Mexico City, Mexico


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Ruiz-Guerrero R.,CIITEC IPN | Norzagaray-Campos M.,CIIDIR IPN Sinaloa
Asian Pacific Journal of Tropical Biomedicine | Year: 2015

OBJECTIVE: To evaluate five indigenous Mexican plants [Hippocratea excelsa, Hippocratea celastroides, Argemone mexicana (A. mexicana), Tagetes lucida, and Pseudosmodingium perniciosum (P. perniciosum)] toxicity against the fourth instar larvae of the dengue primary vector, Aedes aegypti (A. aegypti). METHODS: Each plant part was treated successively with hexane, ethyl acetate, acetone, and methanol to extract potential active components of the plants against the dengue vector. RESULTS: There was a range of toxicity at 24 or 48 h post-exposure for the different plant parts and organic solvent used (LC50 values ranged between 20 and 890 μg/mL). Extracts from seeds of A. mexicana (hexane washing with methanol and acetone) and stem-bark of P. perniciosum (hexane) showed highest toxicity to Ae. aegypti larvae at 48 h post-exposure (LC50 values were 80, 50, and 20 μg/mL, respectively), thus making them potential candidates as biolarvicides. Efforts are on-going to characterize the bioactive components of the extracts, through chromatography, for their use as biological tools for the control of the primary dengue vector. CONCLUSIONS: A. mexicana and P. perniciosum are good candidates to combat the dengue vector, Ae. aegypti, as they were highly toxic to the larvae. © 2015 Hainan Medical University. Production and hosting by Elsevier B.V. All rights reserved.

Almaraz A.,CIITEC IPN | Lopez C.,CIITEC IPN | Arellano I.,CIITEC IPN | Barron M.A.,Metropolitan Autonomous University | And 4 more authors.
Minerals Engineering | Year: 2014

Copper converting is mainly conducted in Peirce-Smith converters. Extensive work has been conducted to understand fluid flow phenomena as air is injected into molten mattes. High momentum must be transferred from the gas to the melt in order to refine the metal. In this work, we present a CFD analysis of gas injection with one and three tuyeres. Results show that by increasing the number of injection points, the flow pattern within the converter change considerably. Such changes result in the development of large recirculation zones and localised eddy formation. Additionally, it was found that the gas plumes in the melt are asymmetrical thus flow paths constantly interfere between themselves. Bubbling-jetting transition is found to be better represented by the Kutateladze number. © 2013 Elsevier Ltd. All rights reserved.

Muinonen M.,Vale Inc. | Plascencia G.,CIITEC IPN | Utigard T.,University of Toronto
Canadian Metallurgical Quarterly | Year: 2010

Fluid bed roasting of Bessemer matte containing copper, nickel and sulphur was carried out on a laboratory scale at temperatures from 900°C to 1050°C. Below 900°C the kinetics are too slow and above about 1050°C, fluid bed roasting becomes difficult due to rapid agglomeration caused by liquid phase sintering. The oxidation of the first 80% of the total sulphur in the samples was rapid while the remaining 20% took significantly longer. The initial rapid oxidation allowed for the formation of oxide layers around the otherwise molten sulphides minimizing the tendency for agglomeration and sticking. The roasted calcine formed a NiO phase saturated with 30% tenorite (CuO) in solid solution. © Canadian Institute of Mining, Metallurgy and Petroieum Published by Canadian Institute of Mining, Metallurgy and Petroleum Printed in Canada. All rights reserved.

Muinonen M.,Vale Technical Services Ltd | Plascencia G.,CIITEC IPN | Utigard T.,University of Toronto
Canadian Metallurgical Quarterly | Year: 2010

Thermogravimetric oxidation tests were carried out on Bessemer mattes containing copper, nickel and sulphur to investigate the feasibility of high temperature fluid bed roasting. It was not possible to heat the nickel-copper sulphide particles in an inert gas since the discrete particles would melt before reaching the required temperatures, resulting in large liquid droplets. The sulphides were therefore heated in air, leading initially to sulphate formation and oxidation of metallics, followed by sulphate decomposition and sulphide oxidation. It was found that below 900°C the oxidation kinetics were too slow for any practical application. Above 1050°C, the copper-nickel oxide calcine starts to agglomerate due to sintering. In the suitable operating range from 900°C to about 1050°C the rate of oxidation was found to increase with increasing temperature. © Canadian Institute of Mining, Metallurgy and Petroleum.

