WorldWideScience

Sample records for colossendeis megalonyx hoek

  1. Youngest radiocarbon age for Jefferson's ground sloth, Megalonyx jeffersonii (Xenarthra, Megalonychidae)

    DEFF Research Database (Denmark)

    Gregory McDonald, H.; Stafford, Thomas W.; Gnidovec, Dale M.

    2015-01-01

    A partial skeleton of the extinct ground sloth, Megalonyx jeffersonii, recovered from a farm near Millersburg, Ohio in 1890, was radiocarbon dated for the first time. The ungual dated is part of a skeleton mounted for exhibit at the Orton Geological Museum at Ohio State University and was the fir...

  2. Discovery of scientific correspondence of P.P.C. Hoek (1851—1914), including three unpublished letters by Charles Darwin

    NARCIS (Netherlands)

    Pieters, Florence F.J.M.; Winthagen, Diny

    1990-01-01

    Recently the scientific correspondence of the Dutch zoologist P.P.C. Hoek (1851—1914) turned up in the Artis Library. This collection contains three hitherto unpublished letters from Charles Darwin. It appears that Charles Darwin recommended Hoek to the favour of Sir Charles Wyville Thomson upon

  3. Implementation of the Modified Hoek-Brown Model into the Finite Element Method

    DEFF Research Database (Denmark)

    Sørensen, Emil Smed; Clausen, Johan Christian; Merifield, Richard S.

    2015-01-01

    The Hoek-Brown model for near-homogeneous rock masses will, in some cases, overpredict the tensile strength of the material. In some cases this can lead to unsafe design of structures. Therefore, a tension cut-off is introduced and the model is implemented into an elasto-plastic framework for use...

  4. Numerical Implementation of the Hoek-Brown Material Model with Strain Hardening

    DEFF Research Database (Denmark)

    Sørensen, Emil Smed; Clausen, Johan; Damkilde, Lars

    2013-01-01

    A numerical implementation of the Hoek-Brown criterion is presented, which is capable of modeling important aspects of the different post-failure behaviors observed in jointed rock mass. This is done by varying the material parameters based on the accumulated plastic strains. The implementation i....... The constitutive model is demonstrated on a simulation of a tunnel excavation and the results are compared with an analytical solution for a tunnel excavation in elastic-brittle rock material.......A numerical implementation of the Hoek-Brown criterion is presented, which is capable of modeling important aspects of the different post-failure behaviors observed in jointed rock mass. This is done by varying the material parameters based on the accumulated plastic strains. The implementation...

  5. Analytical Solution of Displacements Around Circular Openings in Generalized Hoek-Brown Rocks

    Directory of Open Access Journals (Sweden)

    Huang Houxu

    2017-09-01

    Full Text Available The rock in plastic region is divided into numbers of elements by the slip lines, resulted from shear localization. During the deformation process, the elements will slip along the slip lines and the displacement field is discontinuous. Slip lines around circular opening in isotropic rock, subjected to hydrostatic stress are described by the logarithmic spirals. Deformation of the plastic region is mainly attributed to the slippage. Relationship between the shear stresses and slippage on slip lines is presented, based on the study of Revuzhenko and Shemyakin. Relations between slippage and rock failure are described, based on the elastic-brittle-plastic model. An analytical solution is presented for the plane strain analysis of displacements around circular openings in the Generalized Hoek-Brown rock. With properly choosing of slippage parameters, results obtained by using the proposed solution agree well with those presented in published sources.

  6. Extratos metanólico e acetato de etila de Solanum megalonyx Sendtn. (Solanaceae apresentam atividade espasmolítica em íleo isolado de cobaia: um estudo comparativo

    Directory of Open Access Journals (Sweden)

    Rita de Cássia M. Oliveira

    Full Text Available Solanum megalonyx Sendtn. (Solanaceae é conhecida popularmente por "jurubeba" no Nordeste do Brasil e se apresenta na forma de arbusto. Várias espécies de Solanum apresentam efeito espasmolítico em órgãos isolados. Assim, objetivou-se investigar e comparar o efeito dos extratos metanólico (SM-MeOH e acetato de etila (SM-AcOEt, obtidos das partes aéreas de S. megalonyx, em íleo isolado de cobaia. SM-MeOH e SM-AcOEt antagonizaram (n = 5 as contrações fásicas induzidas por 1 mM de acetilcolina (logCI50 = 3,2 ± 0,1 e 1,8 ± 0,6 mg/mL, respectivamente ou de histamina (logCI50 = 2,8 ± 0,5 e 1,7 ± 0,3 mg/mL, respectivamente. SM-MeOH e SM-AcOEt também relaxaram (n = 5 o íleo pré-contraído por 40 mM de KCl (logCE50 = 1,9 ± 0,09 e 1,9 ± 0,1 mg/mL, respectivamente, por 1 mM de histamina (logCE50 = 1,9 ± 0,07 e 1,7 ± 0,08 mg/mL, respectivamente ou de acetilcolina (logCE50 = 1,9 ± 0,02 e 1,7 ± 0,09 mg/mL, respectivamente de maneira dependente de concentração e equipotente. Demonstra-se pela primeira vez que S. megalonyx apresenta efeito espasmolítico não seletivo em íleo isolado de cobaia, sugerindo que os extratos podem estar agindo em um passo comum da via de sinalização dos agentes contráteis testados.

  7. Seismic stability analysis of rock slopes by yield design theory using the generalized Hoek-Brown criterion

    Directory of Open Access Journals (Sweden)

    Belghali Mounir

    2018-01-01

    Full Text Available The stability of rock slope is studied using the kinematic approach of yield design theory, under the condition of plane strain and by considering the last version of the Hoek-Brown failure criterion. This criterion, which is suitable to intact rock or rock mass highly fractured regarded as isotropic and homogeneous, is widely accepted by the rock mechanics community and has been applied in numerous projects around the world. The failure mechanism used to implement the kinematic approach is a log-spiral rotational mechanism. The stability analysis is carried out under the effects of gravity forces and a surcharge applied along the upper plateau of the slope. To take account of the effects of forces developed in the rock mass during the passage of a seismic wave, the conventional pseudo-static method is adopted. This method is often used in slope stability study for its simplicity and efficiency to simulate the seismic forces. The results found are compared with published numerical solutions obtained from other approaches. The comparison showed that the results are almost equal. The maximum error found is less than 1%, indicating that this approach is effective for analyzing the stability of rock slopes. The relevance of the approach demonstrated, investigations are undertaken to study the influence of some parameters on the stability of the slope. These parameters relate to the mechanical strength of the rock, slope geometry and loading.

  8. Effect of Small Numbers of Test Results on Accuracy of Hoek-Brown Strength Parameter Estimations: A Statistical Simulation Study

    Science.gov (United States)

    Bozorgzadeh, Nezam; Yanagimura, Yoko; Harrison, John P.

    2017-12-01

    The Hoek-Brown empirical strength criterion for intact rock is widely used as the basis for estimating the strength of rock masses. Estimations of the intact rock H-B parameters, namely the empirical constant m and the uniaxial compressive strength σc, are commonly obtained by fitting the criterion to triaxial strength data sets of small sample size. This paper investigates how such small sample sizes affect the uncertainty associated with the H-B parameter estimations. We use Monte Carlo (MC) simulation to generate data sets of different sizes and different combinations of H-B parameters, and then investigate the uncertainty in H-B parameters estimated from these limited data sets. We show that the uncertainties depend not only on the level of variability but also on the particular combination of parameters being investigated. As particular combinations of H-B parameters can informally be considered to represent specific rock types, we discuss that as the minimum number of required samples depends on rock type it should correspond to some acceptable level of uncertainty in the estimations. Also, a comparison of the results from our analysis with actual rock strength data shows that the probability of obtaining reliable strength parameter estimations using small samples may be very low. We further discuss the impact of this on ongoing implementation of reliability-based design protocols and conclude with suggestions for improvements in this respect.

  9. An Illustration of Determining Quantitatively the Rock Mass Quality Parameters of the Hoek-Brown Failure Criterion

    Science.gov (United States)

    Wu, Li; Adoko, Amoussou Coffi; Li, Bo

    2018-04-01

    In tunneling, determining quantitatively the rock mass strength parameters of the Hoek-Brown (HB) failure criterion is useful since it can improve the reliability of the design of tunnel support systems. In this study, a quantitative method is proposed to determine the rock mass quality parameters of the HB failure criterion, namely the Geological Strength Index (GSI) and the disturbance factor ( D) based on the structure of drilling core and weathering condition of rock mass combined with acoustic wave test to calculate the strength of rock mass. The Rock Mass Structure Index and the Rock Mass Weathering Index are used to quantify the GSI while the longitudinal wave velocity ( V p) is employed to derive the value of D. The DK383+338 tunnel face of Yaojia tunnel of Shanghai-Kunming passenger dedicated line served as illustration of how the methodology is implemented. The values of the GSI and D are obtained using the HB criterion and then using the proposed method. The measured in situ stress is used to evaluate their accuracy. To this end, the major and minor principal stresses are calculated based on the GSI and D given by HB criterion and the proposed method. The results indicated that both methods were close to the field observation which suggests that the proposed method can be used for determining quantitatively the rock quality parameters, as well. However, these results remain valid only for rock mass quality and rock type similar to those of the DK383+338 tunnel face of Yaojia tunnel.

  10. Invasion and morphological variation of the non-indigenous barnacle Chthamalus challengeri (Hoek, 1883) in Yangshan Port and its surrounding areas

    Science.gov (United States)

    Liu, Yan; Xue, Junzeng; Lin, Junda; Wu, Huixian

    2015-06-01

    Invasive species generally possess unique characteristics that allow them to survive the invasion process in order to establish and spread in new habitats. Successful invaders must resist both physical and physiological stresses associated with the changing environment. A common littoral barnacle, Chthamalus challengeri Hoek, 1883 (Crustacea, Cirripedia), which is native to Japan, South Korea and northern China, has become established in the high-littoral zone adjacent to Yangshan Port, Shanghai, China. A comparison of the morphology of Chthamlus species from Zhoushan archipelago with previous description indicates the occurrence of C. challengeri. The new immigrant becomes a dominant species in certain high-intertidal habitats of the adjacent area to of Yangshan Port. C. challengeri was found in part of sampling sites in Zhoushan in 2010; however, it dispersed to all the eleven sampling sites in 2012. Densities of C.challengeri had increased over 10 times in the last 2 years, with the highest mean value reaching 39533 ± 6243 ind. m-2 in the new habitat. The specific ratios of both operculum area ( Sa) to base area ( SA) and average height of parietal plates ( H) to length of base ( L) revealed that C. challengeri displays morphological changes to resist stronger currents in the new habitats for invasion.

  11. Modified Stability Charts for Rock Slopes Based on the Hoek-Brown Failure Criterion / Zmodyfikowane Diagramy Stabilności Skalistych Zboczy Otrzymane W Oparciu O Warunek Wytrzymałości Hoeka-Browna

    Science.gov (United States)

    Nekouei, Mahdi; Ahangari, Kaveh

    2013-09-01

    Only an article rendered by Lia et al. in 2008 has represented charts based on Hoek-Brown criterion for rock slopes, however, these charts are not precise and efficient. Because of this problem, a modification is suggested for the mentioned charts in this study. The new charts are calculated according to four methods. Among the methods, one relates to finite element method using Phase2 software. The other three methods are Janbu, Bishop and Fellenius that belong to limit equilibrium method by using Slide software. For each slope angle, the method having high correlation coefficient is selected as the best one. Then, final charts are rendered according to the selected method and its specific equations. Among forty equations, twenty-five ones or 62.5% relate to numerical method and Phase2 software, six ones or 15% belong to Fellenius limit equilibrium, six ones or 15% relate to Bishop limit equilibrium, and three ones or 7.5% belong to Janbu limit equilibrium. In order to validate new charts, slope stability analysis is carried out for several sections of Chadormalu iron ore open pit mine, Iran. The error percentage of new charts in limit equilibrium method using Slide software and in Bishop method for slopes of Chadormalu iron ore mine are rendered and compared. The charts on a basis of Hoek-Brown failure criterion for rock slopes show less than ±4% error. This indicates that these charts are appropriate tools and their safety factor is optimal for rock slopes. Diagramy stabilności skalistych zboczy otrzymane w oparciu o warunek wytrzymałości Hoeka- Browna znaleźć można jedynie w pracy Lia et al. (2008), choć wykresy te nie są absolutnie dokładne i jasne. Dlatego też w niniejszym artykule zaproponowano pewną modyfikację diagramów. Nowe wykresu sporządzono w oparciu o cztery metody. Jedna z metod opiera się na metodzie elementów skończonych i wykorzystuje oprogramowanie Phase2. Pozostałe trzy podejścia to metody Janbu, Bishopa i Felleniusa bazuj

  12. Concurrentie uit onverwachte hoek voor aanbieders live sportcontent

    NARCIS (Netherlands)

    Rene Foolen

    2016-01-01

    We bevinden ons in een snel veranderend medialandschap. Technologische ontwikkelingen zorgen voor veranderingen in het mediagedrag van de consument. On demand kijken is volledig ingeburgerd en zeker Millennials kijken nauwelijks nog op een lineaire manier televisie. Live sport lijkt een

  13. Finite element implementation of the Hoek-Brown material model with general strain softening behavior

    DEFF Research Database (Denmark)

    Sørensen, Emil Smed; Clausen, Johan Christian; Damkilde, Lars

    2015-01-01

    A numerical implementation of the Hoek–Brown criterion is presented, which is capable of modeling different post-failure behaviors observed in jointed rock mass. This is done by making the material parameters a function of the accumulated plastic strain. The implementation is for use in finite...... for perfectly-plastic, brittle and strain softening material behavior and the results are compared with known solutions....

  14. Removal of Pb (II Ions from Aqueous Solutions by Cladophora rivularis (Linnaeus Hoek

    Directory of Open Access Journals (Sweden)

    Naser Jafari

    2012-01-01

    Full Text Available Biosorption of Pb(II using Cladophora rivularis was examined as a function of initial pH heavy metal concentration and temperature. The optimum pH value for the biosorption of lead was 4.0. The adsorption equilibriums were well described by Langmuir and Freundlich isotherm models and it was implied by the results that the C. rivularis biomass is suitable for the development of efficient biosorbent in order to remove Pb(II from wastewater and to recover it. The high values of correlation coefficient (2=0.984 demonstrate equilibrium data concerning algal biomass, which is well fitted in Freundlich isotherms model equations. The dimensionless parameter RL is found in the range of 0.0639 to 0.1925 (0<<1, which confirms the favorable biosorption process. Fourier transform infra-red (FTIR spectroscopy of C. rivularis was used to reveal the main function groups of biosorption, which were hydroxyl, amine groups, C–H stretching vibrations of –CH3 and –CH2, and complexation with functional groups. All these results suggest that C. rivularis can be used effectively for removal of Pb(II.

  15. Removal of Pb (II) ions from aqueous solutions by Cladophora rivularis (Linnaeus) Hoek.

    Science.gov (United States)

    Jafari, Naser; Senobari, Zoreh

    2012-01-01

    Biosorption of Pb(II) using Cladophora rivularis was examined as a function of initial pH heavy metal concentration and temperature. The optimum pH value for the biosorption of lead was 4.0. The adsorption equilibriums were well described by Langmuir and Freundlich isotherm models and it was implied by the results that the C. rivularis biomass is suitable for the development of efficient biosorbent in order to remove Pb(II) from wastewater and to recover it. The high values of correlation coefficient (R(2) = 0.984) demonstrate equilibrium data concerning algal biomass, which is well fitted in Freundlich isotherms model equations. The dimensionless parameter R(L) is found in the range of 0.0639 to 0.1925 (0 < R(L) < 1), which confirms the favorable biosorption process. Fourier transform infra-red (FTIR) spectroscopy of C. rivularis was used to reveal the main function groups of biosorption, which were hydroxyl, amine groups, C-H stretching vibrations of -CH3 and -CH2, and complexation with functional groups. All these results suggest that C. rivularis can be used effectively for removal of Pb(II).

  16. PPO Glastuinbouw en LEI helpen biologische ketenprojecten op weg: "vernieuwing moet wel uit de biologische hoek komen"

    NARCIS (Netherlands)

    Staalduinen, van Jan; Poot, E.H.; Wertheim-Heck, S.C.O.

    2006-01-01

    Het biologische marktsegment is vanwege de hogere kostprijs van het geteelde product een natuurlijke kraamkamer voor productinnovatie. De zoektocht naar tastbaar onderscheid en aansprekende verkoopconcepten vereist multidisciplinaire samenwerking van teelt- en marktonderzoek. LEI en PPO Glastuinbouw

  17. [The fossil record of the Eurasian Neogene insectivores (Erinaceomorpha, Soricomorpha, Mammalia) : Part I / L.W. van den Hoek Ostende, C.S. Doukas and J.W.F. Reumer (editors)]: Czech Republic and Slovak Republic

    NARCIS (Netherlands)

    Fejfar, O.; Sabol, M.

    2005-01-01

    Introduction The fossil record of insectivores in Czech Republic comes from two different settings: A. in the stratified deposits in the North Bohemian tectonic rift (the sites; Tuchořice, the Open Mine Merkur-Nord near Chomutov, Dolnice and Františkovy Lázně (Franzensbad), and Β. in the karstic

  18. Temporalized Epistemic Default Logic

    NARCIS (Netherlands)

    van der Hoek, W.; Meyer, J.J.; Treur, J.; Gabbay, D.

