Nanoporous graphene oxide membrane and its application in molecular sieving

S. Mahmood Fatemi,Masoud Arabieh,Hamid Sepehrian 한국탄소학회 2015 Carbon Letters Vol.16 No.3

Gas transport through graphene-derived membranes has gained much interest recently due to its promising potential in filtration and separation applications. In this work, we explore Kr-85 gas radionuclide sequestration from natural air in nanoporous graphene oxide membranes in which different sizes and geometries of pores were modeled on the graphene oxide sheet. This was done using atomistic simulations considering mean-squared displacement, diffusion coefficient, number of crossed species of gases through nanoporous graphene oxide, and flow through interlayer galleries. The results showed that the gas features have the densest adsorbed zone in nanoporous graphene oxide, compared with a graphene membrane, and that graphene oxide was more favorable than graphene for Kr separation. The aim of this paper is to show that for the well-defined pore size called P-7, it is possible to separate Kr-85 from a gas mixture containing Kr-85, O2 and N2. The results would benefit the oil industry among others.

Role of Computerized Physician Order Entry Usability in the Reduction of Prescribing Errors

Hamid Reza Peikari,Mohamad Shanudin Zakaria,Norjaya M. Yasin,Mahmood Hussain Shah,Abdelbary Elhissi 대한의료정보학회 2013 Healthcare Informatics Research Vol.19 No.2

Objectives: Some hospitals have implemented computerized physician order entry (CPOE) systems to reduce the medical error rates. However, research in this area has been very limited, especially regarding the impact of CPOE use on the reduction of prescribing errors. Moreover, the past studies have dealt with the overall impact of CPOE on the reduction of broadly termed “medical errors”, and they have not specified which medical errors have been reduced by CPOE. Furthermore, the majority of the past research in this field has been either qualitative or has not used robust empirical techniques. This research examined the impacts of usability of CPOE systems on the reduction of doctors’ prescribing errors. Methods: One hundred and sixty-six questionnaires were used for quantitative data analyses. Since the data was not normally distributed, partial least square path modelling−as the second generation of multivariate data analyses−was applied to analyze data. Results: It was found that the ease of use of the system and information quality can significantly reduce prescribing errors. Moreover, the user interface consistency and system error prevention have a significant positive impact on the perceived ease of use. More than 50% of the respondents believed that CPOE reduces the likelihood of drug allergy, drug interaction, and drug dosing errors thus improving patient safety. Conclusions: Prescribing errors in terms of drug allergy, drug interaction, and drug dosing errors are reduced if the CPOE is not error-prone and easy to use, if the user interface is consistent, and if it provides quality information to doctors.

Clinicohematological parameters and outcomes in a cohort of chronic lymphocytic leukemia patients with Deletion 17p from Pakistan

Rafia Mahmood,Saleem Ahmed Khan,Chaudhry Altaf,Hamid Saeed Malik,Muhammad Tahir Khadim 대한혈액학회 2018 Blood Research Vol.53 No.4

BackgroundChronic lymphocytic leukemia (CLL) exhibits profound heterogeneity in its clinical course. Its clinicohematological and cytogenetic features play a significant role in de-termining the clinical course and in predicting the treatment response and prognosis. In this context, 17p deletion is known to predict a poor prognosis, as these cases are re-fractory to conventional therapy. This study aimed to evaluate the clinicohematological characteristics, outcomes, and prognostic factors among CLL patients with and without del 17p in Pakistan.MethodsThis prospective observational study was conducted at the Department of Haematology, Armed Forces Institute of Pathology (Rawalpindi, Pakistan) between January 2013 and December 2017. Patients were diagnosed based on the International Workshop on Chronic Lymphocytic Leukaemia IWCLL criteria, their clinicohematological parameters were recorded, and cytogenetic analyses were performed. The time from diagnosis to treatment and the 2-year overall survival rate were also evaluated.ResultsWe evaluated 130 CLL cases, including 24 patients (18.5%) with del 17p, who included 18 men (75%) and 6 women (25%). The median age was 68 years. Binet stage C was de-tected at the presentation in 16 patients (67%). Treatment was administered to 14 patients (70%) at a median interval of 11 months (range, 0‒28 mo) after diagnosis. The overall response rate was 64.3%, the median event-free survival was 9 months (range, 1‒23 mo), and the 2-year overall survival rate was 65%.ConclusionDel 17p is relatively common in Pakistan, and patients harboring this deletion had poor treatment response and survival outcomes.

