bluuebunny/crossref_metadata_2025 huggingface dataset:
Long-term Settlement of the National Museum, Ottawa, Canada
Authors: Bozozuk M.
Published: July 2008

The settlement record of a point on the National Museum building in Ottawa for the period 1951 to 1974 is given. It shows that the average rate of settlement for this period was about 0.003 ft (0.9 mm) per year. Total settlement of the point since the structure was completed in 1910 is estimated to be 0.27 ft (82 mm).
Measuring total volumetric strains during triaxial tests on frozen soils: a new approach
Authors: O'Connor M. J. , Mitchell R. J.
Published: July 2008

A triaxial cell has been modified to permit measurement of volumetric strains during deformation-rate-controlled and stress-controlled triaxial tests on frozen soils. In the system described here, a volume change in the soil sample alters the level of fluid in the triaxial cell. The fluid level can be monitored during the test using a sloping tube volumeter. Theoretical accuracy with this arrangement can exceed 0.1% of the sample volume.
Sediment removal during an extreme summer storm: Muskwa River, northeastern British Columbia
Authors: Sherstone David A.
Published: July 2008

Extreme summer storms in northwestern Canada can produce large changes in river channels and sediment loads in a short time. These infrequent events cause effects downstream that persist over several years. Photogrammetric measurement was made of sediment removed during a 36-h storm flood in June, 1977, on the Muskwa River near its confluence with the Fort Nelson River. The approximate volume of material removed was 1 398 000 m3. The sediment load added to the Fort Nelson River was between 2.3 and 2.4 million tonnes. Photogrammetric measurement techniques, combined with field samples, can provide adequate information on sediment removed during severe storms. Keywords: erosion, sediment, photogrammetry, storms, floods.
Measurement of slope runoff in a permafrost region
Authors: Steer Peter , Woo Ming-ko
Published: July 2008

Installations at a High Arctic experimental site that is underlain by continuous permafrost allowed the measurement of slope runoff. Surface flow was collected near the base of the slope and the water was led to a flume with a V-notch weir. The water level in the flume was recorded and subsequently converted to discharge measurements. Subsurface flow was intercepted by an impermeable flow barrier set in a trench dug down to the permafrost table and later back-filled by the excavated slope materials. Water draining from above the flow barrier was fed into another flume unit similar to that for surface runoff. During the operational period, regular inspection of the flumes was required to ensure the prevention of ice formation or evaporative losses from the water in the flumes. Keywords: surface flow, subsurface flow, slope hydrology, permafrost.
Frost sensitivity of core materials: Case histories
Authors: Solymar Z. V. , Nunn J. O. H.
Published: July 2008

Waterloo Lake, White Lake, and Charlot River Power Projects are situated some 60 km west of Uranium City, Saskatchewan, on the north shore of Lake Athabasca.Waterloo Lake Dam is a simple zoned earth–rockfill structure with a wide central impervious core of silt. Since the first winter, frost penetration of the silt core has caused gradual deterioration of the dam. Pronounced longitudinal cracking and silt outflows have been evident along almost the entire length of the crest.Based on the experience gained from Waterloo Lake Dam and other northern projects the designs of the White Lake Dam and the Charlot River Dam incorporated safeguards against frost heave cracking of the core.This paper presents details of both in situ and laboratory test programs and the subsequent construction of the White Lake and Charlot River Dams. Keywords: bentonite, core material, frost, northern dam construction, plastic membrane.
Stability of installation of marine caisson anchors in clay
Authors: Burgess I. W. , Hird C. C.
Published: July 2008

If they can be installed, steel caissons offer a number of advantages over more traditional marine anchors in the exploitation of offshore resources. The stability of insertion of such caissons into clay has been studied both theoretically and experimentally. A relatively simple theory is presented, which shows that directional stability depends primarily upon the method of insertion, gravity loading (self-weight or load imposed on top of the caisson) being much more likely to result in instability than suction (pumping out water from inside the caisson). The relative dimensions of the caisson and soil stiffness are also taken into account, and both plain circular and internally stiffened caissons are considered. A brief account is given of some model tests that have been carried out, at two different scales, which give substantial support to the theory, at least within a certain range of soil stiffness. Although in principle suction appears to be a very good way of inserting caisson anchors, its use in practice may involve certain difficulties. Keywords: caissons, soil-structure interaction, stability, anchors, offshore structures, clay.
Cohesive soil compaction by water jetting
Authors: Laba Jan T.
Published: July 2008

This paper examines the water jetting method used to compact cohesive soils. In order to gain better understanding of the process associated with water jetting compaction, including the selection of jetting equipment and technique for carrying on this operation, the investigation includes both the theoretical and experimental aspects. Based on theoretical analysis of the hydraulics of water jetting, equations for calculating the compactive force applied by the water jet to the soil and the magnitude of applied jetting energy are derived and used to evaluate jetting performance in the field. Records of full scale field experiments are presented, showing the influence of the nozzle pressure, nozzle diameter, jetting time, and the jetting probe spacing on the backfill compaction and settlement. This study is supported by discussion of the present state in the art of water jetting and by records from jetting projects completed in the past. Keywords: water jetting, jet compaction, jetting energy, clay backfill, settlement, soil moisture.
Design and construction of Revelstoke earthfill dam
Authors: Taylor H. , Lou J. K.
Published: July 2008

