Bioinspired reorientation strategies for application in micro/nanorobotic control

Engineers have recently been inspired by swimming methodologies of microorganisms in creating micro-/nanorobots for biomedical applications. Future medicine may be revolutionized by the application of these small machines in diagnosing, monitoring, and treating diseases. Studies over the past decade have often concentrated on propulsion generation. However, there are many other challenges to address before the practical use of robots at the micro-/nanoscale. The control and reorientation ability of such robots remain as some of these challenges. This paper reviews the strategies of swimming microorganisms for reorientation, including tumbling, reverse and flick, direction control of helical-path swimmers, by speed modulation, using complex flagella, and the help ofmastigonemes. Then, inspired by direction change in microorganisms,methods for orientation control for microrobots and possible directions for future studies are discussed. Further, the effects of solid boundaries on the swimming trajectories of microorganisms and microrobots are examined. In addition to propulsion systems for artificial microswimmers, swimming microorganisms are promising sources of control methodologies at the micro-/nanoscale

Predicting the effects of dimensional and material stiffness variations on a compliant bistable microrelay performance

In this paper we investigate the effects of dimensional and material stiffness variations on a microrelay performance. A linear displacement bistable micromechanism is modelled by pseudo-rigid-body model method and fully characterized. To find the effects of dimensional and material stiffness variation, an analysis of mechanical error is used. The method is a stochastic one and takes into account the random nature of variations. Variations of the contact force and required power of a microrelay example is obtained by the method introduced and the performance of the microrelay is determined. The method introduced is a simple, effective and general that may be used at the design level

Calculation of Natural Frequency of Earth Dams by Means of Analytical Solution

Earth dams are 3-Dimensional, huge and inhomogeneous structures that interact with water and soil. They are the most common type of dams used in the world and developing countries like Iran. Seismic analysis of earth dam is very important in regions which have been subjected with earthquake impaction several times. Calculating the natural frequency of dams is the essential part for its seismic behavior analysis. So it is very important to present an appropriate solution for calculation of natural frequency. Natural frequency of earth dams is usually calculated by means of experimental correlations, shear beam analysis (base on the height of dam and shear wave velocity) and time historical dynamic analysis. The present study concerns a new formulation for natural frequency of earth dams by means of analytical method. In this method, shear wave velocity and height of dam are two parameters which are used for obtaining natural frequency. Geometry of dam body, rigidity of foundation, modulus of elasticity and Poisson\u27s ratio are essential in calculating process. Results from proposed method are compared with case histories, numerical method and other formulations. Comparison shows that there is no significant difference in dams with various heights up to 100m

Comparison of astigmatism after cataract surgery with separate & running sutures

عمل جراحی آب مراورید یکی از رایج ترین اعمال جراحی است و در تمام دنیا از جمله کشور ایران شایع ترین تکنیک جراحی روش خارج کپسولی (Extra Capsular Cataract Extraction= ECCE) است که نیاز به برش قرنیه در ناحیه لیمیوس و در آخر عمل بخیه دارد. یکی از فاکتورهای موثر در بهبود دید بیمار بعد از جراحی در این روش کاستن از میزان آستیگماتیسم ناشی از بخیه ها می باشد. چون بخیه ها به دو روش ممتد (Running (R)) و جدا از هم (Separate (s)) زده می شوند بر آن شدیم که مقایسه ای بین آستیگماتیسم حاصله از این دو روش انجام دهیم. در تحقیق فوق 157 بیمار که تحت جراحی آب مراورید به روش ECCE قرار گرفتند و بخیه آنها به دو روش R و S زده شده بود انتخاب و میزان آستیگماتیسم ایجاد شده روز بعد از عمل، هفته اول، دوم، چهارم، ششم و سه ماه بعد با روش کراتومتری تعیین و با آستیگماتیسم موجود قبل از عمل مقایسه گردیدند. بخیه زدن ها در 104 مورد (3/66) به روش ممتد و در 53 مورد (7/33) به صورت جدا از هم بودند. متوسط آستیگماتیسم روز بعد از عمل 19/5 دیوپتر (در گروه R 7/4 و در گروه S 7/5 دیوپتر)، سه ماه پس از عمل 58/1 دیوپتر (در گروه R 12/1 و در گروه s 05/2دیوپتر) بود. از هفته چهارم تفاوت معنی دار آماری بین دو روش R، S مشاهده شد (05/0

