17,872 research outputs found
Recommended from our members
Validation of data analysis routines for a thermal probe apparatus using numerical data sets
Most thermal properties of construction materials used in the analysis of building performance have been measured under laboratory conditions, using a guarded hot box or hot plate apparatus. As a consequence, these properties seldom reflect the impact of actual conditions (especially moisture content) on the values of conductivity and diffusivity. Hence there is a need to develop techniques that allow to take into account local conditions, and measure building material properties in situ. One option available is the use of a thermal probe. The thermal probe technique is based on creating a line source in a material sample, and measuring the temperature rise in the sample in reaction to heat being applied. Obviously the data analysis routines used to calculate thermal conductivity and thermal diffusivity based on the temperature rise observed are crucial to the success of the technique. Transient thermal simulation of a of a model representing a line source in an infinite material sample has been used to generate a set of numerical data sets to validate analysis routines in conjunction with an experimental thermal probe apparatus. Findings show that by careful application of these routines, a close agreement with simulation input values can be achieved, with errors of less than one percent. This validates the analysis routines and provides a deeper appreciation of the theoretical behaviour of a thermal probe
Recommended from our members
Thermal probe technology for buildings: the transition from laboratory to field measurements
This article reports the results of an investigation into the transfer of thermal probe measurement technology from laboratory use to actual buildings in order to undertake the in situ determination of thermal material properties. The imperative for using in situ measurements is 1) the impact of moisture content on thermal properties, 2) the possible wide range of variation of properties across most materials used in construction, and 3) the lack of data for new and innovative materials. Thermal probe technology offers the prospect of taking building specific data, addressing these issues. Based on commercially available thermal probes a portable measurement kit and accompanying measurement procedure have been developed. Three case study buildings, each having different materials, have been studied to ascertain whether or not the technique can be transferred to relatively uncontrolled environments while remaining capable of achieving a precision that is similar to an ASTM standard that can be related to thermal conductivity measurements of building materials. The results show that this is indeed the case, and that the use of thermal probe technology may yield thermal properties that vary significantly from the laboratory values currently used in building thermal engineering calculations
Recommended from our members
Game Transfer Phenomena in video game playing: a qualitative interview study
Video game playing is a popular activity and its enjoyment among frequent players has been associated with absorption and immersion experiences. This paper examines how immersion in the video game environment can influence the player during the game and afterwards (including fantasies, thoughts, and actions). This is what we describe as Game Transfer Phenomena (GTP). GTP occurs when video game elements are associated with real life elements triggering subsequent thoughts, sensations and/or player actions. To investigate this further, a total of 42 frequent video game players aged between 15 and 21 years old were interviewed. Thematic analysis showed that many players experienced GTP, where players appeared to integrate elements of video game playing into their real lives. These GTP were then classified as either intentional or automatic experiences. Results also showed that players used video games for interacting with others as a form of amusement, modeling or mimicking video game content, and daydreaming about video games. Furthermore, the findings demonstrate how video games sometimes triggered intrusive thoughts, sensations, impulses, reflexes, optical illusions, and dissociations
Recommended from our members
Design for manufacture and sustainability in new product development
Design for manufacture is well recognised by industry and is about optimising design to aid production. Today there is a significant and growing trend of recognising what happens to a product once its user phase has finished. Post-consumer processes are now an important consideration during the ab-initio stages of design. Rather than a focus limited to design for manufacture or (more recently) design for assembly now the pressure is on for post consumer design. Companies need to do this because legislative pressures are increasing and consumers are becoming ever more aware of, and concerned about, environmental issues. End-of-life processing and design for the environment are therefore areas of growing of interest. This conference paper investigates with industry practitioners their experiences regarding for both the environmental and economic advantages of product life-cycle planning. Legislative pressures and consumer awareness are driving businesses to develop sustainable product design strategies (Jones et al, 2001 p. 27). Changes within the law, to protect our environment, cause companies to pay attention as they begin to affect profitability. The first British Standard to address design for end-of-life processing, and therefore support industry, is BS 8887-1. Over 60 UK manufacturing and design companies that had bought BS 8887-1 contributed to this by being interviewed or providing a written response. The research investigated multiple aspects of sustainable design in practice however, in this conference paper the focus is its application within the design process
How is the Reionization Epoch Defined?
We study the effect of a prolonged epoch of reionization on the angular power
spectrum of the Cosmic Microwave Background. Typically reionization studies
assume a sudden phase transition, with the intergalactic gas moving from a
fully neutral to a fully ionized state at a fixed redshift. Such models are at
odds, however, with detailed investigations of reionization, which favor a more
extended transition. We have modified the code CMBFAST to allow the treatment
of more realistic reionization histories and applied it to data obtained from
numerical simulations of reionization. We show that the prompt reionization
assumed by CMBFAST in its original form heavily contaminates any constraint
derived on the reionization redshift. We find, however, that prompt
reionization models give a reasonable estimate of the epoch at which the mean
cosmic ionization fraction was ~50%, and provide a very good measure of the
overall Thomson optical depth. The overall differences in the temperature
(polarization) angular power spectra between prompt and extended models with
equal optical depths are less than 1% (10%).Comment: 5 pages, 3 figures; accepted on MNRA
Breaking of the adjoint string in 2+1 dimensions
The roughly linear rise of the potential found between adjoint sources in
SU(N) in lattice simulations is expected to saturate into a state of two
`gluelumps' due to gluonic screening. We examine this in SU(2) in 2+1
dimensions. Crossover between string-like and broken states is clearly seen by
the mixing-matrix technique, using different operators to probe the two states;
the breaking behaviour is rather abrupt. Furthermore, we are able to show that
both types of operator have a finite overlap with both states; in the case of
the Wilson loops the overlap with the broken string is, as predicted, very
small.Comment: LaTeX2e, 20 pages, 15 figures with epsfig; uses amstex, amssymb,
a4wide; minor change to presentation (notation for operators) onl
Internet addiction in adolescents: prevalence and risk factors
As new media are becoming daily fare, Internet addiction appears as a potential problem in adolescents. From the reported negative consequences, it appears that Internet addiction can have a variety of detrimental outcomes for young people that may require professional intervention. Researchers have now identified a number of activities and personality traits associated with Internet addiction. This study aimed to synthesise previous findings by (i) assessing the prevalence of potential Internet addiction in a large sample of adolescents, and (ii) investigating the interactions between personality traits and the usage of particular Internet applications as risk factors for Internet addiction. A total of 3,105 adolescents in the Netherlands filled out a self-report questionnaire including the Compulsive Internet Use Scale and the Quick Big Five Scale. Results indicate that 3.7% of the sample were classified as potentially being addicted to the Internet. The use of online gaming and social applications (online social networking sites and Twitter) increased the 2 risk for Internet addiction, whereas extraversion and conscientiousness appeared as protective factors in high frequency online gamers. The findings support the inclusion of 'Internet addiction' in the DSM-V. Vulnerability and resilience appear as significant aspects that require consideration in further studies
- …