997 resultados para monumental time
Time dependent rotational flow of a viscous fluid over an infinite porous disk with a magnetic field
Resumo:
Both the semi-similar and self-similar flows due to a viscous fluid rotating with time dependent angular velocity over a porous disk of large radius at rest with or without a magnetic field are investigated. For the self-similar case the resulting equations for the suction and no mass transfer cases are solved numerically by quasilinearization method whereas for the semi-similar case and injection in the self-similar case an implicit finite difference method with Newton's linearization is employed. For rapid deceleration of fluid and for moderate suction in the case of self-similar flow there exists a layer of fluid, close to the disk surface where the sense of rotation is opposite to that of the fluid rotating far away. The velocity profiles in the absence of magnetic field are found to be oscillatory except for suction. For the accelerating freestream, (semi-similar flow) the effect of time is to reduce the amplitude of the oscillations of the velocity components. On the other hand the effect of time for the oscillating case is just the opposite.
Resumo:
The properties of the manifold of a Lie groupG, fibered by the cosets of a sub-groupH, are exploited to obtain a geometrical description of gauge theories in space-timeG/H. Gauge potentials and matter fields are pullbacks of equivariant fields onG. Our concept of a connection is more restricted than that in the similar scheme of Ne'eman and Regge, so that its degrees of freedom are just those of a set of gauge potentials forG, onG/H, with no redundant components. The ldquotranslationalrdquo gauge potentials give rise in a natural way to a nonsingular tetrad onG/H. The underlying groupG to be gauged is the groupG of left translations on the manifoldG and is associated with a ldquotrivialrdquo connection, namely the Maurer-Cartan form. Gauge transformations are all those diffeomorphisms onG that preserve the fiber-bundle structure.
Resumo:
In this study I look at what people want to express when they talk about time in Russian and Finnish, and why they use the means they use. The material consists of expressions of time: 1087 from Russian and 1141 from Finnish. They have been collected from dictionaries, usage guides, corpora, and the Internet. An expression means here an idiomatic set of words in a preset form, a collocation or construction. They are studied as lexical entities, without a context, and analysed and categorized according to various features. The theoretical background for the study includes two completely different approaches. Functional Syntax is used in order to find out what general meanings the speaker wishes to convey when talking about time and how these meanings are expressed in specific languages. Conceptual metaphor theory is used for explaining why the expressions are as they are, i.e. what kind of conceptual metaphors (transfers from one conceptual domain to another) they include. The study has resulted in a grammatically glossed list of time expressions in Russian and Finnish, a list of 56 general meanings involved in these time expressions and an account of the means (constructions) that these languages have for expressing the general meanings defined. It also includes an analysis of conceptual metaphors behind the expressions. The general meanings involved turned out to revolve around expressing duration, point in time, period of time, frequency, sequence, passing of time, suitable time and the right time, life as time, limitedness of time, and some other notions having less obvious semantic relations to the others. Conceptual metaphor analysis of the material has shown that time is conceptualized in Russian and Finnish according to the metaphors Time Is Space (Time Is Container, Time Has Direction, Time Is Cycle, and the Time Line Metaphor), Time Is Resource (and its submapping Time Is Substance), Time Is Actor; and some characteristics are added to these conceptualizations with the help of the secondary metaphors Time Is Nature and Time Is Life. The limits between different conceptual metaphors and the connections these metaphors have with one another are looked at with the help of the theory of conceptual integration (the blending theory) and its schemas. The results of the study show that although Russian and Finnish are typologically different, they are very similar both in the needs of expression their speakers have concerning time, and in the conceptualizations behind expressing time. This study introduces both theoretical and methodological novelties in the nature of material used, in developing empirical methodology for conceptual metaphor studies, in the exactness of defining the limits of different conceptual metaphors, and in seeking unity among the different facets of time. Keywords: time, metaphor, time expression, idiom, conceptual metaphor theory, functional syntax, blending theory
Resumo:
In open-cut strip mining, waste material is placed in-pit to minimise operational mine costs. Slope failures in these spoil piles pose a significant safety risk to personnel, along with a financial risk from loss of equipment and scheduling delays. It has been observed that most spoil pile failures occur when the pit has been previously filled with water and then subsequently dewatered. The failures are often initiated at the base of spoil piles where the material can undergo significant slaking (disintegration) over time due to overburden pressure and water saturation. It is important to understand how the mechanical properties of base spoil material are affected by slaking when designing safe spoil pile slope angles, heights, and dewatering rates. In this study, fresh spoil material collected from a coal mine in Brown Basin Coalfield of Queensland, Australia was subjected to high overburden pressure (0 – 900 kPa) under saturated condition and maintained over a period of time (0 – 6 months) allowing the material to slake. To create the above conditions, laboratory designed pressure chambers were used. Once a spoil sample was slaked under certain overburden pressure over a period of time, it was tested for classification, permeability, and strength properties. Results of this testing program suggested that the slaking of saturated coal mine spoil increase with overburden pressure and the time duration over which the overburden pressure was maintained. Further, it was observed that shear strength and permeability of spoil decreased with increase in spoil slaking.
