139 research outputs found
Entrepreneurship Education in Iranian Higher Education: The Current State and Challenges
Entrepreneurship has long been considered a significant factor for socioeconomic growth and development because it provides millions of job opportunities, offers a variety of consumer goods and services, and generally increases national prosperity and competitiveness. Due to this positive impact of entrepreneurship, recent decades have seen a tremendous rise in entrepreneurship education at various universities and colleges around the globe, including in Iran. In the middle of this expansion remains the challenges and problems of development and changes for entrepreneurship.This paper investigates the state, trends, challenges and solutions in entrepreneurship education in Iran which emerged from an extensive review of literature. The literature reviewed indicates that entrepreneurship education in Iranian higher education faces with economic, political, social, and cultural challenges. Also this article offers some approaches and recommendations for resolving the challenges as well as encouraging and fostering entrepreneurship in higher education. The findings of this study provide valuable insights for policy makers, educators, students and graduate entrepreneurs. Stakeholders could use this study to make better choices in relation to the improvement of entrepreneurship education in Iranian higher education system
Online discussion compensates for suboptimal timing of supportive information presentation in a digitally supported learning environment
This study used a sequential set-up to investigate the consecutive effects of timing of supportive information presentation (information before vs. information during the learning task clusters) in interactive digital learning materials (IDLMs) and type of collaboration (personal discussion vs. online discussion) in computer-supported collaborative learning (CSCL) on student knowledge construction. Students (N = 87) were first randomly assigned to the two information presentation conditions to work individually on a case-based assignment in IDLM. Students who received information during learning task clusters tended to show better results on knowledge construction than those who received information only before each cluster. The students within the two separate information presentation conditions were then randomly assigned to pairs to discuss the outcomes of their assignments under either the personal discussion or online discussion condition in CSCL. When supportive information had been presented before each learning task cluster, online discussion led to better results than personal discussion. When supportive information had been presented during the learning task clusters, however, the online and personal discussion conditions had no differential effect on knowledge construction. Online discussion in CSCL appeared to compensate for suboptimal timing of presentation of supportive information before the learning task clusters in IDLM
Slippery motion between the limbs of a double tendon graft
Relative motion of tendon limbs of a double tendon graft for the application of anterior cruciate ligament (ACL) reconstruction may affect the mechanical behaviour of a tendon graft structure. The biomechanical data derived from the standard tensile testing machines may not be able to show the relative motion of the graft limbs. This paper uses the non-destructive digital stereo imaging recording system, synchronized with the standard test machine, to precisely determine the biomechanical properties of 10 bovine flexor tendon grafts which hanged from the loop side to the rig and the other end was fixed in a bone block. The study showed there is a relative motion between graft limbs
F3TM: flooding factor based trust management framework for secure data transmission in MANETs
Due to the absence of infrastructure support, secure data dissemination is a challenging task in scalable mobile ad hoc networks (MANETs) environment. In most of the traditional routing techniques for MANETs, either security has not been taken into account or only one aspect of security concern has been addressed without optimizing the routing performance. This paper proposes Flooding Factor based Framework for Trust Management (F3TM) in MANETs. True flooding approach is utilized to identify attacker nodes based on the calculation of trust value. Route Discovery Algorithm is developed to discover an efficient and secure path for data forwarding using Experimental Grey Wolf algorithm for validating network nodes. Enhanced Multi-Swarm Optimization is used to optimize the identified delivery path. Simulations are carried out in ns2 to assess and compare the performance of F3TM with the state-of-the-art frameworks: CORMAN and PRIME considering the metrics including delay, packet delivery ration, overhead and throughput. The performance assessment attests the reliable security of F3TM compared to the state-of-the-art frameworks
Additively manufacturable micro-mechanical logic gates.
Early examples of computers were almost exclusively based on mechanical devices. Although electronic computers became dominant in the past 60 years, recent advancements in three-dimensional micro-additive manufacturing technology provide new fabrication techniques for complex microstructures which have rekindled research interest in mechanical computations. Here we propose a new digital mechanical computation approach based on additively-manufacturable micro-mechanical logic gates. The proposed mechanical logic gates (i.e., NOT, AND, OR, NAND, and NOR gates) utilize multi-stable micro-flexures that buckle to perform Boolean computations based purely on mechanical forces and displacements with no electronic components. A key benefit of the proposed approach is that such systems can be additively fabricated as embedded parts of microarchitected metamaterials that are capable of interacting mechanically with their surrounding environment while processing and storing digital data internally without requiring electric power
Applications of ultrasonic testing and machine learning methods to predict the static & fatigue behavior of spot-welded joints
© 2020 The Society of Manufacturing Engineers. This manuscript is made available under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International licence (CC BY-NC-ND 4.0). For further details please see: https://creativecommons.org/licenses/by-nc-nd/4.0/Ultrasonic Testing (UT) is one of the well-known Non-Destructive Techniques (NDT) of spot-weld inspection in the advanced industries, especially in automotive industry. However, the relationship between the UT results and strength of the spot-welded joints subjected to various loading conditions isunknown. The main purpose of this research is to present an integrated search system as a new approach for assessment of tensile strength and fatigue behavior of the spot-welded joints. To this end, Resistance Spot Weld (RSW) specimens of three-sheets were made of different types of low carbon steel. Afterward, the ultrasonic tests were carried out and the pulse-echo data of each sample were extracted utilizing Image Processing Technique (IPT). Several experiments (tensile and axial fatigue tests) were performed to study the mechanical properties of RSW joints of multiple sheets. The novel approach of the present research is to provide a new methodology for static strength and fatigue life assessment of three-sheets RSW joints based on the UT results by utilizing Artificial Neural Network (ANN) simulation. Next, Genetic Algorithm (GA) was used to optimize the structure of ANN. This approach helps to decrease the number of tests and the cost of performing destructive tests with appropriate reliability.Peer reviewe
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Effect of suturing of a tendon graft in ACL reconstruction
Permanent viscoplastic elongation in response to cyclic loading in the early postoperative period might affect a sutured graft function. The objective of this study is to test the hypothesis that suturing of a tendon graft may affect the material properties of the corresponding tendon site, due to local changes in tendon matrix composition. Several digital flexor tendons were armed with a whipstitch and examined under tension or cyclic loading. In parallel a 3D numerical modelling was performed to analyse the mechanical behaviour of the sutured tendon. The experimental data and numerical evaluation show suturing of tendon graft has no significant effect on the mechanical properties of the graft for the application of ACL reconstruction. In general no correlation was found between suturing and the material properties of the tendon segments
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Microstructural analysis of a girth welded subsea pipe
This research focuses on simulation of the dissimilar materials’ welding, stainless steel and mild steel, using finite element and experiment to enhance the method and better understand the transient temperature profiles and the stress distribution in a cladded pipe. The microstructural come as fenestrated and the computer results show that the temperature distribution in the modelled pipe is a function of the thermal conductivity of each weld metal as well as the distance away from the heat source
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Experimental and Numerical Simulation of Girth Welded Joints of Dissimilar Metals in Clad Pipes
Welding of two dissimilar materials was carried out in-house with the aid of a Tungsten Arc weld having dynamic measurement of temperature profiles in the vicinity areas of the welding track using high temperature thermocouples. Comparison was shown previously of the simulated and measured transient temperatures versus finite element simulation. Stress analyses of the pipe were carried out using FEA simulations with two different clad thicknesses. Results of thermal analysis showed a close match and laboratory tests revealed the occurrences at the welded joints, FZ and HAZ; the result of stress analysis also showed a good agreement when validated with ND experimental results.The Petroleum Technology Development Fund (PTDF
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