971 resultados para Polímers -- Proves


Relevância:

10.00% 10.00%

Publicador:

Resumo:

Two hundred million people are displaced annually due to natural disasters with a further one billion living in inadequate conditions in urban areas. Architects have a responsibility to respond to this statistic as the effects of natural and social disasters become more visibly catastrophic when paired with population rise. The research discussed in this paper initially questions and considers how digital tools can be employed to enhance rebuilding processes, but still achieve sensitive, culturally appropriate and accepted built solutions. Secondly the paper reflects on the impact ‘real-world’ projects have on architectural education. Research aspirations encouraged an atypical ‘research by design’ methodology involving a focused case study in the recently devastated village Keigold, Ranongga, Solomon Islands. Through this qualitative approach specific place data and the accounts of those affected were documented through naturalistic and archival methods of observation and participation. Findings reveal a number of unanticipated results which would have been otherwise undetected if field research within the design and rebuilding process was not undertaken, reflecting the importance of place specific research in the design process. Ultimately, the study proves that it is critical for issues of disaster to be addressed on a local rather than global scale; decisions cannot be speculative, or solved at a distance, but require intensive collaborative work with communities to achieve optimum solutions. Architectural education and design studios would continue to benefit from focused community engagement and field research within the design process.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The coupling of kurtosis based-indexes and envelope analysis represents one of the most successful and widespread procedures for the diagnostics of incipient faults on rolling element bearings. Kurtosis-based indexes are often used to select the proper demodulation band for the application of envelope-based techniques. Kurtosis itself, in slightly different formulations, is applied for the prognostic and condition monitoring of rolling element bearings, as a standalone tool for a fast indication of the development of faults. This paper shows for the first time the strong analytical connection which holds for these two families of indexes. In particular, analytical identities are shown for the squared envelope spectrum (SES) and the kurtosis of the corresponding band-pass filtered analytic signal. In particular, it is demonstrated how the sum of the peaks in the SES corresponds to the raw 4th order moment. The analytical results show as well a link with an another signal processing technique: the cepstrum pre-whitening, recently used in bearing diagnostics. The analytical results are the basis for the discussion on an optimal indicator for the choice of the demodulation band, the ratio of cyclic content (RCC), which endows the kurtosis with selectivity in the cyclic frequency domain and whose performance is compared with more traditional kurtosis-based indicators such as the protrugram. A benchmark, performed on numerical simulations and experimental data coming from two different test-rigs, proves the superior effectiveness of such an indicator. Finally a short introduction to the potential offered by the newly proposed index in the field of prognostics is given in an additional experimental example. In particular the RCC is tested on experimental data collected on an endurance bearing test-rig, showing its ability to follow the development of the damage with a single numerical index.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The use of Wireless Sensor Networks (WSNs) for Structural Health Monitoring (SHM) has become a promising approach due to many advantages such as low cost, fast and flexible deployment. However, inherent technical issues such as data synchronization error and data loss have prevented these distinct systems from being extensively used. Recently, several SHM-oriented WSNs have been proposed and believed to be able to overcome a large number of technical uncertainties. Nevertheless, there is limited research examining effects of uncertainties of generic WSN platform and verifying the capability of SHM-oriented WSNs, particularly on demanding SHM applications like modal analysis and damage identification of real civil structures. This article first reviews the major technical uncertainties of both generic and SHM-oriented WSN platforms and efforts of SHM research community to cope with them. Then, effects of the most inherent WSN uncertainty on the first level of a common Output-only Modal-based Damage Identification (OMDI) approach are intensively investigated. Experimental accelerations collected by a wired sensory system on a benchmark civil structure are initially used as clean data before being contaminated with different levels of data pollutants to simulate practical uncertainties in both WSN platforms. Statistical analyses are comprehensively employed in order to uncover the distribution pattern of the uncertainty influence on the OMDI approach. The result of this research shows that uncertainties of generic WSNs can cause serious impact for level 1 OMDI methods utilizing mode shapes. It also proves that SHM-WSN can substantially lessen the impact and obtain truly structural information without having used costly computation solutions.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The work of Gilles Deleuze has influenced an increasing number of music scholars and practicing musicians, particularly those interested in experimental, electronic and popular music. This is despite the notoriously complex nature of his writings, and the specialised theoretical vocabulary that he employs. This thesis both demystifies some of the key terms and concepts of this vocabulary, before demonstrating how Deleuze’s ideas may be put to work in new and fruitful ways; this is achieved with specific reference to the relationships that music has with thought, time and machines. In Chapter 1, Deleuze’s understanding of the power of thought is examined, in particular his approach to communication, transcendence and immanence, and the “powers of thought.” Each of these concepts helps us to understand Deleuze’s work within broad problem of how to think about music immanently: that is, how to maintain that thought and music are both immanent aspects of life and experience. Chapter 2 examines time within a Deleuzian framework, linking his work on cinema with the concept of the “refrain”; both of these areas prove crucial to his understanding of music, as seen in Deleuze’s approach to the work of Varese, Messiaen, and Boulez. In addition, Deleuze’s understanding of time proves fruitful in examining various aspects of music production, as seen in contemporary electronic dance music. Finally, Chapter 3 looks at the concept of the machine, as developed by Deleuze and Guattari, with reference to the sorts of “machinic” connections that a Deleuzian approach encourages us to seek out in music. Once again, examples from contemporary electronic music are presented, in relation to the notions of becoming and subjectivity. Throughout these chapters, Deleuze’s broad understanding of philosophy as the “creation of concepts” is deployed. This means introducing new ideas and specific types of music that encourage creative and novel engagements with the study of music.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

