scholarly journals Risks involved in vertical shafts construction for the eastern drainage tunnel in Mexico

2021 ◽  
Vol 37 (1) ◽  
Author(s):  
Victor Jiménez Arguelles ◽  
◽  
Luis Rocha Chiu ◽  
Aurora Poó Rubio ◽  
◽  
...  
Keyword(s):  
Mexico City ◽  
Soil Type ◽  
Large Diameter ◽  
Vertical Wells ◽  
Drainage Tunnel ◽  
Different Types

This article describes the main stages involved in the construction of the vertical shafts (large-diameter vertical wells), which are necessary for the subsequent construction of the tunnel´s sections. The different risk situations existing during the construction of the Eastern Drainage Tunnel in the valley of Mexico City (in Spanish, "Tunel Emisor Oriente") are analyzed. In order for this 52 km-long and 7.5 m-wide tunnel to carry part of the city’s sewage, 25 shafts must first be built, ranging from 55 to 150 meters deep. The magnitude of such a project implies working in different geographical areas and varied geological strata involving the presence of groundwater, which increases the risks due to possible landslides or flooding during excavation. As digging will occur in different types of soil, varying procedures must be used depending on soil type. Likewise, due to the magnitude of this kind of project, detailed scheduling and planning are required as simultaneous works on different fronts are necessary to meet deadlines. The study mentions that, while projects like these involve high risks for workers, analysis of activities and situations are conducted precisely to demonstrate that such risks can be considerably reduced.

Coupling CFD-BES Simulation of a glazed office with different types of windows in Mexico City

2013 ◽  
Vol 68 ◽  
pp. 22-34 ◽  
Author(s):  
M. Gijón-Rivera ◽  
J. Xamán ◽  
G. Álvarez ◽  
J. Serrano-Arellano
Keyword(s):  
Mexico City ◽  
Different Types

scholarly journals Forage diversity and nutrition supply of reindeer

Rangifer ◽  
1993 ◽  
Vol 13 (4) ◽  
pp. 169 ◽  
Author(s):  
Hans Staaland ◽  
Stein Sæbø
Keyword(s):  
Soil Type ◽  
Nutritional Requirements ◽  
Reindeer Herding ◽  
Environmental Diversity ◽  
Forage Plants ◽  
Different Types ◽  
Nitrogen Concentrations ◽  
Forage Diversity ◽  
Different Levels ◽  
Eastern Norway

This study describes the mineral and nitrogen concentrations of reindeer forage plants from the Elgå reindeer herding district of south-eastern Norway. The data are compared with results from 5 other areas in Norway. Emphasis is put on the importance of environmental diversity. Different plant species accumulate Ca, Mg, P, S, Na, K, CI and K to a varying degree but reindeer can meet their nutritional requirements by eating different types of forage. Examples are sodium from aquatic herbs, sulphur and sodium from horsetails etc. Of further importance are variations in soil type, phenological development of plants in relation to differences in time for snowmelting, as well as different levels of nutrients in forage from different geographical.

scholarly journals Temperature deformation of frozensoils at sharp change of temperature

2017 ◽  
pp. 66-71
Author(s):  
S. S. Volokhov ◽  
I. N. Nikitin ◽  
D. S. Lavrov
Keyword(s):  
Temperature Change ◽  
Soil Type ◽  
Sudden Change ◽  
Frozen Soil ◽  
Temperature Deformation ◽  
Sharp Change ◽  
Frozen Soils ◽  
One Stage ◽  
Different Types ◽  
Number Of Cycles

The results are described of the study of temperature deformation of different types of frozen soil in the cycles of cooling-heating at sudden change in temperature. The differences in the nature of the temperature deformation at step and one stage temperature change are shown. The dependences are investigated of the temperature deformation of frozen soils on soil type, moisture and total number of cycles of cooling-heating.

scholarly journals Genesis and characteristics of the soil in A-R stage in forest ecosystems of NP 'Tara'

