Effect of groundwater regime on the behaviour of clayey slopes

2004 ◽  
Vol 41 (3) ◽  
pp. 467-484 ◽  
Author(s):  
Luciano Picarelli ◽  
Gianfranco Urciuoli ◽  
Claudia Russo
Keyword(s):  
Pore Pressure ◽  
Water Table ◽  
Slope Failure ◽  
Slope Movements ◽  
The World ◽  
Landslide Reactivation ◽  
Groundwater Regime ◽  
Pressure Changes ◽  
First Time ◽  
Simple Models

It is well known that many landslides, which occur every year in the world, are triggered by rainfall. The mechanics of slope movements due to pore pressure changes are not completely understood, however, and thus are the focus of this paper. Both the case of first-time slides and that of landslide reactivation are examined. It is shown that simple models can reproduce the processes of slope failure and may help in predicting slope behaviour.Key words: slope, failure, landslide, analysis, water table, clay.

Interpreting pore-water pressure changes induced by water table fluctuations and mechanical loading due to soil moisture changes

2012 ◽  
Vol 49 (3) ◽  
pp. 357-366 ◽  
Author(s):  
Collins Ifeanyichukwu Anochikwa ◽  
Garth van der Kamp ◽  
S. Lee Barbour
Keyword(s):  
Soil Moisture ◽  
Pore Pressure ◽  
Mechanical Loading ◽  
Water Table ◽  
Pressure Response ◽  
Stress Strain ◽  
Near Surface ◽  
Water Table Fluctuations ◽  
Pore Pressure Response ◽  
Pressure Changes

Pore pressures within saturated subsurface formations respond to stress changes due to loading as well as to changes in pore pressure at the boundaries of the formation. The pore-pressure dynamics within a thick aquitard in response to water table fluctuations and mechanical loading due to soil moisture changes have been simulated using a coupled stress–strain and groundwater flow finite element formulation. This modelling approach isolates the component of pore-pressure response of soil moisture loading from that caused by water table fluctuations, by using a method of superposition. In this manner, the contributions to pore-pressure fluctuations that occur as a result of surface moisture loading (e.g., precipitation, evapotranspiration) can be isolated from the pore-pressure record. The required elastic stress–strain properties of the aquitard were obtained from the measured pore-pressure response to barometric pressure changes. Subsequently, the numerical simulations could be calibrated to the measured response by adjusting only the hydraulic conductivity. This paper highlights the significance of moisture loading effects in pore-pressure observations and describes an efficient technique for obtaining in situ stress–strain and hydraulic properties of near-surface aquitards.

Atmospheric pressure compared to rainfall as landslide triggering factors along a hillslope

2021 ◽  
Author(s):  
Lucas Pelascini ◽  
Philippe Steer ◽  
Laurent Longuevergne
Keyword(s):  
Slope Stability ◽  
Pore Pressure ◽  
Water Table ◽  
Atmospheric Pressure ◽  
Pressure Change ◽  
Unconfined Aquifer ◽  
Air Pressure ◽  
Water Infiltration ◽  
Landslide Occurrence ◽  
Pressure Changes

<p>Landslides are one of the sources of natural hazards that cause damages and losses but also shapes the landscape. A better understanding the factors triggering or pre-conditioning landslide occurrence is therefore critical for risk assessment, with implications for hillslope erosion and landscape dynamics Triggering of catastrophic landslides is generally associated with events such as earthquakes or intense rainfalls. In Taiwan, a minimum of 22,705 landslides were reported during the typhoon Morakot in 2009 (Lin et al., 2011). Landslides triggered during storms are generally associated to the intensity and cumulated amount of rainfall, as water infiltration destabilize slopes (Iverson, 2000). However, a correlation has also been reported between slope stability and the change in atmospheric pressure (Schulz, 2009). Indeed, a change in air-pressure can lead in a readjustment in pore pressure, and cause fluid movements normal to the surface. The aim of this study is to characterize the effect of atmospheric pressure changes and define its specific contribution on slope stability when combined with rainfall</p><p>A 2-dimensional analytical model has been developed based on diffusion equations to describe the destabilization induced by water infiltration and atmospheric pressure changes induced by typhoons. As both mechanisms are function of pore pressure, and especially groundwater pore pressure, the water table within a finite-length hillslope is modelled using Townley’s (1995) analytical expression of water flow in a unconfined aquifer. The hillslope itself is a simple tilted half-space with a water divide at the top and a river at the toe forcing the water table to the surface. Slope stability is inferred through a safety factor computed using the coulomb criterion. Both rainfall infiltration and air pressure modify pore pressure through a diffusion process. While rainfall increases water table height and induce large increases in pore pressure within days or hours, , we show that atmospheric-induced pore pressure change is instantaneous and can occur even if the hillslope is fully saturated.</p><p>The model allows to separate the hillslope response into two regimes, upslope or downslope, where the destabilization is mainly linked to rainfall or to atmospheric pressure change, respectively.  Our results suggest that landslide occurring during storms in the downstream part of the hillslope are likely candidate for being triggered by atmospheric pressure change, in particular if the storm occurs with a humid initial condition. We show that the effect of atmospheric pressure changes is not negligible. On contrary, it is crucial to define the amplitude, timing and geometry of the hillslope instability, especially when combined to rainfall.</p>

