiations by luminous vapours in the carbon tube resistance furnace</i>