    2001-01-01

    The nonmonotonic logic Epistemic Default Logic (EDL) [Meyer and van der Hoek, 1993] is based on the metaphore of a meta-level architecture. It has already been established [Meyer and van der Hoek, 1993] how upward reflection can be formalized by a nonmonotonic entailment based on epistemic states,

  19. De "ander" als steun en spanningsbron: De precaire praktijk van lichte steun aan mensen met een psychiatrische achtergrond vanuit een welzijnsvoorziening

    Directory of Open Access Journals (Sweden)

    Anne Elberse

    2015-09-01

    Full Text Available The “other” as a source of both support and tension: the precarious practice of support for people with mental health problemsIn the 1960s, those living with mental health problems in the Netherlands stopped being placed into secluded institutions “in the woods”. Then, social policy began to aim at care in smaller institutions set in “normal” neighbourhoods. In the 1960s and 1970s, the general view was that it was not the person with mental health problems that needed to change, but rather that it was society that made this person ill. In the 1980s and 1990s, the focus of social policy shifted towards the individual and the notion that people with mental health problems need support from society to live like others. Nowadays, the expectation in social policy is that people with mental health problems should rely on their social networks and policy aims to increase the participation in society by those living with mental health problems.The empirical material in this paper is derived from a small-scale study that evaluated a programme called “Koffie om de Hoek” (Coffee around the corner, a place where people who have, or have had, mental health problems can meet in a community centre. The goal of Koffie om de Hoek is to minimize the barriers that users may experience when they want to participate in activities in their neighbourhood and wider society. Koffie om de Hoek focuses on people with mental health problems, but everyone who feels comfortable is welcome. Koffie om de Hoek started more than 10 years ago and it was only evaluated after the conclusion of the pilot period. Considering all the changes that have occurred in the social care sector, it was expected that there would be an increased need for facilities such as Koffie om de Hoek. However, visitor numbers were decreasing. Why do people come to Koffie om de Hoek? And why do some drop out, or not come at all? This was translated into the following research question:

  20. Slope Safety Factor Calculations With Non-Linear Yield Criterion Using Finite Elements

    DEFF Research Database (Denmark)

    Clausen, Johan; Damkilde, Lars

    2006-01-01

    The factor of safety for a slope is calculated with the finite element method using a non-linear yield criterion of the Hoek-Brown type. The parameters of the Hoek-Brown criterion are found from triaxial test data. Parameters of the linear Mohr-Coulomb criterion are calibrated to the same triaxial...... are carried out at much higher stress levels than present in a slope failure, this leads to the conclusion that the use of the non-linear criterion leads to a safer slope design...

  1. Landforms along transverse faults parallel to axial zone of folded ...

    Indian Academy of Sciences (India)

    Himalaya, along the Kali River valley, is defined by folded hanging wall ... role of transverse fault tectonics in the formation of the curvature cannot be ruled out. 1. .... Piedmont surface is made up of gravelliferous and ... made to compute the wedge failure analysis (Hoek .... (∼T2) is at the elevation of ∼272 m asl measured.

  2. Auditory Weighting Functions and TTS/PTS Exposure Functions for Marine Mammals Exposed to Underwater Noise

    Science.gov (United States)

    2016-12-01

    male I’a nui hahai TYH WEN MUK, NOC female HF Jacobs and Hall, 1972 Kastelein et al., 2002** Kastelein, Hoek, de Jong, and Wensveen...Ridgway, S. H., D. A. Carder, T. Kamolnick, R. R. Smith, C. E. Schlundt, and W. R. Elsberry. 2001. “Hearing and Whistling in the Deep Sea: Depth

  3. Journal of Chemical Sciences | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    The effectiveness of solvation as a dynamical probe in such complex systems has been discussed. pp 123-133. Time-resolved fluorescence analysis of the mobile flavin cofactor in -hydroxybenzoate hydroxylase · Petra A W Van Den Berg Koert Grever Arie Van Hoek Willem J H Van Berkel Antonie J W G Visser.

  4. The influence of environmental variables on the presence of white sharks, Carcharodon carcharias at two popular Cape Town bathing beaches: a generalized additive mixed model.

    Directory of Open Access Journals (Sweden)

    Kay Weltz

    Full Text Available Shark attacks on humans are high profile events which can significantly influence policies related to the coastal zone. A shark warning system in South Africa, Shark Spotters, recorded 378 white shark (Carcharodon carcharias sightings at two popular beaches, Fish Hoek and Muizenberg, during 3690 six-hour long spotting shifts, during the months September to May 2006 to 2011. The probabilities of shark sightings were related to environmental variables using Binomial Generalized Additive Mixed Models (GAMMs. Sea surface temperature was significant, with the probability of shark sightings increasing rapidly as SST exceeded 14 °C and approached a maximum at 18 °C, whereafter it remains high. An 8 times (Muizenberg and 5 times (Fish Hoek greater likelihood of sighting a shark was predicted at 18 °C than at 14 °C. Lunar phase was also significant with a prediction of 1.5 times (Muizenberg and 4 times (Fish Hoek greater likelihood of a shark sighting at new moon than at full moon. At Fish Hoek, the probability of sighting a shark was 1.6 times higher during the afternoon shift compared to the morning shift, but no diel effect was found at Muizenberg. A significant increase in the number of shark sightings was identified over the last three years, highlighting the need for ongoing research into shark attack mitigation. These patterns will be incorporated into shark awareness and bather safety campaigns in Cape Town.

  5. Obesity and anorexia

    NARCIS (Netherlands)

    Van Dijk, Gertjan; Kas, Martien J H

    2014-01-01

    Eating disorders frequently develop during adolescence or early adulthood. Much attention is paid to anorexia nervosa (AN) and bulimia nervosa (BN), both eating disorders that are more likely to be found in females than in males (Hoek, 2006). As of now, it is estimated that AN and BN affect about 3%

  6. Technostress

    NARCIS (Netherlands)

    2017-01-01

    Steeds meer werknemers kunnen onafhankelijk van plaats en tijd werken. Dit is het gevolg van (onder andere) technologische ontwikkelingen. Dit betekent dat vergaderingen onder het genot van een broodje en koffie in dat hippe tentje op de hoek plaatsvinden en dat die ene e-mail ook wel even kan

  7. Serious gaming ; onderzoek naar knelpunten en mogelijkheden van serious gaming

    NARCIS (Netherlands)

    Kranenburg, K. van; Mijke Slot, M.; Staal, M.; Leurdijk, A.; Burgmeijer, J.

    2006-01-01

    Gaming is een wereldwijde, omvangrijke industrie geworden. In deze industrie komt uit onverwachte hoek een interessante innovatie: serious gaming. In serious gaming gaat het niet om entertainment, maar staat een nuttige toepassing centraal. De toepassingen zijn zeer divers en kunnen variëren van

  8. Fulltext PDF

    Indian Academy of Sciences (India)

    from Delft, Netherlands. Making microscopes was Leeuwen- hoek's passion and he used his lenses to observe virtually every- thing around him. His microscope consisted of a single lens ... In 1675, he discovered 'living things' in ordinary ditch water, which ... species and also to produce a systematic classification of them.

  9. Slope stability analysis using limit equilibrium method in nonlinear criterion.

    Science.gov (United States)

    Lin, Hang; Zhong, Wenwen; Xiong, Wei; Tang, Wenyu

    2014-01-01

    In slope stability analysis, the limit equilibrium method is usually used to calculate the safety factor of slope based on Mohr-Coulomb criterion. However, Mohr-Coulomb criterion is restricted to the description of rock mass. To overcome its shortcomings, this paper combined Hoek-Brown criterion and limit equilibrium method and proposed an equation for calculating the safety factor of slope with limit equilibrium method in Hoek-Brown criterion through equivalent cohesive strength and the friction angle. Moreover, this paper investigates the impact of Hoek-Brown parameters on the safety factor of slope, which reveals that there is linear relation between equivalent cohesive strength and weakening factor D. However, there are nonlinear relations between equivalent cohesive strength and Geological Strength Index (GSI), the uniaxial compressive strength of intact rock σ ci , and the parameter of intact rock m i . There is nonlinear relation between the friction angle and all Hoek-Brown parameters. With the increase of D, the safety factor of slope F decreases linearly; with the increase of GSI, F increases nonlinearly; when σ ci is relatively small, the relation between F and σ ci is nonlinear, but when σ ci is relatively large, the relation is linear; with the increase of m i , F decreases first and then increases.

  10. Measurements of air pollution emission factors for marine transportation in SECA

    NARCIS (Netherlands)

    Alföldy, B.; Lööv, J.; Lagler, F.; Mellqvist, J.; Berg, N.; Beecken, J.; Weststrate, J.H.; Duyzer, J.H.; Bencs, L.; Horemans, B.; Cavalli, F.; Putaud, J.P.; Janssens-Maenhout, G.; Csordas, A.P.; Grieken, R. van; Borowiak, A.; Hjorth, J.

    2013-01-01

    The chemical composition of the plumes of seagoing ships was measured during a two week long measure- ment campaign in the port of Rotterdam, Hoek van Holland The Netherlands, in September 2009. Altogether, 497 ships were monitored and a statistical evaluation of emission factors (g kg−1 fuel) was

  11. metateoretiese perspektiewe op liggaamlike probleme as moontlike ...

    African Journals Online (AJOL)

    Liezel

    E-pos: wentzelcoetzer@telkomsa.net. Ds. H.P. Kotzé ..... vanuit 'n pastorale hoek was die Franse medikus en teoloog, Paul Tournier ... (1996); Arterburn (2005); Richardson (2005); Seamands (2003); John & Paula ... Collins (1988); Anderson et al. ... The healing power of the Christian mind: How Biblical truth can keep you.

  12. Privacy een grondrecht, maar ook handelswaar

    NARCIS (Netherlands)

    Olsthoorn, P.

    2015-01-01

    Snoeihard uit journalist Brenno de Winter zijn commentaar op sprekers over privacy tijdens het NLIGF congres 2015. Hij zet Bart Schermer, adviseur van bedrijven en organisaties in de hoek. Die heeft net betoogd dat privacy geen juk (‘korvee’) mag vormen maar inzet moet zijn van innovatie door

  13. An Exact Implementation Of The Hoek–Brown Criterion For Elasto-Plastic Finite Element Calculations

    DEFF Research Database (Denmark)

    Clausen, Johan; Damkilde, Lars

    2007-01-01

    A simple stress update algorithm for generalised Hoek-Brown plasticity is presented. It is intended for use in elasto-plastic finite element computations and utilises the return mapping concept for computing the stress increment belonging to a given increment in strain at a material point. In the...

  14. Hammarskjöld's visit to South Africa

    African Journals Online (AJOL)

    the Herero people of that territory had, through their Chiefs' Council, been petitioning the UN and ..... to major tourist sites in the city, then to Stellenbosch, Fransch Hoek, where he visited the .... would unite on the South African issue. A much ...

  15. Grote Hotels in Amsterdam

    NARCIS (Netherlands)

    Vermeer, G.

    2014-01-01

    De reiziger die Amsterdam binnenkomt via het Centraal Station ziet rechts van het Damrak meteen een beknopte geschiedenis van de hotelbouw in Amsterdam. Op de hoek, om twee kleinere huisjes heen, staat het oudste deel van het Victoriahotel (nu Victoria Plaza Hotel), dat in 1890 zijn deuren opende.

  16. verification by joint hydraulic factor

    Indian Academy of Sciences (India)

    sity, weak rocks, poor rock stability, and enhanced fluid flow (Hoek ..... The Seyahoo dam, which is a zoned earthfill clay core dam, is 32 m .... fracture may conduit cement, and thereby trig- .... cal imaging and tunnel documentation at the Hallandsas. Tunnel ... 57 1–12. Kutzner C 1996 Grouting of Rock and Soil; Balkema,.

  17. Assessment of characteristic failure envelopes for intact rock using results from triaxial tests

    OpenAIRE

    Muralha, J.; Lamas, L.

    2014-01-01

    The paper presents contributions to the statistical study of the parameters of the Mohr-Coulomb and Hoek-Brown strength criteria, in order to assess the characteristic failure envelopes for intact rock, based on the results of several sets of triaxial tests performed by LNEC. 10p DBB/NMMR

  18. Young children and obesity : development and evaluation of familiy-oriented treatment

    NARCIS (Netherlands)

    Hoek, van E.

    2015-01-01

    Thesis: Young Children and Obesity – Development and Evaluation of Family-oriented Treatment, Esther van Hoek

    Introduction

    The prevalence of childhood obesity has increased rapidly during the last decades. Childhood obesity is a multisystem disease with serious consequences such as

  19. Hammarskjöld's visit to South Africa

    African Journals Online (AJOL)

    His visit followed another police shooting – this time of unarmed protestors against the pass laws at Sharpeville, south of Johannesburg, on 21 March 1960 – and .... road is paved to Pretoria, not only through good intentions, but, I hope, also by .... to major tourist sites in the city, then to Stellenbosch, Fransch Hoek, where he.

  20. Baccharis halimifolia L. in Nederland: waar blijft Struikaster?

    NARCIS (Netherlands)

    Valkenburg, van Johan L.C.H.; Duistermaat, Leni H.; Meerman, Han

    2014-01-01

    Baccharis halimifolia L. (Struikaster) is voor het eerst in 2003 in Nederland waargenomen bij Kwade Hoek op Goeree. Sindsdien is de soort nog eenmaal waargenomen, in een verwaarloosde volkstuin. Ondertussen bleek hij tijdens een inspectie in 2012 te zijn verdwenen van de eerste locatie. De

  1. Crop model usefulness in drylands of southern Africa: an application ...

    African Journals Online (AJOL)

    Data limitations in southern Africa frequently hinder adequate assessment of crop models before application. ... three locations to represent varying cropping and physical conditions in southern Africa, i.e. maize and sorghum (Mohale's Hoek, Lesotho and Big Bend, Swaziland) and maize and groundnut (Lilongwe, Malawi).

  2. Evaluation of the Impact of Hydrostatic Pressure and Lode Angle on the Strength of the Rock Mass Based on the Hoek–Brown Criterion

    Directory of Open Access Journals (Sweden)

    Marczak Halina

    2015-06-01

    Full Text Available Determination of the global uniaxial compressive strength of rock mass on the basis of the Hoek-Brown failure criterion requires knowledge of the strength parameters: cohesion and the angle of internal friction. In the conventional method for the determination of these parameters given by Balmer, they are expressed by the minimum principal stress. Thus, this method does not allow for the assessment of an impact of hydrostatic pressure and stress path on the value of cohesion, friction angle and global uniaxial compression of rock mass. This problem can be eliminated by using the Hoek-Brown criterion expressed by the invariants of the stress state. The influence of hydrostatic pressure and the Lode angle on the strength parameters of the rock mass was analysed.

  3. Liability for the Payment of Public School Fees

    Directory of Open Access Journals (Sweden)

    M Carnelley

    2011-10-01

    Full Text Available The author highlights some legal issues regarding the liability of parents and other individuals to pay public school fees in the light of recent judicial precedent, specifically Fish Hoek Primary School v GW 2009 JOL 24624 (SCA. The various possible legal bases for the liability for such fees are examined. In this regard the common law duty to maintain as amended by legislation; contractual liability; and the concepts of household necessaries, stipulatio alteri, negotiorum gestio and unjustified enrichment are considered.

  4. An exploration of women entrepreneurship in Lesotho / M.A. Lebakeng

    OpenAIRE

    Lebakeng, Mampoi Agnes

    2008-01-01

    Women entrepreneurs are a vital contribution to today's economy, yet there is still a dearth of research on women entrepreneurs. The main part of the study presents an analysis of 54 women entrepreneurs in three districts of Lesotho, namely Maseru, Mafeteng and Mohale's Hoek. The Ministry of Trade and Industry in Lesotho provided a database of entrepreneurs in Lesotho. The survey instrument used was a structured questionnaire which was administered at women entrepreneurs in Lesotho and a resp...

  5. Evidence from Central Mexico Supporting the Younger Dryas Extraterrestrial Impact Hypothesis

    Science.gov (United States)

    2012-03-05

    numerous sites across North America, Greenland, and Western Europe. We have examined multiple hy- potheses to account for these observations and find...ka, a difference of approximately 20 kyr. Accounting for this shift requires major contamination of the TOC by radiocarbon- dead or very old carbon...before present; char, charcoal. §Van Hoesel A, Hoek W, Braadbaart F, van der Plicht H, Drury MR, Nanodiamonds and the Usselo layer, INQUA XVIII, July 21

  6. Vertebrate paleontology, stratigraphy, and paleohydrology of Tule Springs Fossil Beds National Monument, Nevada (USA)

    Science.gov (United States)

    Springer, Kathleen; Pigati, Jeffery S.; Scott, Eric

    2017-01-01

    Tule Springs Fossil Beds National Monument (TUSK) preserves 22,650 acres of the upper Las Vegas Wash in the northern Las Vegas Valley (Nevada, USA). TUSK is home to extensive and stratigraphically complex groundwater discharge (GWD) deposits, called the Las Vegas Formation, which represent springs and desert wetlands that covered much of the valley during the late Quaternary. The GWD deposits record hydrologic changes that occurred here in a dynamic and temporally congruent response to abrupt climatic oscillations over the last ~300 ka (thousands of years). The deposits also entomb the Tule Springs Local Fauna (TSLF), one of the most significant late Pleistocene (Rancholabrean) vertebrate assemblages in the American Southwest. The TSLF is both prolific and diverse, and includes a large mammal assemblage dominated by Mammuthus columbi and Camelops hesternus. Two (and possibly three) distinct species of Equus, two species of Bison, Panthera atrox, Smilodon fatalis, Canis dirus, Megalonyx jeffersonii, and Nothrotheriops shastensis are also present, and newly recognized faunal components include micromammals, amphibians, snakes, and birds. Invertebrates, plant macrofossils, and pollen also occur in the deposits and provide important and complementary paleoenvironmental information. This field compendium highlights the faunal assemblage in the classic stratigraphic sequences of the Las Vegas Formation within TUSK, emphasizes the significant hydrologic changes that occurred in the area during the recent geologic past, and examines the subsequent and repeated effect of rapid climate change on the local desert wetland ecosystem.

