bluuebunny/crossref_metadata_2025 huggingface dataset:
EFFECTS OF BENZENEHEXACHLORIDE ON SOIL MICROORGANISMS: I. EXPERIMENTS WITH AUTOTROPHIC BACTERIA
Authors: Gray P. H. H.
Published: May 2008

Benzenehexachloride (BHC) and its gamma isomer were toxic against bacteria that oxidize ammonia to nitrite, and those that oxidize nitrite to nitrate, in solution media inoculated with soils. They were not toxic against nitrifying bacteria in soils nor against those of a vegetable compost in solution cultures. They were also toxic against bacteria that oxidize thiosulphate in solution cultures of mineral soils. Additional organic matter reduced toxicity of the gamma isomer. The toxic component was in the benzenehexachloride and not in the "filler" materials. The gamma isomer was less effective than some other component or combination of components of the BHC. Neither the BHC nor the gamma isomer stimulated nitrification.
EFFECTS OF BENZENEHEXACHLORIDE ON SOIL MICROORGANISMS: II. EXPERIMENTS WITH UREA-HYDROLYZING BACTERIA
Authors: Gray P. H. H.
Published: May 2008

Benzenehexachloride (BHC), as "Gammexane" or "Benexane 50" reduced the hydrolysis of urea by mixed and pure cultures of soil bacteria in solution cultures. It suppressed the development of urea hydrolyzing bacteria in gelatine plate cultures. The reduction or suppression was apparently due to the benzenehexachloride (and not to the "filler" materials in the wettable powder), by interference with the action of the urease, as well as by preventing growth of the bacteria; the gamma isomer had no effect. BHC did not suppress nitrate production from urea in soil.
STUDIES ON THE RESPIRATION OF RESTING AND GERMINATING UREDOSPORES OF WHEAT STEM RUST
Authors: Shu Ping , Tanner Kathleen G. , Ledingham G. A.
Published: May 2008

Chemical analyses of wheat stem rust uredospores before and after germination indicated that the lipid fraction was the major endogenous substrate used up during the germination. Some nitrogenous material, presumably protein, was also utilized and increase in chitin was observed during the germination. A number of commercially available metabolic intermediary compounds did not affect the respiration of germinated spores. Heavy metal enzyme inhibitors, such as cyanide and azide, strongly retarded the respiration of spores and of germinated spores. This, together with the findings that the spore material contained hematin and reacted positively to the Nadi reagent, suggested that a cytochrome system was operative in the respiration process. Compounds such as malonate, maleate, fluoride, and fluoroacetate, known to be the inhibitors of succinic dehydrogenase and related enzymes, did not show significant inhibition of the respiration of rust spores. However, pyrophosphate, another specific succinic acid dehydrogenase inhibitor, retarded carbon dioxide production. Other inhibitors, such as iodoacetate, benzoate, and arsenate, inhibited respiration appreciably.
A SIMPLE SEROLOGICAL TEST FOR CERTAIN ACTINOMYCETES
Authors: Douglas R. J. , Garrard E. H.
Published: May 2008

A serological technique for differentiating between certain actinomycetes is described, in which satisfactory flocculation occurs with extracts from homogenized mycelium.
THE RELATIVE PREVALENCE OF SPECIALIZED FORMS OF PUCCINIA CORONATA THAT OCCUR ON RHAMNUS CATHARTICA IN CANADA
Authors: Peturson B.
Published: May 2008

