The damping properties of the foam‑filled shaft of primary feathers of the pigeon Columba livia

The avian feather combines mechanical properties of robustness and flexibility while maintaining a low weight. Under periodic and random dynamic loading, the feathers sustain bending forces and vibrations during flight. Excessive vibrations can increase noise, energy consumption, and negatively impact flight stability. However, damping can alter the system response, and result in increased stability and reduced noise. Although the structure of feathers has already been studied, little is known about their damping properties. In particular, the link between the structure of shafts and their damping is unknown. This study aims at understanding the structure-damping relationship of the shafts. For this purpose, laser Doppler vibrometry (LDV) was used to measure the damping properties of the feather shaft in three segments selected from the base, middle, and tip. A combination of scanning electron microscopy (SEM) and micro-computed tomography (μCT) was used to investigate the gradient microstructure of the shaft. The results showed the presence of two fundamental vibration modes, when mechanically excited in the horizontal and vertical directions. It was also found that the base and middle parts of the shaft have higher damping ratios than the tip, which could be attributed to their larger foam cells, higher foam/cortex ratio, and higher percentage of foam. This study provides the first indication of graded damping properties in feathers

Effect of manganese oxide nanoparticle on growth performance and blood cells of rainbow trout (Oncorhynchus mykiss Walbaum 1792) fingerlings

This study was aimed to use nano manganese oxide (Mn2O3) as a mineral premix on growth parameters followed by the erythrocyte and leukocyte properties of rainbow trout (Oncorhynchus mykiss) fingerlings. 450 specimens of rainbow trout fingerlings with an average weight of 9.1±0.3 g after acclimation to the experimental condition were randomly distributed in triplicate to five treatments of raceways ponds with open flow. Basal diet as control treatment was prepared by adding no supplemental manganese mineral. Other experimental diets were prepared by adding 4, 8, 12 mg and 12 mg nano manganese oxide followed by 12 mg manganese sulfate (as positive control treatment) to each kg diet. The Fish were fed for 8 weeks under experimental conditions with the corresponding diets. At the end of feeding trial, growth performance followed by the hematological parameters were determined by cutting the caudal peduncle (n=5). Results demonstrated no significant differences in final weigh, specific growth rate, protein efficiency ratio, and condition factor of the fish among the treatments. However, erythrocytes, hemoglobin, and hematocrit of fish fed by 12 mg kg-1 nanoparticle manganese oxide were significantly higher than fish in other treatments (p<0.05), while no significant difference was found in erythrocyte indices including mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), and mean corpuscular hemoglobin concentration (MCHC) between the treatments. There is also no significant difference in former variables of the fish fed manganese sulfate and control diet. Findings of the present study showed that the use of nano manganese oxide increase some blood parameters of rainbow trout fingerlings including number of erythrocytes, hemoglobin, and hematocrit

Investigating The Effect Of Information and Communication Technology (ICT) Courses On The Creativity Of Students

The present study aims to investigate the effect of Information and Communication Technology (ICT) courses on the creativity of students at Isfahan’s Vocational Education Center. The research method is  a quasi-experimental type. The population of the research involves all the technical vocational students of Isfahan’s ICT Center. The subjects were selected using availability sampling and include 110 students comprising 57 students in the experimental group and 53 students in the control group. The means used for collecting data was Ravens Progressive Matrices Test accounting for homogeneity among the subjects and Dr Abedi’s creativity test involving sub-tests including Fluency, Elaboration, Originality and Flexibility. The latter test was used to compare the creativity of experimental and control groups pre-testing and post testing. The analysis of the findings was carried out using Analysis of covariance at the significance level of P < %05. The results of the study indicated that while there was no significant difference between Fluency and Elaboration creativity tests, there was a significant distinction between Originality and Flexibility creativity tests. In addition, the total result of students’ creativity tests proved to be significant. Thus, it can be concluded that the educational courses of information and communication technology (ICT) have had a positive effect on the creativity of students of Isfahan’s ICT Technical Vocational Center

Membrane Separation for Gases: Materials, Preparation Methods and Transport Mechanism

Gas adsorption and permeation of CO2 gas weremeasured on two carbon molecular sieve membranes over awide pressure range. The two membrane samples werefabricated under similar conditions but with different degreesof carbonization. The pressure dependence of the permeationtime lag was investigated and it is found that the diffusioncoefficient takes a stronger functional dependence on loadingthan the Darken relation and this dependence increases withthe degree of carbonization

In Situ Reconfigurable Continuum Robot with Varying Curvature Enabled by Programmable Tensegrity Building Blocks

Reconfigurable continuum robots exhibit programmable interaction capability, enabling them to cope with challenges poorly addressed by conventional rigid robots. However, the regulation of the module type and/or sequence may result in time-consuming and labor-intensive problems. Therefore, in situ reconfiguration schemes are required to develop in a simple yet robust solution for continuum robot design. Herein, inspired by the structure characteristics of the seahorse tail, an original template based on a tensegrity building block (TBB) for creating an in situ reconfigurable continuum robotic paradigm is proposed. As the length of the stretchable struts in the TBB could be programmed, five typical homologous types from the template are derived. Then, ten TBBs into a continuum robot are assembled and the multi-body dynamic framework is employed to develop a mechanical model for predicting the profile after deformation. Theoretical predictions demonstrate that the robotic shape can be customized in situ by switching the type of TBBs, without disassembling the robot. Furthermore, the tailored continuum robotic configurations are applied to conformally interact with the varying-curvature objects. The experimental results suggest that the proposed programmable template offers a facile and rapid reconfiguration scheme for the continuum robots, which greatly improves the robotic interaction capability