SEROPREVALENCE OF HIV AND HBsAg AMONGST BLOOD DONORS IN A TERTIARY CARE HOSPITAL, CHHATTISGARH.

2019 ◽  
Vol 3 (8) ◽  
Author(s):  
Anusha P ◽  
Bankar Nandkishor J ◽  
Karan Jain ◽  
Ramdas Brahmane ◽  
Dhrubha Hari Chandi
Keyword(s):  
Hepatitis B ◽  
Blood Donors ◽  
Hepatitis B Surface Antigen ◽  
Tertiary Care ◽  
Laboratory Diagnosis ◽  
Blood Bank ◽  
Care Hospital ◽  
Medical College ◽  
The World ◽  
First Time

INTRODUCTION: India being the second highly populated nation in the world. HIV/AIDS has acquired pandemic proportion in the world. Estimate by WHO for current infection rate in Asia. India has the third largest HIV epidemic in the world. HIV prevalence in the age group 15-49 yrs was an estimate of 0.2%. India has been classified as an intermediate in the Hepatitis B Virus (HBV) endemic (HBsAg carriage 2-7%) zone with the second largest global pool of chronic HBV infections. Safety assessment of the blood supply, the quality of screening measures and the risk of transfusion transmitted infectious diseases (TTIs) in any country can be estimated by scrutinizing the files of blood donors. After the introduction of the blood banks and improved storage facilities, it became more extensively used. Blood is one of the major sources of TTIs like hepatitis B, hepatitis C, HIV, syphilis, and many other blood borne diseases. Disclosure of these threats brought a dramatic change in attitude of physicians and patients about blood transfusion. The objective of this study is to determine the seroprevalence of transfusion transmitted infections amidst voluntary blood donors at a rural tertiary healthcare teaching hospital in Chhattisgarh. MATERIAL AND METHODS: This retrospective study was carried out in Chandulal Chandrakar Memorial Medical College, Kachandur, Durg. Blood donors were volunteers, or and commercial donors who donated the blood and paid by patients, their families, or friends to replace blood used or expected to be used for patients from the blood bank of the hospital. After proper donation of blood routine screening of blood was carried out according to standard protocol. Laboratory diagnosis of HIV 1 and HIV 2 was carried out by ELISA test. Hepatitis B surface antigen was screened by using ELISA. RESULTS: A total of 1915 consecutive blood donors’ sera were screened at Chandulal Chandrakar Memorial Medical College, blood bank during study period. Of these 1914 were male and 1 female. The mean age of patients was found to be 29.34 years with standard deviation (SD) of 11.65 Years. Among all blood donors in present study, 759(39.63%) were first time donors and 1156(60.37%) were repeated donors. 1 patient was HIV positive in first donation group while 3 (75%) were positive in repeat donation group. 7 (38.9%) were HBsAg positive in in first donation group while 11(61.1%) were positive in repeat donation group. Two patients in first donation group had dual infection of HIV and HBsAg. CONCLUSION: Seropositivity was high in repeated donors as compared to first time donors. The incidence of HIV is observed to be 0.2% and that of HBsAg is 0.94%. Strict selection of blood donors should be done to avoid transfusion-transmissible infections during the window period.