We recently developed a binding assay format by incorporating native transmembrane receptors into artificial phospholipid bilayers on biosensor devices for surface plasmon resonance spectroscopy. By extending the method to surface plasmon-enhanced fluorescence spectroscopy (SPFS), sensitive recording of the association of even very small ligands is enabled. Herewith, we monitored binding of synthetic mono- and oligomeric RGD-based peptides and peptidomimetics to integrins alphavbeta3 and alphavbeta5, after having confirmed correct orientation and functionality of membrane-embedded integrins. We evaluated integrin binding of RGD multimers linked together via aminohexanoic acid (Ahx) spacers and showed that the dimer revealed higher binding activity than the tetramer, followed by the RGD monomers. The peptidomimetic was also found to be highly active with a slightly higher selectivity toward alphavbeta3. The different compounds were also evaluated in in vitro cell adhesion tests for their capacity to interfere with alphavbeta3-mediated cell attachment to vitronectin. We hereby demonstrated that the different RGD monomers were similarly effective; the RGD dimer and tetramer showed comparable IC50 values, which were, however, significantly higher than those of the monomers. Best cell detachment from vitronectin was achieved by the peptidomimetic. The novel SPFS-binding assay platform proves to be a suitable, reliable, and sensitive method to monitor the binding capacity of small ligands to native transmembrane receptors, here demonstrated for integrins.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

In this paper, we propose a new blind steganalytic method to detect the presence of secret messages embedded in black and white images using the steganographic techniques. We start by extracting several sets of matrix, such as run length matrix, gap length matrix and pixel difference. We also apply characteristic function on these matrices to enhance their discriminative capabilities. Then we calculate the statistics which include mean, variance, kurtosis and skewness to form our feature sets. The presented empirical works demonstrate our proposed method can effectively detect three different types of steganography. This proves the universality of our proposed method as a blind steganalysis. In addition, the experimental results show our proposed method is capable of detecting small amount of the embedded message.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

A comparison of relay power minimisation subject to received signal-to-noise ratio (SNR) at the receiver and SNR maximisation subject to the total transmitted power of relays for a typical wireless network with distributed beamforming is presented. It is desirable to maximise receiver quality-of-service (QoS) and also to minimise the cost of transmission in terms of power. Hence, these two optimisation problems are very common and have been addressed separately in the literature. It is shown that SNR maximisation subject to power constraint and power minimisation subject to SNR constraint yield the same results for a typical wireless network. It proves that either one of the optimisation approaches is sufficient.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