  7. Dining in the Pleistocene—Who's on the menu?

    Science.gov (United States)

    Kohn, Matthew J.; McKay, Moriah P.; Knight, James L.

    2005-08-01

    The Camelot local fauna, a new fossil locality in southeastern South Carolina, has yielded a spectacularly abundant and well-preserved late Irvingtonian (ca. 400 ka) megafauna, including saber-toothed cat (Smilodon fatalis), wolf (Canis armbrusteri), cheetah (Miracinonyx inexpectatus), “camels” (Hemiauchenia macrocephala and Paleolama mirifica), tapir (Tapirus veroensis), deer (Odocoileus virginianus), sloth (Megalonyx jeffersoni), and horse (Equus sp.). Of particular interest is the number of well-preserved fossil teeth and the ability to decipher paleoecologies and paleodiets, especially for carnivores, by using carbon isotope compositions (δ13C) of these teeth. P. mirifica, M. jeffersoni, O. virginianus, and T. veroensis have the lowest δ13C values (-16‰ to -13‰, Vienna Peedee belemnite standard); C. armbrusteri, S. fatalis, and H. macrocephala have intermediate values (-13‰ to -8‰); and Equus sp. has the highest values (-7‰ to -1‰). High (>-5‰) vs. low (≤-9‰) δ13C values for herbivores indicate local habitats dominated by warm-climate grasses vs. trees and shrubs. The high δ13C values for Equus sp. indicate the presence of grasslands, whereas the low δ13C values for the other herbivores generally indicate the presence of forests. Although few data are available for carnivores, moderate δ13C values for C. armbrusteri indicate that it preyed mainly upon forest herbivores. S. fatalis appears to have preferred marginal woodland-grassland areas.

  8. Geotechnical properties of rock

    Energy Technology Data Exchange (ETDEWEB)

    Jackson, R.; Gorski, B.; Gyenge, M.

    1995-12-31

    The manual is a compilation of the geotechnical properties of many types of rock that are typical of Canadian mining environments. Included are values for density, porosity, compressive and shear wave velocity, uniaxial compressive strength, Young`s modulus, and Poisson`s ratio. The data base contains material constants that were determined using the Hoek and Brown failure criteria for both before and after failure conditions. 76 data sheets of rock properties in Canadian mines are included. 7 refs., 85 figs., 3 tabs.

  9. Geomechanical properties of rocks from the Altnabreac area

    International Nuclear Information System (INIS)

    McEwen, T.J.; Horseman, S.T.; Lai, S.F.

    1980-06-01

    Laboratory test results are presented for core samples of Strath Halladale Granite and Moine metasediments from the Altnabreac Research Site in Caithness, Scotland. Properties measured include indirect tensile strength, uniaxial compressive strength, shear strength under triaxial confinement, stress-strain parameters, density and porosity. Strength data are interpreted using Hoek and Brown's (1980) empirical failure criterion which is found to provide an adequate fit to the failure envelopes. The rocks at the site have been classified using Deere and Millers' (1966) engineering classification system for intact rocks. (author)

  10. Bolt-Grout Interactions in Elastoplastic Rock Mass Using Coupled FEM-FDM Techniques

    Directory of Open Access Journals (Sweden)

    Debasis Deb

    2010-01-01

    Full Text Available Numerical procedure based on finite element method (FEM and finite difference method (FDM for the analysis of bolt-grout interactions are introduced in this paper. The finite element procedure incorporates elasto-plastic concepts with Hoek and Brown yield criterion and has been applied for rock mass. Bolt-grout interactions are evaluated based on finite difference method and are embedded in the elasto-plastic procedures of FEM. The experimental validation of the proposed FEM-FDM procedures and numerical examples of a bolted tunnel are provided to demonstrate the efficacy of the proposed method for practical applications.

  11. Rock properties data base

    Energy Technology Data Exchange (ETDEWEB)

    Jackson, R.; Gorski, B.; Gyenge, M.

    1991-03-01

    As mining companies proceed deeper and into areas whose stability is threatened by high and complex stress fields, the science of rock mechanics becomes invaluable in designing underground mine strata control programs. CANMET's Mining Research Laboratories division has compiled a summary of pre- and post-failure mechanical properties of rock types which were tested to provide design data. The 'Rock Properties Data Base' presents the results of these tests, and includes many rock types typical of Canadian mine environments. The data base also contains 'm' and 's' values determined using Hoek and Brown's failure criteria for both pre- and post-failure conditions. 7 refs., 3 tabs., 9 figs., 1 append.

  12. Relative scale and the strength and deformability of rock masses

    Science.gov (United States)

    Schultz, Richard A.

    1996-09-01

    The strength and deformation of rocks depend strongly on the degree of fracturing, which can be assessed in the field and related systematically to these properties. Appropriate Mohr envelopes obtained from the Rock Mass Rating (RMR) classification system and the Hoek-Brown criterion for outcrops and other large-scale exposures of fractured rocks show that rock-mass cohesive strength, tensile strength, and unconfined compressive strength can be reduced by as much as a factor often relative to values for the unfractured material. The rock-mass deformation modulus is also reduced relative to Young's modulus. A "cook-book" example illustrates the use of RMR in field applications. The smaller values of rock-mass strength and deformability imply that there is a particular scale of observation whose identification is critical to applying laboratory measurements and associated failure criteria to geologic structures.

  13. DEM Particle Fracture Model

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Boning [Univ. of Colorado, Boulder, CO (United States); Herbold, Eric B. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Homel, Michael A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Regueiro, Richard A. [Univ. of Colorado, Boulder, CO (United States)

    2015-12-01

    An adaptive particle fracture model in poly-ellipsoidal Discrete Element Method is developed. The poly-ellipsoidal particle will break into several sub-poly-ellipsoids by Hoek-Brown fracture criterion based on continuum stress and the maximum tensile stress in contacts. Also Weibull theory is introduced to consider the statistics and size effects on particle strength. Finally, high strain-rate split Hopkinson pressure bar experiment of silica sand is simulated using this newly developed model. Comparisons with experiments show that our particle fracture model can capture the mechanical behavior of this experiment very well, both in stress-strain response and particle size redistribution. The effects of density and packings o the samples are also studied in numerical examples.

  14. Strength and deformation behaviors of veined marble specimens after vacuum heat treatment under conventional triaxial compression

    Science.gov (United States)

    Su, Haijian; Jing, Hongwen; Yin, Qian; Yu, Liyuan; Wang, Yingchao; Wu, Xingjie

    2017-10-01

    The mechanical behaviors of rocks affected by high temperature and stress are generally believed to be significant for the stability of certain projects involving rocks, such as nuclear waste storage and geothermal resource exploitation. In this paper, veined marble specimens were treated to high temperature treatment and then used in conventional triaxial compression tests to investigate the effect of temperature, confining pressure, and vein angle on strength and deformation behaviors. The results show that the strength and deformation parameters of the veined marble specimens changed with the temperature, presenting a critical temperature of 600 °C. The triaxial compression strength of a horizontal vein (β = 90°) is obviously larger than that of a vertical vein (β = 0°). The triaxial compression strength, elasticity modulus, and secant modulus have an approximately linear relation to the confining pressure. Finally, Mohr-Coulomb and Hoek-Brown criteria were respectively used to analyze the effect of confining pressure on triaxial compression strength.

  15. New data on distribution, morphology and ecology of Oedogonium capillare Kützing ex Hirn (Oedogoniales, Chlorophyta in Poland

    Directory of Open Access Journals (Sweden)

    Marta Pikosz

    2015-12-01

    Full Text Available Algological investigations were focused on taxonomy, chorology and ecology of threatened filamentous green alga species in Poland. Studies on Oedogonium capillare Kützing ex Hirn growing in large quantities in association with Cladophora rivularis (Linnaeus Hoek in pond were conducted. The aim of these studies was to describe the distribution, ecology and morphology of O. capillare as part of a more comprehensive study of this filamentous green alga. It is the eighth record in Poland for O. capillare. Filaments of O. capillare were grown over a wide pH range (7.3-9.6 and in high variability of nutrients. Vegetative cells, oogonia and antheridia were observed, which allowed taxonomic identification. O. capillare occurs in eutrophic waters which requires protection of its habitat.

  16. Metal surveys in South African estuaries I. Swartkops River

    International Nuclear Information System (INIS)

    Watling, R.J.; Watling, H.R.

    1982-01-01

    Water, surface sediment and sediment core samples were collected from sites in the Swartkops River up to 15 km from the mouth and analysed for up to sixteen elements. The results indicate the presence of four main areas of contamination in the river, at Redhouse, Swartkops, the brickworks and Amsterdam Hoek. The accumulation of zinc, copper, lead and nickel by oysters grown at the mouth of the river confirms the presence of greater than normal metal concentrations in the river. Fish-water Flats outfall contributes metals to the nearshore marine environment, but the strong tidal sweep disperses the effluent relatively quickly so that metal build-up in the area is minimal. In general, metal levels in the Swartkops River are low and, as yet, the area cannot be described as 'polluted' in the true sense of the word

  17. Slope Stability Problems and Back Analysis in Heavily Jointed Rock Mass: A Case Study from Manisa, Turkey

    Science.gov (United States)

    Akin, Mutluhan

    2013-03-01

    This paper presents a case study regarding slope stability problems and the remedial slope stabilization work executed during the construction of two reinforced concrete water storage tanks on a steep hill in Manisa, Turkey. Water storage tanks of different capacities were planned to be constructed, one under the other, on closely jointed and deformed shale and sandstone units. The tank on the upper elevation was constructed first and an approximately 20-m cut slope with two benches was excavated in front of this upper tank before the construction of the lower tank. The cut slope failed after a week and the failure threatened the stability of the upper water tank. In addition to re-sloping, a 15.6-m deep contiguous retaining pile wall without anchoring was built to support both the cut slope and the upper tank. Despite the construction of a retaining pile wall, a maximum of 10 mm of displacement was observed by inclinometer measurements due to the re-failure of the slope on the existing slip surface. Permanent stability was achieved after the placement of a granular fill buttress on the slope. Back analysis based on the non-linear (Hoek-Brown) failure criterion indicated that the geological strength index (GSI) value of the slope-forming material is around 21 and is compatible with the in situ-determined GSI value (24). The calculated normal-shear stress plots are also consistent with the Hoek-Brown failure envelope of the rock mass, indicating that the location of the sliding surface, GSI value estimated by back analysis, and the rock mass parameters are well defined. The long-term stability analysis illustrates a safe slope design after the placement of a permanent toe buttress.

  18. Population pharmacokinetics of teicoplanin in hospitalized elderly patients using cystatin C as an indicator of renal function.

    Science.gov (United States)

    Kasai, Hidefumi; Tsuji, Yasuhiro; Hiraki, Yoichi; Tsuruyama, Moeko; To, Hideto; Yamamoto, Yoshihiro

    2018-04-01

    Serum cystatin C (CysC) has recently been proposed as an alternative marker to serum creatinine (SCR) for estimating renal clearance. In the present study, we performed a population pharmacokinetic analysis of teicoplanin (TEIC), which is mainly eliminated through the kidneys, using CysC as a predictor for renal clearance. Thirty-six patients with MRSA infections who were administrated to the National Hospital Organization Beppu Medical Center between January 2012 and December 2013 were enrolled and gave 123 sets of blood TEIC concentration data. Renal clearance was estimated by the Hoek equation using CysC, by creatinine clearance predicted by the Cockcroft-Gault equation using SCR, or directly by CysC. One compartment open model with inter-individual variabilities for renal clearance and the volume of distribution as well as an additional residual error model was used to estimate population pharmacokinetic parameters for TEIC. The model with the best predictability was that with CysC as a predictor for renal clearance; it showed better significance than the models using estimated the glomerular filtration rate by the Hoek equation or CLcr. The final model was as follows: CL (L/hr) = 0.510 × (CysC/1.4) -0.68  × Total body weight/60 0.81 , omega (CL) = 19.8% CV, VC (L) = 78.1, omega (V) = 42.7% CV. The present results show the usefulness of CysC to more accurately predict the pharmacokinetics of drugs mainly eliminated through the kidneys, such as TEIC. However, since the sample size in this study was relatively small, further investigations on renal clearance predictability using CysC are needed. Copyright © 2017 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

  19. Laboratory study of the characteristics of fault breccias in Busan area in Korea

    Science.gov (United States)

    Woo, I.; Um, J.

    2012-12-01

    The physical and mechanical characteristics of fault breccias from near the Mt. Kumjung were estimated from laboratory tests on fractured fault breccias. Mt. Kumjung is surrounded by Yangsan Fault and Dongrae Fault which are major faults traversing the southeast part of Korea in the direction of NE-SW. The undisturbed samples were obtained from boreholes drilled in this region. The microscopic analysis on the thin sections of fault breccias showed the microstructure and the porosity of breccias. The fault breccias are composed of mainly fine quartz grains, and of angular quartz grains and weathered microcline grains. This microstructure of fault breccias might be formed by the catalasis during brittle deformation processes of the fault. 20 to 40% porosity of fault breccias could play an important role in the passage of groundwater and then in the development of fault gouge in the core part of fault. The mechanical characteristics were estimated by means of uniaxial compressive strength tests on the undisturbed breccias samples. Since fault breccias are not cohesive enough to use it directly as a test specimen, the epoxy resin was utilized to fix the outer surface of core samples. The thin plastic wrap had been enveloped before the epoxy resin was applied in order that the epoxy resin could not penetrate into the core specimens. The thickness of epoxy resin was less than 1mm not to disturb the results of uniaxial compressive strength of core samples. The measured uniaxial compressive strengths are 10 to 15MPa for the only physically fractured breccias and 8 to 10 MPa for the core specimens with hydrothermally altered surface. These results can be compared with the Hoek and Brown failure criteria : 7 to 10MPa for GSI value 40 to 50 for fault breccias with fresh surface. The overall measured strength of fault breccias is less than the strength obtained empirically by Hoek and Brown failure criteria.; ;

  20. Slope Stability Analysis Based on Type, Physical And Mechanical Properties Rock in Teluk Pandan District, East Kutai Regency, East Kalimantan

    Directory of Open Access Journals (Sweden)

    Sujiman Kusnadi

    2017-12-01

    Full Text Available Research was located In Teluk Pandan District, East Kutai Regency, East Kalimantan Province.  It’s aimed to determine the lithology in the  research area and to find out how the amount of slope that will be a landslide at that location. The research conducted with the analysis of coring drilling results and then analyzed in the laboratory of rock mechanics to get the characteristic of physical and mechanical properties of the rocks. The data analysis using Hoek and Bray Method. The results showed that in the area study has a sedimentary rock lithology fine to medium detritus, such as claystone, siltstone and sandstone, as well as inserts are coal and shale. Based on the results of laboratory analysis of rock mechanics obtained density between 2,648 to 2,770. While the test results obtained value triaxial cohesion between (6.66 - 9:05 Kg / cm2, friction angle in between (37.19 - 44.08o, cohesion residual (2.72 - 3.10 Kg / cm2, residual friction angle (27.22 - 32.44o. While the direct shear test the cohesion of the summit between (6.66 - 9:05 Kg / cm2, friction angle in the cohesion peak (36.15 - 43.00o, cohesion residual (2:22 to 3:10 Kg / cm2, friction angle in the cohesion residual (37.22 - 33.85o. The simulation results stability of the slope stability Hoek and Bray using rockslide software, the result is that if the slope with a single slope stability, the stability of the slope is 60o, and if the slope with the stability of the slope overall stability of the slope is 48o.