Surveys were made during the period 1947–1951 to determine the prevalence and distribution of the specialized forms (formae speciales) of Puccinia coronata Corda which occur on Rhamnus cathartica L. in Canada. From 96 aecial collections obtained in Manitoba and in Eastern Canada on R. cathartica, three distinct forms of P. coronata were isolated. Two of these, f. sp. avenae and f. sp. festucae, had been isolated previously in both Europe and North America. The third form, which could not be identified with any previously described form, was pathogenic on many species of wild and cultivated grasses, as well as on many varieties of barley and rye, but was nonpathogenic on oats. It is given the designation P. coronata f. sp. secalis f. sp. nov. The uredial stage of f. sp. secalis is much darker in color than the corresponding stage of the other two forms and it can be distinguished from them quite readily. The forms avenae and secalis occurred in Manitoba and Eastern Canada, while the form festucae was found in Eastern Canada only. In Eastern Canada the forms avenae, secalis, and festucae, in the order named, comprised 60.6, 36.6, and 2.8% of the isolates. In Manitoba, the form avenae comprised 16 and the form secalis 84% of the isolates.
METHYL BROMIDE AS A SOIL FUMIGANT FOR CONTROLLING SOIL-BORNE PATHOGENS AND CERTAIN OTHER ORGANISMS IN VEGETABLE SEEDBEDS
Authors: McKeen C. D.
Published: May 2008

The effectiveness of methyl bromide (Dowfume MC-2, 98% methyl bromide and 2% chloropicrin) as a fumigant for controlling diseases in seedbed soils used for the production of vegetable seedlings under glass was studied. A differential response of the microfloral components of a sandy loam compost soil to the lethal action of methyl bromide was observed. In general, fungi were destroyed at lower concentrations than were bacteria and actinomycetes. Of the pathogenic fungi tested, Fusarium oxysporum f. niveum and a Fusarium sp. causing root decay of onion seedlings were found to be the most resistant to the lethal action of methyl bromide. Whereas the former was destroyed by a dosage of [Formula: see text]. per 100 cu. ft. in sandy loam soil and the latter by a dosage of 2 lb. in muck soil, Pythium sp. Rhizoctonia solani, and several other pathogenic fungi were destroyed by a much lower dosage, namely, that of [Formula: see text]. per 100 cu. ft. Bacteria showed a broader range of variability than the fungi in their tolerance of methyl bromide. Whereas Xanthomonas vesicatoria and Rhizobium trifolii were destroyed at dosages of 1–2 lb. per 100 cu. ft., Pseudomonas tomato occurring in shallow lesions on tomato fruits and several spore-forming bacteria occurring in the soil were not destroyed at dosages of 4 lb. per 100 cu. ft. The benefits derived from the fumigation of a sandy loam compost soil with methyl bromide were reflected not only in the freedom of vegetable seedlings from disease but also in their increased and uniform growth. Some vegetables showed greater growth in fumigated than in steam-sterilized soil, whereas others showed the opposite effect.
THE GENUS DURANDIELLA
Authors: Groves J. Walton
Published: May 2008

The genus Durandiella, founded on Peziza fraxini Schw., includes a group of inoperculate Discomycetes occurring on twigs and branches of woody plants. The apothecia are flat, black, very hard in consistency, and have eight-spored asci with filiform ascospores. All of the species have subfiliform conidia of similar form, but the form of the conidial fruiting body varies in different species. Nine species are included in the genus of which two are described as new species, and new combinations are created for five.
STUDIES IN FOREST PATHOLOGY: XII. DECAY OF WESTERN HEMLOCK IN THE UPPER COLUMBIA REGION, BRITISH COLUMBIA
Authors: Foster R. E. , Craig H. M. , Wallis G. W.
Published: May 2008