The Revelstoke earthfill dam, located on the Columbia River in Central British Columbia, consists of a central till core with upstream and downstream granular shells. A core trench up to 76 m (250 ft) deep had to be excavated through the overburden in order to found the core on rock and approximately 7.6 × 106 m3(10 × 106 yd3)of overburden was removed. In one area, the core trench was excavated through 61 m (200 ft) of soft wet silt and clay. The dam axis crosses two deep buried channels and adjustments were made in the design to suit field conditions. Electroosmosis treatment was used to stabilize the core trench cut slopes in the area of the soft wet silt. Extensive field and lab testing was carried out to determine the density and strength of the overburden material. Empirical and analytical methods were used to assess the liquefaction potential under seismic loading of the silt/clay and fine sands under the shells of the earthfill dam.The Revelstoke earthfill dam was about 57% complete by the end of 1981. The construction has proceeded well and is on schedule. It is expected that the earthfill dam will be completed by mid-1983, well in advance of proposed reservoir filling in the fall of 1983. Keywords: excavations embankment design, foundation treatment, liquefaction, construction, electroosmosis.
Application of the NCB Cone Indenter to strength index testing of sedimentary rocks from Western Canada
Authors: Stimpson B. , Acott C. P.
Published: July 2008

The NCB Cone Indenter is a portable static hardness tester for index testing of small fragments of rock. Correlations between the standard cone indenter number, Is, and uniaxial compressive strength have been determined by the National Coal Board (NCB). This note describes the application of this tool to some Western Canadian sedimentary rocks, and finds that the linear regression equation relating the indenter number and uniaxial compressive strength is different than the suggested NCB equation. Other uses for the index tests are suggested, including geotechnical mapping and the development of blasting and 'cuttability' criteria. Keywords: rock index test, indentation, hardness, uniaxial compressive strength.
Frost action as the cause of dolostone popouts in asphalt, Kingston, Ontario
Authors: Rogers Chris
Published: July 2008

A portion of Highway 15 in eastern Ontario was repaved in 1973. After a number of years, about 10% of the coarse aggregate particles were lost from the surface, leaving "popouts." Petrographic examination of these argillaceous dolostone particles was used to determine the source of the rock. It is postulated that these popouts were due to the action of freezing and thawing. Popouts can occur from the lack of bond between asphalt and porous chert; however, dolostones are not susceptible to this asphaltic bond problem. Keywords: dolostone, chert, asphalt, popouts.
Hydraulic fracturing from induced pore pressures in clay soils
Authors: Poorooshasb H. B. , Yong Raymond N.
Published: July 2008

The possibility of induced high excess pore pressures during consolidation of a clay soil with transverse drainage developing hydraulic fracturing in the soil is presented. The elastic analysis pursued herein examines the stress and pore pressure fields generated under vertical consolidation loading with drainage allowed only in the transverse direction. The results indicate that when the load step increments are too large, in comparison with previous loads, the transverse effective stress associated with the central elements of the soil being loaded can become negative. At that time, a state of tension will be created and a form of hydraulic fracturing will result. Key words: pore pressure, hydraulic fracture, elastic analysis, transverse drainage, consolidation.
A model of soil–pile interaction owing to cyclic loading
Authors: Swinianski Jerzy , Sawicki Andrzej
Published: July 2008

A model of a pile–soil system subjected to vertical cyclic loading is proposed. The model is based on the classical t–z concept and on the compaction theory of granular materials to study the reduction of shearing resistance around a shaft owing to cyclic loading and the redistribution of loads carried by the shaft and tip of a pile. The model is applied to predict the behaviour of cyclically loaded piles in experimental conditions. Theoretical predictions against experimental data are presented. The model gives realistic predictions from a qualitative view point. Quantitative agreement is obtained for large-scale tests. Key words: piles, theoretical model, cyclic loading, compaction theory, redistribution of load transfer.
Analysis of a sanitary-embankment failure over the Rio de Janeiro soft clay deposit
Authors: Cunha Renato Pinto Da , Lacerda Willy Alvarenga
Published: July 2008

This paper presents the analysis of an embankment failure over a soft clay deposit in the district of Caju, Rio de Janeiro. The uncommon feature of the analysis is related to the embankment's material, which is mainly composed of dumped sanitary and rubble fill, and the unconsolidated state of the subjacent clay layer. Index tests were performed to obtain geotechnical characteristics and a profile of the soft clay deposit, which were compared with a well-known Brazilian clay from the same area (Guanabara Bay). Oedometer tests, in situ and laboratory vane tests, standard penetration tests, and conventional triaxial tests were also carried out. Total stress calculations were used to interpret and back analyze the failure and also to obtain the mobilized shear strength at both the fill and clay foundation. It was concluded that for an embankment cohesion of 0–20 kPa, the ratio between the back-analyzed Cu and the in situ postfailure Cu has a magnitude similar to the soft clay sensitivity. Key words: case history, sanitary fill, soft clay.
Use and interpretation of a research dilatometer
Authors: Campanella R. G. , Robertson P. K.
Published: July 2008

