Increase In Environmental Pressure Research Articles

Exploring the relationships between human consumption and environmental pressure: A case study of the Yangtze river economic zone in China.

It is crucial to decouple and coordinate human consumption and its environmental pressure for achieving sustainable development. As an important aspect of United Nations Sustainable Development Goal (SDG12), sustainability on material consuming is still in its early stages of research. To address the research gap in sustainable consumption of vegetation net primary productivity (NPP), this study analyzed the spatio-temporal dynamics of human consumption and environmental pressure in the Yangtze River Economic Zone (YREZ) using consumption-based HANPP (cHANPP) and Human Appropriation of Net Primary Production (HANPP) as indicators. Later, we measured their decoupling relationship using Tapio decoupling approach. We found that distribution of HANPP and cHANPP were regionally separated, with the former mainly concentrated in the middle and upper reaches provinces, while the latter concentrated in the lower reach provinces. From 2004 to 2019, the relationship between HANPP and cHANPP changed from strong negative decoupling to weak decoupling in the YREZ. Furthermore, the relationship was differed among different regions. As a whole, developing regions showed a weak decoupling state, experiencing an increase in environmental pressure (i.e., HANPP) alongside increased human consumption (i.e., cHANPP). In contrast, developed regions showed a strong decoupling state, experiencing a decrease in environmental pressure (i.e., HANPP) alongside increased human consumption (i.e., cHANPP). Our study highlights that different countermeasures should be formulated by regions according to their own situation to realize sustainable regional development.

Study on Coal Wettability under Different Gas Environments Based on the Adsorption Energy.

Coal seam water injection is a kind of comprehensive prevention and control measure to avoid gas outburst and coal dust disasters. However, the gas adsorbed in the coal seriously influence the coal-water wetting effect. With the deepening of coal seam mining, the gas pressure also gradually increases, but there is still a lack of in-depth understanding of the coal-water wetting characteristics under the high-pressure adsorbed gas environment. Therefore, the mechanism of coal-water contact angle under different gas environments was experimentally investigated. The coal-water adsorption mechanism in pre-absorbed gas environment was analyzed by molecular dynamics simulation combined with FTIR, XRD, and 13C NMR. The results showed that the contact angle in the CO2 environment increased most significantly, with the contact angle increasing by 17.62° from 63.29° to 80.91°, followed by the contact angle increasing by 10.21° in the N2 environment. The increase of coal-water contact angle in the He environment is the smallest, which is 8.89°. At the same time, the adsorption capacity of water molecules decreases gradually with increasing gas pressure, and the total system energy decreases after the coal adsorbs gas molecules, leading to a decrease in the coal surface free energy. Therefore, the coal surface structure tends to be stable with rising gas pressure. With the increase in environmental pressure, the interaction between coal and gas molecules enhances. In addition, the adsorptive gas will be adsorbed in the pores of coal in advance, occupying the primary adsorption sites and thus competing with the subsequent water molecules, resulting in a decline of coal wettability. Moreover, the stronger the adsorption capacity of gas, the more obvious the competitive adsorption of gas and liquid, which further weakens the wetting capacity of coal. The research results can provide a theoretical support for improving the wetting effect in coal seam water injection.

A Multi-Level Fuzzy Evaluation Method for the Reliability of Integrated Energy Systems

With the increase in environmental pressure and rapid development of renewable energy technologies, an integrated energy system has been recognized as an effective approach to accommodate large-scale renewables and achieve environmental sustainability. While an integrated energy system significantly improves energy efficiency, the interaction between different energy systems may also bring multiple operational risks to its reliability, which necessitates an effective reliability assessment technique. In this paper, we proposed a multi-level fuzzy evaluation model based on combined empowerment for the reliability evaluation of an integrated energy system. The analytic hierarchy process method and entropy weight method were used to calculate the weight of each index in the evaluation model. Fuzzy evaluation matrix was constructed by the membership degree of a single factor, which was defined by the fuzzy comprehensive evaluation method. The multi-level fuzzy evaluation results were obtained based on single-level evaluation results. Finally, case studies were carried out based on a practical integrated energy system; we proposed 5 first-level indicators such as reliability and economy and 12 second-level indicators such as mean time of incapacity. The simulation results (85.15) showed the effectiveness and advantages of the proposed model.