An investigation of western hemlock (Tsuga heterophylla (Raf.) Sarg.) in the Upper Columbia region has shown that decay losses are excessive, amounting to 52 and 74% in terms of cubic and board foot computations respectively. The logs of 833 hemlock on 36 sample plots located in mature timber were analyzed in detail. Twenty-six decay-producing fungi have been isolated. Sixty-two per cent of the total decay was attributed to Echinodontium tinctorium Ell. & Ever. and 25% to Fomes pini (Thore) Lloyd. Considerable variation in the fungi responsible for decay was encountered intraregionally. Stand defect losses varied from 38 to 71%. Some of this variation could be predicted on the basis of the site index determinations of hemlock. Relative to the total incidence and importance of decay, Echinodontium tinctorium decreased and Fomes pini increased in significance with increasing site quality. Sporophores, scars, dead tops, large rotten branches, swollen knots, frost cracks, forked trees, and trunk infections of mistletoe were classed as indicators of significance in relation to hidden defect. Living trees, classed as Suspect or Residual depending on the presence or absence of one or more reliable indicators of defect, were found to differ appreciably in average defect. Within each of the preceding classes decay increased progressively with increasing diameter and decreasing site quality. Immature hemlock was found to be susceptible to appreciable decay and mature stands reached an advanced stage of deterioration at 250 years. Multiple correlation analyses between percentage of decay, site, age, and the relative percentage of Residual trees weighted by volume permitted an estimate of total stand defect within ± 7%.
GNOMONIA FRUCTICOLA ON STRAWBERRY
Authors: Bolton A. T.
Published: May 2008

Gnomonia fructicola (Arnaud) Fall was isolated from strawberries growing in various localities in Ontario and Quebec. This fungus was found to be capable of causing serious damage to strawberries under certain environmental conditions. The disease occurs on fruits, peduncles, and leaf petioles and blades. On the leaves, the first symptoms are numerous pin-point lesions which enlarge and coalesce, and finally cover large areas of the blades or entirely girdle the petioles. The fungus was found to enter the stomata of artificially inoculated leaf blades. In the host, the fungus tends to follow the vascular elements along which the pycnidia and perithecia are usually formed. Pathogenicity of G. fructicola was compared with that of leaf blight, leaf scorch, and leaf spot of the strawberry. It was demonstrated that, under the conditions described, it was capable of causing as much damage as any of the three diseases. The results obtained from nutritional experiments indicate that high concentrations of dextrose suppress, whereas those of starch, cellulose, and pectin favor the growth and reproduction of G. fructicola.
CYTOTAXONOMY OF THREE SPECIES OF CENTAUREA ADVENTIVE IN CANADA
Authors: Moore R. J. , Frankton C.
Published: May 2008

The chromosome numbers of three introduced species of Centaurea are here reported: C. diffusa Lam., 2n = 18; C. maculosa, Lam., 2n = 36; C. repens L., 2n = 26. The chromosome counts of C. diffusa and of C. maculosa, which are here reported for the first time, help to clarify a taxonomic problem. A pappus is usually lacking on the achenes of C. diffusa but is present on those of C. maculosa. As a result, plants of C. diffusa with a short pappus have been considered to be possible hybrids between these species. Three such plants here studied had the diploid chromosome number 18, rather than the triploid number to be expected in such a hybrid. Examination of pollen of suspected hybrid specimens shows that the percentage of normal pollen is high. This fact also supports the belief that plants of C. diffusa with a short pappus on the achene are not hybrids with C. maculosa.
STUDIES OF CANADIAN THELEPHORACEAE: XI. CONIDIUM PRODUCTION IN THE THELEPHORACEAE
Authors: Maxwell Mary Barbara
Published: May 2008

