31,823 research outputs found
Investigation of combustion and performance characteristics of CAI combustion engine with positive and negative valve overlap
No full textThis thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.In the first part of studies, Controlled Auto-Ignition (CAI) combustion was investigated in a Ricardo E6 single cylinder, four stroke gasoline engine. CAI combustion is achieved by employing positive valve overlap configuration in combination with various compression ratios and intake air temperature strategies. The CAI operational region is limited by engine load due to knock and partial burned boundaries. The combustion characteristics and emissions are studied in order to understand the major advantages and drawbacks of CAI combustion with positive valve overlap.
The enlargement of the CAI operational region is obtained by boosting intake air and external EGR. The lean-boosted operation elevators the range of CAI combustion to the higher load region, and the use of external EGR allows the engine to operation with CAI combustion in the mid range of region between boosted and N/A CAI operational range. The results are analyzed and combustion characteristics, performance and emissions are investigated.
A Ricardo Hydra single cylinder, four stroke optical gasoline engine with optical access is then experimented to investigate CAI combustion through negative valve overlap configuration and an intake heater. The effects of direct fuel injection timings spark timings and air/fuel ratio are studied by means of simultaneous incylinder heat release study and direct visualization, chemiluminescence techniques which uses full, OH radical and CHO species. Both heat release analysis and chemiluminescence results have identified the pressure of minor combustion during the NVO period. Both the charge cooling and local air/fuel ratio effects are also investigated by varying the quantity of direct air injection
Performance and analysis of a 4-stroke multi-cylinder gasoline engine with CAI combustion
No full textCopyright © 2002 SAE International. This paper is posted on this site with permission from SAE International. Further use of this paper is not permitted without permission from SAEControlled Auto-Ignition (CAI) combustion was realised in a production type 4-stroke 4-cylinder gasoline engine without intake charge heating or increasing compression ratio. The CAI engine operation was achieved using substantially standard components modified only in camshafts to restrict the gas exchange process
The engine could be operated with CAI combustion within a range of load (0.5 to 4 bar BMEP) and speed (1000 to 3500 rpm). Significant reductions in both specific fuel consumption and CO emissions were found. The reduction in NOx emission was more than 93% across the whole CAI range. Though unburned hydrocarbons were higher under the CAI engine operation.
In order to evaluate the potential of the CAI combustion technology, the European NEDC driving cycle vehicle simulation was carried out for two identical vehicles powered by a SI engine and a CAI/SI hybrid engine, respectively. The simulation results showed only moderate improvement in fuel economy and exhaust emissions because of low utilisation of CAI during the drive cycle.
In order to take full advantage of the CAI combustion technology, detailed analyses were carried out on the engine’s performance, heat release and combustion characteristics, emissions and the effect of gas exchange processes. These analyses showed that the engine’s performance and emissions were mainly affected by the trapped residual fractions and residual temperature. In addition, the backflow was found to affect the combustion and emission as well
CAI Tools for Consecutive Interpreters. Present Solutions and Development Perspectives
No full textCelem artykułu jest przedstawienie CAI, czyli narzędzi informatycznych wspierających tłumacza w trakcie wykonywania tłumaczeń konsekutywnych. W pierwszej części przedstawiona jest definicja CAI oraz opis i przykłady pierwszej, drugiej i trzeciej generacji tego narzędzia. Na podstawie analizy przedmiotu stwierdzono, że istniejące rozwiązania, w postaci komercyjnej lub testowej, ograniczają swoje działanie głównie do zarządzania terminologią. Następnie autor odnosi się do możliwości wykorzystania pamięci tłumaczeniowych w tłumaczeniu konsekutywnym. Kolejna część opisuje dwa najważniejsze komponenty CAI, czyli oprogramowanie do rozpoznawania mowy (ASR) oraz narzędzie kompresujące. W dalszej części przedstawiono możliwe problemy rozwojowe narzędzia oraz opisano kompresję w tłumaczeniu konsekutywnym. W ostatniej części artykułu autor opisuje kompleksowe narzędzie CAI, jego komponenty, a taże scenariusz zastosowania w trakcie tłumaczenia konsekutywnego.The aim of the article is to present CAI tools, i.e. Computer-Assisted Interpreting tools supporting the interpreter during consecutive interpreting. The first part presents the definition of CAI, a description and examples of the first, second and third generation of this tool. Based on the analysis of the subject, it was found that the existing solutions, either in commercial or test form, are limited to terminology management. Then the author refers to the possibility of using translation memories in consecutive interpreting. The following part describes the twomost important components of CAI, namely speech recognition software (ASR) and a compression tool. In the next part, possible development issues are presented
Cai Lei in a Faculty Recital
No full textThis is the program for the faculty recital featuring pianist Lei Cai. This recital took place on October 6, 2003, in the W. Francis McBeth Recital Hall
Experimental studies of CAI combustion in a four-stroke GDI engine with an air-assisted injector