2009 ◽  
pp. 75-89 ◽  
Author(s):  
Milan Knezevic ◽  
Olivera Kosanin
Keyword(s):  
Scots Pine ◽  
Soil Type ◽  
Forest Ecosystems ◽  
Specific Effect ◽  
Basal Area ◽  
Physical Characteristics ◽  
Average Volume ◽  
Humid Climate ◽  
Different Types ◽  
Volume Current

Different types of soil in A-R stage formed on limestone and serpentinite in forest ecosystems in NP 'Tara' were researched. Based on the specific effect of limestone on the soil genesis and evolution, two types of calcareous limestone bedrocks were distinguished: dense limestones, and soft, marly limestones. Three subtypes of black earth were studied on dense limestones. They are: organogenic, organo-mineral and brownised soils. One soil type was researched on soft, marly limestones: rendzina, the leached variety. One soil type was researched on serpentinites, within the A-R stage: humus-siliceous soil (ranker), subtype eutric ranker. This paper also presents the evaluation of ecological and productive characteristics of the study soils. If the soil is observed separately, regardless of the tree species growing on it, the soils in A-R stage in NP 'Tara' cannot be evaluated as highly productive. However, in all plant communities on the soils in A-R stage on limestone, the values of average volume, current volume increment, and basal area were high. The unfavourable physical characteristics of the soil in the area of NP 'Tara' are compensated by the effect of humid climate. On the study eutric humus siliceous soils in the area of NP 'Tara', in the natural and artificially established stands of Scots pine and Austrian pine, the ecological and productive value is conditioned by numerous factors and it is mainly limited by unfavourable physical characteristics. Regardless of the unfavourable ecological and productive characteristics of the soil, the natural and artificially established stands of Scots pine and Austrian pine are in the coeno-ecological optimum.

Experimental Study of Well Deviation Correction Model in Deviated and Horizontal Wells Production Profile

2012 ◽  
Vol 490-495 ◽  
pp. 2205-2209
Author(s):  
Jun Feng Liu ◽  
Hai Min Guo
Keyword(s):  
Experimental Data ◽  
Fluid Flow ◽  
Large Diameter ◽  
Horizontal Wells ◽  
Velocity Model ◽  
Data Interpretation ◽  
Internal Diameter ◽  
Affecting Factors ◽  
Vertical Wells ◽  
Two Phase

There are big difference of fluid flow patterns between horizontal wells and vertical wells, so the current interpretation models of production logging multiphase flow in vertical wells are not suitable for data interpretation in highly deviated and horizontal wells. In this paper, firstly, the two-phase flow (oil-water and gas-water) simulation experiments have been carried out in large-diameter (0.124 meter internal diameter) uphill, horizontal and downhill Plexiglas pipe with practical production logging tools. Secondly, based on the conclusions of fluid flow mechanism from experimental data analysis, and considering the affecting factors (i.e. Logging tool and well deviation ), we have obtained slip velocity model after well deviation correction in highly deviated and horizontal wells, which have been corrected by the mature interpretation models. Finally, this proposed method has been proved correct and feasible through the experimental data validation.

scholarly journals Soil susceptibility to compaction under use conditions in southern Brazil

2017 ◽  
Vol 41 (1) ◽  
pp. 60-71 ◽  
Author(s):  
Michael Mazurana ◽  
Renato Levien ◽  
Alberto Vasconcellos Inda Junior ◽  
Osmar Conte ◽  
Luiz Antônio Bressani ◽  
...  
Keyword(s):  
Soil Type ◽  
Organic Matter Content ◽  
Matter Content ◽  
Soil Resistance ◽  
Mineralogical Characteristics ◽  
Compressibility Index ◽  
Different Types ◽  
Precompression Stress ◽  
Agricultural Use ◽  
The Impact

