Sensitivity analysis for seismic response of a ship-block system

Kuchaksarai, Masoud Moghaddasi,Bargi, Khosrow Techno-Press 2006 Structural Engineering and Mechanics, An Int'l Jou Vol.23 No.3

In this paper, seismic response of a free-standing ship located in a dry dock and supported by an arrangement of n keel blocks due to base excitation is addressed. Formulation of the problem including derivation of governing equations in various modes of motion as well as transition conditions from one mode to another is given in Moghaddasi and Bargi (2006) by same authors. On the base of numerical solution for presented formulation, several numbers of analyses are conducted to study sensitivity of system's responses to some major contributing parameters. These parameters include friction coefficients between contacting surfaces, block dimensions, peak ground acceleration, and the magnitude of vertical ground acceleration. Finally, performance of a system with usual parameters normally encountered in design is investigated.

Optimization of LQR method for the active control of seismically excited structures

Behrang Moghaddasie,Ali Jalaeefar 국제구조공학회 2019 Smart Structures and Systems, An International Jou Vol.23 No.3

This paper introduces an appropriate technique to estimate the weighting matrices used in the linear quadratic regulator (LQR) method for active structural control. For this purpose, a parameter is defined to regulate the relationship between the structural energy and control force. The optimum value of the regulating parameter, is determined for single degree of freedom (SDOF) systems under seismic excitations. In addition, the suggested technique is generalized for multiple degrees of freedom (MDOF) active control systems. Numerical examples demonstrate the robustness of the proposed method for controlled buildings under a wide range of seismic excitations.

Evaluation of Nursing Information Systems: Application of Usability Aspects in the Development of Systems

Hamid Moghaddasi,Reza Rabiei,Farkhondeh Asadi,Negin Ostvan 대한의료정보학회 2017 Healthcare Informatics Research Vol.23 No.2

Objectives: As the largest group providing healthcare services, nurses require well-designed information systems in their practice. This study aims to evaluate the usability of nursing information systems (NIS). Methods: This cross-sectional survey was conducted in 2015. The settings of the study consisted of four hospitals affiliated with three medical universities in Tehran (Iran). The subjects of the study included nurses who had access to and used a NIS developed by four major software companies. The data were collected using a modified version of a usability questionnaire known as IsoMetrics, based on the International Standard ISO 9241, Part 11. The questionnaire is composed of 35 questions divided into seven general criteria. The validity of the questionnaire was determined by experts in the field, and the reliability was checked using Cronbach’s alpha (α = 0.91). The questionnaire was then distributed to 184 nurses. Results: The response rate was 64.6%. Among the seven ISO usability criteria, suitability for the task (3.10 ± 1.24) and suitability for learning (3.10 ± 1.27) had the highest mean value. The lowest mean value (2.37 ± 1.29) was related to the suitability for individualization. Conclusions: Addressing issues related to individualization and self-descriptiveness could improve the usability of nursing systems. Considering usability requirements in the design of a NIS will lead to the efficient and effective use of these systems.

Formulation for seismic response of a ship-block system

Kuchaksarai, Masoud Moghaddasi,Bargi, Khosrow Techno-Press 2006 Structural Engineering and Mechanics, An Int'l Jou Vol.23 No.3

This paper presents a complete and consistent formulation to study the seismic response of a free-standing ship supported by an arrangement of n keel blocks which are all located in a dry dock. It is considered that the foundation of the system is subjected to both horizontal and vertical in plane excitation. The motion of the system is classified in eight different modes which are Rest (relative), Sliding of keel blocks, Rocking of keel blocks, Sliding of the ship, Sliding of both keel blocks and the ship, Sliding and rocking of keel blocks, Rocking of keel blocks with sliding of the ship, and finally Sliding and rocking of keel blocks accompanied with sliding of the ship. For each mode of motion the governing equations are derived, and transition conditions between different modes are also defined. This formulation is based on a number of fundamental assumptions which are 2D idealization for motion of the system, considering keel blocks as the rigid ones and the ship as a massive rigid block too, allowing the similar motion for all keel blocks, and supposing frictional nature for transmitted forces between contacted parts. Also, the rocking of the ship is not likely to take place, and the complete ship separation from keel blocks or separation of keel blocks from the base is considered as one of the failure mode in the system. The formulation presented in this paper can be used in its entirety or in part, and they are suitable for investigation of generalized response using suitable analytical, or conducting a time-history sensitivity analysis.

Estimating the Region of Attraction via collocation for autonomous nonlinear systems

Rezaiee-Pajand, M.,Moghaddasie, B. Techno-Press 2012 Structural Engineering and Mechanics, An Int'l Jou Vol.41 No.2

This paper aims to propose a computational technique for estimating the region of attraction (RoA) for autonomous nonlinear systems. To achieve this, the collocation method is applied to approximate the Lyapunov function by satisfying the modified Zubov's partial differential equation around asymptotically stable equilibrium points. This method is formulated for n-scalar differential equations with two classes of basis functions. In order to show the efficiency of the suggested approach, some numerical examples are solved. Moreover, the estimated regions of attraction are compared with two similar methods. In most cases, the proposed scheme can estimate the region of attraction more efficient than the other techniques.