Application of Life Cycle Assessment (LCA) to cereal production: an overview

Cereals have been the basis of human and animal nutrition for centuries, and according to the Intergovernmental Panel on Climate Change (IPCC) (2020), between 1961-2019 their global production increased by +240%, reaching about 3 billion tons, accounting for 18% of climate-changing emissions from the agro-food sector. Continued population growth will lead to the need to produce more food, and to keep up it is estimated that cereal production will need to increase by 900 million tons by 2050, posing an inevitable increase in environmental pressures. Therefore, the new challenge will be to reconcile increased production with sustainable agricultural practices, in line with the Sustainable Development Goals (SDGs) and the new Common Agricultural Policy (CAP). Since cereal production is essential to produce globally relevant commodities, it is important to assess and study its associated environmental effects. In this context, the Life Cycle Assessment (LCA) is recognized by the international scientific community as a useful tool for the assessment of environmental impacts caused by products, processes or systems and for the validation of new production paradigms. Therefore, the aim of this research is to carry out an overview of the literature on the most recent applications of LCA related to the production of cereals, in order to highlight the main criticalities, also according to the different production methods of the various Countries. Therefore, the three major cereals (corn, wheat and rice) and five minor ones (barley, sorghum, millet, oats and rye) were considered and the results showed that for all crops the main hotspot is the application and use of fertilizers. However, studies often differed in terms of functional unit, impact assessment methods, and respective environmental indicators. Therefore, a complete comparison was not always possible. Finally, the literature overview did not identify studies in which the social impacts of cereal production were considered, although economic assessments are present in some cases. Therefore, it is believed that consistent with the achievement of the SDGs, it is desirable to apply Social Life Cycle Assessment (S-LCA) in agricultural and development policies to consider not only environmental impacts, but also economic and social impacts, in order to ensure a truly sustainable development and thus on all three dimensions

Digital systems in agriculture of the Republic of Kazakhstan: a vector of success

The relevance of the topic is due to the importance of using digital technologies in agriculture, which contribute to improving product quality, increasing their volumes, and reducing human factor in production process. In addition, digital transformation of agro-industrial complex is aimed at overcoming global challenges: increase in food demand, depletion of productive agricultural land, increase in environmental pressure, change in consumer preferences, and disproportions in the level and quality of life between urban and rural areas. The goal is to analyze international experience in implementation of information systems in agricultural sector, assess the current state of digitalization in agro-industrial production of the Republic of Kazakhstan, and determine the main directions of development. Methods – analytical, systematization, accumu-lation and selection of facts, establishing links between them. Results – the advantages and risks of using information and communication mechanisms in AIC are analyzed based on the example of developed countries. The results of providing IT developments, computer methods within the framework of the state program "Digital Kazakhstan" were studied. The experience of creating and expanding regional hubs was studied. Vectors of optimization of digital platforms are shown. Conclusions – digitalization of Kazakhstani economy in agriculture will be carried out by optimizing production and logistics processes, improving efficiency of labor market, reducing resource consumption and production losses, increasing the efficiency of R&D and is a prerequisite for the competitiveness of the industry. The study reveals the potential economic effect of digital devices in agro-industrial complex and the importance of using them in the near future by agricultural enterprises to achieve their goals.

