900 resultados para Transport and communications


Relevância:

90.00% 90.00%

Publicador:

Resumo:

The monitoring of temperature and moisture changes in response to different micro-environment of building stones is essential to understand the material behaviour and the degradation mechanisms. From a practical point of view, having a continuous and detailed understanding of micro-environmental changes in building stones helps to assist in their maintenance and repair strategies. Temperature within the stone is usually monitored by means of thermistors, whereas wide ranges of techniques are available for monitoring the moisture. In the case of concrete an electrical resistance method has previously been used as an inexpensive tool for monitoring moisture changes. This paper describes the adaptation of this technique and describes its further development for monitoring moisture movement in building stones.
In this study a block of limestone was subjected to intermittent infrared radiation with programmed cycles of ambient temperature, rainfall and wind conditions in an automated climatic chamber. The temperature and moisture changes at different depths within the stone were monitored by means of bead thermistors and electrical resistance sensors. This experiment has helped to understand the thermal conductivity and moisture transport from surface into deeper parts of the stone at different simulated extreme climatic conditions. Results indicated that variations in external ambient conditions could substantially affect the moisture transport and temperature profile within the micro-environment of building stones and hence they could have a significant impact on stone decay.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

This book is a study of the British Board of Film Censors in the 1970s. In permitting and refusing specific material to be shown on cinema screens the BBFC were dictating patterns of taste and helping shape and determine notions of acceptability. Contentious and controversial texts like A Clockwork Orange (1971), Straw Dogs (1971) The Devils (1971) and Life of Brian (1979) have been used to draw attention to the way in which the BBFC operated in the 1970s. While it is true to say that these films encountered major censorship problems, what of the hundreds of other films which were being classified at the same time? Did all films struggle with the British censors in this period, and can these famous examples be fitted into broader patterns of censorship policy and practice?

In studying over 250 film files from the BBFC archive, this work reveals how 1970s films such as Vampire Circus (1971), Confessions of a Window Cleaner (1974) and Carry on Emmannuelle (1978) also ran in to trouble with the film censor. This work explores the complex process of negotiation and compromise which affected all film submissions in the 1970s and the way in which the BBFC actively, and often sympathetically, negotiated with film directors, producers and distributors to assign the correct category to each film. The lack of any defined formal censorship policy in this period allowed the BBFC to work alongside the film industry and push cultural, social and artistic boundaries; however it also left the Board open to accusations of favouritism, subjectivity and personal bias.

This work is not simply a study of controversial films and contentious issues, but rather engages with wider issues of changing permission, legal struggles, the influence of the media and the legislative and governmental controls which both helped and hindered the BBFC in this important post-war decade. The approach used within this work focuses on historical and archival research, making it importantly inter-textual and offering a great deal to scholars from a number of associated disciplines, including history, social policy, media and communications and politics.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

Introducing automation into a managed environment includes significant initial overhead and abstraction, creating a disconnect between the administrator and the system. In order to facilitate the transition to automated management, this paper proposes an approach whereby automation increases gradually, gathering data from the task deployment process. This stored data is analysed to determine the task outcome status and can then be used for comparison against future deployments of the same task and alerting the administrator to deviations from the expected outcome. Using a machinelearning
approach, the automation tool can learn from the administrator's reaction to task failures and eventually react to faults autonomously.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

