PDF superior Load rating assessment of a corroded pier structure in the Gulf of Mexico

Load rating assessment of a corroded pier structure in the Gulf of Mexico

Load rating assessment of a corroded pier structure in the Gulf of Mexico

Once the finite element model was calibrated to field conditions, engineering analysis was followed to address any optimized parameter that could possibly change over time or that could be unreliable with heavy loads or further damage. The Load Rating Factor was determined by a formula based on a certain element capacity, the applied live and dead loads (and their corresponding factors), and a considered impact effect. It is known that a load-rating factor greater than 1.0 indicates a member capacity exceeds the applied loads with the desired factors of safety (AASHTO, 2002). A rating factor less than 1.0 indicates a structural member is deficient such that a specific vehicle or load cannot cross the bridge with the desired factor of safety. A number near 0.0 indicates the structure cannot carry its own dead weight and maintain the desired safety factor. The lowest component rating-factor generally controls the load rating of the entire structure. As mentioned before, the rating equation specified by the AASHTO - Manual for the Condition Evaluation of Bridges was applied (1).
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Load rating assessment of a corroded pier structure in the Gulf of Mexico

Load rating assessment of a corroded pier structure in the Gulf of Mexico

This work assesses the structural integrity of a pier located in the Gulf of Mexico through a live- load testing analysis of a corroded structure that withstands heavy loads. Procedures included instrumentation for load application of four different loads (50, 60, 350, and 700 Ton) to examine its structural performance, then calibrate the resultant finite-element models of the structure, and finally estimate the load rating factors using AASHTO methodology. Results showed that corrosion damages did not appear to represent an extreme structural menace; however, it was found that several piers’ structural elements are currently overloaded and need to be externally reinforced. This paper outlines the testing procedures, describing both the followed analysis and the data management criteria.
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Load rating assessment of a corroded pier structure in the Gulf of Mexico

Load rating assessment of a corroded pier structure in the Gulf of Mexico

This original work assesses the structural integrity of a pier located in the Gulf of Mexico through a live-load testing analysis of a corroded structure that withstands heavy loads. Procedures included instrumentation for load application of four different loads (50, 60, 350, and 700 Ton) to examine its structural performance, then calibrate the resultant finite-element models of the structure, and finally estimate the load rating factors using AASHTO methodology. Results showed that corrosion damages did not appear to represent an extreme structural menace; however, it was found that several piers’ structural elements are currently overloaded and need to be externally reinforced. This paper outlines the testing procedures, describing both the followed analysis and the data management criteria.
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Marine Planktonic dinoflagellates of the order Dinophysiales (Dinophyta) from coasts of the tropical Mexican Pacific, including two mew species of the genus Amphisolenia

Marine Planktonic dinoflagellates of the order Dinophysiales (Dinophyta) from coasts of the tropical Mexican Pacific, including two mew species of the genus Amphisolenia

Despite a recent revision of the dinoflagellates of the order Dinophysiales on Mexican coasts and a checklist of dinoflagellates from the Mexican Pacific, many records still need to be confirmed, for there are very few reliable illustrations and/or descrip- tions. In this paper, species composition and distribution of dinoflagellates belonging to the Dinophysiales, the product of the analysis of net phytoplankton material collected from coasts of the tropical Mexican Pacific (Jalisco to Chiapas) are presented. The material has been studied using light microscopy, although a few species were also studied by scanning electron microscopy (SEM). Forty-one species from five genera were identified, with two new records annotated for the Mexican Pacific: Amphisolenia thrinax and Metaphalacroma skogsbergii, and two new species of the genus Amphisolenia, Amphisolenia fusiformis sp. nov. and Amphisolenia michoacana sp. nov. Illustrations, dimensions and distribution data are provided for each species, and descriptions of the new species are also given. Amphisolenia palmata, A. rectangulata, A. truncata, Dinophysis apicata, D. hindmarchii, Histioneis biremis, H. crateriformis, H. pulchra, Ornithocercus cristatus, O. heteroporoides and O. orbiculatus are illustrated for the first time in the waters of the Mexican Pacific. The number of species found in this study is relatively low. The species Dinophysis norvegica and D. sacculus, reported in previous papers, do not seem to occur in Mexican waters, as their distribution is rather limited to the Mediterranean Sea and the North Atlantic, respectively. Finally, the identity of certain species of Dinophysis and the nature of the new species described here are discussed.
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Peridinium quinquecorne var. trispiniferum var. nov. (Dinophyceae) de un ambiente salobre

