A Comparison of Inlet Valve Operating Strategies in a Single-Cylinder Spark-Ignition Engine

This experimental work was concerned with comparison of inlet valve actuation strategies in a thermodynamic single cylinder spark ignition research engine equipped with a mechanical fully variable valvetrain on both the inlet and exhaust. The research involved study of the effects of the valvetrain on combustion, fuel economy and emissions when used to achieve variable valve timing alone and when applied together with early inlet valve closing for so-called unthrottled operation. The effects of such early inlet valve closure were examined using either fully variable events or by simulating two-stage cam profile switching. While fully variable operation enabled the maximum fuel savings over the widest operating map, it was apparent that two-stage switching mechanisms can provide an attractive compromise in terms of cost versus CO 2 benefit on engines of moderate to large capacity. However, from speed-load maps obtained in the current study it would appear that a wide range of inlet valve durations would be necessary to obtain fuel savings sufficient to warrant a system any more sophisticated than current variable valve timing mechanisms in future aggressively downsized gasoline engines. © IMechE, 2009

Are the attitudes of exercise instructors who work with older adults influenced by training and personal characteristics?

Little is known about the relationship between attitudes and characteristics of instructors and uptake and adherence of older people to exercise classes. This article explores these issues.Methods:The authors surveyed 731 UK exercise instructors with specialist older adult exercise qualifications. A questionnaire investigated instructors’ characteristics and attitudes toward older adults’ participation in exercise.Results:For mostly seated classes, EXTEND qualification (B = 0.36, p = .005) had a positive effect on instructors’ attitudes. Later Life Training qualification (B = −2.80, p = .003), clinical background (B = −3.99, p = .005), and delivering classes in National Health Services (B = −3.12, p &lt; .001), leisure centers (B = −2.75, p = .002), or nursing homes (B = −2.29, p = .005) had a negative effect on attitudes. For mostly standing classes, experience (B = 0.20, p = .003) and delivering in leisure centers (B = 0.46, p = .032) had a positive and clinical background (B = −1.78, p = .018) had a negative effect on instructors’ attitudes.Conclusions:Most instructors have positive attitudes, but training and work context can influence attitudes toward older people’s participation in exercise classes both positively and negatively.</jats:sec

Feedback Synthesis for Controllable Underactuated Systems using Sequential Second Order Actions

This paper derives nonlinear feedback control synthesis for general control affine systems using second-order actions---the needle variations of optimal control---as the basis for choosing each control response to the current state. A second result of the paper is that the method provably exploits the nonlinear controllability of a system by virtue of an explicit dependence of the second-order needle variation on the Lie bracket between vector fields. As a result, each control decision necessarily decreases the objective when the system is nonlinearly controllable using first-order Lie brackets. Simulation results using a differential drive cart, an underactuated kinematic vehicle in three dimensions, and an underactuated dynamic model of an underwater vehicle demonstrate that the method finds control solutions when the first-order analysis is singular. Moreover, the simulated examples demonstrate superior convergence when compared to synthesis based on first-order needle variations. Lastly, the underactuated dynamic underwater vehicle model demonstrates the convergence even in the presence of a velocity field.Comment: 9 page

Do We Need a New Legal Framework for Fighting Non-Conventional Wars? The International Law of War, Human Rights and the Global Fight Against Extremism and Terrorism

This paper examines the existing legal framework for fighting violent extremism and terrorism. Highlighting the inherent limitations of the current International Law of War in dealing with the growing challenges posed by terrorists and violent extremist groups, the paper discusses the problem facing military commanders, security agents, state actors and the international community in confronting extremist groups while upholding human rights values and respecting the law of war. The paper poses the question as to whether the current legal framework for dealing with extremist groups is sufficient without contravening the essential provisions and ethos of the International Law of War and Human Rights. Using examples, the paper examines how extremist groups flagrantly disregard the rule of law and disrespect human rights in their campaign of terror. The paper also notes instances in which the current Western strategy in fighting terrorism may be viewed or considered as conflicting with human rights and international law

State vs non-state armed groups - a political economy of violence

The early 21st century has witnessed the rise in violent extremism with groups such as Al Qaeda and Islamic State of Iraq and the Levant (ISIL) in the Middle East, the Boko Haram in West Africa, and Al Shabaab in East Africa. The activities of these and other non-state armed groups have created a general state of panic and fear that is spreading beyond their areas of operation to other parts of the political world. Rather than diminishing the influence of these groups, the states' counter extremism strategies seem to be further fuelling the extremism and creating new waves of violence that threatens global security and undermines the very essence of our collective wellbeing. This paper examines the socio-economic and political environment in which these armed groups have thrived and poses the question as to whether the failure of politics and development are to blame for the rise of extremism. The paper proposes a new approach to combating extremism that involves re-connecting people with politics and development. The basic contention of this paper is that there has been a failure of the state to satisfy the wellbeing of its citizens. The paper provides an explanation of, but by no means a justification of, the use of violent extremism in the early 21st century

