Maicao, Colombia
Maicao, Colombia

The University of La Guajira , also known as Uniguajira, is a public, departmental, coeducational, university based primarily in the city of Riohacha, La Guajira, Colombia. The university was established by ordinance No. 011 and 012 of 1976, by the Departmental Assembly, and began its labor in February 1977. Its main campus, known as the University Citadel , is located in the outskirts of the city, and it hosts the faculties of Basic science, Economic and Administrative science, Education science, Engineering, and Social and Humanity science. The university also counts with several satellite campuses across the department in the cities of Albania, Fonseca, Maicao, Manaure, and Villanueva, and one campus in the department of Córdoba in the city of Montería. The university offers education at technical, undergraduate and postgraduate levels. Their school mascot is a jellyfish because it symbolizes power and simplicity. Wikipedia.


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Moreno-Pirajan J.C.,University of Los Andes, Colombia | Bastidas-Barranco M.J.,University of La Guajira | Giraldo L.,National University of Colombia
Journal of Thermal Analysis and Calorimetry | Year: 2017

The scope of this investigation is to relate textural and surface characteristics of activated carbon prepared from Cerrejon coal (Colombia) to their methane quantity adsorption. Sub-bituminous coal from the Cerrejon coal mine in Colombia was used as a raw material for the preparation of pore size-controlled activated carbon adsorbents. A subsequent chemical treatment was carried out, after making a physical activation with CO2. Samples were treated with CO2 flow at 850 °C by varying activation time to achieve different burn-off activated carbons. The samples chemically activated with H3PO4 under CO2 atmosphere showed higher activation rates, surface area, and micropore volume compared to other activation methods, although not all the samples prepared by this method presented storage quantities methane in function of surface area development. Moreover, it was shown that using small proportion of KCl and H3PO4 creates an initial narrow microporosity. Further physical activation grantees better development of pore structure. In terms of pore size distribution, the combined preparation method resulted in a better and more homogenous pore size distribution than the conventional physical activation method. Controlling the pore size of activated carbon by this combined activation technique can be utilized for tuning the pore size distribution. Storage studies of methane up to 60 bar were realized. It was concluded that the high surface area and micropore volume of activated carbons do not unequivocally determine methane capacities. Adsorption microcalorimetry is a useful technique to follow the process of the adsorption reaction of CH4, and its results are in agreement with the results found study by adsorption at high pressure. © 2017 Akadémiai Kiadó, Budapest, Hungary


Perez R.,University of La Guajira | Vilardy J.M.,University of La Guajira | Jimenez C.J.,University of La Guajira
Journal of Physics: Conference Series | Year: 2017

A new nonlinear system for image encryption using the Gyrator transform (GT) and the truncation operations is proposed in this work. The original image is encoded in phase at the beginning of the encryption process. The encryption-decryption system is based on the double random phase encoding (DRPE) in the Gyrator domain (GD). The rotation angle of the Gyrator transform is a new key that increases the security of the encryption system. The amplitude and phase truncation operations are nonlinear and no unitary, these truncation operations allow to select the information of amplitude or phase from a complex-valued image. We apply the truncation operations in the image encryption-decryption system in order to generate two new keys, convert the system in nonlinear and increase the security of the system. To retrieve the original image without error (noise-free) in the decryption system, it is needed all the correct security keys: the two RPMs, the rotation angle of the GT and the two key generated by the amplitude and phase truncation operations. The feasibility of this nonlinear encryption-decryption system is verified and analyzed by numerical simulations. © Published under licence by IOP Publishing Ltd.


Jimenez C.J.,University of La Guajira | Vilardy J.M.,University of La Guajira | Perez R.,University of La Guajira
Journal of Physics: Conference Series | Year: 2017

In this work we develop a new encryption system for encoded image in phase using the fractional Hartley transform (FrHT), truncation operations and random phase masks (RPMs). We introduce a simplification of the FrHT with the purpose of computing this transform in an efficient and fast way. The security of the encryption system is increased by using nonlinear operations, such as the phase encoding and the truncation operations. The image to encrypt (original image) is encoded in phase and the truncation operations applied in the encryption-decryption system are the amplitude and phase truncations. The encrypted image is protected by six keys, which are the two fractional orders of the FrHTs, the two RPMs and the two pseudorandom code images generated by the amplitude and phase truncation operations. All these keys have to be correct for a proper recovery of the original image in the decryption system. We present digital results that confirm our approach. © Published under licence by IOP Publishing Ltd.


Perez R.,University of La Guajira | Vilardy J.M.,University of La Guajira | Torres C.O.,Popular University of Cesar
Journal of Physics: Conference Series | Year: 2017

Information security with optical processing, such as the double random phase encoding and the Gabor transform (GT) has been investigated by various researchers. We present a two-dimensional (2-D) generalization of the one-dimensional GT. This 2-D GT is applied to encrypt digital images in this paper. The scaling factors of the GT can be used as new keys, providing a new encryption system with a high security characteristics. This method can encrypt and protect the information of the digital images with a high security for information processing systems. © Published under licence by IOP Publishing Ltd.


