Constant V/Hz control based on DSP for open winding doubly-fed wind power generator

A DSP implementation of Space Vector PWM (SVPWM) using constant V/Hz control for the open winding doubly-fed generator is proposed. This control of SVPWM modulation mode and open winding structure combination has the high voltage utilization ratio, greatly improves the control precision of the system, and reduces the stator winding output current distortion rate, though the complexity of the system is increased. This paper describes the basic principle of SVPWM and discusses the particularity of SVPWM waveform generated by hybrid vector under the condition of open winding. This method is applied to a state of doubly-fed wind power generator. The experimental verification shows that this control method can make the output voltage amplitude of the doubly-fed induction generator be 380V and the frequency be 50Hz by using of TMS32028335 chip based on constant V/Hz control of symmetric SVPWM modulation wave.

Argument structure and specific language impairment: retrospect and prospect

This article reflects a collaboration between the Universities of Groningen and Reading of which Frans Zwarts was the promoter. One of the outcomes was a close attention to the learning of various aspects of argument structure by children with specific language impairment (SLI) in Dutch and English. At that time and since, the focus on deficits in grammatical morphology in these children has left verb complementation as something of a syntactic Cinderella. Here we review the findings from our studies in the 1990s. We confirm that children with SLI in both languages have problems with verb specificity, with argument structure alternations and with resultative verb predicates. The very limited number of subsequent studies on verb syntax appear to support our findings. We conclude that this is an area which will repay further scrutiny – it is high time argument structure received an invitation to the ball.

Geodesically reversible Finsler 2-spheres of constant curvature

A Finsler space is said to be geodesically reversible if each oriented geodesic can be reparametrized as a geodesic with the reverse orientation. A reversible Finsler space is geodesically reversible, but the converse need not be true. In this note, building on recent work of LeBrun and Mason, it is shown that a geodesically reversible Finsler metric of constant flag curvature on the 2-sphere is necessarily projectively flat. As a corollary, using a previous result of the author, it is shown that a reversible Finsler metric of constant flag curvature on the 2-sphere is necessarily a Riemannian metric of constant Gauss curvature, thus settling a long- standing problem in Finsler geometry.

Makarios Now: Plundering Athens and Hippo

A Christian doctrine of happiness differs greatly from contemporary and pseudo-Christian conceptions of happiness, which are measured subjectively and by the accumulation of external goods. In order to develop a fresh account with objective standards, I critique, integrate and revise Aristotle and Augustine’s accounts of happiness. Additionally, I rely heavily on scriptures to present a telos of godlikeness that in turn informs a robust account of makarios. Throughout the thesis, the argument is made that happiness (eudaimonia) and blessedness (makarios) are equivalents. Despite the skepticism of liberal theologians, Christian happiness (makarios) is promised in the New Testament and achievable in this life. Fundamentally, makarios is relational, active, constant, and dependent.

Constant Beauty Within and PCOS as Cacti

Travail créatif / Creative Work

News agencies, their constant reinvention as a strategy to face competition

News agencies compete for a foothold as providers of information and mass media. Covered by a technological class infrastructure, Associated Press, Reuters, Agence FrancePresse (AFP) and EFE are leaders of the global media system because they introduce revolutionary changes in their production routines, professional culture, journalistic genres and styles; also for its innovative product offerings and services. This article also focuses on the strategies of the agencies to get closer to their audiences, from the agreements established and the treatment of very specific themes. Some solutions that contribute to the future survival of these entities are also proposed.

“I am in a constant state of insecurity trying to make ends meet, like our service users”: Shared austerity reality between social workers and service users: Towards a preliminary conceptualization

This article introduces the concept of an emerging shared austerity reality, which refers to the socio-economic context of austerity that is shared both by social workers and service users, albeit to different degrees. Traditionally, the concept of the shared reality has been utilized to encompass the experiences of welfare professionals working in situations where both they and service users are exposed to the adverse effects of a natural disaster, war or terrorist attack. Here, the concept of shared reality is expanded through the introduction of the context of austerity. Drawing on 21 in-depth interviews with public sector social work practitioners in Greece it discusses, among other things, social anxieties about their children’s future, and their inability to take care of their elderly relatives that suggest an emerging shared austerity reality, reflecting the deterioration of socio-economic conditions. The paper ends with a discussion about the possibilities of alliance and division that emerge from the concept and future research directions. Moreover, it concludes with a reflection on the role of the social work profession and recent political developments in Greece in anti-austerity struggles.

