The particulate matter (PM) emissions of gasoline vehicles were much lower than those of diesel vehicles until the introduction of diesel particulate filters (DPFs) in the early 2000s. At the same ...time, gasoline direct injection (GDI) engines started to become popular in the market due to their improved efficiency over port fuel injection (PFI) ones. However, the PM mass and number emissions of GDI vehicles were higher than their PFI counterparts and diesel ones equipped with DPFs. Stringent PM mass levels and the introduction of particle number limits for GDI vehicles in the European Union (EU) resulted in significant PM reductions. The EU requirement to fulfill the proposed limits on the road resulted to the introduction of gasoline particulate filters (GPFs) in EU GDI models. This review summarizes the evolution of PM mass emissions from gasoline vehicles placed in the market from early 1990s until 2019 in different parts of the world. The analysis then extends to total and nonvolatile particle number emissions. Care is given to reveal the impact of ambient temperature on emission levels. The discussion tries to provide scientific input to the following policy-relevant questions. Whether particle number limits should be extended to gasoline PFI vehicles, whether the lower limit of 23 nm for particle number measurements should be decreased to 10 nm, and whether low ambient temperature tests for PM should be included.
•Sales data by powertrain type and market share presented for various global light-duty markets from 2015 to 2020.•Forecast/prediction of future powertrain market share in the US, Europe and Global ...based on different electric vehicle adoption scenarios•Review of fuel economy, CO2 and criteria pollutant emissions in major markets as well as discussion of future regulations.•Review of light-duty gasoline and heavy-duty diesel internal combustion engine and aftertreatment technologies announced in 2020.•Review of current state of battery charging infrastructure and vehicle range.
Fossil fuels are currently the most convenient on-board energy sources for vehicles in terms of energy density and refueling time. However, the increase in global temperature together with the increase in transported people and goods in recent years has forced regulatory authorities around the world to establish strict regulations on pollutant and CO2 emissions. These scenarios are challenging for vehicle manufacturers, but they also create opportunities for the development of new technologies and concepts. For example, automotive companies and researchers are currently exploring hybrid powertrains with either advanced internal combustion engine technologies and low levels of electrification, or with high levels of electrification combined with simpler internal combustion engines. While these hybridization approaches can provide significant improvements in efficiency and emissions. There is also a global movement at the, consumer, manufacturing and government level to accelerate the adoption of zero tailpipe emitting vehicles (e.g., battery electric vehicles and fuel cell electric vehicles). This paper reviews the current state of powertrain technologies, analyzing first the evolution of emissions regulations in major markets and emphasizing the future tighter measures that will be adopted in Europe and the US. After that, an analysis of current global vehicle sales considering the COVID situation is performed, followed by a forecast of future powertrain technology market share trends. Finally, reviews of internal combustion engine, hybrid, and battery electric vehicle technologies announced in 2020 are carried out.
This paper reviews the recent advances in the management of nitrogen oxide (NOx) emissions from the internal combustion engine of light-duty and heavy-duty vehicles, addressing both technical and ...legal aspects. Particular focus is devoted to the often-virtuous interaction between new legislation imposing more restrictions on the permitted pollutant emission levels and new technologies developed in order to meet these restrictions. The review begins first with the American and then European directives promulgated in the 1970s, aimed at limiting emissions of pollutants from road transport vehicles. Particular attention is paid to the introduction of the Euro standards in the European Union for light- and heavy-duty vehicles, used as a legal and time frame reference for the evolution of emission aftertreatment systems (ATSs). The paper also describes governmental approaches implemented for the control of pollutant emissions in circulating vehicles, such as market surveillance and in-service conformity. In parallel, it is explained how the gradual introduction of small-scale devices aimed at the NOx control, such as lean NOx traps (LNTs) systems, and, most of all, the selective catalytic reduction (SCR) of NOx, permitted the application to road-transport vehicles of this ATS, originally designed in larger sizes for industrial usage. The paper reviews chemical processes occurring in SCR systems and their advantages and drawbacks with respect to the pollutant emission limits imposed by the legislation. Their potential side effects are also addressed, such as the emission of extra, not-yet regulated pollutants such as, for example, NH3 and N2O. The NOx, N2O, and NH3 emission level evolution with the various Euro standards for both light- and heavy-duty vehicles are reported in the light of experimental data obtained at the European Commission’s Joint Research Centre. It is observed that the new technologies, boosted by increasingly stricter legal limits, have led in the last two decades to a clear decrease of over one order of magnitude of NOx emissions in Diesel light-duty vehicles, bringing them to the same level as Euro 6 gasoline vehicles (10 mg/km to 20 mg/km in average). On the other hand, an obvious increase in the emissions of both NH3 and N2O is observed in both Diesel and gasoline light-duty vehicles, whereby NH3 emissions in spark-ignition vehicles are mainly linked to two-reaction mechanisms occurring in three-way catalysts after the catalyst light-off and during engine rich-operation. NH3 emissions measured in recent Euro 6 light-duty vehicles amount to a few mg/km for both gasoline and Diesel engines, whereby N2O emissions exceeding a dozen mg/km have been observed in Diesel vehicles only. The present paper can be regarded as part of a general assessment in view of the next EU emission standards, and a discussion on the role the SCR technology may serve as a NOx emission control strategy from lean-burn vehicles.
