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In this paper, a theoretical formula is derived to predict the instantaneous folding force of a single-cell square column under axial loading. Calculation is based on analys of “Basic Folding Mechanism” introduced by Wierzbicki and Abramowicz to calculate the instantaneous folding force. For this purpose, three mechanisms of energy dissipation were assumed. The formula obtained in this paper, can predicts the instantaneous folding force variations versus folding distance and versus folding angle with good precision and can predict folding force in each time instance instead of the average value. The results of theoretical formula were compared with experimental data and good agreement was observed. Keywords: Instantaneous Force, Folding, Honeycomb, Square Column.

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The human amniotic membrane (HAM) is one of the rare allograft tissues that are in use in clinical trials. Biocompatibility, antibacterial effect, low immunogenicity, and scar prevention are properties that have made HAM attractive for tissue engineering (TE) applications, for example, as a cell carrier, injectable hydrogel, and cell culture substrate. In this research, the effect of digestion time on the structure, gelation kinetics, rheological and biological properties of amniotic membrane-derived hydrogels was studied. The results determined that digestion with pepsin should be performed at least for 24 h.  Prolonging the digestion time to 72 h increased the shear modulus, fiber diameter, and gelation rate. Cytocompatibility assays with L929 fibroblast cells showed that the digestion time had no effect on the cell toxicity of the hydrogels. However, cell proliferation was improved due to preserved constitutive bioactive molecules. The results of this research can be used to develop amniotic membrane-derived hydrogels for TE applications.

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Although the hearing skills of children with hearing loss are improved with the help of hearing aids, cochlear implants, and speech therapy, they have difficulties understanding and producing language because of their delayed hearing onset. Considering that these children go to school with their hearing peers, it is needed that their oral language performance be compared with the hearing students. Hence, the present study analyzed and compared the oral language skills of children with hearing loss having hearing aids and cochlea implants, with their hearing counterparts. For this purpose, 39 children aged 6-8 years were examined by the Told-p:3 test. The participants included 16 hearing children, 13 children with cochlear implants, and 10 children with hearing aids. The data were analyzed using Kruskal-Wallis and Mann-Whitney U tests. The results showed no significant difference in syntactic and semantic skills of children having hearing aids and cochlear implants. However, the findings indicated a significant difference between hearing children and children with hearing loss ones having hearing aids and cochlear implants in their semantic and syntactic skills. Therefore, it is needed that children with hearing loss go through verbal-auditory rehabilitation training until they reach the hearing level of hearing children. Neglecting this issue can have detrimental effects on their educational achievements and future job performance.

1.  Introduction

Today, in the Iranian context, children with any kind of physical-motor and hearing disabilities go to public schools to study with other students if they have normal IQs. Although the language skills of hearing-loss children are improved with the help of hearing aids, cochlear implants, and speech therapy, because the onset of hearing in these children is delayed and given that the education of hearing-loss children is done in public schools, it is necessary that the quality of oral language and, consequently, the quality of the written language of deaf children in comparison with their hearing peers be carefully examined. Therefore, in the present study, the quality of oral language in hearing-loss children with their hearing counterparts has been analyzed and compared.

2. Method
In this study, oral language of hearing and hearing loss children was compared from two aspects of listening and speaking. For this purpose, 39 children aged 6-8 years, including 16 hearing children, 13 children with cochlear implants, and 10 children with hearing aids were examined by using the told-p3 test. Deaf children had pre-lingual deafness and had received hearing aids or cochlear aids before the age of two, and have gradually been able to speak with auditory-verbal rehabilitation training. The Told-p3 test was used for data collection. The collected data were analyzed using descriptive statistics for all variables. For inferential statistics, the Kruskal-Wallis test was used to examine the difference between the means in all three groups of children, and then the Mann-Whitney U test was used to compare the groups.

3. Results
The gathered data were analyzed using SPSS. Descriptive and inferential statistics were used for data analysis. The results showed no significant difference in syntactic and semantic skills of children having hearing aids and cochlear implants (P.>0.05). However, the findings indicated a significant difference between hearing children and children with hearing loss ones having hearing aids and cochlear implants in their semantic and syntactic skills (P.<0.05). These children had a significantly worse performance than that of hearing children in receiving and understanding the meanings of words and sentences, providing verbal definitions of words and recognizing them, and understanding and applying the forms.

4. Conclusion
The findings of the study showed no significant difference in the quality of oral language between children with cochlear implants and hearing aids. However, there was a significant difference between hearing children and the two groups of hearing-loss children in the quality of oral language in terms of listening and speaking. Accordingly, because deaf children have poorer performance than that of hearing children, not paying enough attention to this issue can have detrimental effects on their educational achievements and future job performance.  Therefore, the policy of teaching hearing-loss children in public schools along with hearing peers needs more reflection by educational policymakers. It is suggested that hearing loss children be helped by different interventions and rehabilitation programs before they start their education with their hearing peers. 
 