In November 2002, a man with ‘atypical pneumonia’ treated in Foshan hospital, Guangdong Province, in the People's Republic of China, was the first known case of Severe Acute Respiratory Syndrome (SARS). However, it was not until April 2003 that the Chinese government admitted to the full scale of ‘atypical pneumonia’ cases infected with SARS, two months after the disease had rapidly spread across the world with initial infections in Hong Kong and Vietnam sourced to Guangdong. In 2008, Zimbabwe experienced one of the biggest outbreaks of cholera ever recorded. By February 2009, the disease had spread across all of Zimbabwe's 10 provinces and to neighbouring countries—Botswana, South Africa, Zambia and Mozambique—causing thousands of infections amongst their populations. This article seeks to examine what duties the Chinese and Zimbabwe states had to protect their citizens and the international community from these outbreaks. The article refers to the findings of the International Law Commission's study into the role of states and international organisations in protecting persons in the event of a disaster to consider whether there is an international duty to protect persons from epidemics. The article concludes that both cases reveal a growing concept of protection that entails an international duty to assist individuals when an affected state proves unwilling or unable to assist its own population in the event of a disease outbreak.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

In 2006, the International Law Commission began a study into the role of states and international organizations in protecting persons in the event of a disaster. Special Rapporteur Mr. Eduardo Valencia-Ospina was appointed to head the study, and in 2011 the findings of the study will be presented to the United Nations General Assembly. Of interest to this paper has been the inclusion of “epidemics” under the natural disaster category in all of the reports detailing the Commission’s program of work on the protection of persons. This paper seeks to examine the legal and political ramifications involved in including “epidemic” into the concept of protection by exploring where sovereign responsibility for epidemic control begins and ends, particularly in light of the revisions to the International Health Regulations by the World Health Assembly in 2005. The paper will first analyze the findings already presented by the Special Rapporteur, examining the existing “responsibilities” of both states and international organizations. Then, the paper will consider to what extent the concept of protection entails the duty to assist individuals when an affected state proves unwilling or unable to assist their own population in the event of a disease outbreak. In an attempt to answer this question, the third part of the paper will examine the recent cholera outbreak in Zimbabwe.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

To prevent unauthorized access to protected trusted platform module (TPM) objects, authorization protocols, such as the object-specific authorization protocol (OSAP), have been introduced by the trusted computing group (TCG). By using OSAP, processes trying to gain access to the protected TPM objects need to prove their knowledge of relevant authorization data before access to the objects can be granted. Chen and Ryan’s 2009 analysis has demonstrated OSAP’s authentication vulnerability in sessions with shared authorization data. They also proposed the Session Key Authorization Protocol (SKAP) with fewer stages as an alternative to OSAP. Chen and Ryan’s analysis of SKAP using ProVerif proves the authentication property. The purpose of this paper was to examine the usefulness of Colored Petri Nets (CPN) and CPN Tools for security analysis. Using OSAP and SKAP as case studies, we construct intruder and authentication property models in CPN. CPN Tools is used to verify the authentication property using a Dolev–Yao-based model. Verification of the authentication property in both models using the state space tool produces results consistent with those of Chen and Ryan.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Hedging against tail events in equity markets has been forcefully advocated in the aftermath of recent global financial crisis. Whether this is beneficial to long horizon investors like employees enrolled in defined contribution (DC) plans, however, has been subject to criticism. We conduct historical simulation since 1928 to examine the effectiveness of active and passive tail risk hedging using out of money put options for hypothetical equity portfolios of DC plan participants with 20 years to retirement. Our findings show that the cost of tail hedging exceeds the benefits for a majority of the plan participants during the sample period. However, for a significant number of simulations, hedging result in superior outcomes relative to an unhedged position. Active tail hedging is more effective when employees confront several panic-driven periods characterized by short and sharp market swings in the equity markets over the investment horizon. Passive hedging, on the other hand, proves beneficial when they encounter an extremely rare event like the Great Depression as equity markets go into deep and prolonged decline.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The US dollar is still considered as the main strategic deposit among the currencies of different countries of the world and the policies of the World Bank and the International Financial Organizations have been and will always be influenced by the US economy. Despite the economic crises and commercial balance deficits in the United States, dollar has maintained its high position in and its domination over foreign exchanges and foreign-currency deposits of the countries. The novelty of the present research relies on its consideration of the political properties of the governments and the geopolitical effects of these countries on the position of their monetary and foreign-currency policies and consequently, on the international financial organizations such as the International Monetary Fund and the World Bank, which can determine the future of international economy and the political relations among countries. Our research proves that the political development of the United States and its geopolitical situation have been of the effective factors on dollar growth; and unless the competitors acquire such a relative advantage, they will not be able to seriously challenge the currency of dollar and the monetary policies of the United States, at least in a short time