Versatile Like a Seahorse Tail: A Bio-Inspired Programmable Continuum Robot For Conformal Grasping

Compliant grasping is an important function of continuum robots that interact with humans and/or unpredictable environments. However, the existing robots often have cross-sections that remain constant along their length. This causes the robots to exhibit poor grasping ability, especially when dealing with objects with diverse curvatures. Here, inspired by the high adaptability of seahorse tails in grasping, we proposed a cable-driven continuum robot with tapered tensegrity, capable of conformally grasping objects with various curvatures. To characterize the effects of the tapering on the robot’s kinematics, we derived a mechanical model using multi-body dynamic framework for both predicting the configuration and developing a control strategy for cables. Theoretical predictions indicate that the curvature of each unit can be regulated by altering the length of the cables, allowing the robot to conform to objects with curvatures ranging from 1.48 m-1 to 28.21 m-1. We further employed a continuum robot and tested the control strategy that can be used for grasping floating objects when the curvature of the objects is used as the input. Our robotic design, which presents an example of embedded physical intelligence, can inspire in situ characterization techniques for collecting marine debris

A semi-relativistic treatment of spinless particles subject to the nuclear Woods-Saxon potential

By applying an appropriate Pekeris approximation to deal with the centrifugal term, we present an approximate systematic solution of the two-body spinless Salpeter (SS) equation with the Woods-Saxon interaction potential for arbitrary -state. The analytical semi-relativistic bound-state energy eigenvalues and the corresponding wave functions are calculated. Two special cases from our solution are studied: the approximated Schr\"odinger-Woods-Saxon problem for arbitrary l -state and the exact s-wave (l=0).Comment: 14 pages; 4 figures, to appear in Chinese Physics C (2012

Is correction for metallic artefacts mandatory in cardiac SPECT/CT imaging in the presence of pacemaker and implantable cardioverter defibrillator leads?

Introduction: Metallic artifacts due to pacemaker/ implantable cardioverter defibrillator (ICD) leads in CT images can produce artifactual uptake in cardiac SPECT/CT images. The aim of this study was to determine the influence of the metallic artifacts due to pacemaker and ICD leads on myocardial SPECT/CT imaging. Methods: The study included 9 patients who underwent myocardial perfusion imaging (MPI). A cardiac phantom with an inserted solid defect was used. The SPECT images were corrected for attenuation using both artifactual CT and CT corrected using metal artifact reduction (MAR). VOI-based analysis was performed in artifactual regions. Results: In phantom studies, mean-of-relative-difference in white-region, between artifact-free attenuation-map without/with MAR were changed from 9.2 and 2.1 to 3.7 and 1.2 for ICD and pacemaker lead, respectively. However, these values for typical patient were 9.7±7.0 and 3.8±2.4 for ICD and pacemaker leads respectively, in white-region. MAR effectively reduces the artifacts in white-regions while this reduction is not significant in black-regions. Conclusion: Following application of MAR, visual and quantification analyses revealed that while quality of CT images were significantly improved, the improvements in the SPECT/CT images were not as pronounced or significant. Therefore cardiac SPECT images corrected for attenuation using CT in the presence of metallic-leads can be interpreted without correction for metal artefacts. © 2018 Tehran University of Medical Sciences. All rights reserved

Nurses� perception of patient safety culture and its relationship with adverse events: a national questionnaire survey in Iran

Background: Patient safety culture is an important factor in determining hospitals� ability to address and reduce the occurrence of adverse events (AEs). However, few studies have reported on the impact of nurses� perceptions of patient safety culture on the occurrence of AEs. Our study aimed to assess the association between nurses� perception of patient safety culture and their perceived proportion of adverse events. Methods: A cross-sectional survey was carried out among 2295 nurses employed in thirty-two teaching hospitals in Iran. Nurses completed the Persian version of the hospital survey of patients� safety culture between October 2018 and September 2019. Results: Positive Response Rates of overall patient safety culture was 34.1 and dimensions of patient safety culture varied from 20.9 to 43.8. Also, nurses estimated that the occurrence of six adverse events varied from 51.2�63.0 in the past year. The higher nurses� perceptions of �Staffing�, �Hospital handoffs and transitions�, �Frequency of event reporting�, �Non-punitive response to error�, �Supervisor expectation and actions promoting safety�, �Communication openness�, �Organizational learning continuous improvement�, �Teamwork within units�, and �Hospital management support patient safety� were significantly related to lower the perceived occurrence at least two out of six AEs (OR = 0.69 to 1.46). Conclusions: Our findings demonstrated that nurses� perception regarding patient safety culture was low and the perceived occurrence of adverse events was high. The research has also shown that the higher level of nurses� perception of patient safety culture was associated with lowered occurrence of AEs. Hence, managers could provide prerequisites to improve patient safety culture and reduce adverse events through different strategies, such as encouraging adverse events� reporting and holding training courses for nurses. However, further research is needed to assess how interventions addressing patient safety culture might reduce the occurrence of adverse events. © 2021, The Author(s)