Resumo:
In the seasonally dry tropics of northern Australia, breeder cows may lose up to 30% liveweight during the dry season when pasture is of low nutritive value. This is a major cause of low reproductive rates and high mortality. Weaning early in the dry season is effective to reduce this liveweight loss of the breeder (Holroyd et al. 1988). An experiment examined the dry season liveweight loss of breeders for a range of weaning times and levels of nutrition. From April to October through the dry season, 209 Bos indicus x Shorthorn cross cows 4-6 years of age grazed speargrass pastures in north Queensland. The cows had been joined with bulls from late January until April. Twenty-nine breeders had not suckled a calf during the previous wet season (DRY cows). In addition 180 cows lactating in April were weaned in late April, mid July or early September. The cows were allocated by stratified randomisation based on lactational status, stage of pregnancy and body condition to 15 x 40 ha paddocks. Five paddocks with low fertility soils provided LOW nutrition, while 10 paddocks with medium fertility soils and no supplementation or with supplementation provided MEDIUM and HIGH nutrition, respectively. The supplement consisted of molasses containing 14% urea offered ad libitum. Liveweight was measured at intervals and conceptus-free liveweight (CF-LW) calculated. Data were analyses by AOV within groups of paddocks. Animal production for a consuming world : proceedings of 9th Congress of the Asian-Australasian Association of Animal Production Societies [AAAP] and 23rd Biennial Conference of the Australian Society of Animal Production [ASAP] and 17th Annual Symposium of the University of Sydney, Dairy Research Foundation, [DRF]. 2-7 July 2000, Sydney, Australia.
Resumo:
In this work, we theoretically examine recent pump/probe photoemission experiments on the strongly correlated charge-density-wave insulator TaS2.We describe the general nonequilibrium many-body formulation of time-resolved photoemission in the sudden approximation, and then solve the problem using dynamical mean-field theory with the numerical renormalization group and a bare density of states calculated from density functional theory including the charge-density-wave distortion of the ion cores and spin-orbit coupling. We find a number of interesting results: (i) the bare band structure actually has more dispersion in the perpendicular direction than in the two-dimensional planes; (ii) the DMFT approach can produce upper and lower Hubbard bands that resemble those in the experiment, but the upper bands will overlap in energy with other higher energy bands; (iii) the effect of the finite width of the probe pulse is minimal on the shape of the photoemission spectra; and (iv) the quasiequilibrium approximation does not fully describe the behavior in this system.
Resumo:
The potential for large-scale use of a sensitive real time reverse transcription polymerase chain reaction (RT-PCR) assay was evaluated for the detection of Tomato spotted wilt virus (TSWV) in single and bulked leaf samples by comparing its sensitivity with that of DAS-ELISA. Using total RNA extracted with RNeasy® or leaf soak methods, real time RT-PCR detected TSWV in all infected samples collected from 16 horticultural crop species (including flowers, herbs and vegetables), two arable crop species, and four weed species by both assays. In samples in which DAS-ELISA had previously detected TSWV, real time RT-PCR was effective at detecting it in leaf tissues of all 22 plant species tested at a wide range of concentrations. Bulk samples required more robust and extensive extraction methods with real time RT-PCR, but it generally detected one infected sample in 1000 uninfected ones. By contrast, ELISA was less sensitive when used to test bulked samples, once detecting up to 1 infected in 800 samples with pepper but never detecting more than 1 infected in 200 samples in tomato and lettuce. It was also less reliable than real time RT-PCR when used to test samples from parts of the leaf where the virus concentration was low. The genetic variability among Australian isolates of TSWV was small. Direct sequencing of a 587 bp region of the nucleoprotein gene (S RNA) of 29 isolates from diverse crops and geographical locations yielded a maximum of only 4.3% nucleotide sequence difference. Phylogenetic analysis revealed no obvious groupings of isolates according to geographic origin or host species. TSWV isolates, that break TSWV resistance genes in tomato or pepper did not differ significantly in the N gene region studied, indicating that a different region of the virus genome is responsible for this trait.