Peridinium quinquecorne var. trispiniferum var. nov. (Dinophyceae) de un ambiente salobre

Phytoplankton communities of coastal lagoons are complex, as a high diver- sity of freshwater and marine organisms can co-occur in these environments. As a consequence, confusion about the identification of microalgae may arise. Within dinoflagellates, some genera are distinctively freshwater or marine organisms, but others can be found in both environments (Dodge, 1985; Popovský & Pfiester, 1990). The genus Peridinium Ehrenberg was split by Gran in 1902 into the genera Peri- dinium and Protoperidinium Bergh, thus providing a broad separation between the freshwater (Peridinium) and the marine species (Protoperidinium) (Balech, 1974). Thus, the genus Peridinium is commonly regarded to occur only in freshwater envi- ronments, but the subdivision into two genera was based on the number of cingular plates (Peridinium bears more than five plates) and, so far, the only species of this genus that is known to occur in marine and brackish environments is Peridinium quinquecorne. in addition, P. aciculiferum Lemmermann has been recorded in ma- rine environments in Europe (Popovský & Pfiester, 1990), and in estuarine environ- ments in the Gulf of Mexico (Steidinger et al., 2009). As this species is characteristic of freshwater environments (Hansen & Flaim, 2007), its occurrence in marine envi- ronments might be the result of river transportation.
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Reproductive activity and condition index of Holocanthus passer (Teleostei: Pomacanthidae) in the Gulf of California, Mexico

Reproductive activity and condition index of Holocanthus passer (Teleostei: Pomacanthidae) in the Gulf of California, Mexico

In fisheries ecology, the study of condi- tion is a standard practice and assumes that a heavier fish of a given length is in better con- dition (Bolger and Connolly 1989). Condition has been most effectively used to compare monospecific populations living under similar or apparently different environmental condi- tions, in determining the timing and duration of gonad maturation, and as an indication of changing gross nutritional balance during chronic alterations in feeding activity or food supply (Bolger and Connolly 1989).
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Spatio temporal variation of the structural organization of demersal communities in the
    Southwestern Gulf of Mexico

Spatio temporal variation of the structural organization of demersal communities in the Southwestern Gulf of Mexico

Faunal and environmental analysis: matrices of species abundance (catch /trawl) with respect to depth and season were root-root transformed; however, when proportions were used, the arc-sine of the square root was taken instead (Bireley 1984). The cluster analysis was carried out by means of the cordal distance index (0rlóci 1978b), and the resulting matrix was grouped using of the flexible method with B=-0.25 (Sneath and Sokal 1974, Swartz et al. 1986). For the community ordination, principal components analysis was used. The environmental variations were evaluated by kriging technique with a linear variogram model, because the data points were evenly dis- persed in the area (Axis et al. 2001). In order to know the relationship between the abundance and the recorded parameters, a non-parametric analysis, the Spearman’s correlation was car- ried out. The diet data of the most important fish species in one year were analyzed using the similarity coefficient (Horn 1966). The sampled fish were injected with formol at 40 % in the stomach in order to stop any digestive process, subsequently, the stomach contents were dissected and analyzed. The composition of each trophic group was evaluated as the percent of the total area of the stomach con- tent; the comparative weight value and the fre- quency of each food item were used to define the trophic spectra (Overstreet and Heard 1982). Values obtained are an average for each species; Fig. 8 shows the size and number of analyzed specimens. The Horn’s similarity index gives a relative value of trophic overlap (Rice 1988). The analysis was carried out both with and without considering detritus as a com- ponent of the food consumed.
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Habitats and biodiversity of decapod crustaceans in the SE Gulf of California, Mexico