Hernandez-Atonal N.E.,CIITEC IPN | Rivero-Angeles M.E.,CIC IPN | Martinez-Pinon F.,CIITEC IPN
Ad-Hoc and Sensor Wireless Networks | Year: 2016

Major applications of Wireless Sensor Networks (WSNs) are related to safety applications like emergency warnings, rescue operations, and surveillance operations in military among others. In these systems, efficient data dissemination among nodes is of primary importance for the acceptable performance of the network. In this work, the transmission of short messages for different MAC strategies to operate in static and mobile WSNs is studied. Also, the proposal of two MAC hybrid strategies to improve the system performance in terms of energy consumption, successful packet transmission and delay is developed. Numerical results prove that the use of only CSMA/CA or S-ALOHA as the access strategy does not provide the best results for the performance of the system. How- ever, the combined use of these two protocols can increase the success packet transmission and decrease both the data exchange delay and power consumption. Also, the impact of different backoff schemes is investigated. Finally, this paper considers an interest-based approach for the data dissemination where nodes are only interested in certain information from other nodes in the system, analogous to people only interested in certain information from their friends list. © 2016 Old City Publishing, Inc.

Martinez-Franco E.,CIITEC IPN | Martinez-Franco E.,Helmholtz Center Geesthacht | Klassen T.,Helmholtz Center Geesthacht | Dornheim M.,Helmholtz Center Geesthacht | And 3 more authors.
Ceramic Transactions | Year: 2010

Mechano-synthesis through mechanical alloying (MA) has been employed to obtain a nanocrystalline complex sodium lithium alanate, namely, Na 2LiAlH6 from starting materials NaH and LiAlH4. Different Ti-based additives were milled together with starting materials in order to achieve improved hydrogen absorption kinetics. Hydrogen titration experiments showed that the material processed with 5 mol% TiCl3 has the fastest ab- and desorption kinetics, but at the sacrifice of hydrogen capacity. This could be correlated to the formation of NaCl during milling and after absorption. Differential scanning calorimetry (DSC) results demonstrate that the endothermic peak of TiCl3 doped material shifted 53°C to lower temperatures.

Mendez C.,CIITEC IPN | Sanchez C.C.,CIITEC IPN | Plascencia G.,CIITEC IPN | Rubio M.A.,IMASA S.A. de C.V. | Jaramillo D.,CIITEC IPN
TMS Light Metals | Year: 2010

A thermal assessment of the semi-continuous casting facility at IMASA shop was conducted. Temperature measurements were carried out in situ as ingots of the 1XXX and 3XXX aluminum alloys series were processed. Simultaneously, the temperature in the cooling water was measured and recorded. With the data collected at the shop, a thermal balance was performed. It was found that there is a significant excess in the amount of water used for heat extraction during the solidification of the ingots. This major finding; lead to conceptualize a more efficient cooling system, since the current cooling system increase the production cost at IMASA. This new cooling system concept is under development and some first results obtained from finite element analysis are presented and discussed in this paper.

Mendez C.,CIITEC IPN | Sanchez C.C.,CIITEC IPN | Salas E.,CIITEC IPN | Rios M.,CIITEC IPN | And 3 more authors.
Kovove Materialy | Year: 2014

Aluminum alloys are processed by semi continuous casting either by direct chill or open mould casting. However, due to intrinsic complications of the casting process and the size of the solidified ingots, it is difficult to evaluate or even predict the effect of process parameters such as cooling water flow rate or casting velocity on the microstructure of the ingots. In this paper we report some results from a laboratory scale built semi continuous machine. Results show that regardless of the casting parameters used, a fine equiaxed microstructure was obtained in every test.

Arteaga-Arcos J.C.,National Autonomous University of Mexico | Chimal-Valencia O.A.,Polytechnic University of Guanajuato | Yee-Madeira H.T.,National Polytechnic Institute of Mexico | Diaz De La Torre S.,CIITEC IPN
Construction and Building Materials | Year: 2013

The High-Strength Cement (HSC) technology is based on modification of Normal Use Portland Cement (NUPC) by complex admixtures, optimization of mixture design and grinding process. The present work shows the results of preparing and using Ultra-Fine Cement (UFC) as a binder material addition with no extra admixtures of different chemical composition to increase the compressive strength of mortars. The aim of this work is to demonstrate how a NUPC can be converted into a sort of HSC; it was observed that the 70-60 wt%NUPC + 30-40 wt%UFC blend satisfies the goal of increasing mortar's compressive strength. © 2013 Elsevier Ltd. All rights reserved.

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