Relevância:

10.00% 10.00%

Publicador:

Resumo:

For more than 15 years, QUT’s Visual Arts discipline has employed a teaching model known as the ‘open studio’ in their undergraduate BFA program. Distinct from the other models of studio degrees in Australia, the open studio approach emphasizes individual practice by focusing on experimentation, collaboration and cross-disciplinary activities. However, while this activity proves to be highly relevant to exploring and participating in the ‘post medium’ nature of much contemporary art, the open studio also presents a complex of affecting challenges to the artist-teacher. The open studio, it can be argued, produces a different type of student than traditional, discipline-specific art programs – but it also produces a different kind of artist-teacher. In this paper, the authors will provide a reflection on their own experiences as artists and studio lecturers involved with the two ‘bookends’ of the QUT studio program – first year and third year. Using these separate contexts as case studies, the authors will discuss the transformative qualities of the open studio as it is adapted to the particularities of each cohort and the curricular needs of each year level. In particular, the authors will explore the way the teaching experience has influenced and positively challenged their individual (and paradoxically) discipline-focussed, studio practices. It is generally accepted that the teaching of art needs to be continually reconceptualised in response to the changing conditions of contemporary art, culture and technology. This paper will articulate how the authors have worked at that reconceptualisation within both their teaching and studio practices and so practically demonstrate the complex dialogic processes inherent to the teaching of the visual arts studio.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The performance space in which Wesley Enoch’s play Black Diggers is being performed at the Brisbane Festival is a large black box. It features a raised stage in the middle which proves versatile for battlegrounds at home and abroad – and later as ground for discriminatory encounters experienced by Aboriginal returned ex-servicemen. The fire-filled 44-gallon drum off to the side creates another space of encounter; there are few other props. Now and then, dates and other details are whitewashed on the black walls...

Relevância:

10.00% 10.00%

Publicador:

Resumo:

We have studied the mineral poldervaartite CaCa\[SiO3(OH)(OH)] which forms a series with its manganese analogue olmiite CaMn\[SiO3(OH)](OH) using a range of techniques including scanning electron microscopy, thermogravimetric analysis, Raman and infrared spectroscopy. Chemical analysis shows the mineral is reasonably pure and contains only calcium and manganese with low amounts of Al and F. Thermogravimetric analysis proves the mineral decomposes at 485 °C with a mass loss of 7.6% compared with the theoretical mass loss of 7.7%. A strong Raman band at 852 cm−1 is assigned to the SiO stretching vibration of the SiO3(OH) units. Two Raman bands at 914 and 953 cm−1 are attributed to the antisymmetric vibrations. Intense prominent peaks observed at 3487, 3502, 3509, 3521 and 3547 cm−1 are assigned to the OH stretching vibration of the SiO3(OH) units. The observation of multiple OH bands supports the concept of the non-equivalence of the OH units. Vibrational spectroscopy enables a detailed assessment of the molecular structure of poldervaartite.