Occupant behaviour in naturally ventilated and hybrid buildings

Adaptive thermal comfort criteria for building occupants are now becoming established. In this paper we illustrate their use in the prediction of occupant behaviour and make a comparison with a non-adaptive temperature threshold approach. A thermal comfort driven adaptive behavioural model for window opening is described and its use within dynamic simulation illustrated for a number of building types. Further development of the adaptive behavioural model is suggested including use of windows, doors, ceiling fans, night cooling, air conditioning and heating, also the setting of opportunities and constraints appropriate to a particular situation. The integration in dynamic simulation of the thermal adaptive behaviours together with non-thermally driven behaviours such as occupancy, lights and blind use is proposed in order to create a more complete model of occupant behaviour. It is further proposed that this behavioural model is implemented in a methodology that includes other uncertainties (e.g. in internal gains) so that a realistic range of occupant behaviours is represented at the design stage to assist in the design of robust, comfortable and low energy buildings

Ethane and Carbon Dioxide Gas Hydrate Incipient Conditions in Reverse Micelles

A reversed-micellar solution is defined as a system of water, oil and an amphilphile (surfactant). It has been shown that gas hydrate formation in reverse-micelle systems provides a means for in-situ control of the droplet size, which in turn can be used to manipulate the properties of any material that has been formed in the water droplet. In this study, the incipient conditions for ethane and carbon dioxide gas hydrate formation in the presence of AOT-water-isooctane were carried out. Subsequently, the results were modelled using the model of van der Waals and Platteeuw in conjunction with a model for the activity of water in reverse micelles and the Peng Robinson equation of state. The predictions were seen to fit the experimental data well

Utilization of Modified Cashew Nut Shell (Anacardium Occidentale) as an Adsorbent for the Removal of Synthetic Dye (C57) 4-Hydroxyl-3-Carboxy Phenylazophenylazo -2-Nitro-Toluene) From Aqueous Solution Via-Kinetics Approach

The abatement of an azo-dye “4-hydroxyl-3-carboxylphenylazophenylazo-2-nitro toluene” with dye code C57 was carried out with the use of readily available and cheap adsorbent known as cashew nut shell (Anacareium occidentale) for the removal of the C57 dye from used water. The influence of the different system factors such as contact time, temperature, pH, dye ion concentration and adsorbent dosage were all investigated. The result showed the dye ion removal efficacy ncreases with time till optimum pion of 50 minutes (74.4&).The maximum dye adsorption occurred  with 5g of the adsorbent resulting to maximum percentage removal of 73.5. optimum C57 Dye concentration was found to be 10mg/L with efficiency of 72%. low pH results to a positive change in H+ concentration with % Removal of 63.9%, similarly the optimum dye removal was observed at 600C (333K) temperature resulting to 73.5% this maybe due to the chemical reaction the functional group of the cashew nut shell/C57. The Langmuir isotherm gave a smart linear graph with R2 ,  KL and SF values as 0.6013, 8.73L/g, 47.39, and 1.133 respectively, which was able to fit in better of than the Freundlich isotherm. Freundlich isotherm assumes the adsorption intensity of the adsorbent with KF value of 15.95mg/g. Pseudo first and second order have K of 0.014 and 0.0041 respectively, whereas the later was able to fit in properly more than the former

Preconditioning and triggering of offshore slope failures and turbidity currents revealed by most detailed monitoring yet at a fjord-head delta

Rivers and turbidity currents are the two most important sediment transport processes by volume on Earth. Various hypotheses have been proposed for triggering of turbidity currents offshore from river mouths, including direct plunging of river discharge, delta mouth bar flushing or slope failure caused by low tides and gas expansion, earthquakes and rapid sedimentation. During 2011, 106 turbidity currents were monitored at Squamish Delta, British Columbia. This enables statistical analysis of timing, frequency and triggers. The largest peaks in river discharge did not create hyperpycnal flows. Instead, delayed delta-lip failures occurred 8–11 h after flood peaks, due to cumulative delta top sedimentation and tidally-induced pore pressure changes. Elevated river discharge is thus a significant control on the timing and rate of turbidity currents but not directly due to plunging river water. Elevated river discharge and focusing of river discharge at low tides cause increased sediment transport across the delta-lip, which is the most significant of all controls on flow timing in this setting