Towards a circular economy and just transition to net-zero in rural Scotland:Resident perspectives on policy and practice

The circular economy and just transition are key dimensions of the sustainability challenges of the 21st century. These concepts are ambiguous and meanings differ among actors, sectors and contexts. This paper examines the circular economy and a just transition to net-zero in the Scottish context, where both are prominent in national policy discourses and central to the work of Zero Waste Scotland. It is based on qualitative research, co-designed with Zero Waste Scotland, to explore how rural residents in Scotland understand the circular economy and just transition, in their everyday lives and communities. This is an under-researched area and our findings add new knowledge useful for implementing sustainability policies in a rural context. Focus groups were carried out in three rural areas, engaging with a range of residents in a deliberative setting. The findings support the need for a more collaborative, whole systems approach that moves beyond siloed thinking and which focuses on local capacity and knowledge building for transitions to more sustainable rural communities.</p

Diplomacy and the politics of fear: the 21st century challenges to the theory and practice of Diplomacy and International Relations

Conflicts, political unrest, mass migration and the rise of violent extremism by non-state actors are features that have characterized the early 21st century. A huge challenge to world peace and security is posed by volatile economic and political conditions around the world. This situation has led to a growing tension in many inter-state relations which arguably has underpinned the rise of groups such as Al Qaeda and Islamic State of Iraq and the Levant (ISIL) in the Middle East, the Boko Haram in West Africa, and Al Shabaab in East Africa. Arguably, there is a growing sense of fear and unease in every sphere of social, economic and political life. More than at any other time in human history, the future seems uncertain. Relationships and trusts between states and their citizens are breaking down; relations, mutual cooperation and connections between states are under strain; there is growing sense of disillusionment by the governed of the ability of governments and mainstream political establishments to address their concerns and meet their needs. The feeling of uncertainty and general fear for the future is real. While these may not necessarily be universally held views, there is a growing indication that people and communities around the world are feeling dissatisfied and may be threatened by mainstream political systems. Just when it is most needed, diplomacy and diplomatic practice seem to be taking the back seat in the face of growing conflicts. This conference examines the socio-economic and political environment that creates social and political discontent, political apathy, the weakening of inter-state relations, and the general sense of fear

Plasma-tail activity and the interplanetary medium at Halley's Comet during Armada Week: 6-14 March 1986

The encounters of five spacecraft with Halley's Comet during 6-14 March 1986 offered a unique opportunity to calibrate the solar-wind interaction with cometary plasmas as recorded by remote wide-field and narrow-field/narrowband imaging. Perhaps not generally recognized in the comet community is the additional opportunity offered by the Halley Armada to study the structure of the solar-wind and interplanetary magnetic field (IMF) in three dimensions using five sets of data obtained over similar time intervals and heliocentric distances, but at somewhat different heliolatitudes. In fact, the two problems, i.e., comet physics and the structure of the interplanetary medium, are coupled if one wants to understand what conditions pertained at the comet between the encounters. This relationship is discussed

Protons and calcium alter gating of the hyperpolarization-activated cation current (Ih) in rod photoreceptors

AbstractWe investigated the effects of protons and calcium ions on the voltage-dependent gating of the hyperpolarization-activated, nonselective cation channel current, Ih, in rod photoreceptors. Ih is a cesium-sensitive current responsible for the peak-plateau sag during the rod response to bright light. The voltage dependence of Ih activation shifted about 5 mV per pH unit, with external acidification producing positive shifts and alkalinization producing negative shifts. Increasing external [Ca2+] from 3 to 20 mM resulted in a large (∼17 mV) positive shift in Ih activation. External [Ca2+] (20 mM) blocked pH-induced shifts in activation. Cytoplasmic acidification produced by 25 mM sodium acetate led to a negative shift in inactivation (−9 mV) and internal alkalinization produced with 20 mM ammonium chloride resulted in a positive shift (+6 mV). Surface charge binding and screening theory (Gouy–Chapman–Stern) accounted for the observed shifts in Ih activation, with the best fit achieved when protons and calcium ions were assumed to bind to distinct sites on the membrane. Since light induces changes in the retinal ionic environment, these results permit us to gauge the degree to which rod light responses could be modified via alterations in Ih activation