Inter-Comparison of Particle and Gaseous Pollutant Emissions of a Euro 4 Motorcycle at Two Laboratories

The Euro 4 regulation, applicable since 2016 for L-category vehicles (i.e., two and three-wheelers, and mini cars) reduced the emission limits, but also introduced a new cycle, the WMTC (World Harmonized Motorcycle Test Cycle). The emission studies of Euro 4 motorcycles are limited, and most importantly there are no published studies comparing the results of different laboratories applying the new cycle. In this study we compared the particle and gaseous pollutants of one Euro 4 motorcycle measured in two laboratories in 2017 and 2020. The gaseous pollutant results had a variance (one standard deviation of the means) of 0.5% for CO2, 4–19% for CO, NOx, HC (hydrocarbons) and SPN (Solid Particle Number). The particulate matter mass results had higher variance of 50–60%. Additional tests with open configuration to mimic dilution at the tailpipe gave equivalent results to the closed configuration for the gaseous pollutants and SPN. The total particles (including volatiles) had significant differences between the two configurations, with the closed configuration giving higher results. The main conclusion of this study is that the new procedures have very good reproducibility, even for the SPN that is not regulated for L-category vehicles. However, the measurement of total particles needs attention due to the high sensitivity of volatile particles to the sampling conditions.

Open configuration options What Public Policies Do Citizens Want for Combating Crime in Latin America and the Caribbean? A Dataset

Crime is a major problem in Latin America and the Caribbean. With 9 percent of the world's population, the region accounts for 33 percent of global homicides. This dataset makes extensive new survey data available to help identify what anti-crime policies citizens in the region demand from their governments, as well as who is demanding what and why. This dataset accompanies a recent report on Combating Crime in Latin America and the Caribbean.

Coupled sine-Gordon systems in living cellular structure

In this paper, we present a coupled sine-Gordon (CSG) system, which describes the dynamics of two deoxyribonucleic acid (DNA) twisting strands in open configuration. We investigate the associated linear eigenvalue problem of the CSG system and obtain generalized formulae for multiple soliton solutions by employing the Darboux transformation (DT). Explicit expressions of one- and two-kink and line soliton solutions, single breather and first-order degenerate solutions are obtained by using particular solutions to the associated linear eigenvalue problem. We also present the dynamics of the different solutions.

Laterally Extended Field of View Imaging without Geometric Distortion using Image Stitching in Open-Configuration MRI

Open-configuration MRI for easy patient access causes a restricted imaging field of view and geometric distortion resulting in reduced reliability of the quantitation of tissue segmentation. The method proposed in this study is use of MR image stitching, which is merging divided isocentric images without geometric distortion of the same object through the table moving laterally. This study was performed using an open 0.32 T MRI system. MR imaging with lateral shift of the scanner table was conducted using an AAPM MRI Phantom. The composite image produced through the sequential generation of the same object at different table positions has been generated using the image stitching technique. Image stitching consisted of tile configurations using optimized global registration and then seamlessly blending the aligned tiles. The overall image stitching procedure reduced the geometric distortion of image at off-center regions, and the FOV in the stitched image was extended 40% laterally relative to conventional isocenter image. The maximum distortion value was about 16.8 mm in the conventional image and was reduced to < 1.7 mm after the seamless image stitching procedure. Laterally extended FOV without geometric distortion was successfully acquired using seamless image stitching procedure. These methods are beneficial towards defining tissue segmentation in obese patient with large field of view in open MRI.

Identification and Quantification of Uncertainty Components in Gaseous and Particle Emission Measurements of a Moped

The recent Euro 4 and 5 environmental steps for L-category vehicles (e.g., mopeds, motorcycles) were mainly designed to reduce the emissions of particulate matter and ozone precursors, such as nitrogen oxides and hydrocarbons. However, the corresponding engine, combustion, and aftertreatment improvements will not necessarily reduce the solid particle number (SPN) emissions, suggesting that a SPN regulation may be necessary in the future. At the same time, there are concerns whether the current SPN regulations of passenger cars can be transferred to L-category vehicles. In this study we quantified the errors and uncertainties in emission measurements, focusing on SPN. We summarized the sources of uncertainty related to emission measurements and experimentally quantified the contribution of each uncertainty component to the final results. For this reason, gas analyzers and SPN instruments with lower cut-off sizes of 4 nm, 10 nm, and 23 nm were sampling both from the tailpipe, and from the dilution tunnel having the transfer tube in closed or open configuration (i.e., open at the tailpipe side). The results showed that extracting from the tailpipe 23–28% of the mean total exhaust flow (bleed off) resulted in a 24–31% (for CO2) and 19–73% (for SPN) underestimation of the emissions measured at the dilution tunnel. Erroneous determination of the exhaust flow rate, especially at cold start, resulted in 2% (for CO2) and 69–149% (for SPN) underestimation of the tailpipe emissions. Additionally, for SPN, particle losses in the transfer tube with the closed configuration decreased the SPN concentrations around 30%, mainly due to agglomeration at cold start. The main conclusion of this study is that the open configuration (or mixing tee) without any instruments measuring from the tailpipe is associated with better accuracy for mopeds, especially related to SPN measurements. In addition, we demonstrated that for this moped the particle emissions below 23 nm, the lower size currently prescribed in the passenger cars regulation, were as high as those above 23 nm; thus, a lower cut-off size is more appropriate.