The flat dilatometer (DMT) test was introduced by Marchetti (1980) as a new in situ penetration test for soils. The equipment and test procedures are simple, and the test provides repeatable, nearly continuous data that has been empirically correlated to soil type, undrained shear strength (su), coefficient of earth pressure at rest (K0), overconsolidation ratio (OCR), and constrained modulus (M). To better understand the measurements from the DMT, a research flat dilatometer was developed at the University of British Columbia (UBC). The research dilatometer is identical in size, shape, and operation to the Marchetti blade except that instrumentation was added which made passive measurements of pore pressure and deflection at the centre of the membrane, inflation pressure at the membrane, verticality of the blade, and penetration force immediately above the blade. Results from several well-documented sites near Vancouver, British Columbia, using the research DMT are presented and discussed. Results from the research DMT have provided useful insight into the test procedure and interpretation methods of the standard Marchetti DMT. Stress-deflection curves for the DMT are remarkably similar to both self-bored and full displacement pressuremeter test results. Alternate DMT procedures are proposed to estimate ø′ of sands and coefficient of consolidation in clays. A procedure incorporating the closing pressure (P2) using a standard Marchetti DMT is proposed and evaluated. Key words: flat dilatometer test, in situ, research, cone penetration test, pore pressures.'
The permeability of soils with organic fluids
Authors: Budhu Muniram , Giese Jr. R.F. , Campbell George , Baumgrass Lynn
Published: July 2008

Permeability measurements, using a consolidometer, were made for kaolinite, montmorillonite, and a clay-rich soil (the Lockport clay) with a variety of organic liquids and water as permeants. These data, along with selected values from the literature, were used to evaluate several theories that have been proposed as explanations for the general observation that permeabilities of clay soils with organic fluids as the permeants are higher than with water as the permeant. Of the several obvious differences in physical properties between water and organic liquids (e.g., dielectric constant, viscosity, dipole moment, specific gravity, and surface tension), only the dielectric constant provided a consistent correlation with the permeabilities used in this study. The permeabilities for the organic chemicals used in this study can be predicted using the measured permeability for the soil with water as the permeant and the dielectric constant of the organic by way of an exponential equation. For mixtures of acetone–water and methanol–water, the permeabilities did not vary linearly with the composition; the permeabilities remained close to values for pure water until approximately 70% (by volume) of the fluid was organic. Key words: permeability, organics, dielectric constant, soils.
Numerical modelling of vertical ground movements in expansive, soils
Authors: Sattler P. J. , Fredlund D. G.
Published: July 2008

A numerical model was developed to relate matric suction changes and vertical ground movements. The research considers one-dimensional vertical ground movements under open-vegetated fields subject to changing climatic conditions. A percentage of the Thornthwaite potential evapotranspiration model proved to be adequate to characterize the surface flux boundary condition. The infiltration and exfiltration processes were modelled separately for the field conditions. During infiltration, shrinkage cracks and the macrostructure of the soils dominate behavior. During this process, bulk permeabilities in the order of 10−6–10−8 m/s were required to simulate measured ground movements. Exfiltration processes are dominated by flow in the vapour phase as drying occurs in the soil. Bulk permeabilities in the order of 10−9–10−11 m/s were required to simulate the measured ground movement. The simulations of ground movements would also indicate that thermally induced suctions (i.e., winter freezing conditions) could account for a significant portion of the seasonal vertical ground movements. The numerical model can also be used to predict seasonal ground movements beneath light engineered structures. Further research, however, is required to better understand how to establish the surface flux boundary condition. As well, there is need for more case histories to enlarge the database of unsaturated soil parameters. Key words: vertical ground movement, matric suction, modelling, evapotranspiration, field permeabilities.
Interpretation of overconsolidation ratio from in situ tests in Recent clay deposits in Singapore and Malaysia
Authors: Chang M. F.
Published: July 2008

The stress history as indicated by the profile of overconsolidation ratio (OCR) of a soil deposit is one of the most dominant factors that influence the engineering behaviour of the soil. Its assessment, which is traditionally based on the laboratory oedometer test, is not often satisfactory. The problem arises from inevitable sample disturbance and the high cost of a detailed investigation. These difficulties can be overcome by the use of in situ tests. The field vane test, the piezocone test, and the dilatometer test are three such methods that provide indirect means for the estimation of the OCR for clay deposits. A number of empirical correlations are available for this purpose. Calibration of these correlations against results of site investigation in Singapore and Malaysian marine clays reveals the usefulness of these test methods in profiling the OCR for Recent clay deposits. Key words: clay, in situ test, overconsolidation ratio, preconsolidation pressure, stress history.
The influence of near face behaviour on monitoring of deep tunnels
Authors: Pelli F. , Kaiser P. K. , Morgenstern N. R.
Published: July 2008

