Feedback Control Strategies for Diesel Engine Emissions Compliance

Modern diesel engines are equipped with aftertreatment systems which are effective at reducing tailpipe hydrocarbon and oxides of nitrogen (NOx) emissions when the system’s catalysts are lit-off, meaning they are warmed-up to temperatures near 200 degrees Celsius. During engine cold-starts, combustion phasing retard is typically used to provide additional heat to the aftertreatment system to achieve faster light-off. Analysis of emissions cycle data has shown that improved heating during cold-starts could achieve further emission reductions, however combustion phasing retard heating strategies can be limited by combustion variability issues. Aftertreatment temperature issues can also occur after the engine is warmed-up, as real-world driving behaviors like extended idling and low-load operation can result in exhaust temperatures that are insufficient for maintaining catalyst light-off, resulting in emission increases. This thesis presents novel control solutions to achieve emissions reductions during cold-starts and real-world driving. For cold-start emissions, the concept of closed-loop variance control was analyzed and applied to combustion control, which enables more aggressive combustion phasing retard exhaust heating to achieve faster aftertreatment light-off while avoiding excessive combustion variability issues. Diesel combustion variability was characterized experimentally, and the data was used to identify feedback metrics. Conventional linear controls analysis and statistical theory were used to develop a better understanding of variance feedback control, and the understanding was applied to the engine problem. Closed-loop combustion variability control was performed during both steady-state and transient operation and enabled higher exhaust temperatures while avoiding excessive degradation of engine combustion. For real-world driving emissions, a model predictive control (MPC) framework was developed that uses long horizon engine speed and load preview along with onboard NOx measurements to control the engine for good fuel economy subject to emission constraints. To reduce computational complexity the controller output is a decision variable selecting between two engine calibrations, one with low brake-specific fuel consumption (BSFC) but high brake-specific NOx (or BSNOx), and one with high BSFC, low BSNOx, and increased exhaust heat to aid aftertreatment conversion efficiencies.The onboard NOx measurements are used to inform the optimization problem formulations, which include constraining NOx. based on windowed limits. Software-in-the-Loop (SIL) experimental results show that the controller has the ability to track a windowed emissions target, and appropriately responds to noise factors such as aftertreatment temperatures and emission rate errors.PHDMechanical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/169791/1/bieniekm_1.pd

In Search of Common Ground: Japanese Americans’ and African Americans’ Struggle for Citizenship during World War II

During World War II, the U.S. government forcibly removed over 110,000 Japanese Americans from the West Coast and incarcerated them in concentration camps. At the same time, over 150,000 African Americans moved from the South to the West Coast in search of wartime employment, oftentimes building communities in the same neighborhoods from which Japanese Americans had been displaced. The war thrust Japanese Americans and African Americans into close proximity with one another, both physically and ideologically. My senior honors thesis explores the ways the state altered dominant ideas of race and citizenship during World War II and analyzes how these shifts impacted Japanese Americans’ and African Americans’ sense of national belonging and relationship to each other

Smoking and Second Hand Smoking in Adolescents with Chronic Kidney Disease: A Report from the Chronic Kidney Disease in Children (CKiD) Cohort Study

The goal of this study was to determine the prevalence of smoking and second hand smoking [SHS] in adolescents with CKD and their relationship to baseline parameters at enrollment in the CKiD, observational cohort study of 600 children (aged 1-16 yrs) with Schwartz estimated GFR of 30-90 ml/min/1.73m2. 239 adolescents had self-report survey data on smoking and SHS exposure: 21 [9%] subjects had “ever” smoked a cigarette. Among them, 4 were current and 17 were former smokers. Hypertension was more prevalent in those that had “ever” smoked a cigarette (42%) compared to non-smokers (9%), p\u3c0.01. Among 218 non-smokers, 130 (59%) were male, 142 (65%) were Caucasian; 60 (28%) reported SHS exposure compared to 158 (72%) with no exposure. Non-smoker adolescents with SHS exposure were compared to those without SHS exposure. There was no racial, age, or gender differences between both groups. Baseline creatinine, diastolic hypertension, C reactive protein, lipid profile, GFR and hemoglobin were not statistically different. Significantly higher protein to creatinine ratio (0.90 vs. 0.53, p\u3c0.01) was observed in those exposed to SHS compared to those not exposed. Exposed adolescents were heavier than non-exposed adolescents (85th percentile vs. 55th percentile for BMI, p\u3c 0.01). Uncontrolled casual systolic hypertension was twice as prevalent among those exposed to SHS (16%) compared to those not exposed to SHS (7%), though the difference was not statistically significant (p= 0.07). Adjusted multivariate regression analysis [OR (95% CI)] showed that increased protein to creatinine ratio [1.34 (1.03, 1.75)] and higher BMI [1.14 (1.02, 1.29)] were independently associated with exposure to SHS among non-smoker adolescents. These results reveal that among adolescents with CKD, cigarette use is low and SHS is highly prevalent. The association of smoking with hypertension and SHS with increased proteinuria suggests a possible role of these factors in CKD progression and cardiovascular outcomes