Geochemical,spectrographic, microbiological and hydrogeologic studies at the ORIFRC site indicate that groundwater transport in structured media may behave as a system of parallel flow tubes. These tubes are preferred flowpaths that enable contaminant transport parallel to bedding planes (strike) over distances of 1000s of meters. A significant flux of groundwater is focused within an interval defined by the interface between the competent bedrock and overlying highly-weathered saprolite, commonly referred to as the"transition zone." Characteristics of this transition zone are dense fractures and the relative absence of weathering products (e.g. clays)results in a significantly higher permeability compared to both the overlying clay-saprolite and underlying bedrock. Several stratabound low seismic velocity zones located below the transition zone were identified during geophysics studies and were also determined to be fractured high permeability preferred contaminant transport pathways during subsequent drilling activities. XANES analysis of precipitates collected from these deeper flow zones indicate 95% or more of the U deposited is U(VI). Linear combination fitting of the EXAFS data shows that precipitates are ~51±5% U(VI)-carbonate-like phase (e.g., liebigite) and ~49±5% U(VI) associated with an iron oxide phase; inclusion of a third component in the fit suggests that up to 15% of the U(VI) may be associated with a phosphate phase or OH- phase (e.g.,schoepite). Although precipitates with similar U(VI)-carbonate and/or phosphate associations were identified in the transition zone pathways,there were also U(VI) complexes adsorbed to mineral surfaces that would tend to be more readily mobilized. Groundwater in the different flow tubes has been determined to consist of different water quality types that vary with the solid phase encountered (e.g., clays, carbonates, clastics) as contaminants migrate along the flow paths. This lateral and vertical variability in geochemistry, particularly pH, has a significant impact on microbiological community composition and activity. Ribosomal RNA gene analyses coupled with physiological and genomic analyses suggest that bacteria from the genus Rhodanobacter(a diverse population of denitrifiers that are moderately acid tolerant) have a high relative abundance in the acidic source zone at the ORIFRC site.Watershed-scale analysis across different flow paths/tubes revealed strong negative correlation between pH and the absolute and relative abundance of Rhodanobacter. Recent studies also confirmed that the ORIFRC site hosts a diverse fungal community, with significant differences observed between acidic (pH <5) and circumneutral (>5) wells. The lack of nitrous oxide reduction capability in fungi, and the detection of denitrification potential in slurry microcosms suggest that fungi may have aheretofore under appreciated role in biogeochemical transformations, with implications forsite remediation and greenhouse gas emissions. Further research is needed to determine if these organisms can influence U(VI) mobility either directly through immobilization or indirectly through the depletion of nitrate.In conclusion, additional studies are required to quantify the processes (e.g., solid phase reactions, recharge, diffusion, microbial interactions) that are occurring along the groundwater flow tubes identified at the ORIFRC so predictive models can be parameterized and used to assess long-term contaminant fate and transport and remedial options.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

P>In order to gain insights into the transport and distribution of arsenic (As) in intact rice (Oryza sativa) plants and its unloading into the rice grain, we investigated the spatial distribution of As and the temporal variation of As concentration in whole rice plants at different growth stages. To the best of our knowledge, this is the first time that such a study has been performed.

Inductively coupled plasma mass spectroscopy (ICP-MS) and high-performance liquid chromatography (HPLC)-ICP-MS were used to analyze total As concentration and speciation. Moreover, synchrotron-based X-ray fluorescence (SXRF) was used to investigate in situ As distribution in the leaf, internode, node and grain.

Total As concentrations of vegetative tissues increased during the 2 wk after flowering. The concentration of dimethylarsinic acid (DMA) in the caryopsis decreased progressively with its development, whereas inorganic As concentration remained stable. The ratios of As content between neighboring leaves or between neighboring internodes were c. 0.6. SXRF revealed As accumulation in the center of the caryopsis during its early development and then in the ovular vascular trace.

These results indicate that there are different controls on the unloading of inorganic As and DMA; the latter accumulated mainly in the caryopsis before flowering, whereas inorganic As was mainly transported into the caryopsis during grain filling. Moreover, nodes appeared to serve as a check-point in As distribution in rice shoots.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

The process of diffusive shock acceleration relies on the efficacy with which hydromagnetic waves can scatter charged particles in the precursor of a shock. The growth of self-generated waves is driven by both resonant and non-resonant processes. We perform high-resolution magnetohydrodynamic simulations of the non-resonant cosmic ray driven instability, in which the unstable waves are excited beyond the linear regime. In a snapshot of the resultant field, particle transport simulations are carried out. The use of a static snapshot of the field is reasonable given that the Larmor period for particles is typically very short relative to the instability growth time. The diffusion rate is found to be close to, or below, the Bohm limit for a range of energies. This provides the first explicit demonstration that self-excited turbulence reduces the diffusion coefficient and has important implications for cosmic-ray transport and acceleration in supernova remnants.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

Application Specific Instruction Set Processor (ASIP) becomes an attractive substitute for ASIC as transistor density, logic complexity and market competition boost. Similar to ASIC, ASIP is based on customized and tailored architectures. In this way, ASIP delivers high performances with low overheads on cost and power whilst taking the advantages of high flexibility and fast time-to-market as a processor-based solution. To demonstrate this effective solution for embedded applications, this paper performs an overall investigation on ASIP's developments, challenges, trends in terms of architectures and design methodologies.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

The book acts as a companion to the Irish pavilion at the 2014 Venice Biennale for Architecture. This chapter examines the context of roads transport and then analyses how its architectural infrastructure developed in this period, concentrating on the work carried out mainly by one Irish firm: Michael Scott and Partners.