Convergence, radial displacements, and stress changes are often recorded during the advance of a tunnel for the observational tunnel design approach. In deep tunnels, instruments must be installed from underground and can seldom be placed in undisturbed ground. Consequently, observations are only partial records of the total change induced by an excavation and the influence of the three-dimensional state near the face must be considered. This paper presents results from numerical simulations to assess face effects on monitoring data. The influence of such aspects as in situ state of stress, anisotropy, nonlinearity, and plasticity (yielding ground) are evaluated. Guidelines for underground monitoring of deformations are given. Key words: tunnelling, monitoring, back-analysis, convergence, extensometers, numerical modelling.
Measurement of soil strength in simple shear tests
Authors: Atkinson J. H. , Lau W. H. W. , Powell J. J. M.
Published: July 2008

During a simple shear test the axes of stress rotate and, in a conventional apparatus in which the only stresses measured are the normal and shear stresses on horizontal planes, it is not possible to define the stress state completely. As a result, the measured failure stresses may not represent the true strength of the soil. Examination of possible Mohr's circles for soils at failure in simple shear tests demonstrates that the measured strength for a given soil depends on, among other things, the ratio of the horizontal and vertical effective stresses at failure. Results of laboratory tests on Cowden Till and on blue London Clay show the differences between strengths measured in simple shear and triaxial tests. A consequence of the conventional interpretation of the simple shear test is that effective stress failure envelopes have a false cohesion intercept with friction angles smaller than those measured in triaxial tests. Key words: clays, laboratory equipment, shear strength, shear tests, triaxial tests.
In situ tests in a sand dune
Authors: Konrad J.-M.
Published: July 2008

A field testing program using an electric piezocone penetrometer (CPTU) and a flat dilatometer (DMT) probe was carried out in a sand dune. The analysis of the field data in terms of relative density using current empirical correlations showed that significant differences were obtained at this site. It is suggested that any empirical correlation between relative density and CPT or DMT data obtained from calibration chambers should only be used for a sand that has the same slope of the steady-state line as the sand used in the calibration tests. Key words: sand, in situ density, field investigation, piezocone penetrometer, flat dilatometer, steady state.
Thermal analysis of forced-air and thermosyphon cooling systems for the Inuvik airport expansion
Authors: Smith L. B. , Graham J. P. , Nixon J. F. , Washuta A. S.
Published: July 2008

This paper presents a description of thermal analyses of forced-air ventilation and thermosyphon cooling systems, which were carried out in connection with the design of the concrete raft foundations that support hangars and other major structures to be constructed by the Department of National Defence adjacent to the existing airport near Inuvik, N.W.T. The cooling systems are required to prevent heat from the buildings from thawing the ice-rich permafrost present below the site. The analyses identified those parameters that have the most significant effect on the efficiency of each system. Based partially on the results of the analyses, it was decided to utilize air ventilation for cooling. The system is expected to perform satisfactorily under natural convection; however, the design includes a provision to install air blowers, if this should prove necessary in the future. A number of areas in which further research appears useful have been identified. Key words: permafrost, thermal analysis, raft foundation, hangar, ventilated slab, natural convection, thermosyphons.
The Heather Hill landslide: an example of a large scale toppling failure in a natural slope
Authors: Pritchard M. A. , Savigny K. W.
Published: July 2008

This paper is an inquiry into the suspected relationship between toppling and large deep-seated landslides along the Beaver Valley, Glacier National Park, British Columbia. The study area includes the Heather Hill landslide, one of several in the valley, and adjacent slopes that show varying degrees of toppling disturbance. The development of the Heather Hill landslide is simulated using the distinct element method of numerical analysis. The rock mass is modelled using deformable columns whose boundaries represent a coarse approximation of in situ discontinuity patterns. An intercalated change in the predominant lithologies and a concomitant change in discontinuity spacings are modelled by varying column thickness and material properties. The analysis confirms that a deep-seated failure surface can develop as a result of the toppling process. The intercalated change in lithologies and the related change in discontinuity spacings account for the curvilinear failure surface and the headscarp position of the Heather Hill landslide. These variables are believed to also control the overall distribution of landslides in the Beaver Valley. The paper demonstrates that the distinct element method provides an effective basis for quantitative analysis of large scale toppling. Many more applications will be needed to refine the geometric and material property generalizations used in this study. Nevertheless, the method appears to offer considerable promise for elucidating problems of rock slope behaviour in both slope engineering and geomorphology. Key words: toppling, landslide, British Columbia, mountains, numerical modelling, distinct element method.
Behaviour of broken ice as a geomaterial
Authors: Wong T. T. , Morgenstern N. R. , Sego D. C.
Published: July 2008

