14,482 research outputs found

    Architectural implications for context adaptive smart spaces

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    Buildings and spaces are complex entities containing complex social structures and interactions. A smart space is a composite of the users that inhabit it, the IT infrastructure that supports it, and the sensors and appliances that service it. Rather than separating the IT from the buildings and from the appliances that inhabit them and treating them as separate systems, pervasive computing combines them and allows them to interact. We outline a reactive context architecture that supports this vision of integrated smart spaces and explore some implications for building large-scale pervasive systems

    Dispersion corrections in graphenic systems: a simple and effective model of binding

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    We combine high-level theoretical and \emph{ab initio} understanding of graphite to develop a simple, parametrised force-field model of interlayer binding in graphite, including the difficult non-pairwise-additive coupled-fluctuation dispersion interactions. The model is given as a simple additive correction to standard density functional theory (DFT) calculations, of form ΔU(D)=f(D)[UvdW(D)−UDFT(D)]\Delta U(D)=f(D)[U^{vdW}(D)-U^{DFT}(D)] where DD is the interlayer distance. The functions are parametrised by matching contact properties, and long-range dispersion to known values, and the model is found to accurately match high-level \emph{ab initio} results for graphite across a wide range of DD values. We employ the correction on the difficult bigraphene binding and graphite exfoliation problems, as well as lithium intercalated graphite LiC6_6. We predict the binding energy of bigraphene to be 0.27 J/m^2, and the exfoliation energy of graphite to be 0.31 J/m^2, respectively slightly less and slightly more than the bulk layer binding energy 0.295 J/m^2/layer. Material properties of LiC6_6 are found to be essentially unchanged compared to the local density approximation. This is appropriate in view of the relative unimportance of dispersion interactions for LiC6_6 layer binding

    Dimension- and shape-dependent thermal transport in nano-patterned thin films investigated by scanning thermal microscopy

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    Scanning thermal microscopy (SThM) is a technique which is often used for the measurement of the thermal conductivity of materials at the nanometre scale. The impact of nano-scale feature size and shape on apparent thermal conductivity, as measured using SThM, has been investigated. To achieve this, our recently developed topography-free samples with 200 and 400 nm wide gold wires (50 nm thick) of length of 400–2500 nm were fabricated and their thermal resistance measured and analysed. This data was used in the development and validation of a rigorous but simple heat transfer model that describes a nanoscopic contact to an object with finite shape and size. This model, in combination with a recently proposed thermal resistance network, was then used to calculate the SThM probe signal obtained by measuring these features. These calculated values closely matched the experimental results obtained from the topography-free sample. By using the model to analyse the dimensional dependence of thermal resistance, we demonstrate that feature size and shape has a significant impact on measured thermal properties that can result in a misinterpretation of material thermal conductivity. In the case of a gold nanowire embedded within a silicon nitride matrix it is found that the apparent thermal conductivity of the wire appears to be depressed by a factor of twenty from the true value. These results clearly demonstrate the importance of knowing both probe-sample thermal interactions and feature dimensions as well as shape when using SThM to quantify material thermal properties. Finally, the new model is used to identify the heat flux sensitivity, as well as the effective contact size of the conventional SThM system used in this study

    Assessment of radar resolution requirements for soil moisture estimation from simulated satellite imagery

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    Radar simulations were performed at five-day intervals over a twenty-day period and used to estimate soil moisture from a generalized algorithm requiring only received power and the mean elevation of a test site near Lawrence, Kansas. The results demonstrate that the soil moisture of about 90% of the 20-m by 20-m pixel elements can be predicted with an accuracy of + or - 20% of field capacity within relatively flat agricultural portions of the test site. Radar resolutions of 93 m by 100 m with 23 looks or coarser gave the best results, largely because of the effects of signal fading. For the distribution of land cover categories, soils, and elevation in the test site, very coarse radar resolutions of 1 km by 1 km and 2.6 km by 3.1 km gave the best results for wet moisture conditions while a finer resolution of 93 m by 100 m was found to yield superior results for dry to moist soil conditions

