scholarly journals Examination of an Urban City Bus Operating Conditions and Emissions

Author(s):  
Seref Soylu ◽  
Ayda Bal ◽  
Hulya Semercioglu ◽  
Eyup Fatih
2017 ◽  
Vol 168 (1) ◽  
pp. 21-26
Author(s):  
Jerzy MERKISZ ◽  
Łukasz RYMANIAK

The article presents a study of a city bus in real operating conditions (RDE) from the perspective of the latest regulations for the assessment of specific emissions compliance for heavy-duty vehicles (Euro VI standard). The object of the research was a serial configuration hybrid drive vehicle. Measurements were made in the real driving conditions in Poznan agglomeration. The latest mobile equipment PEMS was used for the measurements. This article presents the details of the EU 582/2011 Procedure in operational conformity assessment, the methodology of the study was discussed, and the obtained results were presented, both in terms of vehicle operating conditions and engine operation, as well as specific emissions evaluation.


2016 ◽  
Vol 142 (4) ◽  
pp. 04016018 ◽  
Author(s):  
Carmen Mata ◽  
Wanderson de Oliveira Leite ◽  
Ricardo Moreno ◽  
John R. Agudelo ◽  
Octavio Armas

2019 ◽  
Vol 52 (4) ◽  
pp. 109-115
Author(s):  
Łukasz Rymaniak ◽  
Paweł Fuć ◽  
Piotr Lijewski ◽  
Michalina Kamińska ◽  
Paweł Daszkiewicz ◽  
...  

The article analyzes the environmental costs which consisted of determining the annual cost for gases and particles released into the atmosphere by city buses meeting the Euro VI norm. To this end, exhaust emissions of a city bus equipped with a conventional drive system were performed. The vehicle had a length of 18m and was powered by a CI engine with a swept volume of 10,5 dm3, with a maximum power of 240 kW. In order to measure the ecological indicators, tests were performed in real driving conditions using the PEMS system. The apparatus made it possible to measure the concentration of gaseous compounds and particulate matter in the exhaust, which made it possible to determine the road exhaust emissions of the tested vehicle. The research was carried out on a test route including urban and suburban roads in accordance with legislative guidelines. The measurements showed that the bus met the exhaust emission limits determined on the basis of measuring windows defined in relation to the work generated by the drive system. In addition to information on the emissivity of the vehicle, the annual emissions from city buses meeting the Euro VI standard in Poland were also estimated. The information contained in the central vehicle register for the number of vehicles registered in Poland that meet the latest emission standards has been used for this purpose.


Author(s):  
E.D. Boyes ◽  
P.L. Gai ◽  
D.B. Darby ◽  
C. Warwick

The extended crystallographic defects introduced into some oxide catalysts under operating conditions may be a consequence and accommodation of the changes produced by the catalytic activity, rather than always being the origin of the reactivity. Operation without such defects has been established for the commercially important tellurium molybdate system. in addition it is clear that the point defect density and the electronic structure can both have a significant influence on the chemical properties and hence on the effectiveness (activity and selectivity) of the material as a catalyst. SEM/probe techniques more commonly applied to semiconductor materials, have been investigated to supplement the information obtained from in-situ environmental cell HVEM, ultra-high resolution structure imaging and more conventional AEM and EPMA chemical microanalysis.


Author(s):  
David A. Ansley

The coherence of the electron flux of a transmission electron microscope (TEM) limits the direct application of deconvolution techniques which have been used successfully on unmanned spacecraft programs. The theory assumes noncoherent illumination. Deconvolution of a TEM micrograph will, therefore, in general produce spurious detail rather than improved resolution.A primary goal of our research is to study the performance of several types of linear spatial filters as a function of specimen contrast, phase, and coherence. We have, therefore, developed a one-dimensional analysis and plotting program to simulate a wide 'range of operating conditions of the TEM, including adjustment of the:(1) Specimen amplitude, phase, and separation(2) Illumination wavelength, half-angle, and tilt(3) Objective lens focal length and aperture width(4) Spherical aberration, defocus, and chromatic aberration focus shift(5) Detector gamma, additive, and multiplicative noise constants(6) Type of spatial filter: linear cosine, linear sine, or deterministic


Author(s):  
M. Pan

It has been known for many years that materials such as zeolites, polymers, and biological specimens have crystalline structures that are vulnerable to electron beam irradiation. This radiation damage severely restrains the use of high resolution electron microscopy (HREM). As a result, structural characterization of these materials using HREM techniques becomes difficult and challenging. The emergence of slow-scan CCD cameras in recent years has made it possible to record high resolution (∽2Å) structural images with low beam intensity before any apparent structural damage occurs. Among the many ideal properties of slow-scan CCD cameras, the low readout noise and digital recording allow for low-dose HREM to be carried out in an efficient and quantitative way. For example, the image quality (or resolution) can be readily evaluated on-line at the microscope and this information can then be used to optimize the operating conditions, thus ensuring that high quality images are recorded. Since slow-scan CCD cameras output (undistorted) digital data within the large dynamic range (103-104), they are ideal for quantitative electron diffraction and microscopy.


Author(s):  
D. Goyal ◽  
A. H. King

TEM images of cracks have been found to give rise to a moiré fringe type of contrast. It is apparent that the moire fringe contrast is observed because of the presence of a fault in a perfect crystal, and is characteristic of the fault geometry and the diffracting conditions in the TEM. Various studies have reported that the moire fringe contrast observed due to the presence of a crack in an otherwise perfect crystal is distinctive of the mode of crack. This paper describes a technique to study the geometry and mode of the cracks by comparing the images they produce in the TEM because of the effect that their displacement fields have on the diffraction of electrons by the crystal (containing a crack) with the corresponding theoretical images. In order to formulate a means of matching experimental images with theoretical ones, displacement fields of dislocations present (if any) in the vicinity of the crack are not considered, only the effect of the displacement field of the crack is considered.The theoretical images are obtained using a computer program based on the two beam approximation of the dynamical theory of diffraction contrast for an imperfect crystal. The procedures for the determination of the various parameters involved in these computations have been well documented. There are three basic modes of crack. Preliminary studies were carried out considering the simplest form of crack geometries, i. e., mode I, II, III and the mixed modes, with orthogonal crack geometries. It was found that the contrast obtained from each mode is very distinct. The effect of variation of operating conditions such as diffracting vector (), the deviation parameter (ω), the electron beam direction () and the displacement vector were studied. It has been found that any small change in the above parameters can result in a drastic change in the contrast. The most important parameter for the matching of the theoretical and the experimental images was found to be the determination of the geometry of the crack under consideration. In order to be able to simulate the crack image shown in Figure 1, the crack geometry was modified from a orthogonal geometry to one with a crack tip inclined to the original crack front. The variation in the crack tip direction resulted in the variation of the displacement vector also. Figure 1 is a cross-sectional micrograph of a silicon wafer with a chromium film on top, showing a crack in the silicon.


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