No full textThis thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.CAI combustion and the factors affecting it were intensively investigated in a single cylinder, air-assisted gasoline direct injection engine. CAI was achieved by means of residual gas trapping by utilising low-lift short duration camshafts and early closing of the exhaust valves. The effects of EVC (Exhaust Valve Closure) and IVO (Inlet Valve opening) timings, spark timing, single and split injection timings, coolant temperature, compression ratio, cam lift and duration on exhaust emissions and CAI operation were investigated experimentally. Engine speed throughout the course of the experiments, was varied from 1200rpm to 2400rpm and the air/fuel ratio was altered from stoichiometric to the misfire limit. The results show that the EVC timing, compression ratio, cam lift and duration had significant influences on CAI combustion and emissions. Early EVC when combined with higher compression ratio and higher cam lift, enhance CAI combustion operation and stability. IVO timing had minor effect on CAI combustion while spark timing hardly affects CAI operation as soon as fully-developed CAI conditions were established. Coolant temperature was revealed to have substantial impact on CAI combustion when the coolant temperature was below 65oC. The results also show the importance of injection timing. Early injection gave faster and more stable combustion, less HC and CO emissions, but more prone to knocking combustion and higher NOx emissions. Furthermore, CAI operation range could considerably be extended with injection during the recompression process. Late injection led to slower and unstable combustion, higher HC and CO emissions but lower combustion noise and NOx emissions. Split injection gave even further extension of CAI range in both stoichiometric and lean mixture operations. All the above clearly suggest, that optimising injection timing and using split injection is an effective way to control and extend CAI operation in a direct injection gasoline engine
New performing GC columns with unmatched separation capabilities
No full textGas chromatography (GC) is widely used for qualitative and quantitative analysis in numerous fields, such as petroleum, chemical industry, agriculture, environmental protection, medicine, and so on, due to its high
versatility, high selectivity, simplicity of use, analysis speed, and low sample consumption. The column is the heart of a GC instrumentation, which allows the analyte separation and their recognition and quantification. Commercial columns do not always allow a complete peak separation when compounds (i.e., isomers) are very
similar in molecular weight, polarity, and vapor pressure. The choice of the correct stationary phase, with high selectivity towards target analytes, is the key to obtaining the required chromatographic separation and the subsequent qualitative and quantitative analysis.
Considering the rapid polymer science development and the growing demand for new columns with
improved resolution capabilities, in this work novel stationary phases for capillary GC have been designed, synthesized, and characterized in terms of polarity range, resolution, column efficiency, thermal stability, filmforming properties, and support-deactivating capacity1-5. The separation features of these novel stationary phases allow high-resolution performances for a wide range of compounds, like aromatic anilines, xylenes, aromatic amines, halogenated benzenes, and aromatic aldehydes, with marked capabilities toward isomer separations.References:
[1] T. Sun, M. Ba, Y. Song, W. Li, Y. Zhang, Z. Cai, S. Hu, X. Liu, D. Nardiello, M. Quinto, Analytica Chimica Acta, 2024, 1291, art. no. 342221.
[2] T. Sun, R. Chen, Q. Huang, M. Ba, Z. Cai, H. Chen, Y. Qi, H. Chen, X. Liu, D. Nardiello, M. Quinto, Analytica
Chimica Acta, 2023, 1251, art. no. 340979.
[3] T. Sun, R. Chen, Q. Huang, M. Ba, Z. Cai, S. Hu, X. Liu, D. Nardiello, M. Quinto, ACS Applied Materials and Interfaces, 2022, 14 50, pp. 56132-56142
[4] R. Chen, Z. Cai, W. Li, Q. Huang, D. Nardiello, M. Quinto, X. Liu, S. Hu, T. Sun, Chemistry and Biodiversity, 2022,
19, art. no. e202200829
[5] Q. Huang, Z. Cai, R. Chen, W. Zhang, D. Nardiello, M. Quinto, X. Liu, S. Hu, T. Sun, Microchemical Journal, 2022,
183, art. no. 10808
Lin Chang and Lei Cai in a Faculty Recital
No full textThis is the program for the faculty recital featuring violinist Lin Chang and pianist Lei Cai. This recital took place on April 20, 2004, in the W. Francis McBeth Recital Hall
Angela Park and Lei Cai in a Guest Artist Recital
No full textThis is the program for the guest artist recital featuring cellist Angela Park and pianist Lei Cai. This recital took place on September 14, 2010, in the W. Francis McBeth Recital Hall
Matt Frederickson and Cai Lei in a Faculty Recital
No full textThis is the program for the faculty recital featuring trombonist and euphonium player Matt Frederickson and pianist Cai Lei. This recital took place on April 1, 2003 in the W. Francis McBeth Recital Hall
Concrete Crack images for segmentation
No full textThis is a concrete crack dataset for segmentation. It is partially from Ozgenel FÇ. Concrete crack segmentation dataset. Mendeley Data 2019; 1: DOI: 10.17632/jwsn7tfbrp.1. and @article{liu2019deepcrack, title={DeepCrack: A Deep Hierarchical Feature Learning Architecture for Crack Segmentation}, author={Liu, Yahui and Yao, Jian and Lu, Xiaohu and Xie, Renping and Li, Li}, journal={Neurocomputing}, volume={338}, pages={139--153}, year={2019}, doi={10.1016/j.neucom.2019.01.036}}If the dataset helps your research, please cite our paper:@article{xie2022sparse, title={Sparse-sensing and superpixel-based segmentation model for concrete cracks}, author={Xie, Xiongyao and Cai, Jielong and Wang, Haozheng and Wang, Qiang and Xu, Jieying and Zhou, Yingxin and Zhou, Biao}, journal={Computer-Aided Civil and Infrastructure Engineering}, year={2022}, publisher={Wiley Online Library}
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