Resumo:
Non-thermal plasma (NTP) has been introduced over the last few years as a promising after- treatment system for nitrogen oxides and particulate matter removal from diesel exhaust. NTP technology has not been commercialised as yet, due to its high rate of energy consumption. Therefore, it is important to seek out new methods to improve NTP performance. Residence time is a crucial parameter in engine exhaust emissions treatment. In this paper, different electrode shapes are analysed and the corresponding residence time and NOx removal efficiency are studied. An axisymmetric laminar model is used for obtaining residence time distribution numerically using FLUENT software. If the mean residence time in a NTP plasma reactor increases, there will be a corresponding increase in the reaction time and consequently the pollutant removal efficiency increases. Three different screw thread electrodes and a rod electrode are examined. The results show the advantage of screw thread electrodes in comparison with the rod electrode. Furthermore, between the screw thread electrodes, the electrode with the thread width of 1 mm has the highest NOx removal due to higher residence time and a greater number of micro-discharges. The results show that the residence time of the screw thread electrode with a thread width of 1 mm is 21% more than for the rod electrode.
Resumo:
The Turku castle, founded c. 1300, has changed over the centuries from a medieval defensive structure into a Renaissance palace and from a derelict jailhouse in the late 19th century into a prime example of the Medieval built heritage in Finland. Today, it is first and foremost a monument to the Medieval and Renaissance heyday of the castle. This is apparent in the architectural forms that have been carefully restored and reconstructed. It also becomes clear in all kinds of narratives, both visual (like the set of miniatures about the different stages of the construction of the castle) and textual (as during the guided tours). For the first time in the architectural history of the Turku castle, the Medieval, the Renaissance, the Modern, and the Present as architecturally constructed or reconstructed spaces can all be visited within the same hour. As a result, the monumental Turku castle may even be deemed anachronistic or inauthentic. In this study I look at the ways in which the Turku castle is, indeed, anachronistic and inauthentic. My main objective, however, is to find ways in which the anachronisms and inauthenticities are overcome in a positive way. I base my analysis of the Turku castle on three theoretical standpoints. First, I am studying the castle as space, described by Michel de Certeau as a practiced place (de Certeau 2002). Second, I am approaching the numerous narrative aspects of the castle following Paul Ricoeur s analysis of narrative as a threefold mimetic process (Ricoeur 1990). From these two theoretical settings I have summoned the concept of narrative space. The life and work at the castle are based on expectations and understandings of the historical surroundings. My third theoretical choice is to study this applied knowledge of the place as the management of blocks of knowledge in communication (Robert de Beaugrande 1980). Combining the theoretical starting points of space and narrative , I am approaching the castle as if it were an evolving set of narratives, narrated in space but also through space. Seeing e.g. the restoration teams of the mid-20th century and the present day tour guides as creative narrators, I am looking beyond the dilemma of the anachronistic spaces. What transpires is an inter-connected web of texts and spaces, tangible and intangible narratives. My analytical key to these narrative relationships is the threefold mimetic process of pre-figuration, con-figuration, and re-figuration, inspired by the writings of Paul Ricoeur (1990). This way, the past can be seen as a pool of endless possibilities to emplot place, time, and action into a narrative space. The narratives convey images of the past that may be contested by other images, and the power to narrate in the first place can be challenged and re-distributed.