ABSTRACT The degree of soil compaction is intensified by its inadequate management, compaction being variable depending on soil type since even under identical management conditions, different types have different abilities to withstand load. The objective of this study was to evaluate the susceptibility to compaction of different classes of soils under no-tillage (NT) croping system compared to the original condition. Thus, i) soils with the same source material have distinct resistance to compression with increased NT adoption time; ii) the most sensitive indicators of this change are the ratios mass:volume and volume:volume and; iii) there is a relationship between resistance and compaction susceptibility with the amount and type of oxide. Soil samples were collected in areas under NT and under natural condition in order to assess the impact imposed by the NT on the attributes density and porosity, precompression stress and compressibility index and relate them to the oxide type of, and content in, the soils under study. The results show that the density and macroporosity were those most affected by the NT agricultural use, regardless of soil type, that is, its dynamic is related more to soil use and less to mineralogical characteristics. The soil resistance and compaction susceptibility were higher in soil developed in basalt, followed by those developed in sandstone and granite. Both the organic matter content and type and concentration of iron oxides were related to the soil resistance and susceptibility to compaction.

Prevalence of Yersinia enterocolitica in Raw Cow's Milk Collected from Stables of Mexico City

2013 ◽  
Vol 76 (4) ◽  
pp. 694-698 ◽  
Author(s):  
LIZELDI BERNARDINO-VARO ◽  
ELSA IRMA QUIÑONES-RAMÍREZ ◽  
FRANCISCO J. FERNÁNDEZ ◽  
CARLOS VÁZQUEZ-SALINAS
Keyword(s):  
Mexico City ◽  
Yersinia Enterocolitica ◽  
Cow’S Milk ◽  
Cow's Milk ◽  
Significant Difference ◽  
Different Types ◽  
Time Of Year ◽  
Different Strains ◽  
Raw Cow’S Milk ◽  
Milk And Dairy Products

Yersinia enterocolitica has been isolated from a batch of pork-derived products, from healthy and diseased animals, and from different types of milk and dairy products, among others. We studied the prevalence and diversity of Y. enterocolitica isolated from raw cow's milk collected from stables in Mexico City. Of the 1,300 samples analyzed, Y. enterocolitica was isolated in 454, with an average of 25% positive samples for each stable. Of the total isolated bacteria of the Yersinia genus, 44.25% were Y. enterocolitica, 18.28% were Y. kristensenii, 13.65% were Y. intermedia, 14.85% were Y. frederiksenii, and 9.14% were Y. aldovae. Among the different strains of Y. enterocolitica, biotype 1A was present in 70%, biotype 2 in 13.2%, biotype 3 in 8.54%, and biotype 4 in 8.15% of samples. Serotypes O:5, O:3, O:2, and O:9 were found in all biotypes identified. There were no statistically significant differences in the isolation of this bacterium with respect to the stables where they were found, although there was significant difference regarding the time of year. The data obtained in this work show the need to protect public health in Mexico against infections transmitted by raw cow's milk.

Endovascular treatment of complex abdominal aortic aneurysms by combining different types of endoprostheses

Vascular ◽  
2016 ◽  
Vol 24 (4) ◽  
pp. 425-429 ◽  
Author(s):  
Menno T de Bruijn ◽  
Erik Tournoij ◽  
Daniel AF van den Heuvel ◽  
Debbie de Vries-Werson ◽  
Jan Wille ◽  
...  
Keyword(s):  
Large Diameter ◽  
Abdominal Aortic Aneurysms ◽  
Aortic Aneurysms ◽  
Special Focus ◽  
Technical Success ◽  
Aortic Neck ◽  
Abdominal Aortic ◽  
Different Types

Purpose To describe an off-the-shelf method for the treatment of abdominal aortic aneurysms with hostile (large, >30 mm) neck and/or small (<20 mm) aortic bifurcation. Case report We describe five patients with large aortic necks and/or small aortic bifurcations, which were treated by combining an AFX endoprosthesis with a Valiant Captiva endograft, and additional proximal endoanchors when deemed necessary. Initial technical success was 100%. Follow-up ranged from 228 to 875 days. One patient suffered a type 1A and 1B endoleak at 446 days follow-up, which were successfully treated by endovascular means. Conclusion Combining the AFX and Valiant Captiva endografts is an off-the-shelf solution for treatment of large diameter aortic necks and small aortic bifurcations in patients deemed unfit for open repair or declined for fenestrated endografts. Longer follow-up is required to assess the long-term safety with special focus on aortic neck dilation.

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