Impact of combustion phasing on energy and availability distributions of an internal combustion engine

High fuel efficiency has become an extremely desirable trait for internal combustion engines. This motivation has driven extensive research on methods to improve fuel efficiency on engines of various sizes. Many of these methods involve changes to the properties of the combustion process. One way to induce these property changes is through varying the phasing of combustion. Combustion phasing can be defined as the time in the engine cycle, specifically the compression and expansion strokes, where combustion occurs. A change in combustion phasing causes a change in combustion duration. The duration of combustion impacts how the energy and work potential of the energy (availability) from the fuel are utilized. Analysis techniques based on the first and second law of thermodynamics have been developed to determine the energy and availability distributions. These distributions are utilized to visualize and quantify any improvements made to engine efficiency as combustion phasing is altered. The test engine utilized is a spark ignition (SI) engine meaning that the combustion phasing variations are completed by varying the ignition timing. In light of the test platform being a two-cylinder, industrial-use engine, this thesis focuses on determining the impact of combustion phasing on energy and availability distributions in an air-cooled, rich running utility engine subject to tight manufacturing cost constraints --Abstract, page iii

Population viability analysis of Lower Missouri River shovelnose sturgeon with initial application to the pallid sturgeon

Demographic models for the shovelnose (Scaphirhynchus platorynchus) and pallid (S. albus) sturgeons in the Lower Missouri River were developed to conduct sensitivity analyses for both populations. Potential effects of increased fishing mortality on the shovelnose sturgeon were also evaluated. Populations of shovelnose and pallid sturgeon were most sensitive to age-0 mortality rates as well as mortality rates of juveniles and young adults. Overall, fecundity was a less sensitive parameter. However, increased fecundity effectively balanced higher mortality among sensitive age classes in both populations. Management that increases population-level fecundity and improves survival of age-0, juveniles, and young adults should most effectively benefit both populations. Evaluation of reproductive values indicated that populations of pallid sturgeon dominated by ages \u3e/=35 could rapidly lose their potential for growth, particularly if recruitment remains low. Under the initial parameter values portraying current conditions the population of shovelnose sturgeon was predicted to decline by 1.65% annually, causing the commercial yield to also decline. Modeling indicated that the commercial yield could increase substantially if exploitation of females in age

An address relating to the European convention on human rights

The following is a transcript of an address given by Luzius Wildhaber at the Old University, Au/a Magna, Valletta, Malta 16 January 2003.peer-reviewe