Resumo:
The paper deals with the basic problem of adjusting a matrix gain in a discrete-time linear multivariable system. The object is to obtain a global convergence criterion, i.e. conditions under which a specified error signal asymptotically approaches zero and other signals in the system remain bounded for arbitrary initial conditions and for any bounded input to the system. It is shown that for a class of up-dating algorithms for the adjustable gain matrix, global convergence is crucially dependent on a transfer matrix G(z) which has a simple block diagram interpretation. When w(z)G(z) is strictly discrete positive real for a scalar w(z) such that w-1(z) is strictly proper with poles and zeros within the unit circle, an augmented error scheme is suggested and is proved to result in global convergence. The solution avoids feeding back a quadratic term as recommended in other schemes for single-input single-output systems.
Resumo:
In this paper, we generalize the existing rate-one space frequency (SF) and space-time frequency (STF) code constructions. The objective of this exercise is to provide a systematic design of full-diversity STF codes with high coding gain. Under this generalization, STF codes are formulated as linear transformations of data. Conditions on these linear transforms are then derived so that the resulting STF codes achieve full diversity and high coding gain with a moderate decoding complexity. Many of these conditions involve channel parameters like delay profile (DP) and temporal correlation. When these quantities are not available at the transmitter, design of codes that exploit full diversity on channels with arbitrary DIP and temporal correlation is considered. Complete characterization of a class of such robust codes is provided and their bit error rate (BER) performance is evaluated. On the other hand, when channel DIP and temporal correlation are available at the transmitter, linear transforms are optimized to maximize the coding gain of full-diversity STF codes. BER performance of such optimized codes is shown to be better than those of existing codes.
Resumo:
An efficient geometrical design rule checker is proposed, based on operations on quadtrees, which represent VLSI mask layouts. The time complexity of the design rule checker is O(N), where N is the number of polygons in the mask. A pseudoPascal description is provided of all the important algorithms for geometrical design rule verification.
Resumo:
This paper investigates quality of service (QoS) and resource productivity implications of transit route passenger loading and travel time. It highlights the value of occupancy load factor as a direct passenger comfort QoS measure. Automatic Fare Collection data for a premium radial bus route in Brisbane, Australia, is used to investigate time series correlation between occupancy load factor and passenger average travel time. Correlation is strong across the entire span of service in both directions. Passengers tend to be making longer, peak direction commuter trips under significantly less comfortable conditions than off-peak. The Transit Capacity and Quality of Service Manual uses segment based load factor as a measure of onboard loading comfort QoS. This paper provides additional insight into QoS by relating the two route based dimensions of occupancy load factor and passenger average travel time together in a two dimensional format, both from the passenger’s and operator’s perspectives. Future research will apply Value of Time to QoS measurement, reflecting perceived passenger comfort through crowding and average time spent onboard. This would also assist in transit service quality econometric modeling. The methodology can be readily applied in a practical setting where AFC data for fixed scheduled routes is available. The study outcomes also provide valuable research and development directions.
Resumo:
Equid herpesvirus 1 (EHV1) is a major disease of equids worldwide causing considerable losses to the horse industry. A variety of techniques, including PCR have been used to diagnose EHV1. Some of these PCRs were used in combination with other techniques such as restriction enzyme analysis (REA) or hybridisation, making them cumbersome for routine diagnostic testing and increasing the chances of cross-contamination. Furthermore, they involve the use of suspected carcinogens such as ethidium bromide and ultraviolet light. In this paper, we describe a real-time PCR, which uses minor groove-binding probe (MGB) technology for the diagnosis of EHV1. This technique does not require post-PCR manipulations thereby reducing the risk of cross-contamination. Most importantly, the technique is specific; it was able to differentiate EHV1 from the closely related member of the Alphaherpesvirinae, equid herpesvirus 4 (EHV4). It was not reactive with common opportunistic pathogens such as Escherichia coli, Klebsiella oxytoca, Pseudomonas aeruginosa and Enterobacter agglomerans often involved in abortion. Similarly, it did not react with equine pathogens such as Streptococcus equi, Streptococcus equisimilis, Streptococcus zooepidemicus, Taylorella equigenitalis and Rhodococcus equi, which also cause abortion. The results obtained with this technique agreed with results from published PCR methods. The assay was sensitive enough to detect EHV1 sequences in paraffin-embedded tissues and clinical samples. When compared to virus isolation, the test was more sensitive. This test will be useful for the routine diagnosis of EHV1 based on its specificity, sensitivity, ease of performance and rapidity.