Compaction of Quasi One-Dimensional Elastoplastic Materials

Insight in the crumpling or compaction of one-dimensional objects is of great importance for understanding biopolymer packaging and designing innovative technological devices. By compacting various types of wires in rigid confinements and characterizing the morphology of the resulting crumpled structures, here we report how friction, plasticity, and torsion enhance disorder, leading to a transition from coiled to folded morphologies. In the latter case, where folding dominates the crumpling process, we find that reducing the relative wire thickness counter-intuitively causes the maximum packing density to decrease. The segment-size distribution gradually becomes more asymmetric during compaction, reflecting an increase of spatial correlations. We introduce a self-avoiding random walk model and verify that the cumulative injected wire length follows a universal dependence on segment size, allowing for the prediction of the efficiency of compaction as a function of material properties, container size, and injection force.Comment: 7 pages, 6 figure

Swimming of multi-flagellated bacteria

Many prokaryotes employ rotating helical appendages known as flagella to swim in an aqueous medium. We studied differentially flagellated B. subtilis strains as model systems study the dynamics of swimming bacteria with numerous flagella. We found out that decreasing the number of flagella of individual cells reduces the average turning angle after the tumbling, enhances the run time and directional persistency of the run phase. Consequently, having a few flagella is beneficial for the fast spreading, while having many flagella is advantageous for the processes which require slower spreading. The results of numerical simulations based on the two-state model were used to discuss the search efficiency of different strains. Fluorescence microscopy shows that B. subtilis can make several bundles during the run phase, where the probability distribution of the number of bundles is similar for all strains independent of the flagellar number. The angle between the bundles on the observation plane widens with increasing the number of flagella, which leads to a slight modification of the effective cell aspect ratio while the other bundle properties do not significantly change. The collective motion of dense suspension of bacteria was also investigated to understand how the swimming persistency of individual cells and their geometrical properties can influence characteristic features of the collective behavior. The results show that the characteristic time and length scale of the collective motion are robust to these parameters.Viele Bakterien nutzen Flagellen - kleine spiralförmige Anhänge - um sich zu bewegen. Beispielsweise können E. coli Bakterien ihre Flagellen synchronisieren und bündeln um aktiv zu schwimmen. Die Auswirkungen der Flagellenanzahl auf die Dynamik der Bakterien ist nicht genau verstanden. Daher haben wir Bakterien der Art B. Subtilis mit verschiedener Anzahl an Flagellen untersucht. Die Verringerung der Flagellenanzahl reduziert den mittleren Änderungswinkel zwischen aufeinanderfolgenden Renn-Phassen und erhöht die Renn-Zeit sowie die Richtungsbeständigkeit. Eine geringe Anzahl von Flagellen ist daher vorteilhaft für Transportprozesse, wohingegen eine hohe Anzahl von Flagellen vorteilhaft für eine langsamere Verteilung wichtig ist (Entstehung von Biofilmen). Wir haben ein Zwei-Zustands Random-Walk Modell entwickelt, welches einen exakten analytischen Ausdruck für die Transporteigenschaften liefert. Die Ergebnisse der numerischen Simulationen dienten als Grundlage für die Diskussion der Such-Effizienz verschiedener Stämme. Wir konnten beobachten, dass verschiedene Flagellen-Bündel während der Renn-Phase entstehen. Außerdem untersuchten wir die kollektive Bewegung in einer dichten Suspension von Bakterien. Die Ergebnisse zeigen, dass innerhalb der Reichweite unserer experimentellen Parameter die charakteristische Zeit- und Länge-Skalen der kollektiven Bewegung stabil gegenüber Form- und Persistenzänderungen einzelner Bakterien sind

Lightweight tubular fiberboard: Effect of hole diameters and number on panel properties

Special tubular fiberboard with a density of 550 kg/m3 was manufactured using the round rods for creation of the holes. Physicomechanical properties of tubular fiberboard (6, 8, 10, 12 (mm)) with various hole diameters and number of hole (0, 1, 2 and 3 in a constant cross section) were evaluated. The surface layers density, especially on top of the holes, considerably elevated with increasing the hole diameter. This did create higher bending properties as well as higher internal bond and surface soundness. The structure of webs between the holes, when the holes’ number increases, were predominant factor influencing the panel properties. Weak and loose web structure were obtained by increasing the holes’ number from 1 to 3 within a constant cross section (50 mm × 16 mm) that was due to the less transferred fiber during pressing in the webs’ sections. A corresponding comparison of panel properties with those in American and European standards presents that the minimum requirements according to most of the standards (ANSI A208/2, EN 14755, EN 312/P2 and EN 622-5/P1) were obtained

Pavement Deterioration Modeling for Forest Roads Based on Logistic Regression and Artificial Neural Networks

The accurate prediction of forest road pavement performance is important for efficient management of surface transportation infrastructure and achieves significant savings through timely intervention and accurate planning. The aim of this paper was to introduce a methodology for developing accurate pavement deterioration models to be used primarily for the management of the forest road infrastructure. For this purpose, 19 explanatory and three corresponding response variables were measured in 185 segments of 50 km forest roads. Logistic regression (LR) and artificial neural networks (ANNs) were used to predict forest road pavement deterioration, Pothole, rutting and protrusion, as a function of pavement condition, environmental factors, traffic and road qualify. The results showed ANNs and LR models could classify from 82% to 89% of the current pavement condition correctly. According to the results, LR model and ANNs predicted rutting, pothole and protrusion with 83.5%, 83.00% and 81.75%, 88.65% and 85.20%, 80.00% accuracy. Equivalent single axle load (ESAL), date of repair, thickness of pavement and slope were identified as most significant explanatory variables. Receiver Operating Characteristic Curve (ROC) showed that the results obtained by ANNs and logistic regression are close to each other

Teachers’ self-evaluation of application of moral education principles (case study: Elementary school teachers in Isfahan, Iran.)