  1. The mechanism and field test of permeability improvement by hydraulic flushing in three-soft and single coal seam%“三软”单一煤层水力冲孔卸压增透机理及现场试验

    Institute of Scientific and Technical Information of China (English)

    冯文军; 苏现波; 王建伟; 秦俊宾; 李贤忠

    2015-01-01

    Hydraulic flushing is the most effective way for high-efficient extraction in three-soft coal seam. In this paper, the mechanism was studied by laboratory experiment, theoretical analysis and field test for pressure relief and permeability improvement in three-soft coal seam after hydraulic flushing. The coupling experiment of stress and strain-coal structure-permeability revealed the evolution of permeability along with the change of the structure and stress, and found that permeability of soft coal was improved on a large scale after pressure relief. Based on Hoek-Brown criterion theory, the numerical simulation results show that the relief range increased significantly af-ter hydraulic flushing in coal. The hydraulic flushing tests using self-developed machine for gas drainage borehole in 21141 floor drainage tunnel of Daping Mine shows, the machine made hydraulic flushing more secure and effi-cient, and made it possible to repair the old drainage borehole . The field tests fully tested the reliability of the equipment and the accuracy of the above theoretical analysis, and improved the extraction efficiency significantly.%水力冲孔是实现“三软”煤层瓦斯高效抽采的有效途径之一。通过应力应变–煤体结构–渗透率的耦合实验,揭示了“三软”煤层渗透率随煤体结构和应力变化的演化规律,发现软煤在卸压后渗透率得到大规模提升。以Hoek-Brown准则为理论依据,通过数值模拟,发现水力冲孔出煤后的卸压增透范围显著增加。采用自主研发的“瓦斯抽采孔水力作业机”,在郑煤集团大平煤矿21141底板抽放巷进行了水力冲孔试验,使得水力冲孔更加安全、高效,并使得老孔的修复成为现实。现场试验充分检验了装备的可靠性和理论分析的准确性,显著提高了煤层瓦斯的抽采效率。

  2. The Three-Dimensional (3D) Numerical Stability Analysis of Hyttemalmen Open-Pit

    Science.gov (United States)

    Cała, Marek; Kowalski, Michał; Stopkowicz, Agnieszka

    2014-10-01

    The purpose of this paper was to perform the 3D numerical calculations allowing slope stability analysis of Hyttemalmen open pit (location Kirkenes, Finnmark Province, Norway). After a ramp rock slide, which took place in December 2010, as well as some other small-scale rock slope stability problems, it proved necessary to perform a serious stability analyses. The Hyttemalmen open pit was designed with a depth up to 100 m, a bench height of 24 m and a ramp width of 10 m. The rock formation in the iron mining district of Kirkenes is called the Bjornevaten Group. This is the most structurally complicated area connected with tectonic process such as folding, faults and metamorphosis. The Bjornevaten Group is a volcano-sedimentary sequence. Rock slope stability depends on the mechanical properties of the rock, hydro-geological conditions, slope topography, joint set systems and seismic activity. However, rock slope stability is mainly connected with joint sets. Joints, or general discontinuities, are regarded as weak planes within rock which have strength reducing consequences with regard to rock strength. Discontinuities within the rock mass lead to very low tensile strength. Several simulations were performed utilising the RocLab (2007) software to estimate the gneiss cohesion for slopes of different height. The RocLab code is dedicated to estimate rock mass strength using the Hoek-Brown failure criterion. Utilising both the GSI index and the Hoek-Brown strength criterion the equivalent Mohr-Coulomb parameters (cohesion and angle of internal friction) can be calculated. The results of 3D numerical calculations (with FLA3D code) show that it is necessary to redesign the slope-bench system in the Hyttemalmen open pit. Changing slope inclination for lower stages is recommended. The minimum factor of safety should be equal 1.3. At the final planned stage of excavation, the factor of safety drops to 1.06 with failure surface ranging through all of the slopes. In the case

  3. Determination of the mechanical parameters of rock mass based on a GSI system and displacement back analysis

    Science.gov (United States)

    Kang, Kwang-Song; Hu, Nai-Lian; Sin, Chung-Sik; Rim, Song-Ho; Han, Eun-Cheol; Kim, Chol-Nam

    2017-08-01

    It is very important to obtain the mechanical paramerters of rock mass for excavation design, support design, slope design and stability analysis of the underground structure. In order to estimate the mechanical parameters of rock mass exactly, a new method of combining a geological strength index (GSI) system with intelligent displacment back analysis is proposed in this paper. Firstly, average spacing of joints (d) and rock mass block rating (RBR, a new quantitative factor), surface condition rating (SCR) and joint condition factor (J c) are obtained on in situ rock masses using the scanline method, and the GSI values of rock masses are obtained from a new quantitative GSI chart. A correction method of GSI value is newly introduced by considering the influence of joint orientation and groundwater on rock mass mechanical properties, and then value ranges of rock mass mechanical parameters are chosen by the Hoek-Brown failure criterion. Secondly, on the basis of the measurement result of vault settlements and horizontal convergence displacements of an in situ tunnel, optimal parameters are estimated by combination of genetic algorithm (GA) and numerical simulation analysis using FLAC3D. This method has been applied in a lead-zinc mine. By utilizing the improved GSI quantization, correction method and displacement back analysis, the mechanical parameters of the ore body, hanging wall and footwall rock mass were determined, so that reliable foundations were provided for mining design and stability analysis.

  4. An update of conditions in the Donkin-Morien tunnels

    Energy Technology Data Exchange (ETDEWEB)

    Seedsman, R.W. [Seedsman Geotechnics Pty Ltd., Mt. Kembla (Australia)

    2009-07-01

    Two 7.6 diameter tunnels were constructed in the Donkin-Morien peninsula in Nova Scotia in 1984 and 1985. Ground support designs of the tunnel were based on the identification of rock failure zones using finite element analyses and the Hoek Brown failure criterion. The tunnels were flooded in 1992 when the mining project was abandoned. However, subsequent monitoring data from the tunnels were used to analyze brittle rock behaviour before and after its subsequent dewatering. This paper discussed the results of a feasibility study conducted to compare collapse zones in the roof and sides of the tunnel with results obtained from a simple elastic analysis technique that used brittle parameters, a spalling limit of 5, and a low-dependent shear modulus. Analyses were conducted to examine the potential maximum height of failure as a function of the coal seams. The study showed that coal measure rocks can be analyzed using the brittle failure criterion when both transverse anisotropy and low spalling limits were included. However, it is not possible to determine the contribution of corrosion to the deterioration of the tunnels. The analysis will be used to form a design for re-supporting the tunnels. 7 refs., 2 tabs., 7 figs.

  5. An update on mortality in Denmark caused by fine particulate matter air pollution

    DEFF Research Database (Denmark)

    Bønløkke, Jakob Hjort; Andersen, Mikael Skou; Brandt, Jørgen

    Introduction In terms of effects on mortality fine particulate matter (PM2.5) is considered the most important component of air polllution. Several international studies have investigated the effect size. It is estimated that overall mortality increases 6% per 10µg/m3 increase in annual PM2.......5 and that PM2.5 affects global mortality signficantly (Hoek, 2013). The first attempt to describe the size of the effects of PM2.5 in Denmark were published in 2002 (Raaschou-Nielsen, 2002). At that time only PM10 data were available and only with a great deal of uncertainty. Since then the knowledge of PM2...... to what extent the changes in estimates of mortality from PM2.5 exposure over the years is due to changes in population and in pollution and to what extent they are due to improved models. Methods Several methods of calculation were compared for the year 2012. First the method used in 2002 in which...

  6. An Elasto-Plastic Damage Model for Rocks Based on a New Nonlinear Strength Criterion

    Science.gov (United States)

    Huang, Jingqi; Zhao, Mi; Du, Xiuli; Dai, Feng; Ma, Chao; Liu, Jingbo

    2018-05-01

    The strength and deformation characteristics of rocks are the most important mechanical properties for rock engineering constructions. A new nonlinear strength criterion is developed for rocks by combining the Hoek-Brown (HB) criterion and the nonlinear unified strength criterion (NUSC). The proposed criterion takes account of the intermediate principal stress effect against HB criterion, as well as being nonlinear in the meridian plane against NUSC. Only three parameters are required to be determined by experiments, including the two HB parameters σ c and m i . The failure surface of the proposed criterion is continuous, smooth and convex. The proposed criterion fits the true triaxial test data well and performs better than the other three existing criteria. Then, by introducing the Geological Strength Index, the proposed criterion is extended to rock masses and predicts the test data well. Finally, based on the proposed criterion, a triaxial elasto-plastic damage model for intact rock is developed. The plastic part is based on the effective stress, whose yield function is developed by the proposed criterion. For the damage part, the evolution function is assumed to have an exponential form. The performance of the constitutive model shows good agreement with the results of experimental tests.

  7. LSSVM-Based Rock Failure Criterion and Its Application in Numerical Simulation

    Directory of Open Access Journals (Sweden)

    Changxing Zhu

    2015-01-01

    Full Text Available A rock failure criterion is very important for the prediction of the failure of rocks or rock masses in rock mechanics and engineering. Least squares support vector machines (LSSVM are a powerful tool for addressing complex nonlinear problems. This paper describes a LSSVM-based rock failure criterion for analyzing the deformation of a circular tunnel under different in situ stresses without assuming a function form. First, LSSVM was used to represent the nonlinear relationship between the mechanical properties of rock and the failure behavior of the rock in order to construct a rock failure criterion based on experimental data. Then, this was used in a hypothetical numerical analysis of a circular tunnel to analyze the mechanical behavior of the rock mass surrounding the tunnel. The Mohr-Coulomb and Hoek-Brown failure criteria were also used to analyze the same case, and the results were compared; these clearly indicate that LSSVM can be used to establish a rock failure criterion and to predict the failure of a rock mass during excavation of a circular tunnel.

  8. Hycycle. The feasibility of the introduction of the hydrogen bicycle to the Dutch citizen to promote social acceptance of the hydrogen economy; Hycycle. De haalbaarheid van de introductie van de waterstoffiets aan de Nederlandse burger ter bevordering van de maatschappelijke acceptatie van de waterstofeconomie

    Energy Technology Data Exchange (ETDEWEB)

    Makkus, R.C. [ECN Brandstofcel Technologie, Petten (Netherlands); Van Hoeven, K. [Van Hoeven Consult, Beuningen (Netherlands); Bastianen, H. [Sparta, Apeldoorn (Netherlands); D' Herripon, B. [IDbike, Goirle (Netherlands); Smolenaars, J.; Westendorp, G. [Hexion, Arnhem (Netherlands); De Wit, H. [Hoek Loos, Schiedam (Netherlands)

    2005-04-01

    A feasibility study has been carried out to develop a pedal assisted bicycle for which the required electrical energy is supplied by a PEM Fuel Cell system, the 'hycycle'. The bicycle is based on the existing electric Sparta Ion bicycle. It is concluded that such a 'hycycle' is technically and economically feasible, if the PEM Fuel Cell system is produced on a large scale. However, technical developments are needed before entering into a demonstration project. [Dutch] Hycycle is het concept van een waterstoffiets, gebaseerd op de bestaande elektrische Sparta Ion fiets. Hycycle wordt een trapbekrachtigde fiets die de benodigde (elektrische) energie uit waterstof haalt middels een brandstofcelsysteem. Hycycle is een haalbaarheidsstudie in her kader van het onderzoek naar transitiemogelijkheden naar een duurzame energiehuishouding in Nederland. Deze studie wordt verricht door een coalitie van Sparta, IDbike, ECN, Hexion, Hoek Loos en Van Hoeven Consult. Het project is uitgevoerd in de periode augustus 2004 tot en met februari 2005. Het doel van het onderzoek is om de haalbaarheid na te gaan van een praktisch demonstratieproject in Nederland van het gebruik van de waterstoffiets.

  9. Anaerobic bioleaching of metals from waste activated sludge

    KAUST Repository

    Meulepas, Roel J W

    2015-05-01

    Heavy metal contamination of anaerobically digested waste activated sludge hampers its reuse as fertilizer or soil conditioner. Conventional methods to leach metals require aeration or the addition of leaching agents. This paper investigates whether metals can be leached from waste activated sludge during the first, acidifying stage of two-stage anaerobic digestion without the supply of leaching agents. These leaching experiments were done with waste activated sludge from the Hoek van Holland municipal wastewater treatment plant (The Netherlands), which contained 342μgg-1 of copper, 487μgg-1 of lead, 793μgg-1 of zinc, 27μgg-1 of nickel and 2.3μgg-1 of cadmium. During the anaerobic acidification of 3gdry weightL-1 waste activated sludge, 80-85% of the copper, 66-69% of the lead, 87% of the zinc, 94-99% of the nickel and 73-83% of the cadmium were leached. The first stage of two-stage anaerobic digestion can thus be optimized as an anaerobic bioleaching process and produce a treated sludge (i.e., digestate) that meets the land-use standards in The Netherlands for copper, zinc, nickel and cadmium, but not for lead.

  10. Measurements of air pollution emission factors for marine transportation in SECA

    Directory of Open Access Journals (Sweden)

    B. Alföldy

    2013-07-01

    Full Text Available The chemical composition of the plumes of seagoing ships was measured during a two week long measurement campaign in the port of Rotterdam, Hoek van Holland The Netherlands, in September 2009. Altogether, 497 ships were monitored and a statistical evaluation of emission factors (g kg−1 fuel was provided. The concerned main atmospheric components were SO2, NO2, NOx and the aerosol particle number. In addition, the elemental and water-soluble ionic composition of the emitted particulate matter was determined. Emission factors were expressed as a function of ship type, power and crankshaft rotational speed. The average SO2 emission factor was found to be roughly half of what is allowed in sulphur emission control areas (16 vs. 30 g kg−1 fuel, and exceedances of this limit were rarely registered. A significant linear relationship was observed between the SO2 and particle number emission factors. The intercept of the regression line, 4.8 × 1015 (kg fuel−1, gives the average number of particles formed during the burning of 1 kg zero sulphur content fuel, while the slope, 2 × 1018, provides the average number of particles formed with 1 kg sulphur burnt with the fuel. Water-soluble ionic composition analysis of the aerosol samples from the plumes showed that ~144 g of particulate sulphate was emitted from 1 kg sulphur burnt with the fuel. The mass median diameter of sulphate particles estimated from the measurements was ~42 nm.

  11. Design principles for precision mechanisms

    CERN Document Server

    Soemers, Herman

    2011-01-01

    The successful design of mechanisms for products, tools and equipment relies on excellent concepts and properly designed details. Both are covered in this book. Many of the examples presented have been realised in practice and properly evaluated, giving the reader/designer a high level of confidence. Every example comes with the considerations underlying the application and the limitations of the particular idea. This book is based on the work started in the 1960s by W. van der Hoek at Philips in Eindhoven, the Netherlands, and subsequently continued by M.P. Koster, culminating in the Dutch-language book “Constructieprincipes” [Design principles for accurate movement and positioning]. The core of their design approach has been preserved, while theory and examples were updated and the English language was adopted to reach a broad audience within the Netherlands as well as abroad. Herman (H.M.J.R.) Soemers is associated with the University of Twente, Enschede, the Netherlands. He also works as a technolog...

  12. A Constitutive Model for Strain-Controlled Strength Degradation of Rockmasses (SDR)

    Science.gov (United States)

    Kalos, A.; Kavvadas, M.

    2017-11-01

    The paper describes a continuum, rate-independent, incremental plasticity constitutive model applicable in weak rocks and heavily fractured rockmasses, where mechanical behaviour is controlled by rockmass strength rather than structural features (discontinuities). The model describes rockmass structure by a generalised Hoek-Brown Structure Envelope (SE) in the stress space. Stress paths inside the SE are nonlinear and irreversible to better simulate behaviour at strains up to peak strength and under stress reversals. Stress paths on the SE have user-controlled volume dilatancy (gradually reducing to zero at large shear strains) and can model post-peak strain softening of brittle rockmasses via a structure degradation (damage) mechanism triggered by accumulated plastic shear strains. As the SE may strain harden with plastic strains, ductile behaviour can also be modelled. The model was implemented in the Finite Element Code Simulia ABAQUS and was applied in plane strain (2D) excavation of a cylindrical cavity (tunnel) to predict convergence-confinement curves. It is shown that small-strain nonlinearity, variable volume dilatancy and post-peak hardening/softening strongly affect the predicted curves, resulting in corresponding differences of lining pressures in real tunnel excavations.

  13. Triaxial-compression extraction of pore water from unsaturated tuff, Yucca Mountain, Nevada

    International Nuclear Information System (INIS)

    Yang, I.C.; Turner, A.K.; Sayre, T.M.; Montazer, P.

    1988-01-01

    The purpose of this experiment was to design and validate methods for extracting uncontaminated pore water from nonwelded parts of this tuff. Pore water is needed for chemical analysis to help characterize the local hydrologic system. A standard Hoek-Franklin triaxial cell was modified to create a chemically inert pore-water-extraction system. Experimentation was designed to determine the optimum stress and duration of triaxial compression for efficient extraction of uncontaminated pore water. Experimental stress paths consisted of a series of increasing stress levels. Trial axial stress levels ranged from 41 to 190 megapascals with lateral confining stresses of 34 to 69 megapascals. The duration of compression at any given stress level lasted from 10 minutes to 15 hours. A total of 40 experimental extraction trials were made. Tuff samples used in these tests were collected from drill-hole core from the Paintbrush nonwelded unit at Yucca Mountain. Pore water was extracted from tuff samples that had a water content greater than 13 percent by weight. Two stress paths have been determined to be applicable for future pore-water extraction from nonwelded tuff at Yucca Mountain. The initial water content of a sample affects the selection of an appropriate period of compression. 39 refs., 55 figs

  14. The Cladophora complex (Chlorophyta): new views based on 18S rRNA gene sequences.

    Science.gov (United States)

    Bakker, F T; Olsen, J L; Stam, W T; van den Hoek, C

    1994-12-01

    Evolutionary relationships among species traditionally ascribed to the Siphonocladales/Cladophorales have remained unclear due to a lack of phylogenetically informative characters and extensive morphological plasticity resulting in morphological convergence. This study explores some of the diversity within the generic complex Cladophora and its siphonocladalaen allies. Twelve species of Cladophora representing 6 of the 11 morphological sections recognized by van den Hoek were analyzed along with 8 siphonocladalaen species using 18S rRNA gene sequences. The final alignment consisted of 1460 positions containing 92 phylogenetically informative substitutions. Weighting schemes (EOR weighting, combinatorial weighting) were applied in maximum parsimony analysis to correct for substitution bias. Stem characters were weighted 0.66 relative to single-stranded characters to correct for secondary structural constraints. Both weighting approaches resulted in greater phylogenetic resolution. Results confirm that there is no basis for the independent recognition of the Cladophorales and Siphonocladales. The Siphonocladales is polyphyletic, and Cladophora is paraphyletic. All analyses support two principal lineages, of which one contains predominantly tropical members including almost all siphonocladalean taxa, while the other lineage consists of mostly warm- to cold-temperate species of Cladophora.

