CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / Solar desalination systems operate with a transient heat source, the solar radiation, what makes it difficult to identify of the influence of the process variables and the constructive geometric parameters of the desalination tower. The present work presents the experimental study of thermal a desalination system prototype with heat recovery mechanism and controlled power supply to operate in transient and steady-state regimes. This prototype made possible the study of the operarational parameters that influence the desalinated water production in the tower, namely, the height of the water column in the storage tank, the type of burner, the gas natural gas flow, the number of desalination stages, and the use of a nano film of the condensations surface. Additionally,it was possible to thermally characterize the dessalination tower by determining the experimental overall heat transfer coeddicient (K1) of the simultaneous evaporation, radiation, and the convection processes between the surface of the water in the tank and the condensation walls of the first stage immediately above. The desalination system consisted of a gas natural burning equipment, a tank of storage, and a tower with six desalination stages. By controlling the natural gas flow, it was possible to keep preset and constant operating temperatures. The results showed that the use of the linear burner (ideal burner) and of 6 liters of water in the tank of storage presented the best desalinated water production. They alson showed that the flow of 0,533 g/min of natural gas and the use of 6 or 7 desalination stages are more adequate for tower operation. With the experimental measurements, the determination of the performance coefficient (COP) and of the gain output ratio (GOR) was possible. These values were 4,09 and 5,91, respectively. An increase of 65,59% in the desalinated water production was measured with the use of the nano film; however, chemical tests to verify possible chemical contamination were not carried out.

Yes / Purpose - This study aims to explore: the actual usage of GAS features among Egyptian external auditors, through the technology acceptance model (TAM); how the conceptual complexity of GAS features impact its actual usage; and what factors influencing the GAS use by Egyptian external auditors. Design/methodology/approach - External audit professionals at twelve international audit firms, including the Big 4 and eight medium-sized firms, in Egypt were surveyed. Findings - The results show that the basic features including database queries, ratio analysis, and audit sampling were higher in GAS use, perceived usefulness, and perceived ease of use among Egyptian external auditors than the advanced features: digital analysis, regression/ANOVA, and data mining classification. The SEM analysis by GAS features suggests that perceived ease of use has a stronger effect on GAS use when the conceptual complexity of GAS features is high. The analysis also support that the use of GAS by Egyptian external auditors is more affected by co-worker, supervisor, or organization through perceived usefulness, but not by job relevance, output quality, and result demonstration. Research limitations/implications - Although Egyptian external auditors participated in this study may limit the extent to which the findings may be generalized, the responses provide an insight into the actual usage of GAS features by external auditors and the impact of conceptual complexity of GAS features, which is consistent with the literature concerning the relatively low level of utilizing the advanced features of GAS by internal auditors, suggesting that the issues revealed should be of concern. Practical implications - The results reported in this paper are useful to audit software developers and audit firms in their understanding of factors influencing GAS usage in a different audit context. Originality/value - The study adds value to prior research by providing context-contingent insight into the application of technology acceptance model in an unexplored audit context.