Effect of motion-graphic video-based training on the performance of operating room nurse students in cataract surgery in Iran: a randomized controlled study

Behnaz Fatahi,Samira Fatahi,Sohrab Nosrati,Masood Bagheri 한국보건의료인국가시험원 2023 보건의료교육평가 Vol.20 No.-

Purpose The present study was conducted to determine the effect of motion-graphic video-based training on the performance of operating room nurse students in cataract surgery using phacoemulsification at Kermanshah University of Medical Sciences in Iran. Methods This was a randomized controlled study conducted among 36 students training to become operating room nurses. The control group only received routine training, and the intervention group received motion-graphic video-based training on the scrub nurse’s performance in cataract surgery in addition to the educator’s training. The performance of the students in both groups as scrub nurses was measured through a researcher-made checklist in a pre-test and a post-test. Results The mean scores for performance in the pre-test and post-test were 17.83 and 26.44 in the control group and 18.33 and 50.94 in the intervention group, respectively, and a significant difference was identified between the mean scores of the pre- and post-test in both groups (P=0.001). The intervention also led to a significant increase in the mean performance score in the intervention group compared to the control group (P=0.001). Conclusion Considering the significant difference in the performance score of the intervention group compared to the control group, motion-graphic video-based training had a positive effect on the performance of operating room nurse students, and such training can be used to improve clinical training.

Performance of laterally loaded piles considering soil and interface parameters

Fatahi, Behzad,Basack, Sudip,Ryan, Patrick,Zhou, Wan-Huan,Khabbaz, Hadi Techno-Press 2014 Geomechanics & engineering Vol.7 No.5

To investigate the soil-pile interactive performance under lateral loads, a set of laboratory model tests was conducted on remoulded test bed of soft clay and medium dense sand. Then, a simplified boundary element analysis had been carried out assuming floating pile. In case of soft clay, it has been observed that lateral loads on piles can initiate the formation of a gap, soil heave and the tension crack in the vicinity of the soil surface and the interface, whereas in medium dense sand, a semi-elliptical depression zone can develop. Comparison of test and boundary element results indicates the accuracy of the solution developed. However, in the boundary element analysis, the possible shear stresses likely to be developed at the interface are ignored in order to simplify the existing complex equations. Moreover, it is unable to capture the influence of base restraint in case of a socketed pile. To bridge up this gap and to study the influence of the initial stress state and interface parameters, a field based case-study of laterally-loaded pile in layered soil with socketed tip is explored and modelled using the finite element method. The results of the model have been verified against known field measurements from a case-study. Parametric studies have been conducted to investigate the influence of the coefficient of lateral earth pressure and the interface strength reduction factor on the results of the model.

Soil-structure interaction vs Site effect for seismic design of tall buildings on soft soil

Fatahi, Behzad,Tabatabaiefar, S. Hamid Reza,Samali, Bijan Techno-Press 2014 Geomechanics & engineering Vol.6 No.3

In this study, in order to evaluate adequacy of considering local site effect, excluding soil-structure interaction (SSI) effects in inelastic dynamic analysis and design of mid-rise moment resisting building frames, three structural models including 5, 10, and 15 storey buildings are simulated in conjunction with two soil types with the shear wave velocities less than 600 m/s, representing soil classes $D_e$ and $E_e$ according to the classification of AS1170.4-2007 (Earthquake actions in Australia) having 30 m bedrock depth. Structural sections of the selected frames were designed according to AS3600:2009 (Australian Standard for Concrete Structures) after undertaking inelastic dynamic analysis under the influence of four different earthquake ground motions. Then the above mentioned frames were analysed under three different boundary conditions: (i) fixed base under direct influence of earthquake records; (ii) fixed base considering local site effect modifying the earthquake record only; and (iii) flexible-base (considering full soil-structure interaction). The results of the analyses in terms of base shears and structural drifts for the above mentioned boundary conditions are compared and discussed. It is concluded that the conventional inelastic design procedure by only including the local site effect excluding SSI cannot adequately guarantee the structural safety for mid-rise moment resisting buildings higher than 5 storeys resting on soft soil deposits.