The present research has been done with the aim of analyzing elementary school teachers’ self-evaluation of application of moral education principles in Isfahan. The statistical population of the research included all teachers, teaching at elementary schools in Isfahan in academic year of 2012-2013, being 3922 teachers in number. Among whom, a number of 340 individuals were selected using Chocran’s sample volume formula and simple random sampling method. The research method was descriptive as well as survey type, and the data collection tool was a researcher-made questionnaire, containing several questions about elementary school teachers’ self-evaluation of application of moral education principles in Isfahan, including 25 forced-choice questions based on Lickert’s 5-rate spectrum, its components being as follow: the intertwined nature of moral education and religious training, illumination of appearance and soul, developing a  feeling of moral intellection together with succumbing to reason and revelation, gradual elevation and permanent caring and opposition to egotistical desire Chronbach Alpha coefficient for the questionnaire was obtained 0.93, being considered as possessing sufficient reliability. The validity of the questionnaire was confirmed by related specialists. The data were analyzed using scientific modeling method of structural equations and SPSS 16 & Amos 18 statistical software. The results showed that the mean of all self-evaluation components was above average. Thus, there were no positive and significant relationships among all self-evaluation components. Also, self-evaluation had no significant relationship with none of demographic characteristics. Keywords: elementary school teachers, self-evaluation, moral education, educational system, educational performanc

Prediction the survival of patients with breast cancer using random survival forests for competing risks

Abstract Objectives: Breast cancer (BC) is the most common cause of cancer death in Iranian women. Sometimes death from other causes precludes the event of interest and makes the analysis complicated. The purpose of this study was to identify important prognosis factors associated with survival duration among patients with BC using random survival forests (RSF) model in presence of competing risks. Also, its performance was compared with cause-specific hazard model. Methods: This retrospective cohort study assessed 222 patients with BC who admitted in Ayatollah Khansari hospital, Arak. The cause-specific Cox proportional hazards and RSF models were employed to determine the important risk factors for survival of the patients. Results: The mean and median survival duration of the patients were 90.71 (95%CI: 83.8- 97.6) and 100.73 (95%CI: 89.2-- 121.5) months, respectively. The cause-specific model indicated that type of surgery and HER2 had statistically significant effects on the risk of death of BC. Moreover, the RSF model identified that HER2 was the most important variable for the event of interest. Conclusion: According to the results of this study, the performance of the RSF model was better than the cause-specific hazard model. However, HER2 was the most important variable for death of BC in both of the models

From Expressive Discrepancy to Pervasive Similarity; A Comparative Study of the Meaning Muḥṣanāt in Shi’ite and Sunni Exegeses up to the Seventh Century A.H.

Received: 2021/9/3  |   Correction: 2022/4/7   |   Accepted: 2022/4/7The Qur’anic word muḥṣanāt (wedded women), which has occurred in (Q. 4:24) and elswhere, has various examples in both earlier Shi’ite and Sunni exegeses. Based on some needs and contexts, such as the tradition of Islamic narrations’ transmission, the variety of narrations concerning the behavior of the Prophet (PBUH) and Caliphs in dealing with war captives, as well as legitimizing and sanctifying the way of Caliphs, some former Sunni exegetes have meant the mentioned word as ‘captive married women’. However, the different doctrinal contexts in Shi’a led to the point that such a meaning was not being expressed in previous Shi’ite exegeses. In fact, the majority of Shi’ite exegetes have mostly considered the Qur’anic word muḥṣanāt to mean a bondwoman or free one. But after writing the early comprehensive exegeses, the suggested difference became almost disappeared. The mutual retelling of Shi’ite and Sunni exegetes from each other’s sources caused the first distinction between Shi’ites and Sunnis about the meaning of the word no longer being seen in these exegeses. Thus, as if the contexts that underlie the acceptance of an exegetical viewpoint in previous Muslim sources were not historically given much necessary attention in later periods. This point seems especially important when one heeds that the use of each other’s sources has not happened in a balanced situation between Shi’ites and Sunnis. As a matter of fact, the Shi’ite exegeses were more influenced by the Sunni ones and not vice versa. In particular, this consequence seems to be due to the acceptance of the previous Sunni exegetes’ viewpoints by Shaykh Ṭūsī (385-460/995-1067), and his character’s influence on later Shi’ite ones as well.Beheshti, N; Najafi, M.J. (2022) From Expressive Discrepancy to Pervasive Similarity; A Comparative Study of the Meaning Muḥṣanāt in Shi’ite and Sunni Exegeses up to the Seventh Century A.H.. Biannual Journal of Comparative Exegetical Researches, 8 (15) 37-64 Doi: 10.22091/PTT.2022.7383.2018