  15. Basicladia chelonum (Collins W.E. Hoffmann et Tilden (Chlorophyta, Cladophorophyceae from Cuba (Caribbean: new observation of the ultrastructure of its vegetative cells

    Directory of Open Access Journals (Sweden)

    Joanna Czerwik-Marcinkowska

    2011-01-01

    Full Text Available Basicladia chelonum (Collins W.E. Hoffmann and Tilden (1930 principally known from North America and Hawaii was recently (2004 found in Cuba (Caribbean from artificial pool growing on shells of musk turtles (Trachemys decussata Gray. Specimens collected in Cuba were subjected to detailed examinations also using a transmission electron microscope. On one hand, these studies confirmed many features of this species previously described by earlier authors in the specimens from Texas. On the other hand, the present studies revealed structures unknown so far (pyrenoid structure, which allowed for new analysis of this species. These investigations also have shown that Basicladia chelonum exhibits close similarity to the genus Cladophora and other representatives of the class Cladophorophyceae. The similarities include : siphonocladous level of organization of thallus, numerous chloroplasts forming a network and other structures. Conversely, the pyrenoid in vegetative cells of Basicladia chelonum distinguishes it markedly from representatives of the genus Cladophora, which have bilenticular pyrenoids divided into two hemispheres by a single thylakoids and each hemisphere is covered by a bowlshaped starch grain (Van Hoek et al. 1995. Since in Cladophora the ultrastructure of the pyrenoid is highly constant and characteristic, this contrasts with the genus Basicladia and, therefore, more firmly establishes position of the latter as an independent unit within Cladophorophyceae.

  16. A borehole stability study by newly designed laboratory tests on thick-walled hollow cylinders

    Directory of Open Access Journals (Sweden)

    S.S. Hashemi

    2015-10-01

    Full Text Available At several mineral exploration drilling sites in Australia, weakly consolidated formations mainly consist of sand particles that are poorly bonded by cementing agents such as clay, iron oxide cement or calcite. These formations are being encountered when drilling boreholes to the depth of up to 200 m. To study the behaviour of these materials, thick-walled hollow cylinder (TWHC and solid cylindrical synthetic specimens were designed and prepared by adding Portland cement and water to sand grains. The effects of different parameters such as water and cement contents, grain size distribution and mixture curing time on the characteristics of the samples were studied to identify the mixture closely resembling the formation at the drilling site. The Hoek triaxial cell was modified to allow the visual monitoring of grain debonding and borehole breakout processes during the laboratory tests. The results showed the significance of real-time visual monitoring in determining the initiation of the borehole breakout. The size-scale effect study on TWHC specimens revealed that with the increasing borehole size, the ductility of the specimen decreases, however, the axial and lateral stiffnesses of the TWHC specimen remain unchanged. Under different confining pressures the lateral strain at the initiation point of borehole breakout is considerably lower in a larger size borehole (20 mm compared to that in a smaller one (10 mm. Also, it was observed that the level of peak strength increment in TWHC specimens decreases with the increasing confining pressure.

  17. Single and multiple transverse fracture initiation from horizontal wells

    Energy Technology Data Exchange (ETDEWEB)

    Crosby, D.G.; Rahman, M.M.; Rahman, M.K.; Rahman, S.S. [School of Petroleum Engineering, The University of New South Wales, 2052 Sydney (Australia)

    2002-08-01

    The results of an analytical and experimental study of the initiation of transverse fractures from horizontal wells are presented. Analytical criteria for the initiation of single hydraulic fracture are reviewed, and criterion for initiation of multiple hydraulic fractures was developed by modification of the existing Drucker and Prager criterion for single hydraulic fracture initiation. The developed criterion for multiple fracture initiation was validated by comparisons with actual hydraulic fracture initiation pressures, which were obtained from scaled laboratory experiments and numerical results from boundary element analysis. Other criteria are assessed against the experimental results. Experimentally obtained transverse fracture initiation pressures were found close to longitudinal fracture initiation pressures estimated from maximum tensile stress criterion and Hoek and Brown criterion. One possible explanation of this finding is presented. Results from Drucker and Prager criteria for single and multiple fracture initiation were, however, found closer to experimental values. Therefore, these criteria could be useful to engineers involved with hydraulic fracturing for predicting transverse fracture initiation pressures from horizontal wells drilled parallel to the minimum horizontal in-situ stress.

  18. iSpectra: An Open Source Toolbox For The Analysis of Spectral Images Recorded on Scanning Electron Microscopes.

    Science.gov (United States)

    Liebske, Christian

    2015-08-01

    iSpectra is an open source and system-independent toolbox for the analysis of spectral images (SIs) recorded on energy-dispersive spectroscopy (EDS) systems attached to scanning electron microscopes (SEMs). The aim of iSpectra is to assign pixels with similar spectral content to phases, accompanied by cumulative phase spectra with superior counting statistics for quantification. Pixel-to-phase assignment starts with a threshold-based pre-sorting of spectra to create groups of pixels with identical elemental budgets, similar to a method described by van Hoek (2014). Subsequent merging of groups and re-assignments of pixels using elemental or principle component histogram plots enables the user to generate chemically and texturally plausible phase maps. A variety of standard image processing algorithms can be applied to groups of pixels to optimize pixel-to-phase assignments, such as morphology operations to account for overlapping excitation volumes over pixels located at phase boundaries. iSpectra supports batch processing and allows pixel-to-phase assignments to be applied to an unlimited amount of SIs, thus enabling phase mapping of large area samples like petrographic thin sections.

  19. A Copula-Based Method for Estimating Shear Strength Parameters of Rock Mass

    Directory of Open Access Journals (Sweden)

    Da Huang

    2014-01-01

    Full Text Available The shear strength parameters (i.e., the internal friction coefficient f and cohesion c are very important in rock engineering, especially for the stability analysis and reinforcement design of slopes and underground caverns. In this paper, a probabilistic method, Copula-based method, is proposed for estimating the shear strength parameters of rock mass. The optimal Copula functions between rock mass quality Q and f, Q and c for the marbles are established based on the correlation analyses of the results of 12 sets of in situ tests in the exploration adits of Jinping I-Stage Hydropower Station. Although the Copula functions are derived from the in situ tests for the marbles, they can be extended to be applied to other types of rock mass with similar geological and mechanical properties. For another 9 sets of in situ tests as an extensional application, by comparison with the results from Hoek-Brown criterion, the estimated values of f and c from the Copula-based method achieve better accuracy. Therefore, the proposed Copula-based method is an effective tool in estimating rock strength parameters.

  20. Translation and associative priming with cross-lingual pseudohomophones: evidence for nonselective phonological activation in bilinguals.

    Science.gov (United States)

    Duyck, Wouter

    2005-11-01

    Using a lexical-decision task performed by Dutch-English bilinguals, the author showed that the recognition of visually presented first language (L1; e.g., touw) and second language (L2; e.g., back) targets is facilitated by L2 and L1 masked primes, respectively, which are pseudohomophones (roap and ruch) of the target's translation equivalent (rope and rug). Moreover, recognition of L2 targets (e.g., church) was also facilitated by L1 pseudohomophones (pous) of related words (paus [pope]). Contrastingly, no priming was observed for L1 targets (e.g., been [leg]) and L2 pseudohomophone associative primes (knea). Finally, the author found that an L2 target word (e.g., corner) is facilitated by a more frequent L2 (intralingual) homophone (e.g., hook) of its L1 translation equivalent (hoek). These findings strongly suggest language-independent activation of phonological representations in bilinguals and are compatible with the temporal delay assumption of the bilingual interactive activation plus model (A. Dijkstra & W. Van Heuven, 2002).

  1. Investigation of Rock Mass Stability Around the Tunnels in an Underground Mine in USA Using Three-Dimensional Numerical Modeling

    Science.gov (United States)

    Xing, Yan; Kulatilake, P. H. S. W.; Sandbak, L. A.

    2018-02-01

    The stability of the rock mass around the tunnels in an underground mine was investigated using the distinct element method. A three-dimensional model was developed based on the available geological, geotechnical, and mine construction information. It incorporates a complex lithological system, persistent and non-persistent faults, and a complex tunnel system including backfilled tunnels. The strain-softening constitutive model was applied for the rock masses. The rock mass properties were estimated using the Hoek-Brown equations based on the intact rock properties and the RMR values. The fault material behavior was modeled using the continuously yielding joint model. Sequential construction and rock supporting procedures were simulated based on the way they progressed in the mine. Stress analyses were performed to study the effect of the horizontal in situ stresses and the variability of rock mass properties on tunnel stability, and to evaluate the effectiveness of rock supports. The rock mass behavior was assessed using the stresses, failure zones, deformations around the tunnels, and the fault shear displacement vectors. The safety of rock supports was quantified using the bond shear and bolt tensile failures. Results show that the major fault and weak interlayer have distinct influences on the displacements and stresses around the tunnels. Comparison between the numerical modeling results and the field measurements indicated the cases with the average rock mass properties, and the K 0 values between 0.5 and 1.25 provide satisfactory agreement with the field measurements.

  2. Diversity and distribution Patterns of the infralittoral green macroalgae from Potiguar basin, Rio Grande do Norte, Northeastern Brazil Diversidade e padrão de distribuição das macroalgas verdes da bacia Potiguar, Rio Grande do Norte, Nordeste do Brasil

    Directory of Open Access Journals (Sweden)

    Adilma de Lourdes Montenegro Cocentino

    2010-12-01

    Full Text Available Diversity and distribution pattern of the infralittoral green macroalgae at Potiguar basin, Rio Grande do Norte, Northeastern Brazil were analyzed from material collected at depths varying from 2 to 100 m. Collections were carried out with two types of dredges during four campaigns: July 2002, May and November 2003 and May 2004 at 43 stations. Chlorophyta is represented by 54 species, five varieties and three forms. The most representative family is Caulerpaceae, and the most diverse genus is Caulerpa, with 11 species. The results showed that most taxa (89% are rare, and 10% are present at low frequencies. The most frequent species was Caulerpaprolifera (Forssk. J.V. Lamour. occurring at almost all coastal and inner shelf stations, recorded in all campaigns. Species distribution by depth range showed that higher species number occurred on the inner shelf from 10 to 20 m, and a wide vertical distribution pattern was registered for Anadyomenestellata (Wulfen in Jacq. C. Agardh,Chamaedoris peniculum (J. Ellis & Solander Kuntze, Codium isthmocladum Vickers, Microdictyon sp., Udoteaoccidentalis A. Gepp & E. Gepp and Ventricaria ventricosa (J. Agardh J.L. Olsen & J.A. West. Four species, Cladophoracoelothrix Kütz., C.ordinata (Børgensen C. Hoek, Caulerpellaambigua (Okamura Prud'homme & Lokhorst and Halimedasimulans M. Howe, were recorded for the first time in Rio Grande do Norte.Diversidade e padrão de distribuição das algas verdes do infralitoral da Bacia potiguar, RN, nordeste do Brasil foram analisados a partir de material coletado em profundidades que variaram de 2 a 100 m. As coletas foram feitas em dois tipos de dragas durante as quatro campanhas: julho de 2002, maio e novembro de 2003 e maio de 2004, em 43 estações. Chlorophyta está representada por 54 espécies, cinco variedades e três formas. A família mais representativa é Caulerpaceae e dentro da família, o gênero mais diverso é Caulerpa, com 11 espécies. Os resultados

  3. Book Reviews

    Directory of Open Access Journals (Sweden)

    Malcom W. Mintz

    1997-01-01

    Full Text Available - Peter Boomgaard, Simone Prodolliet, Händlerinnen, Goldgr��ber und Staatsbeamte; Sozialgeschichte einer Kleinstadt im Hochland Südwestsumatras. Berlin: Reimer, 1996, 372 pp. [Berner Sumatra-Forschungen.] - Richard Chauvel, Antje van der Hoek, Religie in Ballingschap; Institutionalisering en Leiderschap onder Christelijke en Islamitische Molukkers in Nederland. Amsterdam: VU Uitgeverij, 1994, 297 pp. - J.E. Lelijveld, Kees Groeneboer, Weg tot het Westen; Het Nederlands voor Indië 1600-1950. Leiden: KITLV Uitgeverij, 1993, xii + 580 pp. - Bernd Nothofer, P.W. Martin, Language Use & Language Change in Brunei Darussalam, Athens, OH: Ohio University Center for International Studies, 1996, xvi + 373 pp. [Monographs in International Studies 100.], C. Ozog, G. Poedjosoedarmo (eds. - Anton Ploeg, Pamela Swadling, Plumes from Paradise; Trade cycles in outer Southeast Asia and their impact on New Guinea and nearby islands until 1920. With contributions by Roy Wagner and Billai Laba. Boroko/Coorparoo (Qld: Papua New Guinea National Museum in association with R. Brown & Ass. (Qld, 1996, 352 pp. Plates, maps, index. - Bernard Sellato, Traude Gavin, The women’s warpath; Iban ritual fabrics from Borneo, Los Angeles: UCLA Fowler Museum of Cultural History, 1996, 99 pp. - Jyh Wee Sew, Malcom W. Mintz, A course in conversational Indonesian (with equivalent Malay vocabulary. Singapore: EPB Publishers, 1994, 558 pp. - Kees Snoek, Liesbeth Dolk, Twee Zielen, Twee Gedachten; Tijdschriften en Intellectuelen op Java (1900-1957, Leiden: KITLV Uitgeverij, 1993, 220 pp. - Nicholas Tarling, Paul H. Kratoska, Malaya and Singapore during the Japanese Occupation. Singapore: National University of Singapore, 1995, xii + 175 pp. [Journal of Southeast Asian Studies Special Publications Series 3.

  4. Anaerobic bioleaching of metals from waste activated sludge

    International Nuclear Information System (INIS)

    Meulepas, Roel J.W.; Gonzalez-Gil, Graciela; Teshager, Fitfety Melese; Witharana, Ayoma; Saikaly, Pascal E.; Lens, Piet N.L.

    2015-01-01

    Heavy metal contamination of anaerobically digested waste activated sludge hampers its reuse as fertilizer or soil conditioner. Conventional methods to leach metals require aeration or the addition of leaching agents. This paper investigates whether metals can be leached from waste activated sludge during the first, acidifying stage of two-stage anaerobic digestion without the supply of leaching agents. These leaching experiments were done with waste activated sludge from the Hoek van Holland municipal wastewater treatment plant (The Netherlands), which contained 342 μg g −1 of copper, 487 μg g −1 of lead, 793 μg g −1 of zinc, 27 μg g −1 of nickel and 2.3 μg g −1 of cadmium. During the anaerobic acidification of 3 g dry weight L −1 waste activated sludge, 80–85% of the copper, 66–69% of the lead, 87% of the zinc, 94–99% of the nickel and 73–83% of the cadmium were leached. The first stage of two-stage anaerobic digestion can thus be optimized as an anaerobic bioleaching process and produce a treated sludge (i.e., digestate) that meets the land-use standards in The Netherlands for copper, zinc, nickel and cadmium, but not for lead. - Highlights: • Heavy metals were leached during anaerobic acidification of waste activated sludge. • The process does not require the addition of chelating or oxidizing agents. • The metal leaching efficiencies (66 to 99%) were comparable to chemical leaching. • The produced leachate may be used for metal recovery and biogas production. • The produced digested sludge may be used as soil conditioner

  5. New true-triaxial rock strength criteria considering intrinsic material characteristics

    Science.gov (United States)

    Zhang, Qiang; Li, Cheng; Quan, Xiaowei; Wang, Yanning; Yu, Liyuan; Jiang, Binsong

    2018-02-01

    A reasonable strength criterion should reflect the hydrostatic pressure effect, minimum principal stress effect, and intermediate principal stress effect. The former two effects can be described by the meridian curves, and the last one mainly depends on the Lode angle dependence function. Among three conventional strength criteria, i.e. Mohr-Coulomb (MC), Hoek-Brown (HB), and Exponent (EP) criteria, the difference between generalized compression and extension strength of EP criterion experience a firstly increase then decrease process, and tends to be zero when hydrostatic pressure is big enough. This is in accordance with intrinsic rock strength characterization. Moreover, the critical hydrostatic pressure I_c corresponding to the maximum difference of between generalized compression and extension strength can be easily adjusted by minimum principal stress influence parameter K. So, the exponent function is a more reasonable meridian curves, which well reflects the hydrostatic pressure effect and is employed to describe the generalized compression and extension strength. Meanwhile, three Lode angle dependence functions of L_{{MN}}, L_{{WW}}, and L_{{YMH}}, which unconditionally satisfy the convexity and differential requirements, are employed to represent the intermediate principal stress effect. Realizing the actual strength surface should be located between the generalized compression and extension surface, new true-triaxial criteria are proposed by combining the two states of EP criterion by Lode angle dependence function with a same lode angle. The proposed new true-triaxial criteria have the same strength parameters as EP criterion. Finally, 14 groups of triaxial test data are employed to validate the proposed criteria. The results show that the three new true-triaxial exponent criteria, especially the Exponent Willam-Warnke criterion (EPWW) criterion, give much lower misfits, which illustrates that the EP criterion and L_{{WW}} have more reasonable meridian

  6. Multi-decadal shoreline changes on Takú Atoll, Papua New Guinea: Observational evidence of early reef island recovery after the impact of storm waves

    Science.gov (United States)

    Mann, Thomas; Westphal, Hildegard

    2016-03-01

    Hurricanes, tropical cyclones and other high-magnitude events are important steering mechanisms in the geomorphic development of coral reef islands. Sandy reef islands located outside the storm belts are strongly sensitive to the impact of occasional high-magnitude events and show abrupt, commonly erosive geomorphic change in response to such events. Based on the interpretation of remote sensing data, it is well known that the process of landform recovery might take several decades or even longer. However, despite the increasing amount of scientific attention towards short- and long-term island dynamics, the lack of data and models often prevent a robust analysis of the timing and nature of recovery initiation. Here we show how natural island recovery starts immediately after the impact of a high-magnitude event. We analyze multi-temporal shoreline changes on Takú Atoll, Papua New Guinea and combine our findings with a unique set of published field observations (Smithers and Hoeke, 2014). Trends of shoreline change since 1943 and changes in planform island area indicate a long-term accretionary mode for most islands. Apparent shoreline instability is detected for the last decade of analysis, however this can be explained by the impact of storm waves in December 2008 that (temporarily?) masked the long-term trend. The transition from negative to positive rates of change in the aftermath of this storm event is indicative of inherent negative feedback processes that counteract short-term changes in energy input and represent the initiation of island recovery. Collectively, our results support the concept of dynamic rather than static reef islands and clearly demonstrate how short-term processes can influence interpretations of medium-term change.

