Assessment the Effect of Skewness and Number of Spans in Seismic Behavior of Bridges with Continuous Multiple Spans Using MPA

S. M. Rasouli,M. Mahmoodi 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.4

The seismic behavior of skewed bridges compared to straight bridges is not well recognized and need more study to investigate itsunique behavior under seismic forces. Much more damage have seen from skewed bridges particularly when its deck rotates in theearthquake. Many causes are involved in this behavior such as columns and piers nonlinear deformation patterns. Through a ModalPushover Analysis (MPA) we will assess the inelastic seismic behavior of reinforced concrete bridges those have skew-angled seattypeabutments. The angle of skewness will change the seismic behavior of this kind of bridges and in this paper this change isexplored with special attention. Maximum nonlinear displacement is sensitive to increase the number of spans and the skew angle ofabutments and piers, but the amount of effects are up to number of spans and angle of skewness. This study showed that as thenumber of spans increases, the deck rotation responses at abutments will be deducted and the adverse effect of skew would subtractedin the bridge.

ON THE EXISTENCE OF POSITIVE SOLUTION FOR A CLASS OF NONLINEAR ELLIPTIC SYSTEM WITH MULTIPLE PARAMETERS AND SINGULAR WEIGHTS

Rasouli, S.H. Korean Mathematical Society 2012 대한수학회논문집 Vol.27 No.3

This study concerns the existence of positive solution for the following nonlinear system $$\{-div(|x|^{-ap}|{\nabla}u|^{p-2}{\nabla}u)=|x|^{-(a+1)p+c_1}({\alpha}_1f(v)+{\beta}_1h(u)),x{\in}{\Omega},\\-div(|x|^{-bq}|{\nabla}v|q^{-2}{\nabla}v)=|x|^{-(b+1)q+c_2}({\alpha}_2g(u)+{\beta}_2k(v)),x{\in}{\Omega},\\u=v=0,x{\in}{\partial}{\Omega}$$, where ${\Omega}$ is a bounded smooth domain of $\mathbb{R}^N$ with $0{\in}{\Omega}$, 1 < $p,q$ < N, $0{{\leq}}a<\frac{N-p}{p}$, $0{{\leq}}b<\frac{N-q}{q}$ and $c_1$, $c_2$, ${\alpha}_1$, ${\alpha}_2$, ${\beta}_1$, ${\beta}_2$ are positive parameters. Here $f,g,h,k$ : $[0,{\infty}){\rightarrow}[0,{\infty})$ are nondecresing continuous functions and $$\lim_{s{\rightarrow}{\infty}}\frac{f(Ag(s)^{\frac{1}{q-1}})}{s^{p-1}}=0$$ for every A > 0. We discuss the existence of positive solution when $f,g,h$ and $k$ satisfy certain additional conditions. We use the method of sub-super solutions to establish our results.

Does mudcake change the results of modeling gamma-gamma well-logging?

Rasouli Fatemeh S. 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.9

Among the different techniques available, nuclear methods, including gamma-gamma logging tools, are of special importance. Though the real environment which surrounds the drilled borehole is a complex fractured medium which the fluid can flow through the porosities, simulation studies generally use the traditional model of a homogeneous mixture of formation and the liquid. Considering a previously published study, which shows that modeling of fluid flow in fractured reservoirs and simulating the formation as an inhomogeneous fractured medium leads to different results compared with those of homogeneous mixture, here we study the effect of the presence of drilling fluid (mudcake) on the response of the detectors in both the models. To study this effect, a typical gamma-gamma logging tool was modeled by using the MCNPX Monte Carlo code. The results show that the responses of the detectors in the mixture model in the presence of various thicknesses of mudcake are sensitive to the density of the formation material. However, this effect is not notable in the inhomogeneous fractured medium. These results emphasize the importance of the model employed for simulation of the medium in gamma-gamma well-logging.

A comparison study between the realistic random modeling and simplified porous medium for gamma-gamma well-logging

Rasouli Fatemeh S. 한국원자력학회 2024 Nuclear Engineering and Technology Vol.56 No.5

The accurate determination of formation density and the physical properties of rocks is the most critical logging tasks which can be obtained using gamma-ray transport and detection tools. Though the simulation works published so far have considerably improved the knowledge of the parameters that govern the responses of the detectors in these tools, recent studies have found considerable differences between the results of using a conventional model of a homogeneous mixture of formation and fluid and an inhomogeneous fractured medium. It has increased concerns about the importance of the complexity of the model used for the medium in simulation works. In the present study, we have suggested two various models for the flow of the fluid in porous media and fractured rock to be used for logging purposes. For a typical gamma-gamma logging tool containing a137Cs source and two NaI detectors, simulated by using the MCNPX code, a simplified porous (SP) model in which the formation is filled with elongated rectangular cubes loaded with either mineral material or oil was investigated. In this model, the oil directly reaches the top of the medium and the connection between the pores is not guaranteed. In the other model, the medium is a large 3-D matrix of 1 cm3 randomly filled cubes. The designed algorithm to fill the matrix sites is so that this realistic random (RR) model provides the continuum growth of oil flow in various disordered directions and, therefore, fulfills the concerns about modeling the rock textures consist of extremely complex pore structures. For an arbitrary set of oil concentrations and various formation materials, the response of the detectors in the logging tool has been considered as a criterion to assess the effect of modeling for the distribution of pores in the formation on simulation studies. The results show that defining a RR model for describing heterogeneities of a porous medium does not effectively improve the prediction of the responses of logging tools. Taking into account the computational cost of the particle transport in the complex geometries in the Monte Carlo method, the SP model can be satisfactory for gamma-gamma logging purposes.

Anesthesia for the patient with a recently diagnosed concussion: think about the brain!

Mohammed R. Rasouli,Michelle Kavin,Stephen Stache,Michael E. Mahla,Eric S. Schwenk 대한마취통증의학회 2020 Korean Journal of Anesthesiology Vol.73 No.1

Some patients require emergent, urgent, or elective surgery in the time period immediately following diagnosis of concussion. However, changes in brain homeostatic mechanisms following a concussion and concern for secondary brain injury can complicate the decision as to whether or not a surgery should proceed or be postponed. Given the paucity of available evidence, further evaluation of the use of anesthesia in a patient with concussion is warranted. This article summarizes what is currently known about the relevant pathophysiology of concussion, intraoperative anesthesia considerations, and effects of anesthesia on concussion outcomes in an attempt to help providers understand the risks that may accompany surgery and anesthesia in this patient population. While most contraindications to the use of anesthesia in concussed patients are relative, there are nonetheless pathophysiologic changes associated with a concussion that can increase risk of its use. Understanding these changes and anesthetic implications can help providers optimize outcomes in this patient population.

A novel approach to the synthesis of a wide range of ink jet printer pigment from yellow to magenta for tiles via gold nanoparticles

Sh. Saket,S. Rasouli,A. M. Arabi,M.A. Faghihi Sani 한양대학교 세라믹연구소 2016 Journal of Ceramic Processing Research Vol.17 No.3

In this study, synthesis of Au and Au/Ag nano-pigments has been investigated. The results showed that pH controlling agents(PCAs) (NH4OH or NaOH) play an important role on the physical properties of Au/Ag nano-pigments and inks. X-raydiffraction (XRD) patterns indicated that pure metallic phase is formed by NH4OH PCAs. Morphological studies revealed theformation of nanometric spherical particles. The smallest size is belonged to Au particles prepared by NH4OH PCA. Becauseof the comparable hue and saturation of synthesized metallic pigments to the commercial inks, the obtained samples have beenintroduced as a suitable candidate for ceramic ink jet printing for tiles.