Beneficial Reuse of Municipal Solid Waste Incineration Bottom Slag in Civil Engineering

Rapid economic development has caused many disturbing problems in many countries. Waste disposal is a prominent one of those problems. Waste incineration has gradually become the most popular treatment method. Waste incineration has many advantages, such as processing capacity, short period, recycling and utilization of resources, etc., but it also produces a lot of incineration bottom slag. Landfilling is one of the methods for waste incineration bottom slag treatment. However, many domestic waste landfill sites no longer accept incineration bottom slag. Therefore, finding sufficient ways to deal with the incineration bottom slag has become an urgent problem. With the increase of environmental pressure and the development of technology, the beneficial use of incineration bottom slag has been gradually considered. Municipal solid waste incineration bottom slag is an atypical particulate material, similar to some construction materials of civil engineering. For a construction material, basic physical properties and engineering properties are important factors in its performance. However, there is limited research about the engineering performance of incineration bottom slag. The purpose of this paper is to investigate the basic physical and mechanical properties of the incineration bottom slag from one incineration plant in Wuhan and provide a theoretical basis for its application in civil engineering. Through laboratory tests, we found that the incineration slag completely meets the engineering requirements and is harmless to the environment. The incineration bottom slag can be used for road embankment filling, sludge dewatering treatment improvement, landfill site covering, it can substitute aggregates in concrete, etc.

LAND USE OPTIMIZATION IN UKRAINE AT THE STAGE OF LAND MARKET FORMATION

In the context of the reform of the sale of agricultural land, the priority is to optimize land use, which is to find a balance of land that would meet their environmental, economic and social compliance with the functions of the agricultural sector. Two main approaches to the optimization process are considered. The first is by intensifying agriculture with significant energy costs, land depletion and the inevitable increase in environmental pressures. And the second is the gradual formation of a balanced agrosphere with alternative agriculture and environmentally friendly livestock.
 The structure of land plots in terms of regions of Ukraine, which in the conditions of the land market does not promote balanced land use, is analyzed. Acquired arable land will not be transferred to other categories of land at auctions, even if it is significantly degraded.
 When forming the pricing policy in the land sector, it is important to compare the value of arable land in Ukraine and European countries. This comparative analysis shows the underestimated value of arable land in Ukraine (the lowest figure in Europe is less than 1 thousand euros / ha) at the initial stage of sale. It is estimated that the six-year lease of arable land at this stage of land reform is more appropriate than their sale.
 The fact of plowing part of pastures under these conditions and increasing the share of arable land in river valleys, drained lands, etc. is alarming. According to the results of the calculations, Table 1 shows the value of arable land, pastures, hayfields by administrative regions. The comparative characteristic of agricultural lands on the available highly productive lands is carried out. The highest share of such lands in Ternopil, Poltava and Cherkasy oblasts was found out, which provides for their highest valuation.
 The created map diagram of the general cost assessment of agricultural lands demonstrates their land resource potential and reflects the spatial differentiation of this indicator by typological groups of regions. The authors analyzed the optimization model of land use in Ukraine, developed by a group of leading domestic scientists under the project "Sustainable Development Programs", and proposed to consider the category of productive lands as basic arable lands, the share of which in Ukraine is 44.8% of arable land.
 The directions of reforming land relations in Ukraine taking into account historical traditions and granting the highest status of the basic land user - the rural community are offered.
 At the same time to make calculations, based on the results of which to identify production types (specialization) of farms, which will be the most objective, as it takes into account local natural and economic conditions;
 - on the basis of specialization of peasant farms, study of types of land use in enterprises of various forms of ownership and data on natural land fertility to perform agricultural zoning of the territory;
 - in each allocated agricultural area, the whole array of land in use, divided into at least 3 groups:
 1) lands of peasant farms, which over time should be granted the right of life ownership with the possibility of inheritance and on which the state should support non-profit, subsistence farming;
 2) lands withdrawn from agricultural circulation due to the destruction of their natural fertility and those to be transferred to the nature reserve fund, and, over time, included in the national ecological network;
 3) lands that have not yet lost their natural fertility and those that are in the use of agricultural enterprises of various forms of ownership.
 Key words: land optimization, monetary valuation of agricultural lands, land resource potential, spatial differentiation of lands, land relations.