Dynamic bending analysis of laminated porous concrete beam reinforced by nanoparticles considering porosity effects

Mohammad Karegar,Mahmood Rabani Bidgoli,Hamid Mazaheri 국제구조공학회 2022 Steel and Composite Structures, An International J Vol.43 No.1

Dynamic response of a laminated porous concrete beam reinforced by nanoparticles subjected to harmonic transverse dynamic load is investigated considering structural damping. The effective nanocomposite properties are evaluated on the basis of Mori-Tanaka model. The concrete beam is modeled by the sinusoidal shear deformation theory (SSDT). Utilizing nonlinear strains-deflection, energy relations and Hamilton's principal, the governing final equations of the concrete laminated beam are calculated. Utilizing differential quadrature method (DQM) as well as Newmark method, the dynamic displacement of the concrete laminated beam is discussed. The influences of porosity parameter, nanoparticles volume percent, agglomeration of nanoparticles, boundary condition, geometrical parameters of the concrete beam and harmonic transverse dynamic load are studied on the dynamic displacement of the laminated structure. Results indicated that enhancing the nanoparticles volume percent leads to decrease in the dynamic displacement about 63%. In addition, with considering porosity of the concrete, the dynamic displacement enhances about 2.8 time.

A Review Study for Creep in Different Nanocomposites

Vahid Monfared,Hamid Reza Bakhsheshi‑Rad,Mahmood Razzaghi,D. Toghraie,Maboud Hekmatifar,Filippo Berto 대한금속·재료학회 2023 METALS AND MATERIALS International Vol.29 No.9

This article presents a brief review regarding the creep behavior (CB) of the nanocomposites (NCs)-based materials in recentyears. The creep (C) in solids under high stress (HS) and temperature (T) is one of the processes of interest to researchersin the industry. Investigating the time-dependent plastic deformation (PD) of NCs is vital in modern sciences. The C studywould be crucial for elevated T and high stresses applications. (e.g., turbine blades, spaceships, shuttles, and nozzle guidevanes). In addition, a comparatively detailed review of the C of metal-based NCs, particularly magnesium (Mg) based ones,has been presented. Mg and its alloys have recently fascinated much interest in replacing existing structural materials invarious applications because of their outstanding properties like good damping capability, high specific strength, and goodmachinability. However, their use is limited because of their low Creep resistance at high Ts. Encapsulation of nanoparticles(NPs) is one efficient way to better the creep resistance of Mg-based NCs. Movement of dislocation can be hindered by NPs,which act as barriers to dislocations.

Seismic response of NFRP reinforced RC frame with shape memory alloy components

Varkani, Mohamad Motalebi,Bidgoli, Mahmood Rabani,Mazaheri, Hamid Techno-Press 2022 Advances in nano research Vol.13 No.3

Creation of plastic deformation under seismic loads, is one of the most serious subjects in RC structures with steel bars which reduces the life threatening risks and increases dissipation of energy. Shape memory alloy (SMA) is one of the best choice for the relocating plastic hinges. In a challenge to study the seismic response of concrete moment resisting frame (MRF), this article investigates numerically a new type of concrete frames with nano fiber reinforced polymer (NFRP) and shape memory alloy (SMA) hinges, simultaneously. The NFRP layer is containing carbon nanofibers with agglomeration based on Mori-Tanaka model. The tangential shear deformation (TASDT) is applied for modelling of the structure and the continuity boundary conditions are used for coupling of the motion equations. In SMA connections between beam and columns, since there is phase transformation, hence, the motion equations of the structure are coupled with kinetic equations of phase transformation. The Hernandez-Lagoudas theory is applied for demonstrating of pseudoelastic characteristics of SMA. The corresponding motion equations are solved by differential cubature (DC) and Newmark methods in order to obtain the peak ground acceleration (PGA) and residual drift ratio for MRF-2%. The main impact of this paper is to present the influences of the volume percent and agglomeration of nanofibers, thickness and length of the concrete frame, SMA material and NFRP layer on the PGA and drift ratio. The numerical results revealed that the with increasing the volume percent of nanofibers, the PGA is enhanced and the residual drift ratio is reduced. It is also worth to mention that PGA of concrete frame with NFRP layer containing 2% nanofibers is approximately equal to the concrete frame with steel bars.

Understanding the Nexus between Conflict, Displacement, and Schooling: A Case Study of IDPs in Pakistan

( Anayat Ullah ),( Karim Khan ),( Hamid Mahmood ) 서울대학교 통일평화연구원 2017 Asian Journal of Peacebuilding Vol.5 No.1

More than fifteen years of intense internal armed conflict has made Pakistan home to one of the largest populations of internally displaced persons (IDPs). This article investigates the impact of conflict on socioeconomic well-being through measuring changes in post conflict levels of schooling, livelihood, and income, and also seeks to understand the challenges faced by IDPs from the Federally Administered Tribal Areas located in Jalozai Camp, Khyber Punkhtoonkhwa (KP). The results of a survey analysis indicate significant gaps in educational attainment due to displacement and this impacts socioeconomic well-being.