Objectives
Bladder dysfunction due to spinal cord injury has a significant impact on the overall health and quality of life of an individual. Clean intermittent catheterization is the gold standard ...for bladder management and is recommended due to having the lowest complication rate. Transitions from intermittent catheterization to other less optimal strategies, such as indwelling catheter, are quite common. However, the research documenting patient perspectives, and epidemiological and demographic factors related to such transition is limited.
Methods
Data from patients with spinal cord injury rehabilitated with clean intermittent catheterization were collected. Demographic and epidemiological details of the patients were documented from the inpatient records. Appropriate statistical tests were applied to the values.
Results
Among the 45 participants, 68.89% continued clean intermittent catheterization. In those who discontinued clean intermittent catheterization, the median duration of practicing clean intermittent catheterization was 3.5 months. The commonest difficulty among compliant patients was carrying out clean intermittent catheterization in outdoor environments due to the unavailability of toilet facilities. Urinary tract infection was the most common (17.78%) complication noted. Dependence (20.00%) was a major procedural difficulty followed by pain. Adaptations to remain continent in special conditions were diapers and condom catheters. The duration of clean intermittent catheterization practiced influenced discontinuation of clean intermittent catheterization. With an increase in the duration of clean intermittent catheterization practiced after discharge, the risk of discontinuation of clean intermittent catheterization decreased with an adjusted odds ratio of 0.773 (95% confidence interval 0.609–0.982).
Conclusions
People with spinal cord injury have many challenging issues in the regulation of bladder function at their level inclusive of procedural difficulties, environmental barriers and medical complications, and understanding of which will help to establish a comprehensive and a holistic program to provide remote/community care.
Gasoline Particulate Filters—a Review Joshi, Ameya; Johnson, Timothy V.
Emission control science and technology (Online),
12/2018, Letnik:
4, Številka:
4
Journal Article
Recenzirano
To improve ambient air quality, several countries have adopted regulations setting stringent limits on vehicular tailpipe emissions of particulates. The issue of high particulate emissions has been ...mostly addressed for diesel vehicles with the widespread adoption of diesel particulate filters (DPFs). Attention is now turned to gasoline direct injection (GDI) technology, which provides improved fuel economy and performance, but also increased particulate emissions, as compared to the port fuel injection (PFI) engines. Europe has set a particle number (PN) limit on emissions from GDI vehicles, while China has expanded that to include all gasoline vehicles. In the USA, these are regulated through particle mass (PM) limits. To meet these regulations, it is anticipated that gasoline particulate filters (GPFs) will be widely applied to gasoline exhaust after-treatment. GPF technology has rapidly advanced, and already a wide range of pore size distribution and cell geometries are being offered to minimize back pressure and offer high ash storage capacity, high filtration efficiency, and, in the case of filters combined with three-way catalytic functionality, high conversion of gas-phase criteria pollutants. This review summarizes representative studies on particulate emissions from gasoline engines, the nature of the particulates, and the advances in GPF technology.