Four species of the Thelephoraceae, Stereum sulcatum Burt, Vararia granulosa (Pers. ex Fries) Laurila, Corticium furfuraceum Bres., and Trechispora raduloides (Karst.) Rog. have been found to produce conidia on both simple-septate, haploid mycelia and clamp-bearing dicaryotic mycelia. The conidia of the first three species are borne on oedocephaloid conidiophores while those of the fourth are formed sympodially. In all four species, the conidia, whether produced on haploid or dicaryotic mycelia, are uninucleate and each germinates to give a simple-septate, haploid mycelium. Interfertility tests were undertaken with monosporous cultures derived from the germination of single conidia or of single basidiospores. By pairing single basidiospore cultures from an individual fruit body of both Stereum sulcatum and Vararia granulosa, it was shown that these species exhibit a bipolar type of interfertility. For each of the species under investigation, complete interfertility was obtained in pairings between single conidium cultures from different isolates of the same species. A series of single conidium cultures for each species, derived from conidia borne on a dicaryotic mycelium, when paired in all possible combinations, fell into two groups on the basis of their ability to produce clamp connections. In S. sulcatum, members of each group of single conidium cultures were interfertile with one or other of the two types of single basidiospore cultures from the same isolate. Cytological studies show that there is no fusion of nuclei prior to conidium formation on the dicaryotic mycelium. Instead, the two nuclei of the dicaryon divide separately to produce approximately equal numbers of each type of nucleus, one of which enters each conidium. As indicated by the interfertility tests, the conidia therefore contain nuclei of two reaction types which are identical with those of the two nuclei of the dicaryon and also with those of the nuclei of the parent basidiospores.
THE WOOD STRUCTURE OF SOME ARIZONAN AND CALIFORNIAN SPECIES OF CUPRESSUS
Authors: Bannan M. W.
Published: May 2008

The microscopic wood structure of nine species of Cupressus native to Arizona and California was studied from approximately 700 samples. Tracheid and ray cell dimensions, size and distribution of rays, size and arrangement of pits, and thickness of cell walls were found to vary in different parts of the tree, the trends resembling those in other Cupressaceae. Comparisons of the data relating to homologous wood samples revealed slight interspecific differences in mean values for some structural features, but the range of intraspecific variability was usually broad. No single microscopic character was discovered which alone could be considered reliable for species differentiation, but certain features such as the frequency of rays, size of crossing field pits, size of tracheids and ray cells, and thickness of ray cell walls may prove valuable for diagnostic purposes when used together. As in the case of morphological characteristics, species differentiation apparently rests upon slight differences in several characters rather than invariable or marked divergence in single features.
STUDIES ON SUNFLOWER RUST: II. LONGEVITY OF UREDIOSPORES OF PUCCINIA HELIANTHI
Authors: Sackston W. E.
Published: May 2008

Urediospores of Puccinia helianthi Schw. collected from sunflower plants in the field and stored in glass vials at 5° C in a refrigerator survived for 846 days. In a freezer at −10° to −22 °C their ability to infect plants and to germinate on agar appeared unimpaired after 1652 days' storage. Storage under mineral oil decreased spore longevity at both refrigerator and freezer temperatures. Viable spores dispersed in oil germinated well on agar and induced heavy infections on sunflowers.The longevity of dry spores of P. helianthi stored at −10 °C to −22 °C and the high level of viability retained greatly exceed those reported for other species of rusts.
THIAMINE REQUIREMENT OF PULLULARIA PULLULANS (DE BARY.) BERKHOUT
Authors: Ward E. W. B.
Published: May 2008

Growth of Pullularia pullulans in shake culture on a synthetic medium, composed of D-glucose, l-asparagine, and mineral salts, was shown to be dependent on a supply of thiamine. The thiamine could be replaced by a combination of equivalent amounts of thiazole and pyrimidine, but not by either alone.
CULTURAL STUDIES OF FLAMMULA ALNICOLA (FR.) KUMMER AND FLAMMULA CONISSANS (FR.) GILLET
Authors: Denver W. B. G.
Published: May 2008

A fungus isolated from a yellow, stringy decay of white spruce and other conifers in Western Canada was at first identified as Flammula conissans sensu Ricken. This fungus was compared with an authentic isolate of Flammula conissans (Fr.) Gillet obtained from Europe. They were shown to be separate species through comparison of cultures, fruit bodies, spores, and the factors affecting fruiting in culture, as well as by pairings of monosporous mycelia. The Canadian fungus was identified as Flammula alnicola (Fr.) Kummer. Basidio-spores of F. alnicola germinated after cold treatment at −7 °C. The requirement of moderate cold-treatment for spore germination may account for the occurrence of the fungus only as a root-rot pathogen.
NOTES ON SOME GRASSES: X. SOME THOUGHTS ON FESTUCEAE, FESTUCINAE WITH SPECIAL REFERENCE TO THEIR MORPHOLOGY
Authors: Tateoka Tuguo
Published: May 2008

