Evaluating Impact Resistance of Aluminum 6061-T651 Plate using Smoothed Particle Hydrodynamics Method

Performing various experimental, theoretical, and numerical investigations for better understanding of behavioural characteristics of metals under impact loading is of primary importance. In this paper, application of smoothed particle hydrodynamics (SPH) method in impact mechanics is discussed and effective parameters on impact strength of an aluminum plate are investigated. To evaluate the accuracy of smoothed particle hydrodynamics method for simulating impact, Recht and Ipson model is first provided thoroughly for both Rosenberg analytical model and smoothed particle hydrodynamics method, and then plots of initial velocity-residual velocity and initial velocity-absorbed energy for target of aluminum 6061-T651 are presented. The derived information and simulation results expresses that the maximum error percentage of smoothed particle hydrodynamics method in compared with Rosenberg analytical model is within an acceptable range. Therefore, the results of smoothed particle hydrodynamics method verify the Rosenberg analytical model with high accuracy. Results reveal that higher initial impact velocity decreases the time of projectile penetration, and so penetration depth and length as well as the local damage rate of plate increases

Neglected simultaneous bilateral femoral neck fractures secondary to narcotic drug abuse treated by bilateral one-staged hemiarthroplasty: a case report

Simultaneous bilateral femoral neck fractures are extremely rare and associated with various conditions. Up to now Most cases had correlations with major trauma, repetitive minor trauma, seizure, parathyroid or renal dysfunction, anti-epileptic medications, seizure, etc. A 28-year-old addict man referred to us with a 10-year history of narcotic drug abuse and history of 8 months bilateral groin pain. He admitted with displaced bilateral femoral neck fracture. Because of long duration of this condition and osteonecrosis revealed on bone scan, one-staged bilateral hip hemiarthroplasty was done. A good function was noted after surgery to 4-month follow up. Up to now, have not be founded in the literature that a case of bilateral femoral neck fracture associated with narcotic drug abuse

Determination of some constant parameters during cutting of canola stem

In this study, the canola stalk cutting parameters including modulus of mass density of stalk, special work of useful cutting, coefficient of cutting useful work and crush resistance coefficient were examined.  For the tests, testing machine Instron (Model Santam STM-5) with 50 N load cell was used.  Cutting was performed with a saw-serrated cutting blade that was attached to the Instron movable jaw.  Stems were cut at three diameter levels (1 to 3, 3 to 5 and more than 5 mm), three cutting speed levels (75, 115 and 150 mm/minute), three cutting angles (0°, 30° and 60°) and three replicates.  Cutting parameters including modulus of mass density of stalk, special work of useful cutting, coefficient of cutting useful work and crush resistance coefficient were examined.  Tests lasted for each stem until the full cut.  Data requirements were obtained from Force-Deformation curve.  The results showed that the modulus of mass density, special work of useful cutting and crush resistance coefficient were enhanced by increasing the diameter and cutting angle.  As well as modulus of mass density, special work of useful cutting and crush resistance coefficient were decreased by increasing the cutting speed.  Also, the coefficient of cutting useful work was enhanced by increasing diameter, but the changes in the diameter and cutting speed had no significant effect on it

Application of Artificial Neural Network (ANN) in predicting mechanical properties of canola stem under shear loading

In this study, at first the shear parameters including the maximum shear force, shear strength, shear energy and power consumption of canola stem were calculated through force-deformation curve; and then these mechanical properties were determined and predicted using artificial neural network.   For the tests, testing machine Instron (Model Santam STM-5) with 50 N load cell was used.  Stems were cut at 3 diameter levels (1 to 3, 3 to 5 and more than 5 mm), 3 cutting speed levels (75, 115 and 150 mm/min ), 3 cutting angles (0°, 30° and 60°) and three replicates.   Cutting parameters including maximum cutting force, shear strength; cutting energy; consumed power and cutting work were examined.  Tests lasted for each stem until the full cut.  Data requirements were obtained from Force-Deformation curve. The results showed that by increasing the diameter and cutting angle, cutting force values, shear strength, cutting energy, cutting power and cutting work increased.   Additionally, with increasing cutting speed, the cutting force, shear strength, cutting energy, cutting power and cutting work declined.  Feedforward network was employed to predict some of the mechanical properties of canola stem.  The results of statistical analysis using artificial neural network showed that the best values for shear energy, shear force, shear strength, shear power and shear work in canola stem were, respectively, in the epochs of 194, 2000, 275, 92 and 350 and also showed that neural networks can be used in intelligent cutting mechanisms and predicting mechanical properties of crops stem

