994 resultados para 125-780C
Resumo:
Dissertação (Mestrado em Tecnologia Nuclear)
Resumo:
Tese (Doutorado em Tecnologia Nuclear)
Resumo:
Fondo Margaritainés Restrepo
Resumo:
A series of 7 cerium double-decker complexes with various tetrapyrrole ligands including porphyrinates, phthalocyaninates, and 2,3-naphthalocyaninates have been prepared by previously described methodologies and characterized with elemental analysis and a range of spectroscopic methods. The molecular structures of two heteroleptic \[(na)phthalocyaninato](porphyrinato) complexes have also been determined by X-ray diffraction analysis which exhibit a slightly distorted square antiprismatic geometry with two domed ligands. Having a range of tetrapyrrole ligands with very different electronic properties, these compounds have been systematically investigated for the effects of ligands on the valence of the cerium center. On the basis of the spectroscopic (UV−vis, near-IR, IR, and Raman), electrochemical, and structural data of these compounds and compared with those of the other rare earth(III) counterparts reported earlier, it has been found that the cerium center adopts an intermediate valence in these complexes. It assumes a virtually trivalent state in cerium bis(tetra-tert-butylnaphthalocyaninate) as a result of the two electron rich naphthalocyaninato ligands, which facilitate the delocalization of electron from the ligands to the metal center. For the rest of the cerium double-deckers, the cerium center is predominantly tetravalent. The valences (3.59−3.68) have been quantified according to their LIII-edge X-ray absorption near-edge structure (XANES) profiles.
Resumo:
We present the first detailed application of Meadows’s cost-based modelling framework to the analysis of JFK, an Internet key agreement protocol. The analysis identifies two denial of service attacks against the protocol that are possible when an attacker is willing to reveal the source IP address. The first attack was identified through direct application of a cost-based modelling framework, while the second was only identified after considering coordinated attackers. Finally, we demonstrate how the inclusion of client puzzles in the protocol can improve denial of service resistance against both identified attacks.
Resumo:
Objective: General practitioners (GPs) play an integral role in addressing the psychological needs of palliative care patients and their families. This qualitative study investigated psychosocial issues faced by GPs in the management of patients receiving palliative care and investigated the themes relevant to the psychosocial care of dying patients. Method: Fifteen general practitioners whose patient had been recently referred to the Mt. Olivet Palliative Home Care Services in Brisbane participated in an individual case review discussions guided by key questions within a semistructured format. These interviews focused on the psychosocial aspects of care and management of the referred patient, including aspects of the doctor/patient relationship, experience of delivering diagnosis and prognosis, addressing the psychological concerns of the patients' family, and the doctors' personal experiences, reactions, and responses. Qualitative analysis was conducted on the transcripts of these interviews. Results: The significant themes that emerged related to perceived barriers to exploration of emotional concerns, including spiritual issues, and the discussion of prognosis and dying, the perception of patients' responses/coping styles, and the GP's personal experience of the care (usually expressed in terms of identification with patient). Significance of results: The findings indicate the significant challenges facing clinicians in discussions with patients and families about death, to exploring the patient's emotional responses to terminal illness and spiritual concerns for the patient and family. These qualitative date indicate important tasks in the training and clinical support for doctors providing palliative care.
Resumo:
The availability of innumerable intelligent building (IB) products, and the current dearth of inclusive building component selection methods suggest that decision makers might be confronted with the quandary of forming a particular combination of components to suit the needs of a specific IB project. Despite this problem, few empirical studies have so far been undertaken to analyse the selection of the IB systems, and to identify key selection criteria for major IB systems. This study is designed to fill these research gaps. Two surveys: a general survey and the analytic hierarchy process (AHP) survey are proposed to achieve these objectives. The first general survey aims to collect general views from IB experts and practitioners to identify the perceived critical selection criteria, while the AHP survey was conducted to prioritize and assign the important weightings for the perceived criteria in the general survey. Results generally suggest that each IB system was determined by a disparate set of selection criteria with different weightings. ‘Work efficiency’ is perceived to be most important core selection criterion for various IB systems, while ‘user comfort’, ‘safety’ and ‘cost effectiveness’ are also considered to be significant. Two sub-criteria, ‘reliability’ and ‘operating and maintenance costs’, are regarded as prime factors to be considered in selecting IB systems. The current study contributes to the industry and IB research in at least two aspects. First, it widens the understanding of the selection criteria, as well as their degree of importance, of the IB systems. It also adopts a multi-criteria AHP approach which is a new method to analyse and select the building systems in IB. Further research would investigate the inter-relationship amongst the selection criteria.