The flowers and caryopses of Festuceae, Festucinae (sensu Pilger, 1954) have been morphologically studied. All the genera, which show non-festucoid features in respect to non-morphological characters, are also different from true Festuceae, Festucinae in such details of their morphology as lodicules, pistils, and caryopses. On the other hand, the festucoid genera are very closely related to one another as regards these organs. The systematic positions of the genera showing non-festucoid traits in non-morphological characters are being considered in connection with their characteristics of flowers and caryopses. The results clearly indicate that the conventional treatment of morphological characteristics, in which stress is laid on some macroscopic characters, such as inflorescences or the appearance of lemmas, is quite inadequate, and that great attention should be paid to the features of flowers and caryopses, as well as spikelets and other morphological characters. A new tribe Brylkinieae is proposed.
AN ENDEMIC SUBSPECIES OF SALIX RETICULATA L. FROM THE QUEEN CHARLOTTE ISLANDS, BRITISH COLUMBIA
Authors: Argus George W.
Published: May 2008

A new taxon, Salix reticulata ssp. glabellicarpa, characterized by glabrous ovaries and capsules, distinct pedicels and styles, and oblong, dark brown bracts is described and compared with related taxa. The new combination S. vestita ssp. leiolepis is proposed.
SEASONAL CHANGES IN WATER INTAKE THROUGH BORE HOLES IN WHITE OAK TRUNKS
Authors: Parker Johnson
Published: May 2008

Water introduced into bore holes in trunks of Quercus alba L. trees over 6-hour daylight periods at different times of the year was taken up as rapidly by trees without leaves as by trees with leaves. In spring, with ample soil moisture, there seemed to be some relationship between volume of water intake and air temperatures during injection. In autumn, water intake appeared mainly unrelated to maximum daily temperature. There was indication of an increase in water intake as the autumn progressed, although soil moisture may have influenced results. Differences among groups of trees regarding volume of intake in spring and autumn were evident, although there were only slight or insignificant differences in site among these groups.
BARREN RING, A DESCRIPTION AND STUDY OF CAUSAL RELATIONSHIPS
Authors: Toohey J. I. , Nelson C. D. , Krotkov G.
Published: May 2008

A description is given of a rare soil disease, called "barren ring", which occurs in some old, deserted pastures. It is an expanding ring-shaped area of diameter up to 17 meters in which the vegetation is killed. Regeneration of normal vegetation occurs in the center of the ring. A number of microorganisms were isolated from the barren soil and tested for phytotoxicity in vitro. Of 24 pure strains of bacteria and fungi isolated, only one bacterium showed phytotoxicity to the test organism, Phleum pratense L. It was identified as a strain of Pseudomonas aureofaciens Kluyver. Bioautography of extracts of the bacterial culture showed that there are two compounds extractable in benzene which have both antibiotic and phytotoxic activity. However, it has not been established that this bacterium is the sole causal agent of the disease and it is suggested that it is caused by an association of microorganisms.
ISOLATION AND IDENTIFICATION OF TWO PHENAZINES FROM A STRAIN OF PSEUDOMONAS AUREOFACIENS
Authors: Toohey J. I. , Nelson C. D. , Krotkov G.
Published: May 2008

A method is described for the purification of two phenazine compounds from cultures of a strain of Pseudomonas aureofaciens. The chemical properties of the compounds are described and the ultraviolet, visible, and infrared absorption spectra are shown. One compound is identified as phenazine-1-carboxylic acid and the other is probably 2-hydroxyphenazine-1-carboxylic acid.
TILLERING AND LEAF PRODUCTION IN WHEAT AS AFFECTED BY TEMPERATURE AND LIGHT INTENSITY
Authors: Friend D. J. C.
Published: May 2008