  7. Influence of the Roof Movement Control Method on the Stability of Remnant

    Science.gov (United States)

    Adach-Pawelus, Karolina

    2017-12-01

    In the underground mines, there are geological and mining situations that necessitate leaving behind remnants in the mining field. Remnants, in the form of small, irregular parcels, are usually separated in the case of: significant problems with maintaining roof stability, high rockburst hazard, the occurrence of complex geological conditions and for random reasons (ore remnants), as well as for economic reasons (undisturbed rock remnants). Remnants left in the mining field become sites of high stress values concentration and may affect the rock in their vicinity. The values of stress inside the remnant and its vicinity, as well as the stability of the remnant, largely depend on the roof movement control method used in the mining field. The article presents the results of the numerical analysis of the influence of roof movement control method on remnant stability and the geomechanical situation in the mining field. The numerical analysis was conducted for the geological and mining conditions characteristic of Polish underground copper mines owned by KGHM Polska Miedz S.A. Numerical simulations were performed in a plane strain state by means of Phase 2 v. 8.0 software, based on the finite element method. The behaviour of remnant and rock mass in its vicinity was simulated in the subsequent steps of the room and pillar mining system for three types of roof movement control method: roof deflection, dry backfill and hydraulic backfill. The parameters of the rock mass accepted for numerical modelling were calculated by means of RocLab software on the basis of the Hoek-Brown classification. The Mohr-Coulomb strength criterion was applied.

  8. Laboratory investigation of crushed salt consolidation and fracture healing

    International Nuclear Information System (INIS)

    1987-01-01

    A laboratory test program was conducted to investigate the consolidation behavior of crushed salt and fracture healing in natural and artificial salt. Crushed salt is proposed for use as backfill in a nuclear waste repository in salt. Artificial block salt is proposed for use in sealing a repository. Four consolidation tests were conducted in a hydrostatic pressure vessel at a maximum pressure of 2500 psi (17.2 MPa) and at room temperature. Three 1-month tests were conducted on salt obtained from the Waste Isolation Pilot Plant and one 2-month test was conducted on salt from Avery Island. Permeability was obtained using argon and either a steady-state or transient method. Initial porosities ranged from 0.26 to 0.36 and initial permeabilities from 2000 to 50,000 md. Final porosities and permeabilities ranged from 0.05 to 0.19 and from -5 md to 110 md, respectively. The lowest final porosity (0.05) and permeability ( -5 md) were obtained in a 1-month test in which 2.3% moisture was added to the salt at the beginning of the test. The consolidation rate was much more rapid than in any of the dry salt tests. The fracture healing program included 20 permeability tests conducted on fractured and unfractured samples. The tests were conducted in a Hoek cell at hydrostatic pressures up to 3000 psi (20.6 MPa) with durations up to 8 days. For the natural rock salt tested, permeability was strongly dependent on confining pressure and time. The effect of confining pressure was much weaker in the artificial salt. In most cases the combined effects of time and pressure were to reduce the permeability of fractured samples to the same order of magnitude (or less) as the permeability measured prior to fracturing

  9. Stress analysis of longwall top coal caving

    Energy Technology Data Exchange (ETDEWEB)

    Alehossein, H.; Poulsen, B.A. [CSIRO Exploration & Mining, Brisbane, Qld. (Australia)

    2010-01-15

    Longwall top coal caving (LTCC) is a relatively new method of mining thick coal seams that is currently achieving high productivity and efficiency. The technique is similar to traditional longwall mining in that a cutting head slices coal from the lower section of the coal seam onto a conveyor belt installed in front of the hydraulic support near the cutting face. In modern LTCC an additional rear conveyor belt is located behind the support, to which the flow of the caved coal from the upper part of the seam can be controlled by a moveable flipper attached to the canopy of the support. The mining method relies on the fracturing of the top coal by the front abutment pressure to achieve satisfactory caving into the rear conveyor. This paper develops a yield and caveability criterion based on in situ conditions in the top coal in advance of the mining face (yield) and behind the supports (caveability). Yielding and caving effects are combined into one single number called caving number (CN), which is the multiplication result of caving factor (CF) and yield factor (YF). Analytical derivations are based on in situ stress conditions, Mohr-Coulomb and/or Hoek-Brown rock failure criteria and an on-associated elastoplastic strain softening material behaviour. The yield and caveability criteria are in agreement with results from both numerical studies and mine data. The caving number is normalised to mining conditions of a reference Chinese mine (LMX mine) and is used to assess LTCC performance at fourteen other Chinese working longwalls that have had varying success with the LTCC technology. As a predictive model, results of this analytical/numerical study are useful to assess the potential success of caving in new LTCC operations and in different mining conditions.

  10. Air Pollution and Deaths among Elderly Residents of São Paulo, Brazil: An Analysis of Mortality Displacement.

    Science.gov (United States)

    Costa, Amine Farias; Hoek, Gerard; Brunekreef, Bert; Ponce de Leon, Antônio C M

    2017-03-01

    Evaluation of short-term mortality displacement is essential to accurately estimate the impact of short-term air pollution exposure on public health. We quantified mortality displacement by estimating single-day lag effects and cumulative effects of air pollutants on mortality using distributed lag models. We performed a daily time series of nonaccidental and cause-specific mortality among elderly residents of São Paulo, Brazil, between 2000 and 2011. Effects of particulate matter smaller than 10 μm (PM 10 ), nitrogen dioxide (NO 2 ) and carbon monoxide (CO) were estimated in Poisson generalized additive models. Single-day lag effects of air pollutant exposure were estimated for 0-, 1- and 2-day lags. Distributed lag models with lags of 0-10, 0-20 and 0-30 days were used to assess mortality displacement and potential cumulative exposure effects. PM 10 , NO 2 and CO were significantly associated with nonaccidental and cause-specific deaths in both single-day lag and cumulative lag models. Cumulative effect estimates for 0-10 days were larger than estimates for single-day lags. Cumulative effect estimates for 0-30 days were essentially zero for nonaccidental and circulatory deaths but remained elevated for respiratory and cancer deaths. We found evidence of mortality displacement within 30 days for nonaccidental and circulatory deaths in elderly residents of São Paulo. We did not find evidence of mortality displacement within 30 days for respiratory or cancer deaths. Citation: Costa AF, Hoek G, Brunekreef B, Ponce de Leon AC. 2017. Air pollution and deaths among elderly residents of São Paulo, Brazil: an analysis of mortality displacement. Environ Health Perspect 125:349-354; http://dx.doi.org/10.1289/EHP98.

  11. Anaerobic bioleaching of metals from waste activated sludge

    Energy Technology Data Exchange (ETDEWEB)

    Meulepas, Roel J.W., E-mail: roel.meulepas@wetsus.nl [UNESCO-IHE, Westvest 7, 2611 AX Delft (Netherlands); Gonzalez-Gil, Graciela [UNESCO-IHE, Westvest 7, 2611 AX Delft (Netherlands); King Abdullah University of Science and Technology, Water Desalination and Reuse Center, Thuwal 13955-69000 (Saudi Arabia); Teshager, Fitfety Melese; Witharana, Ayoma [UNESCO-IHE, Westvest 7, 2611 AX Delft (Netherlands); Saikaly, Pascal E. [King Abdullah University of Science and Technology, Water Desalination and Reuse Center, Thuwal 13955-69000 (Saudi Arabia); Lens, Piet N.L. [UNESCO-IHE, Westvest 7, 2611 AX Delft (Netherlands)

    2015-05-01

    Heavy metal contamination of anaerobically digested waste activated sludge hampers its reuse as fertilizer or soil conditioner. Conventional methods to leach metals require aeration or the addition of leaching agents. This paper investigates whether metals can be leached from waste activated sludge during the first, acidifying stage of two-stage anaerobic digestion without the supply of leaching agents. These leaching experiments were done with waste activated sludge from the Hoek van Holland municipal wastewater treatment plant (The Netherlands), which contained 342 μg g{sup −1} of copper, 487 μg g{sup −1} of lead, 793 μg g{sup −1} of zinc, 27 μg g{sup −1} of nickel and 2.3 μg g{sup −1} of cadmium. During the anaerobic acidification of 3 g{sub dry} {sub weight} L{sup −1} waste activated sludge, 80–85% of the copper, 66–69% of the lead, 87% of the zinc, 94–99% of the nickel and 73–83% of the cadmium were leached. The first stage of two-stage anaerobic digestion can thus be optimized as an anaerobic bioleaching process and produce a treated sludge (i.e., digestate) that meets the land-use standards in The Netherlands for copper, zinc, nickel and cadmium, but not for lead. - Highlights: • Heavy metals were leached during anaerobic acidification of waste activated sludge. • The process does not require the addition of chelating or oxidizing agents. • The metal leaching efficiencies (66 to 99%) were comparable to chemical leaching. • The produced leachate may be used for metal recovery and biogas production. • The produced digested sludge may be used as soil conditioner.

  12. Prediction of Brittle Failure for TBM Tunnels in Anisotropic Rock: A Case Study from Northern Norway

    Science.gov (United States)

    Dammyr, Øyvind

    2016-06-01

    Prediction of spalling and rock burst is especially important for hard rock TBM tunneling, because failure can have larger impact than in a drill and blast tunnel and ultimately threaten excavation feasibility. The majority of research on brittle failure has focused on rock types with isotropic behavior. This paper gives a review of existing theory and its application before a 3.5-m-diameter TBM tunnel in foliated granitic gneiss is used as a case to study brittle failure characteristics of anisotropic rock. Important aspects that should be considered in order to predict brittle failure in anisotropic rock are highlighted. Foliation is responsible for considerable strength anisotropy and is believed to influence the preferred side of v-shaped notch development in the investigated tunnel. Prediction methods such as the semi- empirical criterion, the Hoek- Brown brittle parameters, and the non-linear damage initiation and spalling limit method give reliable results; but only as long as the angle between compression axis and foliation in uniaxial compressive tests is relevant, dependent on the relation between tunnel trend/plunge, strike/dip of foliation, and tunnel boundary stresses. It is further demonstrated that local in situ stress variations, for example, due to the presence of discontinuities, can have profound impact on failure predictions. Other carefully documented case studies into the brittle failure nature of rock, in particular anisotropic rock, are encouraged in order to expand the existing and relatively small database. This will be valuable for future TBM planning and construction stages in highly stressed brittle anisotropic rock.

  13. General load function in geo-mechanics: application to underground works; Fonction de charge generale en geomecanique: application aux travaux souterrains

    Energy Technology Data Exchange (ETDEWEB)

    Maiolino, S

    2006-04-15

    This work deals both with the behavioral and numerical aspects of the mechanical response of a rock massif to the digging out of a tunnel. The comparison between existing criteria has permitted to stress on some key points, like the dependence of the criterion to the average stress and the extension ratio. A load function, easily identifiable with tests, with regular and convex properties, has been proposed which allows to take into account the shape of the Mohr envelope of the criterion and the extension ratio. Regularized forms of Mohr-Coulomb and Hoek-Brown criteria can thus be achieved. The development of this new criterion has been completed by the proposal of a numerical charts method which greatly speeds up the resolution. For the proposed criterion, the physical problem is equivalent to a purely geometrical problem in polar coordinates in the plan. Numerical charts can thus be built which allow to find immediately the value of plastic deformations and to greatly reduce the processing time. Tunnel calculation methods have been the object of a bibliographic synthesis, specifying the domains and limitations of use of tunnel dimensioning methods used by engineers. The modeling of tunnels excavation has been performed with the stationary algorithm designed for the calculation of systems submitted to mobile loads. This algorithm has been adapted to integrate the new criterion and the numerical charts system. These tools have been validated using a real case study and data supplied by the French national agency of radioactive waste management (ANDRA) in the framework of the MODEX-REP European project (5. Euratom plan). The study of these data has permitted to define a rock wear variable, easily identifiable and allowing to parameterize the damaged rock criterion. (J.S.)

  14. General load function in geo-mechanics: application to underground works

    International Nuclear Information System (INIS)

    Maiolino, S.

    2006-04-01

    This work deals both with the behavioral and numerical aspects of the mechanical response of a rock massif to the digging out of a tunnel. The comparison between existing criteria has permitted to stress on some key points, like the dependence of the criterion to the average stress and the extension ratio. A load function, easily identifiable with tests, with regular and convex properties, has been proposed which allows to take into account the shape of the Mohr envelope of the criterion and the extension ratio. Regularized forms of Mohr-Coulomb and Hoek-Brown criteria can thus be achieved. The development of this new criterion has been completed by the proposal of a numerical charts method which greatly speeds up the resolution. For the proposed criterion, the physical problem is equivalent to a purely geometrical problem in polar coordinates in the plan. Numerical charts can thus be built which allow to find immediately the value of plastic deformations and to greatly reduce the processing time. Tunnel calculation methods have been the object of a bibliographic synthesis, specifying the domains and limitations of use of tunnel dimensioning methods used by engineers. The modeling of tunnels excavation has been performed with the stationary algorithm designed for the calculation of systems submitted to mobile loads. This algorithm has been adapted to integrate the new criterion and the numerical charts system. These tools have been validated using a real case study and data supplied by the French national agency of radioactive waste management (ANDRA) in the framework of the MODEX-REP European project (5. Euratom plan). The study of these data has permitted to define a rock wear variable, easily identifiable and allowing to parameterize the damaged rock criterion. (J.S.)

  15. Appearance and disappearance of ferromagnetism in ultrathin LaMnO3 on SrTiO3 substrate: A viewpoint from first principles

    Science.gov (United States)

    An, Ming; Weng, Yakui; Zhang, Huimin; Zhang, Jun-Jie; Zhang, Yang; Dong, Shuai

    2017-12-01

    The intrinsic magnetic state (ferromagnetic or antiferromagnetic) of ultrathin LaMnO3 films on the most commonly used SrTiO3 substrate is a long-existing question under debate. Either strain effect or nonstoichiometry was argued to be responsible for the experimental ferromagnetism. In a recent experiment [X. R. Wang, C. J. Li, W. M. Lü, T. R. Paudel, D. P. Leusink, M. Hoek, N. Poccia, A. Vailionis, T. Venkatesan, J. M. D. Coey, E. Y. Tsymbal, Ariando, and H. Hilgenkamp, Science 349, 716 (2015), 10.1126/science.aaa5198], one more mechanism, namely, the self-doping due to polar discontinuity, was argued to be the driving force of ferromagnetism beyond the critical thickness. Here systematic first-principles calculations have been performed to check these mechanisms in ultrathin LaMnO3 films as well as superlattices. Starting from the very precise descriptions of both LaMnO3 and SrTiO3, it is found that the compressive strain is the dominant force for the appearance of ferromagnetism, while the open surface with oxygen vacancies leads to the suppression of ferromagnetism. Within LaMnO3 layers, the charge reconstructions involve many competitive factors and certainly go beyond the intuitive polar catastrophe model established for LaAlO3/SrTiO3 heterostructures. Our paper not only explains the long-term puzzle regarding the magnetism of ultrathin LaMnO3 films but also sheds light on how to overcome the notorious magnetic dead layer in ultrathin manganites.

  16. Design of Rock Slope Reinforcement: An Himalayan Case Study

    Science.gov (United States)

    Tiwari, Gaurav; Latha, Gali Madhavi

    2016-06-01

    The stability analysis of the two abutment slopes of a railway bridge proposed at about 359 m above the ground level, crossing a river and connecting two hill faces in the Himalayas, India, is presented. The bridge is located in a zone of high seismic activity. The rock slopes are composed of a heavily jointed rock mass and the spacing, dip and dip direction of joint sets are varying at different locations. Geological mapping was carried out to characterize all discontinuities present along the slopes. Laboratory and field investigations were conducted to assess the geotechnical properties of the intact rock, rock mass and joint infill. Stability analyses of these rock slopes were carried out using numerical programmes. Loads from the foundations resting on the slopes and seismic accelerations estimated from site-specific ground response analysis were considered. The proposed slope profile with several berms between successive foundations was simulated in the numerical model. An equivalent continuum approach with Hoek and Brown failure criterion was initially used in a finite element model to assess the global stability of the slope abutments. In the second stage, finite element analysis of rock slopes with all joint sets with their orientations, spacing and properties explicitly incorporated into the numerical model was taken up using continuum with joints approach. It was observed that the continuum with joints approach was able to capture the local failures in some of the slope sections, which were verified using wedge failure analysis and stereographic projections. Based on the slope deformations and failure patterns observed from the numerical analyses, rock anchors were designed to achieve the target factors of safety against failure while keeping the deformations within the permissible limits. Detailed design of rock anchors and comparison of the stability of slopes with and without reinforcement are presented.

  17. Interpretation of the Haestholmen in situ state of stress based on core damage observations

    International Nuclear Information System (INIS)

    Hakala, M.