φ-prime Subsemimodules of Semimodules over Commutative Semirings

Fatemeh Fatahi,Reza Safakish 경북대학교 자연과학대학 수학과 2020 Kyungpook mathematical journal Vol.60 No.3

Let R be a commutative semiring with identity and M be a unitary Rsemimodule.Let φ : S(M) →S(M) ∪ {∅} be a function, where S(M) is the set of all subsemimodules of M. A proper subsemimodule N of M is called φ-prime subsemimodule, if r ∈ R and x ∈ M with rx ∈ N \φ(N) implies that r ∈ (N :R M) or x ∈ N. So if we take φ(N) = ∅ (resp., φ(N) = {0}), a φ-prime subsemimodule is prime (resp., weakly prime). In this article we study the properties of several generalizations of prime subsemimodules.

Characterization of Some Iranians and Foreign Walnut Genotypes Using Morphological Traits and RAPD Markers

Reza Fatahi,Aziz Ebrahimi,Zabihollah Zamani 한국원예학회 2010 Horticulture, Environment, and Biotechnology Vol.51 No.1

Walnut, (Juglans regia), is one of the most important nutritive nut crops. Iran is considered as one of the centers for diversity and cultivation of walnut in middle-eastern part of the world. In this study, some morphological traits in combination with polymorphic RAPD primers were applied to evaluate genetic potential of 35 (31 Iranian and four foreign) walnut genotypes. From 14 RAPD primers, 180 DNA bands were amplified among which 174 were highly polymorphic. The lowest and the highest pair-wise similarity coefficients between examined genotypes were 0.27 and 0.89, respectively. Estimated resolving power index (Rp) were from 2.17 (opAD16) to 8.40 (opAA19) and total resolving power (Rp) 70.61 in all 14 RAPD loci. Cluster analysis based on Jaccard's similarity coefficients and UPGMA method divided the genotypes into five groups at similarity of 0.50, which the main group consisted of 31 genotypes including 4 foreign cultivars. Genetic variation among locations took 9.48% of the total genetic variation detected with Analysis of molecular variances (AMOVA) (p<0.001). Most Iranian genotypes grouped closely with foreign cultivars and showed high similarities indicating their close genetic relatedness. RAPD markers showed to be an efficient technique for studying genetic diversity of walnut genotypes. These genotypes with different genetic bases and suitable horticultural traits seem to be good candidates applicable for direct use as vegetatively propagated material or as parents in walnut improvement programs.

Fabrication and Optimal Design of a Mechanical Piezoelectric Energy Harvester with Re-entrant Honeycomb Substrate for Maximizing Voltage Output

Mohamad Hossein Fatahi,Mohsen Hamedi,Majid Safarabadi 한국정밀공학회 2024 International Journal of Precision Engineering and Vol.25 No.2

The low specific power of mechanical energy harvesters is the biggest shortcoming prevents these harvesters from becoming a viable replacement for batteries used in monitoring structures. In this paper, increasing the output voltage of the mechanically excited piezoelectric harvester beams was investigated. A composite beam consisting of an auxetic honeycomb, skin, piezo layer and end mass was optimally designed and subjected to base excitation. Two samples with homogenous and honeycomb substrates were fabricated and tested. The measured natural frequencies showed good agreement with the FE model results with 7% average error. The equivalent properties of the honeycomb were extracted and verified and formed a homogenous orthotropic layer. Geometry of honeycomb and beam was considered for the optimization process. The length of the beam, as an input parameter, was used in an inner loop inside the optimization cycle to set the natural frequency near 50 Hz. Measuring the performance of the two beams with the same size of the piezoelectric layer showed that auxetic honeycomb substrate improves the open-circuit voltage above 25% and the specific voltage above 30% compared with the simple substrate.

Numerical analysis of vertical drains accelerated consolidation considering combined soil disturbance and visco-plastic behaviour

Azari, Babak,Fatahi, Behzad,Khabbaz, Hadi Techno-Press 2015 Geomechanics & engineering Vol.8 No.2

Soil disturbance induced by installation of mandrel driven vertical drains decreases the in situ horizontal hydraulic conductivity of the soil in the vicinity of the drains, decelerating the consolidation rate. According to available literature, several different profiles for the hydraulic conductivity variation with the radial distance from the vertical drain, influencing the excess pore water pressure dissipation rate, have been identified. In addition, it is well known that the visco-plastic properties of the soil also influence the excess pore water pressure dissipation rate and consequently the settlement rate. In this study, a numerical solution adopting an elastic visco-plastic model with nonlinear creep function incorporated in the consolidation equations has been developed to investigate the effects of disturbed zone properties on the time dependent behaviour of soft soil deposits improved with vertical drains and preloading. The employed elastic visco-plastic model is based on the framework of the modified Cam-Clay model capturing soil creep during excess pore water pressure dissipation. Besides, nonlinear variations of creep coefficient with stress and time and permeability variations during the consolidation process are considered. The predicted results have been compared with V$\ddot{a}$sby test fill measurements. According to the results, different variations of the hydraulic conductivity profile in the disturbed zone result in varying excess pore water pressure dissipation rate and consequently varying the effective vertical stresses in the soil profile. Thus, the creep coefficient and the creep strain limit are notably influenced resulting in significant changes in the predicted settlement rate.