Habitats and biodiversity of decapod crustaceans in the SE Gulf of California, Mexico

(Hendrickx and Wicksten 1987, Wicksten and Hendrickx 1992). Except for the slippery prineeps, which typi­ cally occurs on sandy bottom elose to shore, lobsters and mud-shrimps (Thalassinidea) are scarce. Anomura (20 species in total) ineludes a small series of sized hermit crabs species which feature an unbroken distribution pattern from inside the Bay towards the adja­ cent shelf. crabs are known to be mostIy intertidal, sometimes extending their habitat to the shallow subtidal where rocky bot­ tom and associated fauna and flora (e.g. sponges and coralina) serve as refuges for many species of Petrolisthes, Paehyeheles or Megalobraehiunl. Exelusively subtidal porce­ lain occurring in the Gulf of California inelude the genera Orthochela. Eueeramus, Poreellana, Minyoeerus, Ulloaia and Polyonix, all of them represented at least with one species in the Bay of Mazatlán. The largest group of species is,
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Acid rain in a Mexican site on the coast of the Gulf of Mexico

Acid rain in a Mexican site on the coast of the Gulf of Mexico

The acid deposition effects on several types of potentially sensitive receptors along the coast of the Gulf of Mexico have become a topic of research, in- cluding receptors such as lakes, rivers, forests, soils, and materials from monuments of cultural heritage. It includes those found in the Mayan Zone, the archae- ological zone of El Tajín and the San Juan de Ulúa fortress, all of which were built out of limestone, a material especially susceptible to deterioration by acid rain (Schifter et al., 2005; Bravo et al., 2006; Benítez et al., 2014).
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Seismicity in the southwestern Gulf of Mexico: evidence of active back arc deformation

Seismicity in the southwestern Gulf of Mexico: evidence of active back arc deformation

The earthquake of 23 May 2007, offshore the city of Tuxpan, was not as well recorded by the worldwide network of seismic stations as the 2009 event. In this case, there were not many clearly recorded long- period P waves. The signals recorded at six teleseismic stations were used in the inversion algorithm. As described before, the inversion was conducted at different trial depths. The maximum variance reduction was obtained at a depth of approximately 7 km (Figure 2). At this depth, the fit between the synthetic seismograms generated using the resulting focal mechanism match the observed waveforms (Figure 4). The resulting source mechanism for the 2007 earthquake is different from those determined further south for the 1959, 1967 and 2009 events. The 2007 earthquake is much shallower than the events further south and shows strike-slip faulting with the axes of maximum compression oriented northeast-southwest. Furthermore, this earthquake lies offshore and not along the coastline as the other earthquakes farther south.
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Population structure and conservation status of the bottlenose dolphin population in the Gulf of Guayaquil, Ecuador.

Population structure and conservation status of the bottlenose dolphin population in the Gulf of Guayaquil, Ecuador.

Based on the results in the present study, the pattern of genetic divergence and the lack of gene flow suggest that the Bottlenose Dolphin population inhabiting the inner estuary of the Gulf of Guayaquil is an isolated population with a unique genealogical and adaptive legacy. Therefore, management and conservation strategies need to be developed for the conservation of this population soon, before current activities cause irreversible damage. Such strategies have to be different to those applied to other populations of Tursiops truncatus due to the particular genetic diversity. Besides the low genetic diversity, another aspect of major concern is the high level of inbreeding, which makes this population more vulnerable to environmental stochasticity. This population must be considered as an Evolutionary Significant Unit (ESU) and its conservation status should be reevaluated. Although the sample size is small, our findings provide information on the molecular baseline for management; therefore, actions should not be delayed.
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Competition and market structure of the banking sector in Mexico