To study the mechanical behaviour of ice rubble, triaxial compression tests are performed on broken ice samples. Using the phenomenological approach, the stress–strain curves of normally consolidated broken ice are compared and contrasted with those of other geomaterials that display high plastic compressibility. Key words: broken ice, geomaterials, mechanical behaviour, stress–strain curves.
Analysis of a large moist landslide, Lost River Range, Idaho, U.S.A.
Authors: Shaller Philip J.
Published: July 2008

This paper describes the regional geology, dimensions, morphology, sedimentology, and age relations of the Holocene "Carlson landslide," a large moist landslide composed of basalt breccia located on the eastern margin of the Lost River Range, Idaho. These data are combined to deduce the factors that prompted the slope failure, the kinematics of initiation, travel, and stopping of the landslide, as well as its postemplacement degradation. The landslide is compared with other terrestrial mass movements on the basis of morphology, sedimentology, log(volume) versus fall height –runout length (H/L) relations and estimated Bingham plastic yield strength. Morphology and sedimentology distinguish dry landslides from moist and water-saturated deposits. However, moist and water-saturated landslides plot well within the log(volume) versus H/L envelope for dry terrestrial landslides and exhibit overlapping ranges of estimated Bingham plastic yield strength values with dry landslides, indicating that moist and water-saturated landslides must travel much like dry rock avalanches of similar volume. Thus the mechanism(s) responsible for causing anomalous runout in large dry landslides could operate in moist and water-saturated landslides as well. Morphological comparison of the Carlson landslide with lobate martian landslides suggests a role for water in the martian landslides. Key words: landslides, debris flows, long runout, morphology, water, Mars.
The role that fracture plays during ice failure
Authors: Marcellus R. W. , Heuff D. N.
Published: July 2008

Brittle fracture of ice plays an extremely interesting and complex role in the ice failure process. This paper provides a general overview of the behavior and structure of ice on both the microscopic and macroscopic levels. The idea that the failure load on any type of ice is dependent on the load path that the ice experiences prior to failure is discussed. This paper also provides a general overview of the different fracture mechanisms that occur during ice failure and introduces a new concept for describing the crushing process. Key words: ice, fracture, brittle, failure, ice-structure interaction, ice strength, new crushing concept, microcrack, macrocrack.
Performance of raft foundations for high-rise buildings on the Bouldery Clay in Singapore
Authors: Wong I H , Ooi I K , Broms B B
Published: July 2008

The Bouldery Clay in Singapore consists of sandstone boulders that are embedded in a matrix of very stiff to hard silty and sandy clay. The strength and deformation characteristics of the soil matrix are close to those of a weak rock or a heavily overconsolidated clay. The average value of the second cycle moduli from the pressuremeter tests and the plate load tests is 480 MPa, and the average value of the undrained shear strengh from in situ tests is 1000 kPa. The performance of raft foundations for six high-rise buildings founded on the Bouldery Clay has been vary satisfactory, and the measured maximum and differential settlements are within allowable limits. The average equivalent undrained modulus of elasticity back-calculated from settlement observations is 540 MPa, compared with the average modulus of 480 MPa from in situ tests after unloading and reloading. It is therefore recommended that unloading and reloading of at least two cycles should be carried out for in situ tests so that a more representative modulus of elasticity for the Bouldery Clay and other very stiff or hard soil can be obtained.

Key words: raft foundations, Bouldery Clay, Young's modulus, settlement, high-rise buildings.
Loi de comportement thermo-hydromécanique pour les sols non saturés : identification in situ des indices de compression thermique
Authors: Devillers P , Saix C , El Youssoufi M S
Published: July 2008

This paper deals with thermo-hydromechanical behaviour of nonsaturated soils. The constitutive relationship presented herein allows for the prediction of the settlement or swell of an unsaturated soil under nonisothermal oedometric conditions. Mechanical, hydraulic, and thermal compression indexes are considered for stress, capillary pressure, and temperature variables, respectively. The implementation of the relationship in a prediction scheme requires preliminary characterization of these indexes. The stressstrain and water volume change relationships are first presented from semiempirical point of view for a nonsaturated soil element under nonisothermal conditions. These relationships allow for the expression of a thermo-hydromechanical constitutive law for nonsaturated soils and propose a relationship for the change in the soil water content. The thermal compression indexes are then determined for a clayey silty sand, first using a reverse method and then a direct method. This determination is made from experimental data recorded on a prototype involving heat storage in an aquifer. The values of these thermal compression indexes are finally compared with the laboratory values obtained in a thermal triaxial cell on samples of the same soil.