The pattern of tillering developed during vegetative growth of well-spaced wheat plants agreed closely with calculation, if one assumes constant rates of leaf and tiller emergence. The average number of leaves formed between the appearance of successive tillers on an axis can be calculated from the ratio between the total number of leaves and tillers, and provides an estimate of apical dominance.The increase in total number of leaves per plant obtained by increases in light intensity over the range 200 to 2500 ft-c was brought about by an increase in both the rate of leaf emergence on individual axes and the rate of tillering. As the rate of tillering increased to a greater extent than the rate of leaf emergence, apical dominance was reduced. An increase in temperature over the range 10–25 °C also increased the total number of leaves and tillers, but the rate of leaf emergence was stimulated more than the rate of tillering so that apical dominance was increased.These effects of the environment on the relationship between leaf and tiller production are attributed to the close dependence of tillering on the supply of assimilates.
AN ANALYSIS OF AVENA COLEOPTILE PECTIN FRACTIONS
Authors: Morré D. James , Olson Alfred C.
Published: May 2008

Extraction and determination of pectic materials from growing plant tissues is often complicated by overlapping solubilities and lack of specificity of the pectin assay utilized. We find that the hot water soluble, hot versene soluble, and residual uronide components of Avena coleoptile cell wall represent at least three distinct pectin fractions with little or no overlap in solubility. In situations where hexose interference in colorimetric pectin determinations became appreciable, the polyanhydrogalacturonic acid content of the extract was determined by measurement of isolated galacturonic acid released through the specific action of polygalacturonase.A fourth fraction containing pectin-like materials was extracted from whole tissue in cold acetate buffer. This fraction was associated with heat-stable protein. No pectin identified as polyanhydrogalacturonic acid was found in the cytoplasmic fraction by the same techniques used for identifying pectin on cell wall derived fractions.
WEEDS AS RESERVOIR HOSTS OF THE LETTUCE BIG-VEIN VIRUS
Authors: Campbell R. N.
Published: May 2008

The lettuce big-vein virus (BVV) was recovered from 2 of 23 lettuce plants (Lactuca sativa L.) and 2 of 24 sow thistle (Sonchus oleraceus L.) plants sampled in 1962 and 1963 in areas of the lower Sacramento Valley where lettuce had not previously been grown. BVV is considered to be an indigenous virus of plant species in the Compositae family; these apparently are symptomless hosts and the presence of BVV is noted only when lettuce is planted under favorable environmental conditions. A BVV-Olpidium isolate from sow thistle was shown to be a physiological strain differing from the lettuce isolate in transmitting BVV to sow thistle and multiplying well in sow thistle roots. In addition, the susceptibility of Lactuca spp., Cichorium spp., and Taraxacum officinale to BVV-lettuce Olpidium was tested; only Laciuca serriola, Lactuca saligna, Cichorium sp., and a sow thistle from Japan showed good symptoms, Lactuca gracoglossum and Lactuca virosa showed symptoms poorly. Of the symptomless species, Olpidium and BVV were recovered from Lactuca muralis, T. officinale, and chicory (cv. asparagus) but not from endive (cv. No. 5) or chicory (cv. Large rooted). Sow thistle yellow-vein virus produces symptoms suggestive of big vein in sow thistle but its identity as a distinct virus transmitted by Nasonovia lactucae (L.) was confirmed.
Retrogressive slope failures at Beaver Creek, south of Saskatoon, Saskatchewan, Canada
Authors: Haug M. D. , Sauer E. Karl , Fredlund D. G.
Published: May 2008

