Network numerical simulation of two-dimensional nonlinear micropolar hydrodynamics in a Darcian porous medium

Joaquin Zueco,Tong-Bou Chang,Osman Anwar Bég 한국화학공학회 2009 Korean Journal of Chemical Engineering Vol.26 No.5

The two-dimensional steady-state boundary layer flow of an incompressible micropolar fluid in a Darcian porous medium is studied theoretically and computationally. The governing parabolic partial differential equations are reduced to dimensionless form by using a set of transformations, under appropriate boundary conditions. A network simulation method (NSM) solution is presented. Translational velocities (U, V) are found to increase with a rise in Darcy number (Da) and to increase and decrease, respectively, with a rise in micropolar parameter (Er), i.e., Eringen number (ratio of micropolar vortex viscosity to Newtonian viscosity). Micro-rotation is increased with increasing Er and Da values. Translational velocity gradient, ∂U/∂Y and micro-rotation gradient, ∂Ω/∂Y both increase with Darcy number; however, they are both found to decrease with increasing micropolar parameter, Er. The present study finds applications in polymer flows in filtration systems, chemical engineering, biorheology of porous tissue and plastic sheet processing.

Dense mullite from attrition milled kyanite and α-alumina

Joaquin Aguilar-Santillan,Heberto Balmori-Ramirez,Richard C. Bradt 한양대학교 세라믹연구소 2007 Journal of Ceramic Processing Research Vol.8 No.1

Effects of attrition milling on the decomposition of kyanite (Al2SiO5) and its reaction with α-alumina (Al2O3) to form stoichiometric mullite (3Al2O3·2SiO2) are reported. Kyanite-alumina mixes were attrition milled for times from 1 h to 12 h. With increasing milling time, the kyanite decomposition was accelerated and secondary mullite formation from the reaction between the rejected silica and the added alumina was enhanced. Milling reduced the decomposition expansion from +15.0% to +0.1% and the final contraction or densification from +2.5% to −13.7%. During firing complete mullite formation occurred after firing at only 1623 K/1h (1350oC/1 h) to produce a dense mullite ceramic with a fine grain size (~1 μm). Effects of attrition milling on the decomposition of kyanite (Al2SiO5) and its reaction with α-alumina (Al2O3) to form stoichiometric mullite (3Al2O3·2SiO2) are reported. Kyanite-alumina mixes were attrition milled for times from 1 h to 12 h. With increasing milling time, the kyanite decomposition was accelerated and secondary mullite formation from the reaction between the rejected silica and the added alumina was enhanced. Milling reduced the decomposition expansion from +15.0% to +0.1% and the final contraction or densification from +2.5% to −13.7%. During firing complete mullite formation occurred after firing at only 1623 K/1h (1350oC/1 h) to produce a dense mullite ceramic with a fine grain size (~1 μm).

PHYSICAL PROPERTIES OF THE GIANT H II REGION G353.2+0.9 IN NGC 6357

JOAQUIN BOHIGAS,MIGUEL ROTH,MARIA TERESA RUIZ,MAURICIO TAPIA 한국천문학회 2004 Journal of The Korean Astronomical Society Vol.37 No.5

Optical imaging and spectroscopy of G353.2+0.9, the brightest part of the giant H II regionNGC 6357, shows that this H II region is optically thin, contains 300 M of ionized gas and isprobably expanding into the surrounding medium. Its chemical composition is similar to that found inother H II regions at similar galactocentric distances if temperature uctuations are signicant. Theinner regions are probably made of thin shells and laments, whereas extended slabs of material, maybeshells seen edge-on, are found in the periphery. The radio continuum and H-alpha emission maps are verysimilar, indicating that most of the optical nebula is not embedded in the denser regions traced bymolecular gas and the presence of IR sources. About 10^50 UV photons per second are required to pro-duce the H-beta flux from the 11.3'x10' region surrounding the Pis 24 cluster that is south of G353.2+0.9.Most of the energy powering this region is produced by the O3-7 stars in Pis 24. Most of the 2MASSsources in the eld with large infrared excesses are within G353.2+0.9, indicating that the most recentstar forming process occured within it. The formation of P is 24 preceded and caused the formation ofthis new generation of stars and may be responsible for the present-day morphology of the entire NGC6357 region.

Firm Location, Trade and Economic Integration

( Joaquin Andaluz ),( Agustin Gil ) 세종대학교 경제통합연구소 (구 세종대학교 국제경제연구소) 2002 Journal of Economic Integration Vol.17 No.4

The aim of this paper is to analyse how a process of economic integration between two adjacent countries with different transport costs (different levels of development) affects firms` decisions on location and prices. Considering the situation where one firm is located in each country and manufactures a product that is imported by the more developed country, we find that when there are barriers to trade one of the firms tends to locate on the common frontier and the other at the far extreme. By contrast, with full economic integration, both firms tend to maximise differentiation, locating themselves at the non-neighbouring extremes, which leads to higher prices and profits. Therefore, the firm located in the more developed country increases its market share.