Key words: nonsaturated soils, thermo-hydromechanical, oedometer tests, thermal compression indexes, characterization, reverse method, direct method.[Journal Translation]
The angle of reach as a mobility index for small and large landslides
Authors: Corominas Jordi
Published: July 2008

The relations between the angle of reach (fahrböschung) and other indexes expressing the mobility of landslides and vertical drop, horizontal reach, and volume of landslide mass have been analyzed by means of simplified plots and regression equations. Results for 204 landslides of all sizes show that whatever the mechanism of motion, all kinds of landslides experience a continuous reduction of the angle of reach with volume increase. This reduction starts from the smallest sizes. Scattering in this relation is mostly due to mechanisms of motion and to both obstacles and topographic constraints on the path. This synthesis indicates that small landslides (less than 0.5 × 106 m3), in relative terms, display excesses of travel distance similar to large landslides. Since most small landslides are not expected to develop any change in the mechanism of progression while moving, the decrease in the reach angle with volume suggests that scale effects should be taken into account. The angle of reach is found to be a proper indicator of the relative mobility of landslides and is not dependent on the height of fall.

Key words: mass wasting, landslides, reach angle, runout distance, rock avalanches, shallow landslides.
A method for determination of ϕb for statically compacted soils
Authors: Oloo S Y , Fredlund D G
Published: July 2008

The unsaturated shear strength parameter, ϕb, is usually determined using triaxial of direct shear apparatus that have been modified to allow for the control and (or) measurement of pore-air and pore-water pressures. A fairly high level of expertise is required for the characterization of ϕb using these modified apparatus. A simple procedure for determining ϕb for statically compacted soils at different water contents is presented along with a method of analysis. The tests can be performed on a conventional direct shear apparatus. The unsaturated shear strength parameter, ϕb, obtained using the proposed procedure is shown to be comparable to that obtained using the modified direct shear test. Since the proposed procedure utilizes standard laboratory direct shear equipment and takes a relatively short time to complete, it offers an easy and convenient alternative for the determination of ϕb for statically compacted soils.

Key words: shear strength, matric suction, unsaturated soils, statically compacted soils, direct shear test.
Large-scale testing of the Internet's Border Gateway Protocol (BGP) via topological scale-down
Authors: Carl Glenn , Kesidis George
Published: July 2008

The Internet is a critical communication infrastructure servicing billions of end-users world-wide. Ongoing studies of the Internet's operations show that data loss and increased latency are occurring due to weaknesses in its interdomain routing protocol, BGP. Many solutions have been proposed, but few have experienced widespread adoption. Both the delayed discovery of the protocol's shortcomings, and apathy for its proposed solutions, are partially due to inadequate testing practices. Internet interdomain routing technologies are not evaluated at appropriate scale. Better testing is suggested, which incorporates the specification of large-scale experimental topologies. This is necessary, as BGP performs the distributed operation of interdomain routing across the thousands of networks composing the Internet. However, only small to moderately sized topologies can be currently accommodated by today's testing platforms.

A modeling methodology based on path preserving scale-down is proposed to extend the topological scale of interdomain routing experimentation. A given Internet topology is reduced in terms of its autonomous systems (ASes) using a combination of Gaussian elimination and several graphical heuristics. The interdomain routing paths generated by BGP on this reduced topology are also preserved. Path preservation keeps the length, composition, and ordering of these routing paths unchanged. When the routing paths guiding Internet traffic among ASes are preserved across the size reduction, the large-scale traffic engineering induced by BGP can be estimated at much lower scales. Internet data losses due to certain inappropriate interdomain routing behaviors can be identified. As an example, a persistent multiple origin autonomous system (MOAS) conflict is characterized over a topology containing 8826 ASes. It is shown that this problem's large-scale characterization can be obtained using scale-down models that are 70% smaller, and thus more accommodating to common testing platforms (e.g., simulation and networking testbeds).
Semantic text similarity using corpus-based word similarity and string similarity
Authors: Islam Aminul , Inkpen Diana
Published: July 2008

We present a method for measuring the semantic similarity of texts using a corpus-based measure of semantic word similarity and a normalized and modified version of the Longest Common Subsequence (LCS) string matching algorithm. Existing methods for computing text similarity have focused mainly on either large documents or individual words. We focus on computing the similarity between two sentences or two short paragraphs. The proposed method can be exploited in a variety of applications involving textual knowledge representation and knowledge discovery. Evaluation results on two different data sets show that our method outperforms several competing methods.
Certification process of software components
Authors: Kaur Parminder , Singh Hardeep
Published: July 2008

Component based systems are the result of structuring a system according to particular design pattern which involves components, component frameworks, component models, component composition, component interfaces, contracts and certification. The success of component-based software engineering depends on system integrator's ability to select the most suitable components for their intended application. This is only possible if component suppliers have clear and reliable information about their component's functional and nonfunctional properties. The component attributes allow system integrator to better classify the components. This paper makes an effort to define certain properties of a component, which are helpful during their classification process. This paper also tries to enlighten the component certification/accreditation process, which helps component suppliers to issue the guarantee of claimed functional properties and quality attributes.
An experimental evaluation of SEC+, an enhanced search engine for component-based software development
Authors: Khemakhem Sofien , Drira Khalil , Khemakhem Emna , Jmaiel Mohamed
Published: July 2008