Competition and market structure of the banking sector in Mexico

Currently, other investigations use the Lerner index employing different approaches. The work by Huang, Chiang and Wao (2016) proposes a simultaneous stochastic frontier model based on copulas, the model is comprised by a frontier of costs and two price product frontiers. Their results suggest that banks can direct their production to the bank with the greatest potential measure of the Lerner index to obtain greater profit. Phan, Daly and Akhter (2016) study the relation between banking competition, banking concentration and the efficiency of the banking sector in six Asian countries using two types of the Lerner index. They find that banking competition has a positive effect on efficiency while competition has a negative effect. By investigating the influence of change costs in banking for the three biggest banks of the Eurozone, Egarius and Weill (2016) study if the change costs have an impact on the market power measured by the Lerner index. It is concluded that there is a positive relation between the change costs and the market power. To evaluate the effect of competition on the creation of liquidity by the banks, Horvart, Seidler and Weill (2016) conduct an estimation using a dynamic data panel with GMM on a database of banks in the Czech Republic in the 2002-2010 period. They find that a greater competition measured by the Lerner index reduces the creation of liquidity.
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TítuloEffect of key parameters on the removal of formaldehyde and methanol in gas phase biotrickling filters

TítuloEffect of key parameters on the removal of formaldehyde and methanol in gas phase biotrickling filters

The bioreactor was operated during more than 60 days with 2 L of each solution, at a recirculation rate of 3.0 L/h. The nutrient solution was renewed once a week, with the pH adjusted to 7.5, although a gradual acidification was observed. The inlet formaldehyde concentrations were 0.8 ± 0.3, 0.9 ± 0.2 and 0.8 ± 0.2 g/m 3 , when using solutions A, B and C, respectively. The results show that the average performance of the reactor was similar with the three solutions (Table 2). A small decrease in the removal efficiency was observed when replacing solution A by solution B, though this difference is not really significant. The pH of the medium was 5.5 ± 1.1 when feeding solution A, containing ammonium, while with solution B, containing nitrate, it was 6.0 ± 0.4. A maximum formaldehyde elimination capacity of 101 g/m 3 h was obtained in this experiment, when feeding solution A.
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Intonation focus in the interlanguage of a group of Spanish learners of English

Intonation focus in the interlanguage of a group of Spanish learners of English

The number of errors is rather low (26 errors out of 925 tone units). It is surprising, fhough, that in the absence of contexts that might favour marked tonicity the learners have wron[r]

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Analysis of the presence of Anglicisms in a Spanish internet forum: some terms from the fields of fashion, beauty and leisure

Analysis of the presence of Anglicisms in a Spanish internet forum: some terms from the fields of fashion, beauty and leisure

This piece of research focuses on the lexical influence of English on a Spanish Internet forum. Some previous publications have dealt with the presence of English in various fields of Spaniards’ daily life. For instance, Rodríguez González (2012), Campos (2015) and Rodríguez Medina (2016a) examined the use of Anglicisms in areas such as sports; López-Zurita (2005) showed the importance of Anglicisms in economics. Advertising and TV commercials were also investigated by Rodríguez Díaz (2011) and García-Morales, González-Cruz, Luján-García and Rodríguez-Medina (2016); the fields of eroticism and sexuality were studied by Rodríguez-González, 2011, who includes many Anglicisms in his dictionary, and Crespo-Fernández and Luján- García (2013; 2017); other studies dealt with the employment of Anglicisms in toy leaflets aimed at young children in Spain (Luján-García, 2011) or teenagers in Las Palmas de Gran Canaria (González Cruz, Rodríguez-Medina and Déniz, 2009).
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Revista Ingeniería Investigación y Tecnología | Facultad de Ingeniería UNAM