    2000-01-01

    At the Haestholmen investigation site, direct in situ stress measurements, overcoring and hydraulic fracturing have been unsuccessful because of ring disking and horizontal hydraulic fracturing. Prior to this study, a detailed study on both core disking and ring disking was made, and based on those results an in situ state of stress interpretation method was developed. In this work this method is applied to the Haestholmen site. The interpretation is based on disk fracture type, spacing and shape. Also, the Hoek-Brown strength envelope and Poisson's ratio of intact rock are needed. The interpretation result is most reliable if both core disking and ring disking information at the same depth levels is available. A detailed core logging showed that ring disking is systematic below the -365 m level in the vertical overcoring stress measurement hole, HH-KR6. On the other hand, no representative core disking exists except for two points in two differently oriented subvertical boreholes HH-KR2 and HHKR7. Because the interpretation has to be based on ring disking only, upper and lower estimates for the vertical stress were set. These were gravitational and 67% of gravitational. Furthermore, the in situ stress state was assumed to be in horizontal and vertical planes, because the disking in vertical borehole HH-KR6 was not inclined. The interpretation resulted in a good estimate for the major horizontal stress but none of the horizontal stress rations ( 0.25, 0.5, 0.75 and 1.0 ) or vertical stress assumptions studied are clearly more probable the others. At the 500 m level the resulting maximum horizontal stress is 41 MPa. If a linear fit through the zero depth and zero stress point is applied, the maximum horizontal stress gradient is 0.0818 z MPa/m with a standard deviation between 5 and 12 per cent. The orientation of the major horizontal stress is 108 with standard deviation of 21 degrees. The interpreted major horizontal stress state also indicated that systematic

  18. Slope stability probability classification, Waikato Coal Measures, New Zealand

    Energy Technology Data Exchange (ETDEWEB)

    Lindsay, P.; Gillard, G.R.; Moore, T.A. [CRL Energy, PO Box 29-415, Christchurch (New Zealand); Campbell, R.N.; Fergusson, D.A. [Solid Energy North, Private Bag 502, Huntly (New Zealand)

    2001-01-01

    Ferm classified lithological units have been identified and described in the Waikato Coal Measures in open pits in the Waikato coal region. These lithological units have been classified geotechnically by mechanical tests and discontinuity measurements. Using these measurements slope stability probability classifications (SSPC) have been quantified based on an adaptation of Hack's [Slope Stability Probability Classification, ITC Delft Publication, Enschede, Netherlands, vol. 43, 1998, 273 pp.] SSPC system, which places less influence on rock quality designation and unconfined compressive strength than previous slope/rock mass rating systems. The Hack weathering susceptibility rating has been modified by using chemical index of alteration values determined from XRF major element analyses. Slaking is an important parameter in slope stability in the Waikato Coal Measures lithologies and hence, a non-subjective method of assessing slaking in relation to the chemical index of alteration has been introduced. Another major component of this adapted SSPC system is the inclusion of rock moisture content effects on slope stability. The main modifications of Hack's SSPC system are the introduction of rock intact strength derived from the modified Mohr-Coulomb failure criterion, which has been adapted for varying moisture content, weathering state and confining pressure. It is suggested that the subjectivity in assessing intact rock strength within broad bands in the initial SSPC system is a major weakness of the initial system. Initial results indicate a close relationship between rock mass strength values, calculated from rock mass friction angles and rock mass cohesion values derived from two established rock mass classification methods (modified Hoek-Brown failure criteria and MRMR) and the adapted SSPC system. The advantage of the modified SSPC system is that slope stability probabilities based on discontinuity-independent and discontinuity-dependent data and a

  19. Building Chaotic Model From Incomplete Time Series

    Science.gov (United States)

    Siek, Michael; Solomatine, Dimitri

    2010-05-01

    This paper presents a number of novel techniques for building a predictive chaotic model from incomplete time series. A predictive chaotic model is built by reconstructing the time-delayed phase space from observed time series and the prediction is made by a global model or adaptive local models based on the dynamical neighbors found in the reconstructed phase space. In general, the building of any data-driven models depends on the completeness and quality of the data itself. However, the completeness of the data availability can not always be guaranteed since the measurement or data transmission is intermittently not working properly due to some reasons. We propose two main solutions dealing with incomplete time series: using imputing and non-imputing methods. For imputing methods, we utilized the interpolation methods (weighted sum of linear interpolations, Bayesian principle component analysis and cubic spline interpolation) and predictive models (neural network, kernel machine, chaotic model) for estimating the missing values. After imputing the missing values, the phase space reconstruction and chaotic model prediction are executed as a standard procedure. For non-imputing methods, we reconstructed the time-delayed phase space from observed time series with missing values. This reconstruction results in non-continuous trajectories. However, the local model prediction can still be made from the other dynamical neighbors reconstructed from non-missing values. We implemented and tested these methods to construct a chaotic model for predicting storm surges at Hoek van Holland as the entrance of Rotterdam Port. The hourly surge time series is available for duration of 1990-1996. For measuring the performance of the proposed methods, a synthetic time series with missing values generated by a particular random variable to the original (complete) time series is utilized. There exist two main performance measures used in this work: (1) error measures between the actual

  20. СHARACTERISTICS OF THE HEART FATTY ACID-BINDING PROTEIN, INTERLEUKIN-6 AND INTERLEUKIN-8 AS ALTERNATIVE MARKERS OF DIABETIC NEPHROPATHY PROGRESSION IN PATIENTS WITH TYPE 1 DIABETES MELLITUS

    Directory of Open Access Journals (Sweden)

    Yu. A. Ryzhikova

    2015-01-01

    Full Text Available The aim of this work was to study the levels of the heart fatty acid-binding protein (h-FABP, interleukin6 (IL-6 and interleukin-8 (IL-8, in diabetic nephropathy (DN in patients with type 1 diabetes mellitus (T1DM. Material and methods. We examined 87 patients aged 18 to 54 with T1DM within the study group. 30 patients with type 1 diabetes were diagnosed with normoalbuminuria, 29 patients – with microalbuminuria and 28 patients – with proteinuria. The control group consisted of 24 healthy donor aged 22 to 29. The comparison group included 22 patients aged 20 to 42 with verified diagnosis of essential arterial hypertension (AH without carbohydrate metabolism disorders. The daily urinary albumin excretion was determined by immunoturbidimetric technique. 30 patients with type 1 diabetes were diagnosed with normoalbuminuria, 29 patients – with microalbuminuria and 28 patients with proteinuria.Calculation of glomerular filtration rate was performed according to the Hoek formula with the use of cystatinС serum concentrations. Contents of h-FABP, IL-6 and cystatin C in serum and h-FABP, IL-8 inurine were determined by enzyme-linked immunosorbent assay. Results. Analysis of the h-FABP content in serum showed that the concentration of this marker in individuals with T1DM was higher than in patients of the control group and the comparison group. Analysis of the h-FABP content in the urine revealed that individuals with essential hypertension showed an increased level of h-FABP while patients with T1DM demonstrated the highest concentration of h-FABP. The concentration of IL-6 inindividuals with T1DM and in individuals with AH significantly exceeded the control values. The contents of h-FABP and IL-6 inserum and h-FABP and IL-8 inurine increased with the progression of DN and reached maximum in individuals of the proteinuria subgroup. At the same time, the levels of h-FABP and IL-8 inthe urine of patients in the microalbuminuria (MAU subgroup were

  1. Hydro-mechanical processes

    Energy Technology Data Exchange (ETDEWEB)

    Laouafa, F.; Kazmierczak, J.B. [Institut National de l' Environnement Industriel et des Risques (INERIS), Parc Technologique ALATA, 60 - Verneuil en Halatte (France); Armand, G. [Agence Nationale pour la Gestion des Dechets Radioactifs, Lab. de Souterrain de Meuse/Haute-Marne, 55 - Bure (France); Vaunat, J. [Catalonia UPC- Technical Univ., Barcelona (Spain); Jobmann, M.; Polster, M. [DBETEC- DBE Technology GmbH, Peine (Germany); Su, K.; Lebon, P.; Plas, F.; Armand, G.; Abou-Chakra Guery, A.; Cormery, F.; Shao, J.F.; Kondo, D. [ANDRA - Agence Nationale pour la Gestion des Dechets Radioactifs, 92 - Chatenay Malabry (France); Souley, M. [Institut National de l' Environnement Industriel et des Risques (INERIS), 54 - Nancy (France); Coll, C.; Charlier, R.; Collin, F.; Gerard, P. [Liege Univ., Dept. ArGEnCo (Belgium); Xiang Ling, Li [ESV EURIDICE, SCK.CEN, Belgian Nuclear Research Centre, Mol (Belgium); Collin, F. [Liege Univ., Charge de Recherches FNRS (Belgium); Pellet, F.L.; Fabre, G. [University Joseph Fourier, Laboratory 3S-R, 38 - Grenoble (France); Garcia-Sineriz, J.L.; Rey, M. [AITEMIN - Asociacion para la Investigacion y Desarrollo Industrial de los Recursos Naturales, Madrid (Spain); Mayor, J.C. [ENRESA - Empresa Nacional des Residuos Radioactivos, Madrid (Spain); Castellanos, E.; Romero, E.; Lloret, A.; Gens, A. [Catalunya Univ. Politecnica, UPC (Spain); Villar, M.V. [CIEMAT - Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas, Madrid (Spain); Chambon, R. [Laboratoire 3S, UJF-INPG-CNRS, 38 - Grenoble (France); Czaikowski, O.; Lux, K.H. [Clausthal Univ. of Technology, Professorship for Waste Disposal and Geomechanics, Clausthal-Zellerfeld (Germany); Van Geet, M.; Bastiaens, W.; Volckaert, G.; Weetjens, E.; Sillen, X. [SCK-CEN, Waste and Disposal dept., Mol (Belgium); ONDRAF/NIRAS, Brussel (Belgium); Imbert, Ch. [CEA Saclay, Dept. de Physico-Chimie (DPC/SCCME/LECBA), 91 - Gif sur Yvette (France)] [and others

    2007-07-01

    This session gathers 13 articles dealing with: three-dimensional and time stepping modelling of the whole Meuse/Haute-Marne ANDRA URL (F. Laouafa, J.B. Kazmierczak, G. Armand, J. Vaunat, M. Jobmann, M. Polster); a constitutive model for a deep argillaceous rock using Hoek-Brown criteria (K. Su, C. Chavant, M. Souley); the long term behaviour of the Boom clay: influence of viscosity on the pore pressure distribution (C. Coll, R. Charlier, X.L. Li, F. Collin); the microstructural changes induced by viscoplastic deformations in argillaceous rocks (F.L. Pellet, G. Fabre, K. Su, P. Lebon); the engineered barrier experiment at Mont Terri rock laboratory (J.L. Garcia-Sineriz, M. Rey, J.C. Mayor); the chemical influence on the Hydro-Mechanical behaviour of high-density FEBEX bentonite (E. Castellanos, M.V. Villar, E. Romero, A. Lloret, A. Gens); the influence of water exchanges on the gallery convergence (P. Gerard, R. Charlier, R. Chambon, F. Collin); a new method for ageing resistant storage of argillaceous rock samples to achieve reproducible experimental results even after long intermediate storage times (O. Czaikowski, K.H. Lux); the installation and evaluation of a large-scale in-situ shaft seal experiment in Boom clay the RESEAL project M. Van Geet, W. Bastiaens, G. Volckaert, E. Weetjens, X. Sillen, A. Gens, M.V. Villar, Ch. Imbert, M. Filippi, F. Plas); the hydro-Mechanical response of the Callovo-Oxfordian mud-stone around a deep vertical drift (J. Vaunat, B. Garitte, A. Gens, K. Su, G. Armand); the sensitivity of total stress to changes in externally applied water pressure in KBS-3 buffer bentonite (J.F. Harrington, D.J. Birchall, P. Sellin); the comparison of the poro-elastic behavior of Meuse/Haute Marne and Tournemire argillites: effect of loading and saturation states (E. Bemer, A. Noiret, F. Homand, A. Rejeb); and the multi-scale modelling of the argillites mechanical behaviour (A. Abou-Chakra Guery, F. Cormery, K. Su, J.F. Shao, D. Kondo)

  2. The INTIMATE event stratigraphy and recommendations for its use

    Science.gov (United States)

    Rasmussen, Sune O.

    2014-05-01

    The North Atlantic INTIMATE (INtegration of Ice-core, MArine and TErrestrial records) group has previously recommended an Event Stratigraphy approach for the synchronisation of records of the Last Termination using the Greenland ice core records as the regional stratotypes. A key element of these protocols has been the formal definition of numbered Greenland Stadials (GS) and Greenland Interstadials (GI) within the past glacial period as the Greenland expressions of the characteristic Dansgaard-Oeschger events that represent cold and warm phases of the North Atlantic region, respectively. Using a recent synchronization of the NGRIP, GRIP, and GISP2 ice cores that allows the parallel analysis of all three records on a common time scale, we here present an extension of the GS/GI stratigraphic template to the entire glacial period. In addition to the well-known sequence of Dansgaard-Oeschger events that were first defined and numbered in the ice core records more than two decades ago, a number of short-lived climatic oscillations have been identified in the three synchronized records. Some of these events have been observed in other studies, but we here propose a consistent scheme for discriminating and naming all the significant climatic events of the last glacial period that are represented in the Greenland ice cores. In addition to presenting the updated event stratigraphy, we make a series of recommendations on how to refer to these periods in a way that promotes unambiguous comparison and correlation between different proxy records, providing a more secure basis for investigating the dynamics and fundamental causes of these climatic perturbations. The work presented is a part of a manuscript under review for publication in Quaternary Science Reviews. Author team: S.O. Rasmussen, M. Bigler, S.P.E. Blockley, T. Blunier, S.L. Buchardt, H.B. Clausen, I. Cvijanovic, D. Dahl-Jensen, S.J. Johnsen, H. Fischer, V. Gkinis, M. Guillevic, W.Z. Hoek, J.J. Lowe, J. Pedro, T

  3. Flora ficológica da região sublitorânea rasa de costões rochosos do Núcleo Picinguaba, Parque Estadual da Serra do Mar, Ubatuba, São Paulo Phycological flora from the shallow sublittoral zone of the rocky shores of Serra do Mar State Park, Ubatuba, São Paulo

    Directory of Open Access Journals (Sweden)

    Gisa Eneida Marques Machado

    2011-03-01

    Full Text Available Em unidades de conservação da zona costeira, o conhecimento das macroalgas marinhas é essencial para monitoramento e manejo. Para o Núcleo Picinguaba do Parque Estadual da Serra do Mar (PESM, Ubatuba, norte do Estado de São Paulo, estudos pretéritos realizados na Enseada da Fazenda listam espécies de macroalgas, coletadas em costões rochosos e manguezais. O presente estudo visou complementar o levantamento taxonômico da flora ficológica marinha do Núcleo Picinguaba, avaliando também a adequação da metodologia para amostragens de suas comunidades de costões rochosos. Foram selecionados 13 pontos de coleta, entre a Ponta da Almada e a Ponta do Cambury, área de maior interferência antropogênica na zona costeira do PESM. No verão de 2007, foram efetuadas coletas de macroalgas, desde a franja da região sublitorânea até o limite do substrato rochoso com a areia. Para uniformizar o esforço amostral, estas buscas foram efetuadas, em cada ponto de coleta, pelo mesmo especialista, durante uma hora de mergulho em apnéia, em uma extensão horizontal do costão rochoso de cerca de 20 m. Foram identificados 128 táxons de categoria infragenérica (80 Rhodophyta, 22 Ochrophyta e 26 Chlorophyta. Callithamniella flexilis Baardseth, Cryptonemia seminervis (C. Agardh J. Agardh, Cladophora pseudorupestris C. Hoek e Cladophora cf. pygmaea Reinke são ocorrências novas para o litoral do Estado de São Paulo, tendo sido descritas e ilustradas. Foram acrescentadas 64 espécies de macroalgas para os costões rochosos do PESM. O esforço amostral foi considerado adequado, resultando na identificação de número de espécies de macroalgas similar ao de outros estudos realizados no litoral norte do estado de São Paulo e no extremo sul do estado do Rio de Janeiro. Para o monitoramento da zona costeira desta unidade de conservação, recomenda-se o levantamento taxonômico das macroalgas dos costões rochosos de modo continuado, durante o per

  4. Levantamento florístico das macroalgas da baía de Sepetiba e adjacências, RJ: ponto de partida para o Programa GloBallast no Brasil Floristic survey of the macroalgae from Sepetiba bay and surrounding area, Rio de Janeiro State: starting point for the GloBallast Programme in Brazil

    Directory of Open Access Journals (Sweden)