    Pediatric Resuscitation: Evaluation of a Clinical Curriculum

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    Objective: To assess the impact of a 6-hour pediatric resuscitation curriculum on the comfort levels of resident physicians’ evaluation and treatment of critically ill pediatric patients. Methods: An evaluation instrument assessed resident comfort levels, measured on a seven digit Likert scale ranging from significantly uncomfortable to significantly comfortable, in 13 areas of pediatric resuscitation. To complete the curriculum, residents had to demonstrate proficiency in knowledge and procedural skills during mock resuscitation scenarios and on both written and oral examinations. Results: Thirty-one residents participated in the study: 51.6% were pediatric, 12.9% were medicine/pediatric and 35.5% were emergency medicine residents. Participants in the curriculum had little previous experience with pediatric resuscitation (83% had been involved in five or fewer pediatric resuscitations). In all 13 areas of pediatric resuscitation tested, residents reported improvement in comfort levels following the course (p<0.002; Wilcoxon Signed Rank Tests). The most significant changes were observed for the following items: resuscitation of pulseless arrest, performance of cardioversion and defibrillation, performance of intraosseous needle insertion, and drug selection and dosing for rapid sequence intubation. Fewer than 48% of learners rated themselves as comfortable in these areas prior to training, but after completion, more than 80% rated themselves in the comfortable range. All residents but one received passing scores on their written examinations (97%). During the mock resuscitation scenarios and oral examination, 100% of the residents were assessed to have ‘completely’ met the learning objectives and critical actions Conclusion: Implementation of a pediatric resuscitation curriculum improves pediatric and emergency medicine residents’ comfort with the evaluation and treatment of critically ill pediatric patients. This curriculum can be used in residency training to document the acquisition of core competencies, knowledge and procedural skills needed for the evaluation and treatment of the critically ill child. The results reported in this study support using this model of instructional design to implement educational strategies, which will meet the requirements of graduate education

    Thermocouple heating impact on the temperature measurement of small volume of water in a cooling system

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    Experimental and numerical analyses have been performed to investigate the heating impact of using a thermocouple for the temperature measurement of a small volume of cold water (∌24 mm3), due to thermal conduction through the wires. Two sizes of K-type thermocouple, 80 ”m and 315 ”m, were used to measure the temperature of cold water inside a small, thermally regulated chamber within a Centeo TG40 cooling system. The results show that thermal conduction from the ambient environment into the cold water produces a heating effect. This effect decreases for greater submersion depth of the thermocouple junction and is eliminated when the thermocouple junction is close to the copper bottom of the chamber. The inclusion of an insert into the chamber increases the thermal resistance between the copper block and the water, raising the heating effect of the thermocouple. The cooling effect of the copper block on the water is diminished when the air gap between copper block and plastic insert is increased, consequently raising the temperature inside the small well. Moreover, increasing the water height inside the large well has a negligible effect on the temperature of the small well

    Pricing in inflationary times- the penny drops

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    We investigate micro pricing behaviour in groceries (the UK’s most important consumer market) over eight years including the inflationary period of early 2008. We find behaviour sharply distinguished from most previous work, namely that overall basket prices rise but more individual prices fall than rise! This is consistent with retailers obscuring the fact of rising basket prices. We employ a significant new source of data that captures cross-competitor interplay in prices at a very detailed level. Unusually but importantly, our work takes into account that consumers buy baskets of goods, rather than individual products, when shopping at supermarkets.

    LABOR UNIONS-CLOSED SHOP AND ARBITRARILY CLOSED OR PARTIALLY CLOSED UNION-INJUNCTION

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    The defendants appealed from an order of the lower court awarding a preliminary injunction which restrained the defendants from discharging or causing the discharge of the plaintiff and other Negro employees because they were not members of a labor union with which their employer has a closed shop agreement, but which will not grant Negroes full membership privileges. The defendants were: the plaintiff\u27s employer; the International Brotherhood of Boilermakers, Iron Shipbuilders and Helpers of America which is a labor union; and certain officials of the aforementioned union. There was a written contract between the employer and the International Brotherhood containing a provision for a closed shop. This union did not admit Negroes to membership, but in 1937 it established separate Negro local lodges. The defendants insisted that plaintiff and other Negro workers must be members in good standing in these Negro locals in order to obtain work clearances for employment in the defendant employer\u27s shipyard. The non-Negro locals supervised and controlled the Negro locals, allowing representation for the Negro locals only through the business agents of the supervising locals, but the Negro locals had no voice in the selection of these agents. The lower court found that this, and other provisions which denied the Negroes a voice in determination of union policy and in job classifications, and which denied their locals a permanent status clearly established a substantial discrimination against Negro workers who accepted membership in the auxiliary locals. Held, the order awarding the preliminary injunction is affirmed. The union may not maintain both a closed shop and an arbitrarily closed or partially closed union membership. This is not a proper labor union objective. The holders of a monopoly, such as the defendant union has here, over the supply of labor of this type in this area, must not exercise their power in an arbitrary or unreasonable manner so as to bring injury to others. James v. Marinship Corporation, (Cal. 1944) 155 P. (2d) 329
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