Stability assessment of tunnel face in a layered soil using upper bound theorem of limit analysis

Khezri, Nima,Mohamad, Hisham,Fatahi, Behzad Techno-Press 2016 Geomechanics & engineering Vol.11 No.4

Underground tunnelling is one of the sustainable construction methods which can facilitate the increasing passenger transportation in the urban areas and benefit the community in the long term. Tunnelling in various ground conditions requires careful consideration of the stability factor. This paper investigates three dimensional stability of a shallow circular tunnel in a layered soil. Upper bound theorem of limit analysis was utilised to solve the tunnel face stability problem. A three dimensional kinematic admissible failure mechanism was improved to model a layered soil and limiting assumptions of the previous studies were resolved. The study includes calculation of the minimum support pressure acting on the face of the excavation in closed-face excavations. The effects of the characteristics of the layers on the minimum support pressure were examined. It was found that the ratio of the thickness of cover layers particularly when a weak layer is overlying a stronger layer, has the most significant influence on the minimum tunnel support pressure. Comparisons have been made with the results of the numerical modelling using FLAC3D software. Results of the current study were in a remarkable agreement with those of numerical modelling.

Analyzing consolidation data to obtain elastic viscoplastic parameters of clay

Le, Thu M.,Fatahi, Behzad,Disfani, Mahdi,Khabbaz, Hadi Techno-Press 2015 Geomechanics & engineering Vol.8 No.4

A nonlinear creep function incorporated into the elastic visco-plastic model may describe the long-term soil deformation more accurately. However, by applying the conventional procedure, there are challenges to determine the model parameters due to limitation of suitable data points. This paper presents a numerical solution to obtain several parameters simultaneously for a nonlinear elastic visco-plastic (EVP) model using the available consolidation data. The finite difference scheme using the Crank-Nicolson procedure is applied to solve a set of coupled partial differential equations of the time dependent strain and pore water pressure dissipation. The model parameters are determined by applying the algorithm of trust-region reflective optimisation in conjunction with the finite difference solution. The proposed method utilises all available consolidation data during dissipation of the excess pore water pressure to determine the required model parameters. Moreover, the reference time in the elastic visco-plastic model can readily be adopted as a unit of time; denoting creep is included in the numerical predictions explicitly from the very first time steps. In this paper, the settlement predictions of thick soft clay layers are presented and discussed to evaluate and compare the accuracy and reliability of the proposed method against the graphical procedure to obtain the model parameters. In addition, comparison of the available experimental results to the numerical predictions confirms the accuracy of the numerical procedure.

Lateral seismic response of building frames considering dynamic soil-structure interaction effects

S. Hamid RezaTabatabaiefar,Behzad Fatahi,Bijan Samali 국제구조공학회 2013 Structural Engineering and Mechanics, An Int'l Jou Vol.45 No.3

In this study, to have a better judgment on the structural performance, the effects of dynamic Soil-Structure Interaction (SSI) on seismic behaviour and lateral structural response of mid-rise moment resisting building frames are studied using Finite Difference Method. Three types of mid-rise structures,including 5, 10, and 15 storey buildings are selected in conjunction with three soil types with the shear wave velocities less than 600m/s, representing soil classes Ce, De and Ee, according to Australian Standard AS 1170.4. The above mentioned frames have been analysed under two different boundary conditions: (i) fixed-base (no soil-structure interaction), and (ii) flexible-base (considering soil-structure interaction). The results of the analyses in terms of structural lateral displacements and drifts for the above mentioned boundary conditions have been compared and discussed. It is concluded that the dynamic soil-structure interaction plays a considerable role in seismic behaviour of mid-rise building frames including substantial increase in the lateral deflections and inter-storey drifts and changing the performance level of the structures from life safe to near collapse or total collapse. Thus, considering soil-structure interaction effects in the seismic design of mid-rise moment resisting building frames, particularly when resting on soft soil deposit, is essential.