Current approaches for service discovery are inherently restricted to the exact querying. This may provide incomplete answers since queries are often overspecified and may lead to low precision and recall. To alleviate these problems, we achieved an experimental evaluation that uses of the enhanced search engine, SEC+. This engine is based on the subsumption mechanism and a function that calculates the semantic distance. Both the used rate and the non-functional features are considered to filter the selection. We show that such a solution can improve the quality of the search and can enhance both the recall and the precision.
A comparison of object-oriented languages in software engineering
Authors: Nami Mohammad Reza
Published: July 2008

Object-oriented programming is still a relatively new technology in the world of web development. Object-oriented programming languages directly support the object notions of classes, inheritance, information hiding, and dynamic binding. In Object-Oriented Programming, a program is seen as comprising a collection of individual modules, or objects, that act on each other. Each of these objects could be seen as an independent program in itself, with a distinct role or responsibility. Object-Oriented Programming provides greater flexibility and easier maintenance across large systems and can sometimes make understanding and analyzing complex procedures a lot easier. This paper presents a comparison of object-oriented programming in software engineering including properties of Java, C++, Eiffel, and Smalltalk languages.
Letter from the chair
Authors: Sipior Janice C. , Lending Diane , Amoroso Donald L. , Shayo Conrad , Vowels Susan A.
Published: July 2008

I hope you had an enjoyable summer and are looking forward to the new academic year.

I am pleased to announce the recipients of the Fifth Annual Magid Igbaria Outstanding Conference Paper of the Year Award, presented at the ACM-SIGMIS CPR (Computer Personnel Research) 2008 Conference at the Omni Charlottesville Hotel in Charlottesville, Virginia, USA, from April 3-5, 2008. Please join me in congratulating Eileen M. Trauth, Jeria L. Quesenberry, Haiyan Huang, and Stephen McKnight for their paper entitled, "Linking Economic Development and Workforce Diversity through Action Research." You can find their award-winning paper in the SIGMIS CPR 2008 Conference Proceedings, available in the ACM Digital Library at: http://portal.acm.org/dl.cfm. I would like to invite you to consider sending a submission to next year's SIGMIS CPR 2009 Conference:

Where:
University of Limerick campus, Limerick, Ireland

When:
May 28-30, 2009.

The submission deadline is October 31, 2008. Your participation is welcome and encouraged! For more information, please contact the SIGMIS CPR Conference Committee:

Conference Chair:
Norah Power,
University of Limerick

Program Chair:
Damien Joseph,
Nanyang Technological University

Treasurer:
Indira Guzman,
Touro University International
Or, check our website for conference information at: http://www.acm.org/sigmis.

Our Data Base Editorial Staff also awaits the submission of your best research:

Editor-in Chief:
Tom Stafford,
Fogelman College of Business & Economics, University of Memphis

Global Co-Editor:
Patrick Y.K. Chau,
School of Business, The University of Hong Kong

Managing Editor:
Colleen Schwarz,
E.J. Ourso College of Business, Louisiana State University

Technical Editor:
Loel Kim,
Center for the Study of Rhetoric & Applied Communication, University of Memphis

Submission information is available at the Data Base website at: http://the-database.org.

Finally, we are pleased to invite you to the Eighth Annual ACM-SIGMIS Reception:

Where:
International Conference on Information Systems (ICIS2008), Paris, France Location to be determined

When:
Saturday, December 13, 2008, 5:30 to 7:00 pm

Who:
All ACM-SIGMIS members and their invited guests are welcome!

We appreciate your continued support of SIGMIS. Please feel free to contact any one of us with ideas.
DAFS: A New High-Performance Networked File System
Authors: Kleiman Steve
Published: July 2008

The Direct Access File System (DAFS) is a remote file-access protocol designed to take advantage of new high-throughput, low-latency network technology.
Derivation of Geodesic Flow Fields and Spectrum in Digital Topographic Basins
Authors: Lim Sin Liang , Sagar B. S. Daya
Published: July 2008

We present a framework to characterize terrestrial functions—surficial and bottom topographic regions that are represented, respectively, as raster digital elevation models (DEMs) and digital bathymetric models (DBMs)—through analysis of flow fields that are simulated via geodesic morphology. Characterization of such functions is done via a new descriptor. Computation of this new descriptor involves the following steps: (i) basin in digital form representing topographic fluctuations as an input, (ii) threshold decomposition of basin—that consists of channelized and nonchannelized regions—into sets, (iii) proper indexing of these sets to decide the marker set(s) and its (their) corresponding mask set(s), (iv) performing geodesic propagation that provides basic flow field structures, and (v) finally providing a new basin descriptor—geodesic spectrum. We demonstrated this five‐step framework on five different synthetic and/or realistic DEMs and/or DBMs. This study provides potentially invaluable insights to further study the travel‐time flood propagation within basins of both fluvial and tidal systems.
Simple Evaluation of the Nonlinearity Signature of an ADC Using a Spectral Approach
Authors: Peralías E. J. , Jalón M. A. , Rueda A.
Published: July 2008

