Morphological analysis of SSM Al-4.5wt.% Cu measured by the rheocast quality index
Abstract There is a direct relationship between grain size obtained from macrostructure characterisation and the globule size and shape factor, obtained from microstructure characterisation: the smaller the grain size, the smaller the globule size and shape factor. Due to this a rheocast quality index ( RQI = globule size /( grain size × shape factor) ) was used to evaluate the Al–4.5 wt.% Cu alloy produced by strain induced melting activation (SIMA). The structure that presents the smallest grain size, the smallest shape factor, and the most homogeneous and globular size of the primary phase, has the best RQI and consequently the best behaviour in the semi-solid forming. Four different as-cast structures were cold rolled to obtain 20 and 40% deformation and were partially melted at 635 °C at holding times of 5 min. Both, macro- and microstructure were characterised.
Thixoformability evaluation of AA2011 and AA2014 alloys
Abstract This paper examines the feasibility of thixoforming two commercial aluminum–copper alloys: AA2011 and AA2014. This evaluation was performed in three steps: 1) characterization of the raw materials, including an analysis of their constituents, partial melting range temperatures, and microstructures; 2) characterization of the samples' morphological evolution during partial melting to observe their globularization at two different sets of temperatures, (solid fractions of 45 % and 60 %), and four holding times: 0, 30, 90 and 210 s; and 3) tests of the morphological behavior under the same partial melting conditions of temperature and holding times. The results indicate that, despite the difficulty of controlling the temperature of the semi-solid transition, these two alloys are suitable for thixoforming processes. Their morphology is stable in the semi-solid range and the corresponding viscosity values are lower than 106 Pa · s, resulting in a maximum conformational stress of 2.4 MPa.
Measuring Functional Service Quality Using SERVQUAL in a High-Dependence Health Service Relationship
Although there is a growing concern about health care quality, little research has focused on how to measure quality in long-term care settings. In this article, we make the following observations: (1) most users of the SERVQUAL instrument reassess customers' expectations each time they measure quality perceptions; (2) long-term care relationships are likely to be ongoing, dependent relationships; (3) because of this dependence, customers in the long-term care setting are likely to reduce their expectations when faced with poor service quality; (4) by using this "settled" expectations level, service providers may make biased conclusions of quality improvements. We recommend various methods for overcoming or minimizing this "settling" effect and propose modifications to the SERVQUAL gap 5 measure to assess quality in a long-term care setting.