Engine tests have been performed on a 9.6 liter spark-ignited engine fueled by natural gas and a mixture of 25/75 hydrogen/natural gas by volume. The scope of the work was to test two strategies for low emissions of harmful gases; lean burn operation and stoichiometric operation with EGR and a three-way catalyst. Most gas engines today, used in city buses, utilize the lean burn approach to achieve

This chapter starts with a description of the optics of camera-type eyes, in which an image is projected upon a retina with cornea and lens as refracting elements. Ray tracing is explained with the human eye as an example of a terrestrial vertebrate's eye. Then the comparison is made to camera eyes of aquatic and amphibious animals, with an explanation of different kinds of aberrations, difficulti

This paper discusses the ways in which a critical systemic approach to systems analysis can provide support for a holistic, multicriteria benefits analysis. It highlights the importance of inquiry into the nature and boundaries of a perceived organizational problem space, taking into account unique perspectives of the living, engaged actors who desire beneficial change in their working systems. Th

Auto-ignition with SI-compression ratio can be achieved by replacing some of the fresh charge by hot residuals. In this work an engine is run with a negative valve overlap (NVO) trapping hot residuals. By increasing the NVO, thus raising the initial charge temperature it is possible to investigate the intermediate zone between SI and HCCI as the amount of residuals is increased. Recent research ha

Vård och behandling av personer med långvarig smärta är en utmaning. Vården kan inte bara rikta sig mot smärtan i sig utan måste omfatta hela den komplexitet som uppstår när flera olika faktorer interagerar med såväl smärtan som varandra på olika sätt. Detta kräver god kunskap bland vårdpersonal och då inte bara om hur smärta kan lindras utan även om hur livet förändras vid långvarig smärta. Inne

The incidence of evaporating `black widow' pulsars (BWPs) among all millisecond pulsars is far higher in globular clusters than in the field. This implies a special formation mechanism for them in clusters. Cluster millisecond pulsars in wide binaries with white dwarf companions exchange them for turnoff-mass stars. These new companions eventually overflow their Roche lobes because of encounters a

This chapter provides a novel framework for assessing energy security and illustrates its application by the Global Energy Assessment, the IEA Model for Short-term energy security and in several studies of long-term global energy security.

Because of the stratospheric ozone depletion that took place during the last decades of the past century, the effects of ultraviolet radiation on plants, animals, humans and micro-organisms became intensively studied. In this chapter we describe the role of the ozone layer as a radiation shield and various molecular and organismal effects of ultraviolet radiation, with an emphasis on the UV-B band

Scholars have argued that the end of the Cold War and the War on Terror have radically changed the context of war and defense, diminished the role of nation-states in favor of multi-lateral defense activities, and placed a new focus on human security. International peacekeeping has superseded the traditional act of war-making as the most important defense strategy among wealthy, liberal-democratic

Two 8-year-old Pinus radiata trees growing in a dry-land plantation forest were subjected to a partial shading treatment for 2 years in order to investigate the responses of photosynthesis and tree growth to a long-term reduction in illuminated leaf area. The lower 60% of the crown of shaded trees was surrounded by 50% neutral density shade cloth. This reduced radiation absorption by 13% for the t

This paper provides a survey of the role of feedback control in embedded realtimesystems, presented in the context of a new EU/IST Network of Excellence, ARTIST2.The survey highlights recent research efforts and future research directions in the areasof codesign of computer-based control systems, implementation-aware embedded controlsystems, and control of real-time computing systems.

Given a set U with n elements and a family of subsets S ⊆ 2U we show how to count the number of k-partitions S1 ∪ ... ∪ Sk = U into subsets Si ∈ S in time 2nnO(1). The only assumption on S is that it can be enumerated in time 2nnO(1). In effect we get exact algorithms in time 2nnO(1) for several well-studied partition problems including domatic number, chromatic number, bounded component spanning

The struggle for equality is fundamental to the reduction of poverty in Central America. Besides, one of the foremost goals of urban spatial planning, when implementing social policies, is to contribute to the reduction of poverty. This is done by producing a list of territorially-based actions and selecting those suitable for the implementation of social policies developed at national level. Howe

Background Oral contraceptives were introduced almost 50 years ago, and over 100 million women currently use them. Oral contraceptives can reduce the risk of ovarian cancer, but the eventual public-health effects of this reduction will depend on how long the protection lasts after use ceases. We aimed to assess these effects. Methods Individual data for 23 257 women with ovarian cancer (cases) a

In this work we study polycations as efficient compacting agents of a medium size polyanion by means of Monte Carlo simulations. The systems are characterized in terms of a conformational analysis in which shape, overall dimensions, structure factors, radial distribution functions, and the degree of accumulation of the compaction agent near the polyanion are taken into consideration. Results show

We formulate multi-input multi-output (MIMO) proportional-integral-derivative (PID) controller design as an optimization problem that involves nonconvex quadratic matrix inequalities. We propose a simple method that replaces the nonconvex matrix inequalities with a linear matrix inequality (LMI) restriction, and iterates to convergence. This method can be interpreted as a matrix extension of the c