Revista Ingeniería Investigación y Tecnología | Facultad de Ingeniería UNAM

Fuschsman et al., 2007). The Ni/Al and V/Al ratios pres- ent similar variations along the core and in agreement with those observed for N1. The Pb/Al ratio in the top (5 to 6 cm) show high values that may be a result of an unusual Pb supply originated from either the Grijalva River, the atmospheric supplies, or the oil-industry re- lated activities (Varela, 2007). Furthermore, a correla- tion analyses of normalized data for total metals, namely Fe/Al with Mn/Al, Ni/Al with V/Al, and Ni/Al with V/Al were found to be statistically significant (p < 0.05; n = 24; Table 1). These results further confirm an influence of sediments originated from oil wells. Addi- tional cluster and principal components analyses for normalized data of total metals reveal four conglomer- ates formed by the Fe/Al, Mn/Al, Ni/Al and V/Al ratios, while those presenting no statistical significance were found to be the Pb/Al and Ba/Al ratios (Balsam et al., 2007), (S4, Supplementary Information Section).
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Toxins of the sulfocarbamoyl group, main- ly C1 and C2, predominate during adaptation and maximal growth, and thereafter toxins of the carbamoyl group dominate. Therefore it is plausible to infer that in the sampled bloom, G. catenatum population was in decay. This possibility is supported by the absence or low densities of dinoflagellates observed a week afterwards. It is important to note that natural toxicity and toxin composition is the result of the cell response to specific physical and chemical conditions from the sampled area (Cembella 1998, Montoya et al. 2010). There- fore in a direct comparison with other studies it is only valuable to look for a general pattern of local or regional populations, if any. Studies made in natural conditions of Mexican waters of G. catenatum present important variations in the toxin profile with no clear patterns (Gárate-Lizárraga et al. 2004a, 2004b, 2006, Hernández-Sandoval et al. 2009) indicating a clear necessity for further field investigation for this species.
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Full PDF

Seagrasses, in general terms, appear to be relatively tolerant to many anthropogenic chemicals. Several species have been shown to be less sensitive to chemicals than other species of marine flora, corals and macroinvertebrates. In addition, some seagrasses bioaccumulate chemicals at lower concentrations (Lewis & Devereux 2009). Damage to seagrass communi- ties from oil exposure includes acute mortality resulting from physical impacts and chemical toxicity; indirect mortality as the result of light loss, death of food sources, or the destruction or removal of habitat; destruction of sensitive juve- nile fishes and invertebrates; and accumulation of potentially carcinogenic or mutagenic sub- stances in the food chain (Zieman et al. 1984). Fauna and flora associated with seagrasses are also affected by oil. Infauna, nearly completely killed by oil exposure, gradually returned to abundances above prespill levels. However, only species with high reproductive potential or planktonic stages recovered quickly. The effects of oil on tropical fish have not been extensively studied (Peters et al. 1997).
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Mortality and stock assessment of the brown shrimp, Penaeus aztecus (Crustacea: Penaeidae), in the northwest Gulf of Mexico

Mortality and stock assessment of the brown shrimp, Penaeus aztecus (Crustacea: Penaeidae), in the northwest Gulf of Mexico

Abstract: Fishing mortality of the brown shrimp (Penaeus aztecus) was estimated off Tamaulipas (northwest Gulf of Mexico). Monthly age structure and fishing effort data for the 1974-1980 period, and cohort analysis by the virtual population analysis (VPA) technique were used. Catchability estimates indieate higher values for the first matnrity age (six months old), fishing mortality inereases with age, with an asymptotic tendeney after 8-9 rnoths

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Estatus micorrízico de Jacaratia mexicana y hongos formadores de micorriza arbuscular presentes en selvas bajas caducifolias del Golfo de México

Estatus micorrízico de Jacaratia mexicana y hongos formadores de micorriza arbuscular presentes en selvas bajas caducifolias del Golfo de México

We evaluated the mycorrhizal status of Jacaratia mexicana A. DC. and the presence of arbuscular mycorrhizal fungi (AMF) in three patches of dry deciduous forests located on the slope of the Gulf of Mexico. There were no mycorrhizal structures in any of the materials collected in field, and therefore the susceptibility of this specie to AMF was determined. The study revealed the presence of arbuscles and vesicles 15 days after inoculation. Six morphospecies were identified: Glomus intraradices, G. constrictum, G. sinuosum, Glomus sp. 1, Glomus sp. 2. and Entrophospora infrequens. The only related morphospecies in sampled sites were G. intraradices and G. sinuosum, and they were also fairly abundant in Veracruz (8, 870 and 5), Campeche (958 and 448) and Yucatán (3,708 and 16). All of them have not been reported associated with J. mexicana in our country before.
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