First report of Rinamba opacicollis Cameron (Hymenoptera: Braconidae, Doryctinae) in India as parasitoid of coffee stem borer, Xylotrechus quadripes (Chevrolat) (Coleoptera: Cerambycidae)

ENTOMON ◽  
2020 ◽  
Vol 44 (4) ◽  
pp. 311-314
Author(s):  
A. Roobakkumar ◽  
H.G. Seetharama ◽  
P. Krishna Reddy ◽  
M.S. Uma ◽  
A. P. Ranjith
Keyword(s):  
Integrated Control ◽  
Host Record ◽  
Stem Borer ◽  
Arabica Coffee ◽  
First Report ◽  
The World ◽  
First Time

Rinamba opacicollis Cameron (Hymenoptera: Braconidae) was collected from Chikkamagaluru, Karnataka, India for the first time from the larvae of white stem borer, Xylotrechus quadripes Chevrolat infesting arabica coffee. Its role in the biological or integrated control of X. quadripes remains to be evaluated. White stem borer could be the first host record of this parasitoid all over the world.

PERSPECTIVE DEVELOPMENT OF WORLD PRODUCTION OF FEEDS FOR AQUACULTURE: ALTERNATIVE SOURCES OF RAW MATERIALS

2017 ◽  
pp. 67-78
Author(s):  
Lina Yurievna Lagutkina
Keyword(s):  
Raw Materials ◽  
Limiting Factors ◽  
Current Status ◽  
Feed Production ◽  
The World ◽  
Market Trends ◽  
Alternative Sources ◽  
World Industry ◽  
First Time ◽  
A Current

The author of the article discloses the prospects of development of the world feed production for aquaculture based on the analysis of key innovative technological and market trends. The author specifies that shortage, high cost, low ecological compatibility of traditional raw materials - fish flour - are among major limiting factors in the development of production of feeds for aquaculture. This fact, in turn, limits sustainable development of aquaculture both in Russia, and in the world in general. The article presents the overview of a current status of the world industry of feed production in aquaculture, where the regional situation is studied, as well. For the first time, there is given the outlook of innovative technologies in feed production based on the alternative sources of protein (on the example of projects of leading aquabiotechnological companies) which will determine industry’s objectives for the mid-term perspective.

History Turmoil And Politico-Cultural Conditions of the Sub-Continental Men In Salman Rushdie’s Midnight’s Children

2015 ◽  
Vol 2 (2) ◽  
pp. 26-28
Author(s):  
Gunasekaran N ◽  
Bhuvaneshwari S
Keyword(s):  
Middle Class ◽  
Salman Rushdie ◽  
Fiction Writing ◽  
Pluralistic Society ◽  
Post Colonial ◽  
Cultural Conditions ◽  
The World ◽  
Midnight's Children ◽  
First Time

Salman Rushdie remains a major Indian writer in English. His birth coincides with the birth of a new modern nation on August 15, 1947. He has been justly labelled by the critics as a post-colonial writer who knows his trade well. His second novel Midnight’s Children was published in 1981 and it raised a storm in the hitherto middle class world of fiction writing both in English and in vernaculars. Rushdie for the first time burst into the world of fiction with subversive themes like impurity, illegitimacy, plurality and hybridity. He understands that a civilization called India may be profitably understood as a dream, a collage of many colours, a blending of cultures and nationalities, a pluralistic society and in no way unitary.

Sphagnum mosses (Sphagnaceae, Bryophyta) of South Ossetia (Caucasus)

2017 ◽  
Vol 51 ◽  
pp. 232-241 ◽  
Author(s):  
G. Ya. Doroshina ◽  
E. Yu. Kuzmina ◽  
I. A. Nikolajev
Keyword(s):  
The South ◽  
The Caucasus ◽  
South Ossetia ◽  
Sphagnum Mosses ◽  
Botanical Institute ◽  
Ecological Conditions ◽  
Komarov Botanical Institute ◽  
The World ◽  
First Time

Information on the Sphagnum mosses of the South Ossetia is generalized, the resulted list is presented. Nine species of Sphagnum are included in the list, whereabouts data and references to the publications are given, and the presence of a sample in the Herbarium of the Komarov Botanical Institute RAS (LE) is noted. The species Sphagnum platyphyllum (Lindb. ex Braithw.) Warnst. rarely occurring in the Caucasus is reported in the South Ossetia for the first time. The species was found in the Caucasus, South Ossetia, at the side of the Ertso Lake (42°28ʹN, 43°45ʹE), 1720 m a. s. l., among sedge thickets at the margin of the overgrowing lake. The peculiarities of its occurrence and ecological conditions are considered. Its distribution in the Caucasus and in the world is discussed.