This work presents a new method to estimate the nonlinearity characteristics of analog‐to‐digital converters (ADCs). The method is based on a nonnecessarily polynomial continuous and differentiable mathematical model of the converter transfer function, and on the spectral processing of the converter output under a sinusoidal input excitation. The simulation and experiments performed on different ADC examples prove the feasibility of the proposed method, even when the ADC nonlinearity pattern has very strong discontinuities. When compared with the traditional code histogram method, it also shows its low cost and efficiency since a significant lower number of output samples can be used still giving very realistic INL signature values.
Using Safety Margins for a German Seismic PRA
Authors: Obenland Ralf , Bloem Theodor , Tietsch Wolfgang , Singh Jang-Bahadur
Published: July 2008

The German regulatory guide demands the performance of a probabilistic risk assessment (PRA) including external events. In 2005, a new methodology guideline (Methodenband) based on the current state of science and technology was released to provide the analyst with a set of suitable tools and methodologies for the analysis of all PRA events. In the case of earthquake, a multilevel verification procedure is suggested. The verification procedure which has to be used depends on the seismic risk at the site of the plant. For sites in areas with low seismic activity no analysis or only a reduced analysis is proposed. This paper describes the evaluation of safety margins of buildings, structures, components and systems for plants at sites with high seismic risk, corresponding to the German methodology guideline. The seismic PRA results in an estimation of core damage frequencies caused by earthquakes. Additionally, the described approach can also be adapted for the usage in a reduced analysis for sites with lower earthquake risks. Westinghouse has wide experience in performing seismic PRA for both BWR as well as PWR plants. Westinghouse uses the documented set of seismic design analyses dating from construction phase and from later updates, if done, as a basis for a seismic PRA, which means that usually no costly new structural mechanics calculations have to be performed.
Monitoring of Enzymatic Proteolysis Using Self‐Assembled Quantum Dot‐Protein Substrate Sensors
Authors: Clapp Aaron R. , Goldman Ellen R. , Uyeda H. Tetsuo , Chang Eddie L. , Whitley Jessica L. , Medintz Igor L.
Published: July 2008

We have previously utilized hybrid semiconductor quantum dot‐ (QD‐) peptide substrates for monitoring of enzymatic proteolysis. In this report, we expand on this sensing strategy to further monitor protein‐protease interactions. We utilize QDs self‐assembled with multiple copies of dye‐labeled proteins as substrates for the sensing of protease activity. Detection of proteolysis is based on changes in the rate of fluorescence resonance energy transfer (FRET) between the QDs and the proximal dye‐labeled proteins following protein digestion by added enzyme. Our study focused on two representative proteolytic enzymes: the cysteine protease papain and the serine protease endoproteinase K. Analysis of the enzymatic digestion allowed us to estimate minimal values for the enzymatic activities of each enzyme used. Mechanisms of enzymatic inhibition were also inferred from the FRET data collected in the presence of inhibitors. Potential applications of this technology include drug discovery assays and in vivo cellular monitoring of enzymatic activity.
Nifedipine Improves Endothelial Function
Authors: Sugiura Tomonori , Kondo Takahisa , Kureishi-Bando Yasuko , Numaguchi Yasushi , Yoshida Osamu , Dohi Yasuaki , Kimura Genjiro , Ueda Ryuzo , Rabelink Ton J. , Murohara Toyoaki
Published: July 2008

Nifedipine has been shown to improve endothelial function. Recent studies have indicated that endothelial function is correlated with the number of circulating endothelial progenitor cells (EPCs), but it is unclear whether nifedipine affects the number and function of EPCs. The aims of this study were to determine the effects of nifedipine on the number and function of EPCs and to investigate the relationship between improvement of endothelial function and EPC numbers in patients with hypertension. Stage 1 hypertensive men (n=37) were randomly divided into the nifedipine group and the control untreated group. The nifedipine group was administered slow-release nifedipine (20 mg) once daily. At baseline and after 4 weeks, flow-mediated dilation, blood pressure, biochemical data, and number of circulating CD34+CD133+ progenitor cells and EPCs were measured. The direct effects of nifedipine on EPC number and function were assessed in vitro. In the nifedipine group, flow-mediated dilation and the number
s
of circulating CD34+CD133+ progenitor cells and EPCs were increased, along with a decrease of serum malondialdehyde low-density lipoprotein. The improvement of flow-mediated dilation by nifedipine was correlated with the increase of circulating CD34+CD133+ progenitor cells. Nifedipine also improved angiogenesis-related functions of EPCs (differentiation, migration, and resistance to oxidative stress) in vitro. Thus, nifedipine improved endothelial function and EPC function in stage 1 hypertensive subjects. The latter action may be mediated by reduction of oxidative stress and suppression of EPC apoptosis. These results demonstrate that nifedipine preserves endothelial integrity in patients with hypertension, at least partly, by enhancing EPC numbers and activity.