Active landslides are occurring along the banks of the South Saskatchewan River at Saskatoon. A field investigation and stability analysis indicated that a multiple retrogressive mechanism is valid in explaining the failures at Beaver Creek, 28 km south of Saskatoon. Computations indicated that lateral pressures ranging from the active to something greater than the at-rest condition tend to support the successive blocks but are not high enough to stabilize the slides. It was assumed that the rate of movement of the blocks varies and probably increases downslope. Valuable information was obtained about the soil properties in the area and the mechanism of failure that seems to apply over a long section along the river bank south of Saskatoon.
Design, construction, and performance of a slurry trench wall next to foundations
Authors: Rosenberg Peter , St.-Arnaud G. , Journeaux N. L. , Vallée H.
Published: May 2008

The stability of excavations adjacent to existing structures is an engineering problem and challenge. With the amount of construction increasing many such excavations are being planned and constructed. This paper documents the design, construction, and performance of a tied-back retaining system constructed by the slurry trench method. The system was necessary to retain the sides of a 30-ft (9.1-m) deep cut in glacial till immediately adjacent to the heavily loaded foundations of historically important and settlement sensitive structures. The main structures next to the excavation included the façade of the south transept and the 266-ft (81.1-m) high steeple of St. Jacques Church. Foundation loads imposed by these structures vary from 5.5 to 6.5 tons/ft2 (527–622 kPa)at a depth of 5 ft (1.5 m) below ground level. The slurry trench, up to 50 ft (15.3 m) in depth, approached to within 8 ft (2.44 m) of these foundations. Excavation was in two stages with tiebacks holding the wall at each level. The slurry trench and surrounding structures were instrumented using settlement points, crack movement devices, horizontal measurement points, inclinometers, and load cells. The soil investigation and design methods adopted are described.
The stabilization of a slide in Saint-Jérôme, Lac Saint-Jean
Authors: Rochelle P. La , Lefebvre G. , Bilodeau P. M.
Published: May 2008

One year after the construction of a hospital in Saint-Jérôme, Lac Saint-Jean, a slide occurred in the slope behind the hospital building; that first slide was followed by three other small slides which took place during the following wet seasons. Some remedial works were carried out in order to drain the debris and decrease the pore pressures at the toe and behind the clay face by means of perforated drain pipes and drainage trenches, and to channel the runoff water from the plateau down into the river. The present paper gives a discussion on the causes and the mechanism of the slides, a description of the corrective works carried out, and an evaluation of their effectiveness based on different visual observations, on pore pressure and shear strength measurements, and on stability analysis.
Undrained behavior of embankments on New Liskeard varved clay
Authors: Lacasse Suzanne M. , Ladd Charles C. , Barsvary Alex K.
Published: May 2008

The performance, including a failure, of two embankments in New Liskeard, Ontario is analysed. The underlying medium-to-soft varved clay foundation is studied with respect to stability, undrained deformations, and excess pore pressure distribution.Total stress stability analyses were performed with undrained strengths based on measured and corrected field vane strengths, the average unconfined compression and unconsolidated undrained strength, and SHANSEP strength parameters with and without anisotropy. Several approaches yielded satisfactory factors of safety and reasonable critical arcs. Effective stress analyses using pore pressures predicted from finite element analyses showed that either the effective stress strength parameters were much lower than those measured in the laboratory or the predicted pore pressures at failure were much too low.Undrained deformations and excess pore pressures at end-of-construction were predicted with the finite element program FEECON. The values were generally consistent with field measurements for an embankment located 60 m from the failure area.
Tailings dam constructed on very loose, saturated sandy silt
Authors: Robinson K. E.
Published: May 2008