scholarly journals First Report on the Geologic Occurrence of Natural Na–A Zeolite and Associated Minerals in Cretaceous Mudstones of the Paja Formation of Vélez (Santander), Colombia

Crystals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 218
Author(s):  
Carlos Alberto Ríos-Reyes ◽  
German Alfonso Reyes-Mendoza ◽  
José Antonio Henao-Martínez ◽  
Craig Williams ◽  
Alan Dyer
Keyword(s):  
Natural Zeolite ◽  
Scanning Electron Micrographs ◽  
Total Sulfur ◽  
Zeolite A ◽  
X Ray Diffraction ◽  
X Ray ◽  
Mineral Phases ◽  
The World ◽  
Porosity And Permeability ◽  
First Time

This study reports for the first time the geologic occurrence of natural zeolite A and associated minerals in mudstones from the Cretaceous Paja Formation in the urban area of the municipality of Vélez (Santander), Colombia. These rocks are mainly composed of quartz, muscovite, pyrophyllite, kaolinite and chlorite group minerals, framboidal and cubic pyrite, as well as marcasite, with minor feldspar, sulphates, and phosphates. Total organic carbon (TOC), total sulfur (TS), and millimeter fragments of algae are high, whereas few centimeters and not biodiverse small ammonite fossils, and other allochemical components are subordinated. Na–A zeolite and associated mineral phases as sodalite occur just beside the interparticle micropores (honeycomb from framboidal, cube molds, and amorphous cavities). It is facilitated by petrophysical properties alterations, due to processes of high diagenesis, temperatures up to 80–100 °C, with weathering contributions, which increase the porosity and permeability, as well as the transmissivity (fluid flow), allowing the geochemistry remobilization and/or recrystallization of pre-existing silica, muscovite, kaolinite minerals group, salts, carbonates, oxides and peroxides. X-ray diffraction analyses reveal the mineral composition of the mudstones and scanning electron micrographs show the typical cubic morphology of Na–A zeolite of approximately 0.45 mμ in particle size. Our data show that the sequence of the transformation of phases is: Poorly crystalline aluminosilicate → sodalite → Na–A zeolite. A literature review shows that this is an unusual example of the occurrence of natural zeolites in sedimentary marine rocks recognized around the world.

scholarly journals Remarkable Species Diversity of the Leafhopper Genus Xestocephalus (Hemiptera: Cicadellidae: Aphrodinae) in Thailand

Insects ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 514
Author(s):  
Zonglei Liang ◽  
Christopher H. Dietrich ◽  
Wu Dai
Keyword(s):  
New Species ◽  
Species Diversity ◽  
Single Species ◽  
Comparative Morphology ◽  
Malaise Trap ◽  
Field Sampling ◽  
Tropical Regions ◽  
Trap Field ◽  
The World ◽  
First Time

Xestocephalus Van Duzee is among the most common and widespread genera of Cicadellidae in the temperate and tropical regions of the world. In the present study, 205 specimens of the genus Xestocephalus were collected in Thailand, whereas only a single species of the genus was recorded previously using Malaise trap field sampling, studied by comparative morphology. Seventeen species were recognized, including twelve new species: X. binarius sp. nov., X. chrysanthemum sp. nov., X. cowboyocreus sp. nov., X. densprint sp. nov., X. dimiprocessus sp. nov., X. exproiecturus sp. nov., X. gracilus sp. nov., X. limpidissimus sp. nov., X. malleus sp. nov., X. nonattribus sp. nov., X. recipinams sp. nov., and X. tenusis Liang sp. nov. Four species were recorded in Thailand for the first time: Xestocephalus abyssinicus Heller and Linnavuori, Xestocephalus asper Linnavuori, Xestocephalus ishidae Matsumura, and Xestocephalus toroensis Matsumura. Detailed morphological descriptions of all 17 species are given; photographs of external habitus and male genitalia of the species from Thailand are provided. A checklist of species of the genus is also given, and a key to all Thailand Xestocephalus species is also provided.

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