Under pressure: Rapid lavaka erosion and floodplain sedimentation in central Madagascar

Lavaka (gullies) are often considered as the prime indication of a currently ongoing human-induced environmental crisis in Madagascar's highlands. Yet, lavaka are known to have existed long before human arrival and account for the majority of the long-term sediment input into the highland rivers and floodplains. The role of anthropogenic disturbances in their formation therefore remains highly debated and it is unclear whether lavaka erosion has recently increased. Here, we address these questions by evaluating the dynamics of lavaka in the Lake Alaotra region (central Madagascar). An overall birth to stabilization ratio of 6.1 indicates a rapid lavaka population growth over the period 1949–2010s. Using data on lavaka development we calculated a mean lavaka population age of 410 ± 40 years and estimate that the disequilibrium started at 870 ± 430 cal. BP. Floodplain sedimentation starts to increase around 1000 cal. BP and peaks over the last 400 years, thereby independently confirming this time frame of increased lavaka activity. Lavaka population dynamics modelling shows that a strong increase in environmental pressure over the last centuries is needed to attain current disequilibrium levels. A general drying of the climate since 950 cal. BP in combination with the introduction of cattle and growing human presence around 1000 cal. BP will likely have triggered the increase in lavaka erosion. However, the recent acceleration cannot be explained by climatic changes alone and seems to be linked to increased anthropogenic pressure on the environment. As such, we offer a fresh and quantitatively supported perspective on lavaka dynamics and human impact in central Madagascar, where our methodology can be used in other locations where similar questions on geomorphic equilibrium need to be answered.

Ecological trap in tourism-urbanization: Simulating the stagnation and restoration of urbanization from the perspective of government incentives

For emerging tourism-dominated cities, there is a contradiction between ecological protection and tourism urbanization. This paper explores the causes and solutions of the potential risks that occur in the process of tourism urbanization by simulating the impact of government incentives on tourism urbanization and tourism related-ecological security (TRES). Tourism urbanization in Zhangjiajie has experienced four stages: start-development-stagnation-restoration. This paper analyzes the main obstacles and government incentives at different stages. In the initial stage, government incentives promoting tourism were an efficient method to improve TRES and tourism urbanization. However, with the increase in environmental pressure, ecological overload caused the stagnation of tourism urbanization. The increase in government incentives protected the environment and eventually restored tourism urbanization. Through surveys of tourists and residents, it was confirmed that Zhangjiajie's environmental and tourism problems have improved in recent years. The results indicated that the time mismatch between rapidly developed tourism and the environmental protection policies implemented later caused serious ecological capacity overload. This paper provides a basis for identifying and avoiding ecological risks in tourism-dominated cities to achieve sustainable tourism urbanization. Environmental protection incentives at the end of a rapid development stage are an effective means to avoid ecological traps.

Green data collection strategy in the science domain for environmental sustainability

There is a recognition by modern communities world-wide, that the steadily increasing level of activities in the science domain and population growth, lead to an increase in environmental pressure on critical areas. There is a need, therefore, for stakeholders to critically appraise principles, policies, and practices that could lead to the best practices required for sustainable science activities and environmental management that is driven by green data collection, green principles, and green practices. The models involved in green data collection in science include finance-environment-community-science domain model (FECS), environment-community-science domain-finance model (ECSF), and the science domain, finance, environment-community model (SFEC). SFEC is a novel framework and is being applied in the management of active science domain, abandoned science domain, thus, providing reasonable economic and environmental benefits to the science players and non-science communities. The green data collection strategy is for enhancing social, economic, and environmental resource performance. This strategy has been tested in the Philippines. The formulation of the green data collection strategic framework involved a desktop review of previous and existing local, regional, and national data collection strategies. Consequently, visits are made to active science domain and discussions held with stakeholders. In this paper, the role of information, education, and communication have been revisited and fits adequately into the novel “green data collection model” being advanced for all players in the science domain. The absence of this framework poses the most challenging aspect of prosperity offered by the quality, quantity, diversity, and the sustainability of the science domain. Therefore, this paper has discussed the content of the green data collection strategic plan, anchored on a sustainable-controlled planning cycle. This approach could drive and sustain the harmony between man, science, and the environment.