Study of Kinetics of Bromophenol Blue Fading in the Presence of SDS, DTAB and Triton X-100 by Classical Model

Samiey, Babak,Alizadeh, Kamal,Moghaddasi, Mohammad Ali,Mousavi, Mir Fazlolah,Alzadeh, Nader Korean Chemical Society 2004 Bulletin of the Korean Chemical Society Vol.25 No.5

In this paper, kinetics of reaction between Bromophenol blue (BPB) and $OH^-$, called fading, has been studied through a spectrophotometric method in the presence of nonionic Triton X-100 (TX-100), anionic sodium dodecyl sulfate (SDS) and cationic dodecyl trimethylammonium bromide (DTAB) surfactants. The influence of changes in the surfactant concentration on the observed rate constant was investigated. The results are treated quantitatively by pseudophase ion-exchange (PPIE) model and a new simple model called "classical model". The binding constants of BPB molecules to the micelles and free molecules of surfactants, their stoichiometric ratios and thermodynamic parameters of binding have been evaluated. It was found that SDS has nearly no effect on the fading rate up to 10 mM, whereas TX-100 and DTAB interact with BPB which reduce the reaction rate. By the use of fading reaction of BPB, the binding constants of SDS molecules to TX-100 micelles and their Langmuir and Freundlich adsorption isotherms were obtained and when mixtures of DTAB and TX-100 were used, no interaction was observed between these two surfactants.

Estimating the Region of Attraction via collocation for autonomous nonlinear systems

M. Rezaiee-Pajand,B. Moghaddasie 국제구조공학회 2012 Structural Engineering and Mechanics, An Int'l Jou Vol.41 No.2

This paper aims to propose a computational technique for estimating the region of attraction (RoA) for autonomous nonlinear systems. To achieve this, the collocation method is applied to approximate the Lyapunov function by satisfying the modified Zubov’s partial differential equation around asymptotically stable equilibrium points. This method is formulated for n-scalar differential equations with two classes of basis functions. In order to show the efficiency of the suggested approach, some numerical examples are solved. Moreover, the estimated regions of attraction are compared with two similar methods. In most cases, the proposed scheme can estimate the region of attraction more efficient than the other techniques.

Study of Kinetics of Bromophenol Blue Fading in the Presence of SDS, DTAB and Triton X-100 by Classical Model

Babak Samiey*,Kamal Alizadeh,Mohammad Ali Moghaddasi,Mir Fazlolah Mousavi,Nader Alizadeh 대한화학회 2004 Bulletin of the Korean Chemical Society Vol.25 No.5

Effects of discontinuous submerged breakwater on water surface elevation

Ketabdari, Mohammad J.,lamouki, Mohammad Barzegar Paiin,Moghaddasi, Alireza Techno-Press 2015 Ocean systems engineering Vol.5 No.4

Submerged breakwaters are used to prevent shore line erosion and sediment transportation. One of their advantages is low visual impact. In this paper, the effects of discontinuous submerged breakwaters over water surface elevation was numerically studied considering the extended Boussinesq equations as governing equations using MIKE21 software. The result of discontinuous breakwater was compared with a beach without breakwater. The results showed that the gap dramatically effects on surface elevation from shore line to offshore. It is also evident from results that with approaching the center of the gap, fluctuation of surface elevation is generated. It is because of passing longshore currents towards offshore through the gap which leads to an increase in sediment transportation rate. Nevertheless, transferring water mass from breakwater gap results in powerful rip currents leading to high changes on longshore wave profile.

Pharmacy Information Systems in Teaching Hospitals: A Multi-dimensional Evaluation Study

Alireza Kazemi,Reza Rabiei,Hamid Moghaddasi,Ghasem Deimazar 대한의료정보학회 2016 Healthcare Informatics Research Vol.22 No.3

Objectives: In hospitals, the pharmacy information system (PIS) is usually a sub-system of the hospital information system (HIS). The PIS supports the distribution and management of drugs, shows drug and medical device inventory, and facilitates preparing needed reports. In this study, pharmacy information systems implemented in general teaching hospitals affiliated to medical universities in Tehran (Iran) were evaluated using a multi-dimensional tool. Methods: This was an evaluation study conducted in 2015. To collect data, a checklist was developed by reviewing the relevant literature; this checklist included both general and specific criteria to evaluate pharmacy information systems. The checklist was then validated by medical informatics experts and pharmacists. The sample of the study included five PIS in general-teaching hospitals affiliated to three medical universities in Tehran (Iran). Data were collected using the checklist and through observing the systems. The findings were presented as tables. Results: Five PIS were evaluated in the five general-teaching hospitals that had the highest bed numbers. The findings showed that the evaluated pharmacy information systems lacked some important general and specific criteria. Among the general evaluation criteria, it was found that only two of the PIS studied were capable of restricting repeated attempts made for unauthorized access to the systems. With respect to the specific evaluation criteria, no attention was paid to the patient safety aspect. Conclusions: The PIS studied were mainly designed to support financial tasks; little attention was paid to clinical and patient safety features.