Validity and Cross-Cultural Adaptation of the Persian Version of the Oxford Elbow Score

Oxford Elbow Score (OES) is a patient-reported questionnaire used to assess outcomes after elbow surgery. The aim of this study was to validate and adapt the OES into Persian language. After forward-backward translation of the OES into Persian, a total number of 92 patients after elbow surgeries completed the Persian OES along with the Persian DASH and SF-36. To assess test-retest reliability, 31 randomly selected patients (34%) completed the Persian OES again after three days while abstaining from all forms of therapeutic regimens. Reliability of the Persian OES was assessed by measuring intraclass correlation coefficient (ICC) for test-retest reliability and Cronbach's alpha for internal consistency. Spearman's correlation coefficient was used to test the construct validity. Cronbach's alpha coefficient was 0.92 showing excellent reliability. Cronbach's alpha for function, pain, and social-psychological subscales was 0.95, 0.86, and 0.85, respectively. Intraclass correlation coefficient (ICC) was 0.85 for the overall questionnaire and 0.90, 0.76, and 0.75 for function, pain, and social-psychological subscales, respectively. Construct validity was confirmed as the Spearman correlation between OES and DASH was 0.80. Persian OES is a valid and reliable patient-reported outcome measure to assess postsurgical elbow status in Persian speaking population

Integration of Research, Public Health, and Hospital Interventions as a Successful Model for Controlling COVID-19 Pandemic: A Perspective

The COVID-19 pandemic has been a serious health problem in most countries in the last few months, with every country adopting different preventive and therapeutic measures based on their specific circumstances. The epidemic began in Iran on February 19, 2020, and gradually spread across the country. The epidemic extent varies, and different preventive and therapeutic measures are taken in Iran. Shahroud and Miami Counties, covered by the Shahroud University of Medical Sciences, have experienced the highest incidence of COVID-19 in Iran. However, the epidemic is well controlled by integrating the activities of the health, treatment, and research sectors and using information technology and a proprietary software application. This model can be thus studied as a successful experience. Keywords: COVID-19, Control, Successful model, Ira

Security, privacy and efficiency in RFID systems

Radio frequency identification (RFID) is a ubiquitous wireless technology that allows objects to be identified automatically. Using the RFID technology can simplify many applications and provide many benefits but meanwhile, the security and privacy of RFID systems should be taken into account. In this thesis, we have two goals. The first one is to improve the security and privacy in RFID systems. Our second goal is to provide accurate analytical models for the most important tag singulation schemes. We use these analytical models to evaluate and compare the efficiency of the tag singulation schemes. First, we study the blocking attack in RFID systems and develop an analytical model for it. Using this analytical model, we propose two probabilistic blocker tag detection (P-BTD) algorithms for RFID systems that operate based on the binary tree walking and ALOHA techniques. Then, we study the security and privacy of some recently introduced light-weight authentication protocols, and discuss their advantages and drawbacks. Based on this analysis and considering the hardware limitations of RFID tags, we propose a new authentication protocol that improves the security and privacy in RFID systems. By taking advantage of the analytical model we proposed for the ALOHA-based P-BTD algorithm, we develop an accurate tag estimate method. Using the proposed method, we can estimate the number of tags in RFID systems accurately, and design more efficient ALOHA-based tag singulation mechanisms. Next, we study the EPC Gen-2 protocol and its tag singulation mechanism. We model the EPC Gen-2 protocol as an absorbing Markov chain. Using the model proposed, we derive accurate analytical expressions for the expected number of queries and the expected number of transmitted bits needed to identify all tags in the RFID system. Finally, we study the use of the CDMA technique for RFID systems. We model the CDMA-based tag singulation procedure as an absorbing Markov chain, and derive accurate analytical expressions for the expected number of queries and the amount of transmitted data needed to identify all tags in the system. Using the analytical models developed, we compare the performance of the CDMA-based and the EPC Gen-2 tag singulation schemes.Applied Science, Faculty ofElectrical and Computer Engineering, Department ofGraduat