This review article summarizes major and representative developments in vehicle emissions regulations, engine efficiency, and emission control from 2017. The article starts with the key regulatory ...developments in the field, including newly proposed European light-duty (LD) CO₂ regulations (15 and 30% cuts in 2025 and 2030, respectively, from 2020 levels) and technical improvements of the Euro 6 real driving emissions (RDE) regulations. China finalized their new energy vehicle (NEV) mandates for 2019 and 2020. LD and heavy-duty (HD) engine technology continues showing marked improvements in engine efficiency. Key developments are summarized for gasoline and diesel engines to meet both the emerging criteria and greenhouse gas (GHG) regulations. Several LD gasoline concepts are achieving 10-15% and some up to 35% reductions relative to gasoline direct injection (GDI) engines of today. Projections indicate tight CO₂ regulations will require some degree of hybridization and/or high-performing gasoline and diesel engines. Scoping work on HD engines is reported on achieving 55% break thermal efficiency (BTE) using methods that can reasonably be commercialized. Lean NOx control technologies are summarized, including selective catalytic reduction (SCR), NOx adsorbers, and systems. Fundamentals of the SCR reaction are explored at the atomistic level. Diesel particulate filter (DPF) work has been focused on structure-performance relationships and ash behavior. Research oxidation catalysts are approaching 90% efficiency for hydrocarbon (HC) and CO oxidation at 160-190 °C. Gasoline particulates are a major topic in emission control. The article provides a broad overview of various factors that can impact emissions. The impact of fuel composition and application is summarized. Gasoline particulate filter (GPF) durability and ash loading are better understood. Finally, the article discusses some key developments in three-way catalysts, with improved understanding of low-temperature performance. Advances in lean-burn gasoline emission control from a few labs are also summarized.
Non-catalytic oxidation kinetics of diesel engine soot and more than a dozen commercial carbon black samples was investigated using non-isothermal and isothermal thermogravimetric analysis (TGA) ...experiments. The effect of various operating parameters, such as oxygen flow rate, initial sample mass, oxygen partial pressure, crucible type, and ramp rate, on the oxidation rate was investigated. Three types of TGA experiments (non-isothermal single-ramp rate, non-isothermal multiple-ramp rates, and isothermal) were conducted and analyzed to extract the kinetic parameters for oxidation. Activation energies for oxidation of carbon black samples ranged from 125 to 257 kJ/mol, whereas that for soot oxidation was ∼155 kJ/mol. Furthermore, oxidation rate trends were explained on the basis of structural characteristics, such as scanning electron microscopy (SEM)-based average particle size and Brunauer–Emmett–Teller (BET) surface area. In general, a low particle size and high surface area were associated with a higher oxidation rate and vice versa. A thorough understanding of the non-catalytic oxidation kinetics developed in this work along with the correlation of the oxidation rate with the structural parameters may assist in efficient oxidation of diesel engine soot during the regeneration of diesel particulate filters.
Polycystic ovary syndrome (PCOS) is often the first manifestation, in adolescents and young adults, of metabolic problems that may occur later. Early identification, timely referral and appropriate ...treatment can result in improved reproductive, metabolic and comprehensive health. However, unlike other components of metabolic syndrome, which can be diagnosed at primary care level, there is no inexpensive, clinical tool to screen for PCOS. We share a simple six-item questionnaire, structured in three domains, which can be used as a screening tool for the syndrome. This allows early diagnosis and management of the condition, facilitates a life course approach to health promotion, and lays the foundation for the prevention of other comorbid metabolic disorders. It also helps integrate national programmes concerning non-communicable disease and women's healthcare under one umbrella, thus optimizing and strengthening delivery of community care.
New EU7 emission standards are currently under development. While the timing and exact level of stringency of these standards is not available, both OEMs and suppliers are preparing to meet ...significantly reduced tailpipe NOx and particle number standards for both light- and heavy-duty vehicles. We present here some of the emission control systems that are likely to be implemented and details on the advanced component technologies.
Mashi is a black colored powder formulation obtained after combustion of the plant or animal drug. It is prepared by bahirdhum padhati (outside) or anterdhum padhati (in the close vessel). In this ...dosage form, bulk of raw material is reduced to a greater extent by the application of a certain quantum of energy. Due to this treatment, hidden chemical constituents become prominent and/or a new chemical moiety is formed which is therapeutically active. This formulation is cost-effective and easy to prepare. This review article aims to highlight the different mashi formulations mentioned in Ayurvedic text and also incorporate the formulation not mentioned in the Ayurvedic text but used by Ayurvedic practitioners. The objective was to introduce researchers to the simple yet excellent formulation mashi which should be studied in detail to establish its identity, purity, and therapeutic activity.
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