Vilardy J.M.,Popular University of Cesar | Jimenez C.J.,University of La Guajira | Torres R.,Popular University of Cesar
Journal of Physics: Conference Series | Year: 2017

We show the design and implementation of an optical polarimeter using electronic control. The polarimeter has a software with a graphical user interface (GUI) that controls the optoelectronic setup and captures the optical intensity measurement, and finally, this software evaluates the Stokes vector of a state of polarization (SOP) by means of the synchronous detection of optical waves. The proposed optoelectronic polarimeter can determine the Stokes vector of a SOP in a rapid and efficient way. Using the polarimeter proposed in this paper, the students will be able to observe (in an optical bench) and understand the different interactions of the SOP when the optical waves pass through to the linear polarizers and retarder waves plates. The polarimeter prototype could be used as a main tool for the students in order to learn the theory and experimental aspects of the SOP for optical waves via the Stokes vector measurement. The proposed polarimeter controlled by a GUI of Matlab is more attractive and suitable to teach and to learn the polarization of optical waves. © Published under licence by IOP Publishing Ltd.


Jimenez-Ferbans L.,Institute Ecologia | Jimenez-Ferbans L.,University of La Guajira | Reyes-Castillo P.,University of La Guajira
Invertebrate Systematics | Year: 2014

Ameripassalus, gen. nov., is described as the first genus of Passalini with a distribution restricted to Mesoamerica. The species include A. guatemalensis (Kaup, 1869), comb. nov. from Passalus Fabricius, A. difficilis, sp. nov. and A. tamaulipensis, sp. nov. from Mexico, and A. jacki, sp. nov. and A. nigritus, sp. nov. from Guatemala. A matrix of 46 morphological characters, including the species from Ameripassalus, gen. nov. and 13 species of the genera Paxillus MacLeay, Ptichopus Kaup, Heliscus Zang, Veturius Kaup, Spasalus Kaup, Passipassalus Fonseca & Reyes-Castillo, Passalus Fabricius and Leptaulax Kaup were analysed. Only a single most parsimonious tree was found; in this Ameripassalus is retrieved as a monophyletic group. Ameripassalus difficilis, sp. nov. is shown as the sister group of the rest of the species in the genus. The species with the southernmost distribution (A. guatemalensis (A. nigritus, sp. nov.+A. jacki, sp. nov.)) form a nested clade within the species with the northernmost distribution. Keys to identify adults of the genera of Passalini and to the species of Ameripassalus are provided. © CSIRO 2014.


Wastewater Treatment Plant Works has been facing hycdraulic problem refers to back-mixing, short-circuiting and wind effect, thus reducing of the Mean Hydraulic Retention Time, MHRT. Tracer studies for full-scale WSP and UASB is complex and expensive. For that, a calibrated physical model. PM is better alternative to determine MHRT even though similarities between prototype and physical model are achieved. The aim of this study is to determine the MHRT through out two physical models by using Rhodamine WT dye and Lidsey UK)and (UASB, Colombia), respectively. Hydraulic pathways usíng tracer's lechniques in still and artificial solution water was analysed. The resulls found an agreement of the layout match in terms of MHRT (0.77d against to 0.89d) for WSPs and (4.8h against to 6.17) for an UASB betw en P.M and prototypes over 96% of confidence level. Dispersed-mix d flow was achieved.


Giraldo L.,National University of Colombia | Bastidas-Barranco M.,University of La Guajira | Moreno-Pirajan J.C.,University of Los Andes, Colombia
Oriental Journal of Chemistry | Year: 2014

A series of monoliths are prepared from orange peels and chemically activated with H3PO4, KOH, ZnCl2, and water vapor without a binder. The monoliths were characterized by N2 adsorption-desorption isotherms at 77 K, Boehm titrations and XPS. Thereafter, monoliths were tested for their ability to establish NOx retention. The results show that the retention capacities of NOx were a function of the textural properties and chemistries. The carbons synthesized with ZnCl2 and KOH retained similar amounts of NOx. © 2014, Oriental Scientific Publishing Company. All rights reserved.


Arregoces S.N.,University of La Guajira | Molina R.T.,Universidad del Norte, Colombia
Revista Panamericana de Salud Publica/Pan American Journal of Public Health | Year: 2015

Objective. Identify the inequalities and sociodemographic characteristics that negatively affect maternal mortality in the department of La Guajira, Colombia. Methods. A descriptive study was conducted in which cases of maternal deaths in the department of La Guajira between 2010 and 2012 were analyzed, based on data from secondary sources. The difference in rates, rate ratio, population attributable risk percent, and Gini and concentration coefficients were calculated. Results. 54 maternal deaths were recorded, 61.1% of which were indigenous and 16.7% Afro-Colombians; the majority did not have any schooling (33.3%) or only primary schooling (29.6%). Inequalities in the difference of rates, rate ratio, and population attributable risk percent were calculated for La Guajira and other departments in the Caribbean region and in Colombia; however, the differences were not reflected in the Gini and concentration coefficients. Conclusions. Maternal mortality was significantly higher in indigenous women than in non-indigenous women. Sexual and reproductive health programs should be strengthened and maternal health policies improved through a multicultural approach to eliminate or reduce inequalities related to maternal mortality in this population.


Jimenez C.,University of La Guajira | Torres C.,Popular University of Cesar | Mattos L.,Popular University of Cesar
Journal of Physics: Conference Series | Year: 2011

A new method for image encryption is introduced on the basis of two-dimensional (2-D) generalization of 1-D fractional Hartley transform that has been redefined recently in search of its inverse transform We encrypt the image by two fractional orders and random phase codes. It has an advantage over Hartley transform, for its fractional orders can also be used as addictional keys, and that, of course, strengthens image security. Only when all of these keys are correct, can the image be well decrypted. Computer simulations are also perfomed to confirm the possibilty of proposed method.

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