Time filter

Source Type

Sunle S.,Jose Simeon Canas Central American University | Kusunoki K.,Yokohama National University
Bulletin of the International Institute of Seismology and Earthquake Engineering | Year: 2012

Design codes prescribe equations for ultimate state design of RC walls with flange walls as boundary elements considering part of the length of the flange wall as an effective width to resist lateral loads. However, the damage state and the accuracy of the effective width used in calculation have not been discussed. Therefore, loading test was carried out in Yokohama National University on two 1/3 scale specimens in order to evaluate the strength, damage state, energy dissipation and behavior of RC structural walls in flexure. One specimen without flange walls and one with flange walls were tested. The strength and response of each specimen were described, and the prediction accuracy of the design flexural strength given by design codes ACI, Eurocode and AIJ was examined. Experimental strain data was used to describe the behavior of the flange wall, in order to know the mechanism it develops when the in plane wall is loaded, and to confirm the accuracy of the effective width prescribed by design codes in tension and compression. The result of the experimental study revealed that design prescriptions given by ACI, Eurocode and AIJ guidelines can estimate conservatively the flexural strength for RC walls without flanges, but they underestimate the flexural strength for flanged walls. This underestimation is due to the lack of knowledge of the mechanism developed at the flange. It was not possible to determine a specific value of flexural effective width. However, it was confirmed that the flange width is underestimated by design codes and it increases with imposed drift level. The stress distribution at the flange in the out of plane direction was found not uniform, a fact that is different as the design assumptions.

Osegueda O.,Rovira i Virgili University | Osegueda O.,as Research Center on Engineering of Materials and Micro nanoSystems | Osegueda O.,Jose Simeon Canas Central American University | Dafinov A.,Rovira i Virgili University | And 6 more authors.
Catalysis Today | Year: 2012

Commercial ceramic hollow fibres have been used as a starting material for the preparation of catalytic membrane reactors (CMRs). The original nominal pore sizes of the membranes were 4, 20, 100, 500 and 1400 nm. The CMRs have been produced by palladium precursor impregnation followed by calcinations and reduction in hydrogen flow at 350 °C. The direct generation of hydrogen peroxide from hydrogen and oxygen has been studied at ambient conditions. The efficiency of hydrogen peroxide generation, with respect to hydrogen supply, as well as the rate of H 2O 2 production and the maximum H 2O 2 concentration as a function of the original membrane pore size have been determined. The μ-XRD and SEM analyses have revealed that the Pd is uniformly distributed throughout the entire membranes. The rate of hydrogen peroxide generation has been shown to depend inversely on the membrane pore size. It has been demonstrated that the upper hydrogen peroxide concentration level is set by the catalyst deactivation and therefore not caused by reverse reactions or hydrogen peroxide reduction by the activated hydrogen. This finding has been confirmed by the XPS analysis. The in situ oxidation of phenol by a subsequent heterogeneous Fenton process in phenol-containing water has been assessed using the CMRs prepared. In these cases no significant activity has been detected. Addition of Fe(II) to the reaction solution has resulted in CMRs with considerable activity for phenol oxidation. In another series of ceramic hollow fibre membranes, the Pd impregnation was preceded by the incorporation of a second active phase (Fe 2O 3, CuAl 2O 4, TiO 2 or CeO 2). The rates of hydrogen peroxide generation as well as the maximum H 2O 2 concentration for these bi-functional CMRs have been determined following the same procedure developed for the first series of CMRs. All of them have shown activity in producing H 2O 2. The initial tests for phenol oxidation by the in situ generated H 2O 2 have demonstrated the viability of the proposed reaction system for waste water treatment. © 2012 Elsevier B.V.

Dickson-Gomez J.,Medical College of Wisconsin | Bodnar G.,Fundacion Antidrogas de El Salvador | Guevara C.E.,Fundacion Antidrogas de El Salvador | Rodriguez K.,Jose Simeon Canas Central American University | And 2 more authors.
Substance Use and Misuse | Year: 2011

Crack use has increased dramatically in El Salvador in the last few decades. As with other developing countries with sudden onsets of drug problems, El Salvador has few medical staff trained in addictions treatment. Little research has examined drug users' attempts to reduce or abstain from drug use in countries where government-regulated formal medical treatment for drug addiction is scarce. This paper uses qualitative and quantitative data gathered from active crack users to explore their formal and informal strategies to reduce or abstain from drugs, and compares these with components of informal and formal treatment in developed countries. copyright © 2011 Informa Healthcare USA, Inc.

Negy C.,University of Central Florida | Reig-Ferrer A.,University of Alicante | Gaborit M.,Jose Simeon Canas Central American University | Ferguson C.J.,Stetson University
Journal of Immigrant and Minority Health | Year: 2014

The purpose of this study was to examine the construct psychological homelessness—feelings of not belonging in one’s home country—within the context of deported Salvadorans’ enculturation to El Salvador. Participants (n = 66) who had been deported from the United States completed a set of questionnaires related to their deportation experience. Results indicated that deportees, in various degrees, experienced the phenomenon of psychological homelessness and enculturative stress related to living in El Salvador. As hypothesized, enculturative stress related to re-adapting to life in El Salvador significantly correlated with psychological homelessness after controlling for time spent in the United States, acculturation, and enculturation. Additional analyses revealed that maladaptive cognitions related to the deportation experience also predicted psychological homelessness. Our findings suggest psychological homelessness appears to be a valid construct and is experienced by many undocumented immigrants. © 2014, Springer Science+Business Media New York.

Glasman L.R.,Medical College of Wisconsin | Dickson-Gomez J.,Medical College of Wisconsin | Lechuga J.,University of Texas at El Paso | Tarima S.,Medical College of Wisconsin | And 2 more authors.
AIDS and Behavior | Year: 2016

In El Salvador, crack users are at high risk for HIV but they are not targeted by efforts to promote early HIV diagnosis. We evaluated the promise of peer-referral chains with incentives to increase HIV testing and identify undiagnosed HIV infections among networks of crack users in San Salvador. For 14 months, we offered HIV testing in communities with a high prevalence of crack use. For the following 14 months, we promoted chains in which crack users from these communities referred their peers to HIV testing and received a small monetary incentive. We recorded the monthly numbers of HIV testers, and their crack use, sexual risk behaviors and test results. After launching the referral chains, the monthly numbers of HIV testers increased significantly (Z = 6.90, p < .001) and decayed more slowly (Z = 5.93, p < .001), and the total number of crack-using testers increased nearly fourfold. Testers in the peer-referral period reported fewer HIV risk behaviors, but a similar percentage (~5 %) tested HIV positive in both periods. More women than men received an HIV-positive diagnosis throughout the study (χ2(1, N = 799) = 4.23, p = .040). Peer-referral chains with incentives can potentially increase HIV testing among networks of crack users while retaining a focus on high-risk individuals. © 2015, Springer Science+Business Media New York.

Discover hidden collaborations