The environmental price of socio-economic development: worldwide trends from 1990 to 2016

Plans for achieving sustainable development around the world are based on the assumption that socio-economic progress can be ensured only by staying within the carrying capacity of the environment, which has already been exceeded in a number of areas. In this paper the concepts of human development and ecological footprint have been combined in order to shed light on the current state and trends over time. Using available data for the human development index and the ecological footprint, 175 countries were included in the analysis of the current state (based on data from 2016), while 121 countries were analysed in the study of trends from 1990 to 2016. Based on their degree of success or failure in approaching decoupling targets, the countries were further classified into three types. All countries have shown progress in human development, which has been accompanied on a global scale by a large increase in environmental pressures, and this is still reflected in the high correlation of the human development index and the ecological footprint per capita. However, for only 38% of countries could it be concluded that socio-economic progress in the period 1990-2016 was achieved while reducing the per capita consumption of natural resources and ecosystem services.

Influence of low ambient pressure on the performance of a high-energy array surface arc plasma actuator

In order to solve the problem of single arc plasma actuator’s failure to suppress the boundary layer separation, the effectiveness of the array surface arc plasma actuator to enhance the excitation intensity is verified by experiment. In this study, an electrical parameter measurement system and high-speed schlieren technology were adopted to delve into the electrical, flow field, and excitation characteristics of the high-energy array surface arc plasma actuator under low ambient pressure. The high-energy array surface arc discharge released considerable heat rapidly; as a result, two characteristic structures were generated, i.e., the precursor shock wave and thermal deposition area. The duration increased with the increase in environmental pressure. The lower the pressure, the wider the thermal deposition area’s influence range. The precursor shock wave exhibited a higher propagation speed at the initial phase of discharge; it tended to decay over time and finally remained at 340 m/s. The lower the environmental pressure, the higher the speed would be at the initial phase. High-energy array surface arc plasma actuator can be employed to achieve effective high-speed aircraft flow control.

O neoliberalismo e sua impossibilidade de solucionar os problemas ambientais

Desde a década de 70, ocorreram um conjunto de transformações econômicas, politicas e ideológica que contribuíram, por um lado, com o crescimento da riqueza mundial, e por outro lado, com o aumento das pressões ambientais e da desigualdade social. Nesse contexto, o presente artigo busca compreender como essas mudanças, denominada de neoliberalismo, contribuíram para aprofundar os problemas ambientais, bem como inviabilizar suas soluções efetivas. Considera-se que pensar na questão ambiental significa refletir sobre a relação entre o ser social e a natureza, em outras palavras, reflete as questões sociais.

Efficiency Analysis of Water Conservation Measures in Sanitary Infrastructure Systems by Means of a Systemic Approach

The challenges of urban water management and sanitary infrastructure (water supply (WSS), sewage (SS), urban drainage (UDS) systems) are increasingly frequent in Brazilian cities whether as a combined result of overcrowding and/or a lack governmental interest and hence investments, in the sector. Such an increase in environmental pressure reflects directly on population welfare and well-being related to the availability of drinking water, wastewater treatment, and access to effective drainage systems in order to minimize, or at least reduce, the occurrence of urban flooding and associated public health risks. Thus, alternatives with an integrated approach to urban water management are interesting to the reality of countries such as Brazil. The urban water use (UWU) model is a strategic planning tool with integrated way of thinking, which selects measures to mitigate the urban impacts in sanitary infrastructure and buildings. In this sense, the objective of this research is to apply the UWU model in a case study in Curitiba/Brazil to demonstrate the effect of the systematic approach and its intrinsic synergies in the systems in question, promoting water conservation in urban areas. The results are favorable to integrated systems with synergy use, evidencing quantitatively a greater efficiency in them.

