Numerical Analyses of Piles Subjected to Lateral Soil Movement

Mehmet Rifat Kahyaoglu,Gökhan Imançli,Okan Önal,Arif S. Kayalar 대한토목학회 2012 KSCE Journal of Civil Engineering Vol.16 No.4

Load transfer to piles due to the relative movement between the piles and the moving soil is a fairly complex soil-pile interaction problem. Different analysis methods are available in literature to estimate the loads on piles. However, the predicted loads on the piles calculated by these methods vary due to insufficient representation of loading conditions and ignoring relative pile and soil movement. In this paper, three dimensional finite element analyses have been performed to evaluate the load transfer mechanism of free head passive pile groups in purely cohesionless soils. Numerical analyses are classified to address two most common passive pile cases, namely piles adjacent to embankments and piles used for slope stabilization. The effects of relative pile and soil displacement, pile spacing and pile arrangement on soil arching are investigated by numerical simulations. It is observed that load transfer decreases parallel to a decrease in pile spacing for piles adjacent to embankments contrary to piles used for slope stabilization.

Exergetic Analysis of Power and Freshwater Cogeneration Systems

Iman Janghorban Esfahani,ChangKyoo Yoo 제어로봇시스템학회 2012 제어로봇시스템학회 국제학술대회 논문집 Vol.2012 No.10

This study proposes a systematic approach of energy and exergy analysis of reverse osmosis (RO) desalination system combined with the gas turbine power plant (GT). Three systems of RO for producing freshwater and a gas turbine for generating the power for the pumps and other equipments are compared in energy and exergy aspects. The first system mechanically couples RO with the power plant; while the second and third systems couples are mechanical as well as thermal, using a refrigeration cycle and compressor intercooler. Energy and exergy efficiencies and the rates of exergy destruction for all of the streams and components are identified. The third system with compressor intercooler showed the best performance among three systems, which increases energy and exergy efficiencies by 8.42% and 12.07%, respectively, compared with the first system as the base system.

Reflected shock tube experiments on aeroacoustic signature of hot jets

Iman Bahman Jahromi,Mohammad Ebrahimi,Kaveh Ghorbanian 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.8

We used a reflected shock tube to investigate the acoustic signature of a hot jet at the far-field. Experiments were performed at Mach = 1.4 and a total temperature of T t = 950 Kelvin. Far-field acoustic signatures of the hot jet at six polar angles θ = 15˚ to θ = 90˚ from the jet axis) were measured and imaged by the means of continuous wavelet transform in scalograms. The results were compared with experiments from a steady test facility at similar test conditions. Further, the primary characteristics of noise events in jet far-field were compared with analytical models considering wavepacket as the main source of jet noise. The results indicate that higher frequency events at θ = 90˚ occur with a small time shift relative to the low azimuthal mode base event. This phenomenon might be the main reason why the acoustic signal at the side angles behaves more noisily than at low polar angles.

A Fault-Tolerant Control Strategy for Cascaded H-Bridge Multilevel Rectifiers

Iman-Eini, Hossein,Farhangi, Shahrokh,Schanen, Jean-Luc,Khakbazan-Fard, Mahboubeh The Korean Institute of Power Electronics 2010 JOURNAL OF POWER ELECTRONICS Vol.10 No.1

Reliability is an important issue in cascaded H-bridge converters (CHB converters) because they use a high number of power semiconductors. A faulty power cell in a CHB converter can potentially lead to expensive downtime and great losses on the consumer side. With a fault-tolerant control strategy, operation can continue with the undamaged cells; thus increasing the reliability of the system. In this paper, the operating principles and the control method for a CHB multilevel rectifier are introduced. The influence of various faults on the CHB converter is investigated. The method of fault diagnosis and the bypassing of failed cells are explained. A fault-tolerant protection strategy is proposed to achieve redundancy in the CHB rectifier. The redundant H-bridge concept helps to deal with device failures and to increase system reliability. Simulation results verify the performance of the proposed strategy.

Nonlinear vibration of thin circular sector cylinder: An analytical approach

Iman Pakar,Mahmoud Bayat,Mahdi Bayat 국제구조공학회 2014 Steel and Composite Structures, An International J Vol.17 No.1

In this paper, we try to prepare an accurate analytical solution for solving nonlinear vibration of thin circular sector cylinder. A new approximate solution called variational approach is presented and correctly applied to the governing equation of thin circular sector cylinder. The effect of important parameters on the response of the problem is considered. Some comparisons have been presented between the numerical solution and the present approach. The results show an excellent agreement between these methods. It has been illustrated that the variational approach can be a useful method to solve nonlinear problems by considering the effects of important parameters.