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Drowsy driving is a main cause of severe accidents. Drowsiness is responsible for 30% to 37% of fatal road accident in Iran. In this paper, driver drowsiness is detected based on features related to the steering wheel angle and the lateral position of the vehicle. Data from the vehicle and the virtual road are used to extract drowsiness features. Experimental results using a driving simulator are presented. Participants were 21 to 28 year-old males with a high tendency to sleep (Epworth Sleepiness Scale≥10). The subjects had to drive a lane keeping scenario on a long and monotonous virtual road in both drowsy and alert states. The drowsiness criteria are validated with Karolinska Sleepiness Scale (KSS) and video rating based on KSS measurements. The results illustrate that the phase diagram of the steering wheel angle (Ellipse criterion), the standard deviation of the steering wheel angle, and the mean and the standard deviation of the lateral position of the vehicle are highly correlated with drowsiness. The accuracy of the diagnosis was 77% for the Ellipse criterion, 76% for the standard deviation of the steering wheel angle, 67% for the standard deviation of the lateral position, and 65% for the mean value of the lateral position.

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This article investigates energy absorption capacity and plastic deformation of lateral flattening process on an aluminum profile with special cross-section under the lateral compressive loading in the quasi-static condition by experimental method. The profile section is a circular tube with two symmetric longitudinal grooves. Different samples with various lengths and outer diameters in three different filling conditions consist of empty, core-filled and full-filled by polyurethane foam were prepared. Some specimens with the same geometry and filling condition but, with different loading angles of 0, 30, 45, 60 and 90o respect to symmetric line of two longitudinal grooves, were laterally compressed. Effects of various parameters such as profile length, outer diameter, three different filling conditions, and loading angle are investigated on lateral loading and specific absorbed energy. Experimental results show that specific absorbed energy is independent of specimen length. At the same displacement, when diameter of samples increases compressive loading decreases. Also, in zero loading angle, presence of the filler enhances lateral load; and consequently, increases specific absorbed energy by the structure. In viewpoint of the design of an energy absorber design, optimum specimen is full-filled profile under a loading angle equal to zero. However, if due to some design limitations, assembling the special profile with loading angle of zero is impossible, assembling the structure in empty condition with loading angle of 90o can be the next suggestion. Experiments show that the highest specific absorbed energy occurs in the profile with different diameters under loading angles of zero and 90o.

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This article investigates energy absorption capacity and plastic deformation trend of lateral flattening of an aluminum profile with H-shaped cross section under the quasi-static lateral loading by experimental, numerical and theoretical methods. Samples were prepared with different lengths and three different filling conditions including empty, core-filled and perfectly-filled by polyurethane foam. In addition, samples with the same geometry and filling conditions were laterally compressed with loading angles of 0 and 90 degree. Effect of some parameters such as length, three different filling conditions and loading angle were experimentally investigated on lateral force and specific absorbed energy (SAE). The results show that SAE is independent of samples length. At the loading angle of 90 degree, presence of the filler causes increment of SAE by the structure. Using the perfectly-filled profile under the loading angle of 90 degree is the most optimum condition. Based on two different energy absorption mechanisms, a theoretical equation was derived to estimate total absorbed energy (TAE) by empty sample with loading angle of zero; and predicted results were compared with the experimental samples. Due to present limitations in preparing the samples with different geometrical dimensions, nonlinear ABAQUS software was employed. Some samples with different wall thicknesses were modeled and influence of thickness was investigated on TAE. TAE is directly correlated to the second power of wall thickness; and this relationship can be clearly understood from the theoretical equation and numerical results. High correlation of experimental, numerical and theoretical results indicates precision and accuracy of the performed research.

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In this article, indentation process of thin-walled metal sections with quadrangular cross-section was studied under the applied lateral compressive loading by a rigid cylindrical punch through numerical simulations by the ABAQUS. Based on numerical simulations and by changing one of the parameters and fixing the other parameters, effects of that parameter was investigated on total and specific absorbed energy by the structure. In other words, influences of various geometrical dimensions such as height, width and wall thickness of cross-section, punch diameter, loading rate and also, effects of material were investigated. In each part, physical justifications of the obtained results were presented, based on theoretical and engineering concepts. Comparison of the results showed that in the specimens with the same cross-sectional perimeter, but, with different aspect ratios, the highest ratio of height/width of the cross-section, results in the best energy absorber, in the studied domain. Furthermore, by changing the height and fixing the width of cross-section and the other parameters, when height of the cross-section was selected equal to punch diameter, the maximum value of total and specific absorbed energy was achieved. But, when cross-section width changed and height and the other characteristics remained constant, by reducing the width, energy absorption performance of the structure improved. In addition, numerical simulations showed that total and specific absorbed energy of quadrangular sections are dependent on the second and first power of wall thickness of the cross-section, respectively. Also, in same specimens, by increasing punch diameter, both TAE and SAE increased.

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