Options for keeping the food system within environmental limits

The food system is a major driver of climate change, changes in land use, depletion of freshwater resources, and pollution of aquatic and terrestrial ecosystems through excessive nitrogen and phosphorus inputs. Here we show that between 2010 and 2050, as a result of expected changes in population and income levels, the environmental effects of the food system could increase by 50-90% in the absence of technological changes and dedicated mitigation measures, reaching levels that are beyondthe planetary boundaries that define a safe operating space for humanity. We analyse several options for reducing the environmental effects of the food system, including dietary changes towards healthier, more plant-based diets, improvements in technologies and management, and reductions in food loss and waste. We find that no single measure is enough to keep these effects within all planetary boundaries simultaneously, and that a synergistic combination of measures will be needed to sufficiently mitigate the projected increase in environmental pressures.

USE OF DECUPLING POLICIES TO ADDRESS THE ENVIRONMENTAL CHALLENGES OF WATER RESOURCES IN EGYPT

Water scarcity and unequal geographic distribution of this important resource may be one of the most important environmental challenges affecting the sustainability of water resources. Especially, where water resources are scarce and the rate of its withdrawal is higher than the rate of replenishment through the hydrological cycle.There is a definite risk of depletion, leading to unsustainable use of water resources. Therefore the decoupling of water resources from economic growth is the key of sustainable development, especially for Egypt,in light of the current problems that have become increasingly complicated regarding to water resources.Decoupling refers to the economy's ability to grow without a corresponding increase in environmental pressure. This means, decoupling Natural Resource Use and Environmental Impacts from Economic Growth.This paper provides an overview of how decoupling policies contribute to the water sector. Through a number of interviews done with water resources'experts who emphasize the necessity of using these new policies when managing water resources. The paper also describes some technological solutions that can contribute to the implementation of water decoupling policy in the agricultural, industrial and municipal sectors. It also provides some achievements of some countries regarding the decoupling of water resources and economic this policyisconsidering one of the components of the integrated approach that can be used in water resources management in Egypt.

Optimization of Two-Level Disassembly/Remanufacturing/Assembly System with an Integrated Maintenance Strategy

With an increase of environmental pressure on economic activities, reverse flow is increasingly important. It seeks to save resources, eliminate waste, and improve productivity. This paper investigates the optimization of the disassembly, remanufacturing and assembly system, taking into account assembly-disassembly system degradation. An analytical model is developed to consider disassembly, remanufacturing of used/end-of-life product and assembly of the finished product. The finished product is composed of remanufactured and new components. A maintenance policy is sequentially integrated to reduce the system unavailability. The aim of this study is to help decision-makers, under certain conditions, choose the most cost-effective process for them to satisfy the customer as well as to adapt to the potential risk that can perturb the disassembly-assembly system. A heuristic is developed to determine the optimal ordered date of the used end-of-life product as well as the optimum release dates of new external components. The results reveal that considering some remanufacturing and purchase components costs, the proposed model is more economical in comparison with a model without remanufactured parts. Numerical results are provided to illustrate the impact of the variation of the ordering cost and quality of the used end-of-life product on the system profitability. Finally, the risk due to system repair periods is discussed, which has an impact on managerial decision-making.

Religious Veiling as a Mate-Guarding Strategy: Effects of Environmental Pressures on Cultural Practices

Male parental investment can contribute to the fitness of both sexes through increased fertility and child survivorship. The level and intensity of parental investment are dependent upon ecological variations: in harsh and demanding environments, the need for biparental care increases. Moreover, when environmental pressures increase, uncertainty over paternity may lead to favoring stricter mate-guarding practices, thus directing males to invest more effort toward controlling and guarding their mates from infidelity. In this paper, we test the hypothesis that religious veiling, as a social and cultural practice which regulates and restricts sexuality, will be more important in harsher environments. Our results show that harsh and demanding environments are associated with the importance of religious veiling and the level of religiosity, providing a link between cultural practices such as religious veiling and ecological variation.