Deep Learning Approaches For Prediction of Sequence Specificities of DNA-Binding Proteins

Iman nazari,Kill To Chong 제어로봇시스템학회 2018 제어로봇시스템학회 국내학술대회 논문집 Vol.2018 No.5

Analytical Network Process to Prioritize the Influencing Parameters on Local Participation: The Development of Livestock Drinking Water Resources

Iman Islami,Amir Sadoddin,Hossein Barani,Ahmadreza Asgharpourmasoule,Masih Akhbari 대한산업공학회 2018 Industrial Engineeering & Management Systems Vol.17 No.2

Participation of local ranchers for developing livestock drinking water resources has been identified as inadequate in Yazd Province located in the central part of Iran. Thorough understanding of barriers among various factors influenc-ing the public participation is complex. In this study, to evaluate and prioritize the influencing criteria and parameters, ANP was used in which relationships are considered in form of non-linear. The information required in this study were collected using tools of questionnaire and expert knowledge elicitation. The results show a combined effect of various criteria on level of participation with different relative weights. Economic criterion in this study with normal weight of 0.455 represents 1.5 times more importance compared with climatic criterion and 2 times more importance in comparison to social criterion. Analysis indicates that following parameter of “Low income of animal husbandry” with normal weight of 0.319, as the most important influencing economic factor, climatic parameter of “Recurrent droughts and reduced rainfall” with normal weight of 0.153, and social parameter of “Poor role of NGOs” with nor-mal weight of 0.093, respectively represent the most important parameters in the context of this study. ANP model facilitates assessment and provides more detailed information for the decision makers.

S-FEAR: Secure-Fuzzy Energy Aware Routing Protocol for Wireless Sensor Networks

( Iman Almomani ),( Maha Saadeh ) 한국인터넷정보학회 2018 KSII Transactions on Internet and Information Syst Vol.12 No.4

Secure routing services in Wireless Sensor Networks (WSNs) are essential, especially in mission critical fields such as the military and in medical applications. Additionally, they play a vital role in the current and future Internet of Things (IoT) services. Lightness and efficiency of a routing protocol are not the only requirements that guarantee success; security assurance also needs to be enforced. This paper proposes a Secure-Fuzzy Energy Aware Routing Protocol (S-FEAR) for WSNs. S-FEAR applies a security model to an existing energy efficient FEAR protocol. As part of this research, the S-FEAR protocol has been analyzed in terms of the communication and processing costs associated with building and applying this model, regardless of the security techniques used. Moreover, the Qualnet network simulator was used to implement both FEAR and S-FEAR after carefully selecting the following security techniques to achieve both authentication and data integrity: the Cipher Block Chaining-Message Authentication Code (CBC-MAC) and the Elliptic Curve Digital Signature Algorithm (ECDSA). The performance of both protocols was assessed in terms of complexity and energy consumption. The results reveal that achieving authentication and data integrity successfully excluded all attackers from the network topology regardless of the percentage of attackers. Consequently, the constructed topology is secure and thus, safe data transmission over the network is ensured. Simulation results show that using CBC-MAC for example, costs 0.00064% of network energy while ECDSA costs about 0.0091%. On the other hand, attacks cost the network about 4.7 times the cost of applying these techniques.

Salinity and Trinexapac-Ethyl Effects on Seed Reserve Utilization and Seedling Growth of Two Lolium perenne Cultivars

Iman Roohollahi,Mohsen Kafi 한국원예학회 2010 Horticulture, Environment, and Biotechnology Vol.51 No.2

Plant growth regulators are frequently applied for warm-season turf just before over-seeding to increase the turf performance, and its competitive ability. In situation that the turfs are irrigated with saline water, the time of TE application on turf is critical. Seeds of two perennial ryegrass cultivars were adjusted to different salinity levels (0, 2000, 4000 and 6000 ㎎?L<SUP>-1</SUP> NaCl) and TE (0, 50 and 100 g?㏊<SUP>-1</SUP>) levels which individually performed in agar and soil to detect their effects on germination and initial growth. Seed germination percentage, germination rate, weight of mobilized seed reserve and seed reserve depletion percentage were significantly affected by TE, and salinity with an exception of seed reserve utilization efficiency in the first experiment. TE inhibited germination percentage more severely in higher concentration. The results showed that TE had no significant effect on chlorophyll concentration, height, electrolyte leakage, root length, the fresh and dry weight of seedling, but salinity significantly decreased all of them. It postulated that TE application before over-seeding had deleterious effects on over-seeded grass germination; however, because it had no effects on initial growth of turf, it can be used in this stage.

Improved predictive model to the cross-sectional resistance of CFT

Iman Mansouri,Rolando Chacón,허종완 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.8

This paper proposes an improved theoretical prediction equation for Concrete-filled steel tubes (CFT) subjected to compressive forces. This ultimate load capacity is inferred from a database of 344 experimental results reported in the literature by using Gene expression programming (GEP). Moreover, a series of structural comparisons between design provisions, other mechanically-derived expressions and the proposed prediction are addressed. The levels of accuracy, practical use and phenomenological understanding of the phenomenon are pinpointed. The results obtained are in good agreement with both the experimental and theoretical predictions. Advantages and disadvantages of such type of predictions are pinpointed.