SH 2-128, AN H II AND STAR FORMING REGION IN AN UNLIKELY PLACE

JOAQUIN BOHIGAS,MAURICIO TAPIA 한국천문학회 2004 Journal of The Korean Astronomical Society Vol.37 No.5

Near-infrared imaging photometry supplemented by optical spectroscopy and narrow-band imagingof the H II region Sh 2-128 and its environment are presented. This region contains a developed H II region and the neighboring compact H II region S 128N associated with a pair of water maser sources.Midway between these, the core of a CO cloud is located. The principal ionizing source of Sh 2-128 isan O7 star close to its center. A new spectroscopic distance of 9.4 kpc is derived, very similar to thekinematic distance to the nebula. This implies a galactocentric distance of 13.5 kpc and z = 550 pc.The region is optically thin with abundances close to those predicted by galactocentric gradients. TheJHKs images show that S 128N contains several infrared point sources and nebular emission knots withlarge near-infrared excesses. One of the three redKs knots coincides with the compact H I region.A few of the infrared-excess objects are close to known mid- and far-infrared emission peaks. Starcounts inJ and Ks show the presence of a small cluster of B-type stars, mainly associated with S 128N.The JHKs photometric properties together with the characteristics of the other objects in the vicinitysuggest that Sh 2-128 and S 128N constitute a single complex formed from the same molecular cloud,with ages 10^6 and < 3 10^5 years respectively. No molecular hydrogen emission was detected at2.12m. The origin of this remote star forming region is an open problem.

The Role of Glucose Potassium Ratio in Management of Traumatic Brain Injury

Joaquin Ignacio Marini,Matias Emmanuel Sein 대한신경손상학회 2023 Korean Journal of Neurotrauma Vol.19 No.1

Traumatic brain injury (TBI) has become a worldwide public health issue, raising concerns about which tool might be useful to guide initial management at hospital admission, especially to decide whether the patient would benefit from an opportune surgical intervention. Recently, the glucose-to-potassium ratio has more accurate predictive values than other biomarkers and is useful for its simplicity to obtain. To correlate each biomarker with the outcome for every patient with TBI.

Nonlinear optimal control for reducing vibrations in civil structures using smart devices

Joaquin Contreras-Lopez,Fernando Ornelas-Tellez,Elisa Espinosa-Juarez 국제구조공학회 2019 Smart Structures and Systems, An International Jou Vol.23 No.3

The frequently excessive vibrations presented in civil structures during seismic events or service conditions may result in users’ discomfort, or worst, in structures failure, producing economic and even human casualties. This work contributes in proposing the synthesis of a nonlinear optimal control strategy for semiactive structural control, with the main characteristic that the synthesis considers both the structure model and the semiactive actuator nonlinear dynamics, which produces a nonlinear system that requires a nonlinear controller design. The aim is to reduce the unwanted vibrations in the response of civil structures, by means of intelligent fluid semiactive actuator such as the Magnetorheological Damper (MRD), which is a device with a low level of power consumption. The civil structures for which the proposed control methodology can be applied are those admitting a state-dependent coefficient factorized representation model, such as buildings, bridges, among others. A scaled model of a three storey building is analyzed as a case study, whose dynamical response involves displacement, velocity and acceleration of each one of the storeys, subjected to the North-South component of the September 19th., 2017, Puebla-Morelos (7.1M), Mexico earthquake. The investigation rests on comparing the structural response over time for two different conditions: with no control device installed and with one MRD installed between the first floor and the ground, where a nonlinear optimal signal for the MRD input voltage is determined. Simulation results are presented to show the effectiveness of the proposed controller for reducing the building's dynamical response.

A Software Defined Networking Approach to Improve the Energy Efficiency of Mobile Wireless Sensor Networks

( Joaquin Aparicio ),( Juan Jose Echevarria ),( Jon Legarda ) 한국인터넷정보학회 2017 KSII Transactions on Internet and Information Syst Vol.11 No.6

Mobile Wireless Sensor Networks (MWSN) are usually constrained in energy supply, which makes energy efficiency a key factor to extend the network lifetime. The management of the network topology has been widely used as a mechanism to enhance the lifetime of wireless sensor networks (WSN), and this work presents an alternative to this. Software Defined Networking (SDN) is a well-known technology in data center applications that separates the data and control planes during the network management. This paper proposes a solution based on SDN that optimizes the energy use in MWSN. The network intelligence is placed in a controller that can be accessed through different controller gateways within a MWSN. This network intelligence runs a Topology Control (TC) mechanism to build a backbone of coordinator nodes. Therefore, nodes only need to perform forwarding tasks, they reduce message retransmissions and CPU usage. This results in an improvement of the network lifetime. The performance of the proposed solution is evaluated and compared with a distributed approach using the OMNeT++ simulation framework. Results show that the network lifetime increases when 2 or more controller gateways are used.

Modulation of cloud cluster propagation by super cloud clusters

Joaquin E. Blanco,David S. Nolan,Brian E. Mapes 한국기상학회 2018 한국기상학회 학술대회 논문집 Vol.2018 No.10

Recodificacion y Desplazamiento del Discurso Publicitario y el Discurso Fotografico en la Narrativa de Manuel Puig

( Joaquin Carmona Rodriguez ) 전북대학교 인문학연구소 2013 건지인문학 Vol.10 No.-

Manuel Puig`s narrative presents itself as a clear example of the inextricable relationship between literature and society and the con-flict of the conditioning of the word with its referent. Likewise, Puig`s work functions as an example of the conflict of the adjustment to the text of the socio-historical structures in its epoch. I will use the per-spective of sociocriticism, wherein a fictional text is formed through complex sets of representations and is the result of a concatenation of articulations and different types of discourses, both literary and not literary. I will try to analyze the appropriation this author makes of the discourses of photography and advertising in order to in-corporate them into his work. I will utilize this analysis as an exam-ple of the varied social discourses that arise in Puig`s narrative and are responsible for its configuration, through a constitutive process in which the emptiness between these nonliterary incorporations works as an axis.