Effect of environmental pressure enhanced by a booster on the load capacity of the aerodynamic gas bearing of a turbo expander

To improve the load capacity of the gas bearing by changing environmental pressure, this study analyzes the effect of environmental pressure on the load capacity of a bump foil gas aerodynamic bearing at different rotation speeds. Results show that the load capacity of the bump foil gas aerodynamic bearing increases with the increase in environmental pressure. Specifically, the load capacity of the aerodynamic gas bearing increases by 19.97%, 28.89%, and 44.28% at a speed of 60, 100 and 200kr/min, respectively, when environmental pressure increases from 0.1 to 0.5MPa. And the load capacity of bump foil gas bearing changes with the environment at different slenderness ratio is analyzed when rotation speed is 100kr/min and eccentricity ratio is 0.6, the results show that under the same working load, increasing the environmental pressure of gas bearing and improve the load capacity gas bearing can reduce the slenderness ratio of the bearing; consequently, the shaft length is shortened, and the load of the aerodynamic gas bearing is reduced. Moreover, increasing the environmental pressure of gas bearing can shorten the higher the proportion of rotor length for the bigger slenderness ratio of gas bearing. This characteristic is more beneficial to the steady running of rotor at high speed. For a turbo expander that adopts a fan brake, the fan sucks and discharges air from and to the atmosphere directly; hence, the power provided by the turbo expander is wasted completely. This study recommends replacing the fan brake of a turbo expander with a booster and supplying pressurized gas to the gas bearing to enhance the environmental pressure at both ends of the bearing; this measure can improve the load capacity of the aerodynamic gas bearing and thus reduce energy dissipation. In this paper, Numeca software is utilized to analyze the internal flow of the booster impeller of a turbo expander with 69.68kJ/s refrigerating capacity and 66.2kW effective shaft power. On the premise of the power coupling–matching of the expander and booster, when the total pressure ratio of the booster is 3.5, 4.0, and 4.8, the slenderness ratio of the bearing can be reduced 10%, 15%, 25%, respectively, at a speed of 60, 100 and 200kr/min for the turbo expander rotor system supported by gas bearing that the initial slenderness ratio is 1.

Particulate matter emission comparison from conventional and premixed low temperature combustion with diesel, biodiesel and biodiesel–ethanol fuels

As worldwide energy and environmental pressures increase, interest in biofuels such as biodiesel and ethanol, and low emission diesel combustion modes such as premixed low temperature combustion (LTC), continues to grow. This study takes a detailed look at particulate matter (PM) from a single cylinder common rail diesel engine operated under conventional and premixed LTC combustion modes with diesel, biodiesel and biodiesel–ethanol fuels. Soot, particle number and particle size distribution are investigated.Experiments show that for conventional combustion, accumulation mode particulates are reduced by biodiesel and reduced further by biodiesel-E20 (20% ethanol by volume). The reduction is attributed to higher fuel oxygen content, lower stoichiometric air–fuel ratio and reduced aromatic content reducing carbonaceous soot. Nucleation mode particles from conventional combustion with diesel, biodiesel and biodiesel-E20 fuels show similar size distributions.For premixed LTC, biodiesel shifts the accumulation mode size distribution curve upwards (i.e., more particles) and towards smaller size particles relative to diesel. In LTC, biodiesel produces more semi-volatile organic carbon and lower soot. The shift in size distribution for biodiesel may be caused by more semi-volatile organic carbon in the exhaust causing an increase in the growth of particles nucleated from volatile species, and less soot leading to a reduction in the number of large carbonaceous agglomerates. Biodiesel-E20 decreases accumulation mode particles of all sizes by reducing soot and the amount of biodiesel-derived semi-volatile organic carbon available for growing particles.Biodiesel increases LTC nucleation mode particles relative to diesel. Biodiesel-E20 increases the amount of small nucleation particles (<20nm) and decreases the amount of large nucleation particles (20–50nm) relative to diesel. The increases in nucleation particles for biodiesel and small nucleation particles (<20nm) for biodiesel-E20 are believed to be caused by less soot and more exhaust semi-volatile organic carbon causing increased nucleation. Biodiesel-B20 produces the lowest soot and total particle number concentration, both at conventional and premixed LTC, demonstrating its potential as an alternative fuel for diesel engines.