4,821 research outputs found
Feasibility study of MgSO4 + zeolite based composite thermochemical energy stores charged by vacuum flat plate solar thermal collectors for seasonal thermal energy storage
A primary drawback of solar thermal technologies, especially in a domestic setting, is that collection of thermal energy occurs when solar irradiance is abundant and there is generally little requirement for heating. Thermochemical Energy Storage (TCES) offers a means of storing thermal energy interseasonally with little heat loss. A combination of a Solar Thermal Collector (STC) and TCES system will allow a variety of different heating applications, such as domestic space and hot water heating as well as low temperature industrial process heat applications to be met in a low carbon way. This paper describes and assesses the feasibility of two novel technologies currently under development at Loughborough University; i) an evacuated flat plate STC and ii) composite TCES materials, coupled together into a system designed to store and supply thermal energy on demand throughout the year. Experimental results of composite TCES materials along with predicted performance of STC's are used within a developed model to assess key metrics of conceptual TCES + STC systems feasibility, including; charging time, payback time, cost/kWh, energy savings and CO2 savings. This paper demonstrates the economic, energy and carbon savings potential of conceptual TCES + STC systems suitable for domestic use
Stickiness in Chaos
We distinguish two types of stickiness in systems of two degrees of freedom
(a) stickiness around an island of stability and (b) stickiness in chaos, along
the unstable asymptotic curves of unstable periodic orbits. We studied these
effects in the standard map with a rather large nonlinearity K=5, and we
emphasized the role of the asymptotic curves U, S from the central orbit O and
the asymptotic curves U+U-S+S- from the simplest unstable orbit around the
island O1. We calculated the escape times (initial stickiness times) for many
initial points outside but close to the island O1. The lines that separate the
regions of the fast from the slow escape time follow the shape of the
asymptotic curves S+,S-. We explained this phenomenon by noting that lines
close to S+ on its inner side (closer to O1) approach a point of the orbit 4/9,
say P1, and then follow the oscillations of the asymptotic curve U+, and escape
after a rather long time, while the curves outside S+ after their approach to
P1 follow the shape of the asymptotic curves U- and escape fast into the
chaotic sea. All these curves return near the original arcs of U+,U- and
contribute to the overall stickiness close to U+,U-. The isodensity curves
follow the shape of the curves U+,U- and the maxima of density are along U+,U-.
For a rather long time the stickiness effects along U+,U- are very pronounced.
However after much longer times (about 1000 iterations) the overall stickiness
effects are reduced and the distribution of points in the chaotic sea outside
the islands tends to be uniform.Comment: 28 pages, 12 figure
Learning intrinsic excitability in medium spiny neurons
We present an unsupervised, local activation-dependent learning rule for
intrinsic plasticity (IP) which affects the composition of ion channel
conductances for single neurons in a use-dependent way. We use a
single-compartment conductance-based model for medium spiny striatal neurons in
order to show the effects of parametrization of individual ion channels on the
neuronal activation function. We show that parameter changes within the
physiological ranges are sufficient to create an ensemble of neurons with
significantly different activation functions. We emphasize that the effects of
intrinsic neuronal variability on spiking behavior require a distributed mode
of synaptic input and can be eliminated by strongly correlated input. We show
how variability and adaptivity in ion channel conductances can be utilized to
store patterns without an additional contribution by synaptic plasticity (SP).
The adaptation of the spike response may result in either "positive" or
"negative" pattern learning. However, read-out of stored information depends on
a distributed pattern of synaptic activity to let intrinsic variability
determine spike response. We briefly discuss the implications of this
conditional memory on learning and addiction.Comment: 20 pages, 8 figure
Inspiring to inspire: Developing teaching in higher education
Following a three-year staff development initiative within one faculty in a UK university, the authors reflected on inspiring teaching and the role that staff development can play in enhancing individual practice. Teaching is a core component of Higher Education and is complex and multi-faceted both theoretically and in practice. Through individual reflections to a set of pre-determined questions, a group of Higher Education teachers (n = 5) with a responsibility for the development of learning, teaching and assessment, share their thoughts, feelings and beliefs on inspiring teaching. The interpretive analysis of the data shows from a staff perspective that the notion of inspiring teaching has three main components which are all interrelated, those being; the actual teaching and learning experience; the design of the curriculum and the teacher/student relationship. Staff development initiatives were found to help people explore and develop their own teaching philosophy, to develop new practices and to share and learn from others. However, individual’s mindset, beliefs and attitudes were found to be a challenge. Teachers can frame their development around the different aspects of inspiring teaching and with support from senior leadership as well as a positive culture, teaching communities can work together towards inspiring teaching
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Frailty and Spousal/Partner Bereavement in Older People: A Systematic Scoping Review Protocol
The aim of this project is to conduct a systematic review that will identify and collate published information relating to frailty and spousal/partner bereavement (i.e. the death of a life partner whether married or unmarried co-habiting) in older people (aged 60 years and above). The review will include all relevant national (UK) and international research. This review aims to identify any gaps in literature that can help inform future healthcare policies and models
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