Background: The relation between disfluency and aspects of language, including phonology, has been investigated for many years. Whereas past literature reported that the incidence of phonological difficulties is higher in children who stutter when compared to normally FLUENT children, the suggestion of association between the two disorders also drew several critical evaluation. This study investigated the phonological awareness abilities of four-and five-year old nonFLUENT preschool children. Methods: This cross-sectional comparative study was done on 50 children. 25 non-FLUENT preschool children (21 boys and 4 girls) were paired according to age, sex and socioeconomic status to their typically FLUENT peers. Participants completed multiple measures of phonological awareness abilities, as well as measures of expressive and receptive vocabulary and articulation. Results: Regarding the scores of the phonological awareness test there were significant differences between non-FLUENT children and their typically FLUENT peers. The four year old children who were non-FLUENT performed significantly less well than their typically FLUENT peers on tasks of syllable awareness, intra syllable awareness and phoneme syllable awareness. The five year old non-FLUENT preschool children performed significantly less well than their typically FLUENT peers on tasks of intra syllable awareness and phoneme syllable awareness. Conclusion: Results suggest that non-FLUENT preschool children have phonological differences in aspects of phonological awareness that may contribute to an unstable language planning system in preschool children who stutter.

Fluency in a second language (L2) involves a quintessentially cognitive processing system that operates quickly and effectively. The perceived importance of researching fluency through a psycholinguistic lens has motivated the related L2 research to resort to current cognitive speaking-specific models. This study, drawing on Levelt's (1999a) psycholinguistic model, probed the deficiency sources (DSs) (non) FLUENT L2 speakers encounter in L2 communication and then surveyed the problem-solving mechanisms (PSMs) they happen to engage in to circumvent or mitigate the bottle-neck effects of the deficiencies. First, an analytic fluency rating scale was developed to assess the audio-recorded (monologic and dialogic) speech samples of a large number of L2 speakers and identify the FLUENT and nonFLUENT speakers. Two questionnaires and output-related retrospective interviews were employed to explore the (non) FLUENT L2 speakers' DSs and PSMs. The MANOVA results and the interpretative analysis of retrospective data revealed that the nonFLUENT participants mainly suffered from resource deficits, processing time pressure, and perceived deficiencies in the interlocutor's performance. Specifically, they felt adversely pressured by an onrush of competing plans or the absence of any to chart their minds, floundered on feeling incapable of configuring a viable syntactic structure for their intended meanings, were restrained groping for the right lemma to fit their notions, or faltered due to a daunting uncertainty of the phonological accuracy. Meanwhile, they resorted to ineffective oral-production strategies such as message abandonment and reduction, which resulted in disFLUENT speech. The FLUENT participants, however, did not suffer from these DSs and employed PSMs more consistently. They were able to dynamically reformulate the notions or the preverbal message, apply a revitalized encoding mechanism, use various stalling mechanisms, and negotiate meaning in order to monitor the articulation. The findings suggest that any attempt intended to improve or assess L2 fluency pivot on a psycholinguistic approach to L2 oral production.

Hydraulic jump has been used for dissipation of kinetic energy downstream of hydraulic structures such as spillways, chutes and gates. It is found by many researches that if jumps are made to occur on a corrugated bed, tail water and length of jumps will be reduced significantly. During formation of hydraulic jump on a corrugated bed the flow is turbulent, with water and air being mixed together. In the present study numerical simulations of hydraulic jump on corrugated bed were done by the CFD's FLUENT software in two dimensions using standard k-ε and RNG k-ε models. The free surface was determined using the VOF method. The results showed that the k-ε turbulent models and VOF method for predicting water surface in the jump on the corrugated bed were suitable and the relative error of the predicted water surface profiles and measured values were within 2-7%. The study of the axial velocity profiles at different sections in the jump showed that velocity profiles in different experiments were similar and the agreement between the experimental and numerical results was satisfactory. Also the effects of corrugations on the basic characteristics of the jump such as free surface location, velocity and shear stress distributions were studied for different values of Froude number.

This paper proposed a new methodology which was based on computational fluid dynamics for predicting the scouring process of underwater pipeline. By redeveloping a commercial CFD computer code, the governing equations for the flow model was solved by finite volume method and wall shear stress which acted as the key parameter to judge the incipient motion of sediment was firstly calculated. Then the morphological change of the sandy bed was simulated by dynamic mesh technology. Based on the comparisons between experimental results and numerical results, it was confirmed that present numerical modeling method can simulate the flow field and scouring process around underwater pipeline accurately. Besides, the influence of gap ratios on the scour behaviors was investigated by the present simulation.