Bowdoin Orient v.136, no.1-25 (2006-2007)

https://digitalcommons.bowdoin.edu/bowdoinorient-2000s/1007/thumbnail.jp

Opera in South Africa during the first democratic decade

The author set out to investigate operatic works that were written in South Africa between 1994 and 2004. Original works that included African elements were of interest as was their classification as operas, musical theatre or music drama. Their artistic merit and the process followed in writing successful works in this genre were investigated. Not only was the collaboration between composer and librettist scrutinised, but also the initial stage during which the conception for these theatrical works took shape. Due to the empirical nature of the research, data was collected mostly via interviews held with composers, librettists, directors and conductors of original works written and performed in the said period. The data is presented in six chapters, each one providing a full description of casting details, synopses and brief analyses of the works. In the Preface the premise upon which the research rests is discussed, while the Introduction serves to highlight various issues concerning modem opera and fusion works that have played an important role in providing the groundwork for contemporary ethnic opera in this country. Original works are discussed in each chapter, and a critical evaluation is presented in an Appendix. The author concludes that much effort was expended by pioneers in the fields of music, theatre and dance to create new works and organise performances. What emerged, furthermore, was that many of the works analysed could not be categorised as 'opera' but rather as 'musical theatre' or 'music drama'. It would also seem that uninitiated audiences first need to be made conscious of the aesthetic value of the genre before they may be able to appreciate it. Operatic production companies have always been at the forefront when it comes to decision - making regarding which and whose work shall be performed. Funding is crucial to the success of any production and plays an equally important role in eventually determining a positive outcome. This aspect has, therefore, also been included as part of the research project

The transition and reinvention of British Army infantrymen

Social sciences approaches to the study of Armed Forces Veterans and their capacity to cope with social reintegration, have tended to focus on medicalised accounts of post-service trauma, characterized by Veteran mental health, homelessness, and suicide amongst our Short Service Leavers. Whilst the findings of these largely quantitative projects continue to present new and compelling data, they have a tendency to neglect key aspects of observable phenomenon and often fall-short in representing the broader experience of Veterans transitioning from martial to civilian space. By contrast this study drawns on a mixed-methods approach to reveal a more authentic picture of resettlement, indeed the project proposes that resettlement is better understood when viewed as a component of a much broader occupational life-story; one that has a past, a present and importantly a future. With few notable exceptions (Ashcroft, 2014; Walker 2012; NAO, 2007) research into the British experience of Armed Forces resettlement is extremely difficult to locate, in a sense the process is hindered further by the outsourcing of Resettlement to Right Management Limited in 2015 and delivery, at a cost of £100 million, of the ‘Career Transition Partnership’ (CTP). And whilst the CTP claim to have helped thousands of veterans into sustainable employment within six months of leaving the Armed Forces; beyond such un-evidenced claims made in their own literature, neither UK government nor CTP has published any evidence based research representative of the degrees of success claimed by the CTP, in delivering cost effective programmes of resettlement. Moreover in the absence of empirical data, and on the basis of this analysis, an alternative account of resettlement is proposed, one that tests the assumption that the MoD’s approach to the resettlement of Armed Forces personnel is either fit for purpose or relevant to the contemporary Armed Forces Veteran. Whilst aspects of the martial life-course have been explored, knowledge of the broader journey that carries the schoolchild to the point of being a veteran has not. Nor have notions of transitioning into and out of the Armed Forces been articulated as public and profoundly sociological issues, as opposed to the medical and psychiatric accounts that dominate this field of study