    Maria Teresa Menezes de Széchy

    2005-09-01

    Full Text Available O Porto de Sepetiba, Estado do Rio de Janeiro, foi escolhido, no Brasil, como área-piloto do projeto "Remoção de barreiras para a implementação efetiva do controle de água de lastro e medidas de gestão em países em desenvolvimento" (Programa GloBallast. Para possibilitar comparações, os seis países participantes do Programa GloBallast foram orientados a adotar a mesma metodologia para o levantamento preliminar da biota das áreas-pilotos valorizando a identificação em nível de espécie. O presente estudo teve como objetivo aplicar metodologia estabelecida pelo Centro para Pesquisa sobre Espécies Marinhas Introduzidas, da Austrália (Procedimento CRIMP, com algumas adaptações, no levantamento florístico das macroalgas de substratos consolidados naturais da área-piloto do Porto de Sepetiba. Coletas de macroalgas foram realizadas em novembro/2001, em nove locais da baía de Sepetiba e adjacências, desde a franja da região sublitorânea até cerca de -4 m de profundidade. Em cada local, seis quadrados de 0,1 m² de área foram raspados. O material foi depositado no Herbário do Instituto de Pesquisas Jardim Botânico do Rio de Janeiro (RB. Das 96 espécies identificadas (20 Chlorophyta, 16 Phaeophyta, 60 Rhodophyta, 12 não haviam sido citadas anteriormente para a área de estudo. Cladophora pellucidoidea C. Hoek, Coelothrix irregularis (Harv. Boergesen e Acrochaetium savianum (Menegh. Nägeli são ocorrências novas para o Estado. Não há indícios de que as novas ocorrências equivalem a espécies recentemente introduzidas por meio das atividades portuárias. O procedimento metodológico adotado mostrou-se eficiente, resultando em listagem de espécies comparável às de levantamentos florísticos com maior esforço amostral e complementando os dados pretéritos existentes para a baía de Sepetiba e adjacências. No entanto, ressalta-se a importância de uma reavaliação das escalas temporal e espacial da estratégia de

  5. Viscoplastic behaviour including damage for deep argillaceous rocks: from in situ observations to constitutives equations

    International Nuclear Information System (INIS)

    Souley, Mountaka; Ghoreychi, Mehdi; Armand, Gilles

    2010-01-01

    viscoplastic model which aims to improve the viscoplastic strain prediction in the EDZ (Excavated Damaged Zone) is proposed by introducing damage variable in Lemaitre's model. The mains characteristics of the model are: (a) the short-term behaviour is based on a generalized Hoek-Brown model; (b) the long-term behaviour is based on the modified Lemaitre's model, the changes of viscoplastic strain rates due to damage (in pre peak phase) and failure (post-peak and residual phases) are taken into account by varying the creep activation energy and the strain-hardening as a function of the current damage rate. In addition, in order to prevent the overestimation of volumetric strain the associated flow rule initially assumed is revisited for the short term behaviour. The proposed model is implemented in FLAC3D C . In order to verify both constitutive equations and their implementations, several simulations of classical laboratory tests (uniaxial/triaxial, mono/multi stage creep and relaxation) are performed. As practical applications, the proposed model has been used to predict the behaviour of two galleries of the laboratory (at -490 m level): parallel and perpendicular to the major horizontal stress. Comparison between predicted results and the in situ measurements are then presented and discussed Finally the model limitations as well as possible improvements are discussed in this paper. (authors)

  6. S4. ASYMMETRIC DRUG-INDUCED PARKINSONISM IS RELATED TO PSYCHOPATHOLOGY

    Science.gov (United States)

    Pieters, Lydia; Bakker, P Roberto; Van Harten, Peter N

    2018-01-01

    severity index (CGI-SCH SI). Discussion DIP is asymmetric in 1 of 5 patients. Therefore, the clinical rule that Parkinson’s disease always starts asymmetrically and such may be helpful to differentiate between Parkinson’s disease and DIP is not valid. Asymmetric presentation of DIP is of clinical relevance as it is related to the severity of psychopathology. Asymmetric DIP may alert the clinician of more severe psychopathology. Replication is indicated to examine the robustness of the relationship. References 1. Modestin J, Wehrli MV, Stephan PL, Agarwalla P. Evolution of neuroleptic-induced extrapyramidal syndromes under long-term neuroleptic treatment. Schizophr Res. 2008; 100(1–3): 97–107. 2. Janno S, Holi M, Tuisku K, Wahlbeck K. Prevalence of Neuroleptic-Induced Movement Disorders in Chronic Schizophrenia Inpatients. Am J Psychiatry. 2004; 161(1): 160–163. 3. Harten PN Van, Matroos GE, Hoek HW. The prevalence of tardive dystonia, tardive dyskinesia, parkinsonism and akathisia. The Curaçao Extrapyramidal Syndromes Study I. Schizophr Res. 1996; 19(2): 195–203. 4. Shin H, Chung J. Drug-Induced Parkinsonism. J Clin Neurol. 2012; 8: 15–21. 5. Bakker PR, de Groot IW, van Os J, van Harten PN. Long-Stay Psychiatric Patients: A Prospective Study Revealing Persistent Antipsychotic-Induced Movement Disorder. PLoS One. 2011; 6(10): 1–6.

  7. Complete stress tensor determination by microearthquake analysis

    Science.gov (United States)

    Slunga, R.

    2010-12-01

    the depth based on the assumptions of a fractured crust, widely vary ing stress field, and a general closeness to instability as found by stress measurements (Jamison and Cook 1976). Wheather this approach is working or not is best answered by applying it to real data. This was provided by the IMO network in Iceland. Along Southern Iceland Seismic Zone (SISZ) more than 200,000 microearthquakes and a few M 5 EQs and 2 M=6.6 EQs have been recorded. The results will be presented it is obvious that the use of the stresses determined from the microearthquake recordings may significa ntly improve earthquake warnings and will make it possible to use the absolute C FS method for more deterministic predictions. Note that the microearthquake meth od only shows the part of the stress field that has caused slip. Volumes with st able stress will not show up. However stress measurements (Brown and Hoek 1978, Slunga 1988) have shown that the crustal stresses in general are close to instabi lity and microearthquake source analysis has shown that a large number of differ ent fractures become unstable within longer time windows. This may explain the e xcellent results given by the Icelandic tests of the absolute stress tensor fiel d as given by the microearthquakes. However I prefer to call this stress apparen t.

  8. Long-Term Mechanical Behavior of Yucca Mountain Tuff and its Variability, Final Technical Report for Task ORD-FY04-021

    International Nuclear Information System (INIS)

    Daemen, Jaak J.K.; Ma, Lumin; Zhao, Guohua

    2006-01-01

    The study of the long term mechanical behavior of Yucca Mountain tuffs is important for several reasons. Long term stability of excavations will affect accessibility (e.g. for inspection purposes), and retrievability. Long term instabilities may induce loading of drip shields and/or emplaced waste, thus affecting drip shield and/or waste package corrosion. Failure of excavations will affect airflow, may affect water flow, and may affect temperature distributions. The long term mechanical behavior of rocks remains an elusive topic, loaded with uncertainties. A variety of approaches have been used to improve the understanding of this complex subject, but it is doubtful that it has reached a stage where firm predictions can be considered feasible. The long term mechanical behavior of ''soft'' rocks, especially evaporites, and in particular rock salt, has been the subject of numerous investigations (e.g. Cristescu and Hunsche, 1998, Cristescu et al, 2002), and basic approaches towards engineering taking into account the long term behavior of such materials have long been well established (e.g. Dreyer, 1972, 1982). The same is certainly not true of ''hard'' rocks. While it long has been recognized that the long term strength of ''hard'' rocks almost certainly is significantly less than that measured during ''short'', i.e. standard (ASTM D 2938), ISRM suggested (Bieniawski et al, 1978) and conventionally used test procedures (e.g. Bieniawski, 1970, Wawersik, 1972, Hoek and Brown, 1980, p. 150), what limited approaches have been taken to develop strategies toward determining the long term mechanical behavior of ''hard'' rock remain in the early research and investigation stage, at best. One early model developed specifically for time dependent analysis of underground ''hard'' rock structures is the phenomenological model by Kaiser and Morgenstern (1981). Brady and Brown (1985, p. 93) state that over a wide range of strain rates, from 10 -8 to 10 2 /s the difference in

  9. Book Reviews

    Directory of Open Access Journals (Sweden)

    Ratna Saptari

    1994-07-01

    , Harold Brookfield, South-East Asia’s environmental future; The search for sustainability. Tokyo: United Nations University Press, Kuala Lumpur: Oxford University Press, 1993, xxxii + 422 pp., maps, tables, figures, index., Yvonne Byron (eds. - Antje van der Hoek, Keebet von Benda-Beckmann, De emancipatie van Molukse vrouwen in Nederland. Utrecht: Van Arkel,1992, Francy Leatemia-Toma-tala (eds. - Michael Hitchcock, Brita L. Miklouho-Maklai, Exposing Society’s Wounds; Some aspects of Indonesian Art since 1966. Adelaide: Flinders University Asian studies Monograph No.5, illustrations, 1991, iii + 125 pp - Nico Kaptein, Fred R. von der Mehden, Two Worlds of Islam; Interaction between Southeast Asia and the Middle East.Gainesville etc: University Press of Florida 1993, xiii + 128 pp - Nico Kaptein, Karel Steenbrink, Dutch Colonialism and Indonesian Islam; Contacts and Conflicts 1596-1950. Amsterdam-Atlanta, GA: Rodopi, 1993. - Harry A. Poeze, Rudolf Mrázek, Sjahrir; Politics and exile in Indonesia. Ithaca, N.Y.: Cornell University, Southeast Asia Program, 1994. - W.G.J. Remmelink, Takao Fusayama, A Japanese memoir of Sumatra 1945-1946; Love and hatred in the liberation war. Ithaca: Cornell University (Cornell Modern Indonesia Project Monograph series 71, 1993, 151 pp., maps, illustrations. - Ratna Saptari, Diana Wolf, Factory Daughters; Gender, Household Dynamics, and Rural Industrialization in Java. Berkeley: University of California Press, 1992. - Ignatius Supriyanto, Ward Keeler, Javanese Shadow Puppets. Singapore (etc.: Oxford University Press, 1992, vii + 72 pp.,bibl., ills. (Images of Asia. - Brian Z. Tamanaha,S.J.D., Juliana Flinn, Review of diplomas and thatch houses; Asserting tradition in a changing Micronesia. Ann Arbor: University of Michigan Press, 1992. - Gerard Termorshuizen, Dorothée Buur, Indische jeugdliteratuur; Geannoteerde bibliografie van jeugdboeken over Nederlands-Indië en Indonesië, 1825-1991. Leiden, KITLV Uitgeverij, 1992, 470 pp

  10. Serum AMH levels in healthy women from BRCA1/2 mutated families: are they reduced?

    Science.gov (United States)

    van Tilborg, Theodora C; Derks-Smeets, Inge A P; Bos, Anna M E; Oosterwijk, Jan C; van Golde, Ron J; de Die-Smulders, Christine E; van der Kolk, Lizet E; van Zelst-Stams, Wendy A G; Velthuizen, Maria E; Hoek, Annemieke; Eijkemans, Marinus J C; Laven, Joop S E; Ausems, Margreet G E M; Broekmans, Frank J M

    2016-11-01

    were relatively young. Power was insufficient to analyze BRCA1 and BRCA2 mutation carriers separately. AMH levels may have been influenced by the use of hormonal contraceptives, though similar proportions of carriers and non-carriers were current users and adjustments were made to correct for potential confounding in our analysis. Limitations of the current analysis and limitations of the existing literature argue for prospective, well-controlled follow-up studies with recurrent AMH measurements to determine whether carriers might be at risk for low ovarian reserve and to definitively guide care. This study was partially financially supported by a personal grant for Inge A.P. Derks-Smeets, kindly provided by the Dutch Cancer Society (Grant Number UM 2011-5249). Theodora C. van Tilborg, Inge A.P. Derks-Smeets, Anna M.E. Bos, Jan C. Oosterwijk, Christine E. de Die-Smulders, Lizet E. van der Kolk, Wendy A.G. van Zelst-Stams, Maria E. Velthuizen, Marinus J.C. Eijkemans and Margreet G.E.M. Ausems have nothing to disclose. Ron J. van Golde has received unrestricted research grants from Ferring and Merck Serono, outside the submitted work. Annemieke Hoek received an unrestricted educational grant from Ferring pharmaceutical BV, The Netherlands and a speaker's fee for post graduate education from MSD pharmaceutical company, outside the submitted work. Joop S.E. Laven has received unrestricted research grants from Ferring, Merck Serono, Merck Sharpe & Dome, Organon, and Schering Plough, outside the submitted work. Frank J.M. Broekmans is a member of the external advisory board for Merck Serono (The Netherlands), outside the submitted work. NTR no. 4324. © The Author 2016. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  11. DECOVALEX II project. Nirex RCF Shaft Excavation Task 1C - Coupled hydro-mechanical effects of shaft sinking within Sector 7

    International Nuclear Information System (INIS)

    Hakami, H.

    1999-12-01

    Mohr-Coulomb and Hoek-Brown failure criteria - that takes care of the onset of a brittle failure more explicitly, numerical analyses were carried out in order to capture the Excavation Damage Zone, a feature that could not be studied under the failure criterion and the input data incorporated in the first modelling approach. Regardless of which of the two failure criteria was active in the simulations, the deformational disturbances caused by the numerical excavation of the shaft were typical for stiff and competent crystalline rock masses. The mechanically disturbed zone did not effectively extend farther than about three times the diameter of the shaft, beyond which the disturbance was insignificant. Also, the convergence of the shaft was confined to about 3 mm at the most, once again typical for the hard rocks. As was expected, there was a very significant difference in flow characteristics associated with the two model set-ups; with and without the outstanding flow zones. While both the modelled rock matrices had almost similar flow properties, the flow zones only appearing in the second model were supplied with uppermost values of the permeability and porosity from ranges estimated from the site and laboratory investigations. The extreme values were between x - y order of magnitudes greater than the corresponding values from the rock matrix. Extremely low volumes of water, up to about 2.5 lit/min percolated into a 20-m long section of the shaft, by using the first model set-up with no flow zones included. On the other hand much greater values; e.g. as high as about 260 lit/min flowed into the same section of the shaft, having the three flow zones active. The latter case may be considered as a possible upper bound for the inflow into the shaft over a section of 20 meters long that may take place. An Excavation Damage Zone was numerically captured that extended, at certain points, to about 60 centimetres into the rock from the shaft walls. The thickness of the

  12. DECOVALEX II project. Nirex RCF Shaft Excavation Task 1C - Coupled hydro-mechanical effects of shaft sinking within Sector 7

    Energy Technology Data Exchange (ETDEWEB)

    Hakami, H. [Itasca Geomekanik AB, Stockholm (Sweden)

    1999-12-01

    from both Mohr-Coulomb and Hoek-Brown failure criteria - that takes care of the onset of a brittle failure more explicitly, numerical analyses were carried out in order to capture the Excavation Damage Zone, a feature that could not be studied under the failure criterion and the input data incorporated in the first modelling approach. Regardless of which of the two failure criteria was active in the simulations, the deformational disturbances caused by the numerical excavation of the shaft were typical for stiff and competent crystalline rock masses. The mechanically disturbed zone did not effectively extend farther than about three times the diameter of the shaft, beyond which the disturbance was insignificant. Also, the convergence of the shaft was confined to about 3 mm at the most, once again typical for the hard rocks. As was expected, there was a very significant difference in flow characteristics associated with the two model set-ups; with and without the outstanding flow zones. While both the modelled rock matrices had almost similar flow properties, the flow zones only appearing in the second model were supplied with uppermost values of the permeability and porosity from ranges estimated from the site and laboratory investigations. The extreme values were between x - y order of magnitudes greater than the corresponding values from the rock matrix. Extremely low volumes of water, up to about 2.5 lit/min percolated into a 20-m long section of the shaft, by using the first model set-up with no flow zones included. On the other hand much greater values; e.g. as high as about 260 lit/min flowed into the same section of the shaft, having the three flow zones active. The latter case may be considered as a possible upper bound for the inflow into the shaft over a section of 20 meters long that may take place. An Excavation Damage Zone was numerically captured that extended, at certain points, to about 60 centimetres into the rock from the shaft walls. The thickness of

  13. Scatterometry

    Science.gov (United States)

    Stoffelen, Adrianus Cornelis Maria

    1996-10-01

    Een veelheid aan meteorologische metingen is dagelijks beschikbaar. De meeste van deze waarnemingen bevinden zich echter boven land, en met name windwaarnemingen boven de (Noord Atlantische) oceaan zijn schaars. Bij een westelijke luchtstroming is dit een duidelijke beperking voor de weers- en golfverwachtingen ten behoeve van Nederland. Juist dan is het gevaar voor bijvoorbeeld storm of overstroming het grootst. Ook in het aardse klimaatsysteem speelt de wind aan het oppervlak een grote rol en is de belangrijkste factor voor de aandrijving van de oceaancirculatie. De oceaancirculatie op zijn beurt is cruciaal voor de verschijnselen die samenhangen met bijvoorbeeld El Niño. Dit proefschift gaat over het scatterometer instrument dat vanuit de ruimte, zelfs onder een wolkendek, nauwkeurige en betrouwbare informatie geeft over de wind aan het oceaanoppervlak met een hoge mate van ruimtelijke consistentie. Tijdens de tweede wereldoorlog werden radars aan boord van schepen veelvuldig gebruikt voor de opsporing van vijandige vaartuigen. Hierbij werd vastgesteld dat de detectie slechter werd naarmate de wind aan het zeeoppervlak groter was. Proefondervindelijk was hiermee het principe van een wind scatterometer aangetoond. Al snel ontwikkelde zich dan ook de idee de wind aan het zeeoppervlak te meten met behulp van radar. Vanuit een vliegtuig of een satelliet word dan een microgolfbundel onder een schuine hoek naar het zeeoppervlak gestuurd. De microgolfstraling, met gewoonlijk een golflengte van enkele centimeters, wordt verstrooid aan het ruwe oppervlak, en een klein gedeelte van de uitgezonden puls keert terug naar het detectorgedeelte van de scatterometer. Het fysische fenomeen van belang voor de werking van de scatterometer is de aanwezigheid van zogeheten capillaire gavitatiegolven op het zeeoppervlak. Deze golven hebben een golflengte van enkele centimeters en reageren vrijwel instantaan op de sterkte van de wind. De verstrooiing van microgolven is op zijn beurt