Dynamic analysis by impact load in viscoelastic sandwich plates with FRP layer utilizing numerical method

Mohammad Reza Bayati,Hamid Mazaheri,Mahmood Rabani Bidgoli 국제구조공학회 2022 Steel and Composite Structures, An International J Vol.43 No.2

The main objective of this work is presenting a mathematical model for the concrete slab with fiber reinforced polymer (FRP) layer under the impact load. Impacts are assumed to occur normally over the top slab and the interaction between the impactor and the structure is simulated using a new equivalent three-degree-of-freedom (TDOF) spring–mass–damper (SMD) model. The structure is assumed viscoelastic based on Kelvin-Voigt model. Based on the sinusoidal shear deformation theory (SSDT), energy method and Hamilton’s principle, the motion equations are derived. Applying DQM, the dynamic deflection and contact force of the structure is calculated numerically so that the effects of mass, velocity and height of impactor, boundary conditions, FRP layer, structural damping and geometrical parameters of structure are shown on the dynamic deflection and contact force of system. Results show that considering structural damping leads to lower dynamic deflection and contact force. In addition, increasing the impact velocity of impactor yields to increases in the maximum contact force and deflection while the contact duration is decreased. The result shows that the contact force and the central deflection of the structure decreases and the contact time decreases with assuming FRP layer.

Seismic analysis and optimization of concrete bridge under the moving train utilizing numerical methods and adaptive improved harmony search algorithm

Kalashemi Sajad Haghdadi,Bidgoli Mahmood Rabani,Mazaheri Hamid 한국CDE학회 2022 Journal of computational design and engineering Vol.9 No.3

In this paper, the simultaneous actions of moving force and seismic load on the dynamic displacement and optimization of the concrete bridge are studied. The sinusoidal shear deformation beam theory is employed for the modelling of the concrete bridge mathematically. The structural damping of the concrete bridge is assumed by the Kelvin–Voigt theory. Utilizing the method of energy and Hamilton’s law, the equations of motion are obtained. Three mixed numerical methods, including the integral quadrature, harmonic differential quadrature method, and Newmark technique, are presented for the numerical outcomes of the differential equations. Utilizing adaptive improved harmony search, improved harmony search, harmony search, and global harmony search algorithms, the optimization process of the concrete bridge is examined. The mentioned algorithm is improved adaptively by utilizing dynamic deflection. The harmony memory is corrected at first and second adjustments, respectively, based on emotional bandwidth and step size randomly. The optimum conditions of the concrete bridge are evaluated with various harmony existing search methods. The role of multiple parameters, including the velocity and acceleration of moving load, length and thickness of bridge, boundary conditions, and the amplitude of carrying load, in the dynamic displacement of the bridge is studied. The numerical results indicate that with increasing the velocity and acceleration of the moving train, the dynamic displacement of the concrete bridge increases. In addition, with increasing the length of the bridge, the time of maximum deflection (i.e. when the train is in the middle of the bridge) is increased. It is concluded for the concrete bridge under the seismic load that the optimum values of the bridge’s length and thickness are decreased (about 24%) and increased (about 21%), respectively. The optimum values of amplitude, velocity, and acceleration of moving train are decreased, respectively, about 34%, 33%, and 29% in the case of the concrete bridge under the earthquake load. In addition, the optimum length of the concrete bridge is decreased significantly, with increasing the moving load amplitude, velocity, and acceleration.

Dynamic analysis of quadrilateral concrete foundation integrated with NFRP layers based on numerical method

Mahjoobi, Mahdi,Bidgoli, Mahmood Rabani,Mazaheri, Hamid Techno-Press 2021 Advances in nano research Vol.11 No.5

Mathematical modelling of quadrilateral concrete foundation is a novel topic in the literature. In this paper, dynamic response of quadrilateral concrete foundation resting on soil medium subjected to blast load is presented for the first time. The concrete foundation is covered by nano-fiber reinforced polymer (NFRP) layers at the top and bottom surfaces for improving the stiffness. The NFRP are containing carbon nano-fibers (CNF) and its equivalent material characteristics are calculated by Mori-Tanaka model incorporating the agglomeration effects. On the basis of Sinusoidal shear deformation theory (SSDT) and Hamilton's principle, the motion final equations are obtained assuming structural damping utilizing Kelvin-Voigt model. The dynamic deflection of the quadrilateral concrete foundation is discussed based on transformed weighing (TW) coefficients-differential quadrature method (DQM) in conjunction with Newmark method. The influences of different parameters of soil foundation, blast load, volume fraction and agglomeration of CNFs, structural damping, NFRP layer, geometrical parameters and side angles of the quadrilateral concrete foundation are shown on the dynamic displacement. The results are compared with other published works in the literature for presenting the accuracy of the applied model and method. The outcomes show that the dynamic defection will be reduced with enhancing the CNFs volume fraction. In addition, with with increasing the side angle of quadrilateral plate, the dynamic deflection is increased.