Constant wall heat flux boundary conditions in micro-channels filled with porous material with internal heat generation under local thermal non-equilibrium conditions

Forced convection heat transfer in a micro-channel filled with a porous material saturated with rarefied gas with internal heat generation is studied analytically in this work. The study is performed by analysing the boundary conditions for constant wall heat flux under local thermal non-equilibrium (LTNE) conditions. Invoking the velocity slip and temperature jump, the thermal behaviour of the porous-fluid system is studied by considering thermally and hydrodynamically fully-developed conditions. The flow inside the porous material is modelled by the Darcy–Brinkman equation. Exact solutions are obtained for both the fluid and solid temperature distributions for two primary approaches models A and B using constant wall heat flux boundary conditions. The temperature distributions and Nusselt numbers for models A and B are compared, and the limiting cases resulting in the convergence or divergence of the two models are also discussed. The effects of pertinent parameters such as fluid to solid effective thermal conductivity ratio, Biot number, Darcy number, velocity slip and temperature jump coefficients, and fluid and solid internal heat generations are also discussed. The results indicate that the Nusselt number decreases with the increase of thermal conductivity ratio for both models. This contrasts results from previous studies which for model A reported that the Nusselt number increases with the increase of thermal conductivity ratio. The Biot number and thermal conductivity ratio are found to have substantial effects on the role of temperature jump coefficient in controlling the Nusselt number for models A and B. The Nusselt numbers calculated using model A change drastically with the variation of solid internal heat generation. In contrast, the Nusselt numbers obtained for model B show a weak dependency on the variation of internal heat generation. The velocity slip coefficient has no noticeable effect on the Nusselt numbers for both models. The difference between the Nusselt numbers calculated using the two models decreases with an increase of the temperature jump coefficient.

Electric-Field Dependence of the Effective Dielectric Constant in Graphene

Not Available

Air Temperature Distribution and Energy-balance Modelling of a Debris-covered Glacier

Near-surface air temperature is an important determinant of the surface energy balance of glaciers and is often represented by a constant linear temperature gradients (TGs) in models. Spatiotemporal variability in 2 m air temperature was measured across the debris-covered Miage Glacier, Italy, over an 89 d period during the 2014 ablation season using a network of 19 stations. Air temperature was found to be strongly dependent upon elevation for most stations, even under varying meteorological conditions and at different times of day, and its spatial variability was well explained by a locally derived mean linear TG (MG–TG) of −0.0088°C m−1. However, local temperature depressions occurred over areas of very thin or patchy debris cover. The MG–TG, together with other air TGs, extrapolated from both on- and off-glacier sites, were applied in a distributed energy-balance model. Compared with piecewise air temperature extrapolation from all on-glacier stations, modelled ablation, using the MG–TG, increased by <1%, increasing to >4% using the environmental ‘lapse rate’. Ice melt under thick debris was relatively insensitive to air temperature, while the effects of different temperature extrapolation methods were strongest at high elevation sites of thin and patchy debris cover.

Compassion and its role in the clinical encounter – An argument for compassion training

Empathic communication, (i.e. emotionally engaging with a patient), is an important part of the therapeutic relationship. It has been shown to improve the health and therapeutic outcomes for patients by improving diagnosis and compliance. In the West, front-line medical professionals, including herbal medicine practitioners, put themselves at risk of burnout and compassion fatigue by giving emotionally intensive care. While treatments for compassion fatigue and burnout are available, another way forward is needed to ensure healthcare professionals do not become ill; one that will enable both patients and healthcare professionals to receive the care needed. In this paper it is argued that compassion, which is defined in this paper, involves different neural circuitry to empathy and can protect healthcare professionals from the effects of stress that can, if not addressed, lead to burnout. Traditional Buddhist meditation techniques such as loving-kindness meditation have been shown to increase compassion in non-meditative states. Short daily sessions of such mediation practices have been shown to improve compassion in a way that protects healthcare professionals from burnout.