A statistical study of the luminosity gap in galaxy groups

The luminosity gap between the two brightest members of galaxy groups and clusters is thought to offer a strong test for the models of galaxy formation and evolution. This study focuses on the statistics of the luminosity gap in galaxy groups, in particular fossil groups, e.g. large luminosity gap, in an analogy with the same in a cosmological simulation. We use spectroscopic legacy data of seventh data release (DR7) of SDSS, to extract a volume limited sample of galaxy groups utilizing modified friends-of-friends (mFoF) algorithm. Attention is paid to galaxy groups with the brightest group galaxy (BGG) more luminous than \Mr = -22. An initial sample of 620 groups in which 109 optical fossil groups, where the luminosity gap exceeds 2 magnitude, were identified. We compare the statistics of the luminosity gap in galaxy groups at low mass range from the SDSS with the same in the Millennium simulations where galaxies are modeled semi-analytically. We show that the BGGs residing in galaxy groups with large luminosity gap, i.e. fossil groups, are on average brighter and live in lower mass halos with respect to their counter parts in non-fossil systems. Although low mass galaxy groups are thought to have recently formed, we show that in galaxy groups with 15 galaxies brighter than $M_r\ge -19.5$, evolutionary process are most likely to be responsible for the large luminosity gap. We also examine a new probe of finding fossil group. In addition we extend the recently introduced observational probe based on the luminosity gap, the butterfly diagram, to galaxy groups and study the probe as a function of halo mass. This probe can, in conjunction with the luminosity function, help to fine tune the semi-analytic models of galaxies employed in the cosmological simulations.Comment: 11 pages, 11 figures, accepted to PASP journa

The relationship between emotional intelligence and addiction potential tendency pre-university students

Background and aims: Unfavorable emotional growth in adults may lead to addiction. This study investigated the relationship between emotional intelligence and students’ potential talent pertaining to addiction. Methods: This study is a descriptive analytical study. All male students of pre-universities in Shahrekord city participated in this study One hundred and twelve participnts were chosen based on the stage cluster sampling. In order to collect data emotional intelligence questionnaire and addictive potential survey (APS) were used. Data were analyzed based on Pearson and regression correlation. Results: The results Showed that there is a negative significant relationship among the emotional intelligence (P<0.05, r=-0.37), emotional save order (P<0.01 r=-0.63, P<0.01 r=-0.60) and emotional usability (P<0.01 r=-0.51, P<0.01 r=-0.49) in students resident in city and in rural area respectively and addiction vulnerability. Emotional intelligence and emotional save order components have the potential to predict the addiction tendency (P<0.01). Conclusion: Lack of emotional intelligence is one of the major factors that affect drug using tendency in students. Therefore, training is necessary for students

3D particle-based cell modelling for haptic microrobotic cell injection

Introducing haptic interface to conduct microrobotic intracellular injection has many beneficial implications. In particular, the haptic device provides force feedback to the bio-operator\u27s hand. This paper introduces a 3D particle-based model to simulate the deformation of the cell membrane and corresponding cellular forces during microrobotic cell injection. The model is based on the kinematic and dynamic of spring &ndash; damper multi particle joints considering visco-elastic fluidic properties. It simulates the indentation force feedback as well as cell visual deformation during the microinjection. The model is verified using experimental data of zebrafish embryo microinjection. The results demonstrate that the developed cell model is capable of estimating zebrafish embryo deformation and force feedback accurately

Seismic Behavior of Asphaltic Concrete Core Dams

In current years the use of asphaltic concrete core dams are increased especially in some areas with shortage of clayey materials. These dams also have less earth work in comparison with clay core dams. Despite of many advantages of this kind of dam in compression of other types, the behavior of these dams against earthquakes and seismic condition isn\u27t clearly specified. In this research using CA2 program (Finite difference Code) Some numerical studies about the behavior of asphaltic concrete core dams with various height and slopes to understand the influence of dam geometry on behavior of these dams under earthquake condition were done. Application of dams with asphalt concrete core is a relatively novel method especially in Iran. Iran is among regions with high seismicity risk. Therefore, investigation and studying the behavior of such types of dams in earthquake conditions is of more importance considering the novelty of implementing asphaltic core dams. In this research, behavior of asphaltic core dams have been studied under earthquake loading using nonlinear dynamic analysis method and a method is presented for assessment of seismic stability of these types of dams in earthquake conditions based on nonlinear dynamic analysis. Results of the proposed method in this research beside other existing methods can assist designers of asphaltic core dams in judgment about dam stability during earthquake occurrence