Discrete-time rewards model-checked

This paper presents a model-checking approach for analyzing discrete-time Markov reward models. For this purpose, the temporal logic probabilistic CTL is extended with reward constraints. This allows to formulate complex measures – involving expected as well as accumulated rewards – in a precise and succinct way. Algorithms to efficiently analyze such formulae are introduced. The approach is illustrated by model-checking a probabilistic cost model of the IPv4 zeroconf protocol for distributed address assignment in ad-hoc networks

An interactive 3D virtual environment to reduce the public speaking anxiety levels of novice software engineers

Software engineering is a set of activities that relies no only on technical tasks but also requires abilities focused on social duties such as daily meetings and product introduction presentations. However, engineers may experience elevated levels of anxiety when required to present their work in an unfamiliar environment. More specifically, they may suffer from public speaking anxiety even though they are supposed to be effective in those social tasks as well as in their engineering activities. Fortunately, previous studies suggest that virtual exposure therapy is an effective strategy to reduce public speaking anxiety. In this study, an interactive 3D virtual environment similar to real classrooms and auditoriums was developed to examine if this might decrease the anxiety levels of novice software engineers. To compare traditional and virtual exposure therapy, the sample set (N = 14) was divided equally into 2 groups including one experimental group and one control group. For 4 weeks, the virtual exposure therapy was conducted in the experimental group whereas psychoeducation was used in the control group. The findings from our study illustrate that virtual exposure therapy may be represent an alternative solution to the traditional therapeutic intervention for software engineers seeking to overcome public presentation anxiet

Trends in studies of edge influence on vegetation at human created and natural forest edges across time and space

Submitted VersionForest edges, or boundaries between adjacent ecosystems, play important ecological roles. Both anthropogenic and natural forest edges affect vegetation while contributing to landscape heterogeneity. The recent proliferation of studies on vegetation at edges suggests that a comprehensive review of global edge studies is timely. We reviewed the literature on forest edges to identify trends in edge studies over time, determine types and localities of studied edges, and compare findings on edge influence. We found 446 studies conducted in 55 different countries that considered edge influence on vegetation structure and (or) composition. Research on vegetation at anthropogenic edges has increased and expanded geographically, but studies are still scarce in some areas and at natural forest edges. Forest edges were generally characterized by greater species diversity and nonnative species abundance than interior forest. Distance of edge influence on vegetation extended furthest at tropical anthropogenic forest edges compared with other edge types and locations. Edge influence on responses caused by indirect effects of edges generally extended further into the forest than edge influence on responses related to forest structure. Our findings indicate that vegetation characteristics differ between edge and forest types and should be considered in the sustainable management of heterogeneous forested landscapes. [ABSTRACT FROM AUTHOR

Complementary approaches to understanding the plant circadian clock

Circadian clocks are oscillatory genetic networks that help organisms adapt to the 24-hour day/night cycle. The clock of the green alga Ostreococcus tauri is the simplest plant clock discovered so far. Its many advantages as an experimental system facilitate the testing of computational predictions. We present a model of the Ostreococcus clock in the stochastic process algebra Bio-PEPA and exploit its mapping to different analysis techniques, such as ordinary differential equations, stochastic simulation algorithms and model-checking. The small number of molecules reported for this system tests the limits of the continuous approximation underlying differential equations. We investigate the difference between continuous-deterministic and discrete-stochastic approaches. Stochastic simulation and model-checking allow us to formulate new hypotheses on the system behaviour, such as the presence of self-sustained oscillations in single cells under constant light conditions. We investigate how to model the timing of dawn and dusk in the context of model-checking, which we use to compute how the probability distributions of key biochemical species change over time. These show that the relative variation in expression level is smallest at the time of peak expression, making peak time an optimal experimental phase marker. Building on these analyses, we use approaches from evolutionary systems biology to investigate how changes in the rate of mRNA degradation impacts the phase of a key protein likely to affect fitness. We explore how robust this circadian clock is towards such potential mutational changes in its underlying biochemistry. Our work shows that multiple approaches lead to a more complete understanding of the clock