This paper discusses the design and performance of a tailings dam constructed over very loose, saturated sandy silt foundation soils. A major slide in an iron tailings disposal area in 1948 resulted in liquefied tailings flowing through a valley and depositing up to 6 m of very loose tailings over glacial till. The properties of the saturated tailings foundation soils were critical to the overall dam design. The new dam will eventually reach a height of 30 m.The paper discusses consolidation and strength parameters of the foundation tailings, design considerations including the potential for foundation and stored tailings liquefaction, and the result of monitoring programs during construction of the starter dam which reached a height of about 9 m. During construction the most critical stability conditions developed during placing of the initial 1.2 m lift of pit-run gravel. After foundation pore pressures dissipated additional fill was placed with no further problems. Contrary to experience with other fine grained angular soils having few clay sized particles, the iron tailings foundation soils consolidated significantly under applied load. It was computed that consolidation under the weight of the starter dam would be sufficient to increase the relative density to a value that would remain stable under maximum anticipated earthquake loadings.
Geotechnical aspects of pipeline construction in Alberta
Authors: Marshall Robert G. , Ruban Tony F.
Published: May 2008

Geotechnical engineering is playing an ever-increasing role in the design and construction of pipelines within the Province of Alberta and elsewhere in Canada. There is a growing geotechnical awareness developing within the pipeline industry that has been spurred, to some extent, by the high costs of geotechnical remedial measures and increased environmental concerns.This paper presents major geotechnical problems that the pipeline industry faces in the design, construction, and operation of pipelines within Alberta. Geotechnical considerations involved in the location of pipelines and specific methods incorporated in the design to ensure the stability of slopes and prevent erosion are presented. Recent improvements of existing methods used in the control of surface and subsurface water within the right-of-way are outlined.There have been cases where an operating pipeline has developed geotechnical problems, such as slope instability or severe erosion, that necessitate some form of remedial action. Methods used to monitor potentially unstable right-of-way slopes and the specific remedial measures implemented are presented.
Strength of field compacted clays
Authors: Liang Y. , Lovell C. W.
Published: May 2008

The reported research established the relationships among the compaction variables (dry density, water content, roller type, and number of passes) and the shearing behavior of a residual clay (St. Croix) from sandstone and shale. Compacted material was tube sampled from test pads, and subjected to two test series: unconsolidated-undrained (UU), and saturated consolidated-undrained [Formula: see text] triaxials. Both test series were run at various confining pressures to approximate the end of construction and long-term conditions for several embankment depths.The UU tests showed an increase in strength with an increase in density or a decrease in water content. For the as-compacted samples, significant volume changes occurred during shear. The volumetric strain at failure decreased with increasing prestress effected by the roller.In the [Formula: see text]testing program, sample behavior after saturation under confinement was interpreted in terms of initial compacted conditions (and confinement). The effective stress strength parameters were functions of the compacted water content and void ratio. For a given initial void ratio, as the compaction water content increased, c′ increased and [Formula: see text] decreased. The volumetric strain upon saturation varied with the compacted water content, dry density, compactive energy, and the level of confinement. Skempton's A factor at undrained shear failure was dependent upon the initial void ratio and the degree to which the sample had been prestressed by the roller.Statistically valid regression equations for these dependent variables, viz., as-compacted strength, percent volume change due to saturation and consolidation, Skempton's A parameter at failure, and the effective stress strength parameters, were developed for field compacted St. Croix clay. Uses for such equations are given.
Macroscopic features of earthquake induced soil liquefaction and its influence on ground damage
Authors: Zhong-Qi Wang , Hong-Qi Fang , Shu-Dong Zhao
Published: May 2008

In current methods for evaluating the liquefaction potential of soils, there are many uncertainties. A new approach to this problem is presented which shows that the macrofeatures of liquefaction and the earthquake damage modes of the ground can be predicted by analyzing aerial photographs that show the local microgeomorphic conditions of sites in strongly seismic areas. Using the new approach, a more reliable assessment of the liquefaction potential can be achieved, forming an important basis for the general planning and design of construction projects.This paper deals with the soil liquefaction potential problem using the vast area of the Tangshan earthquake as a model. The macroscopic patterns of liquefaction are divided into three categories, each with three subtypes. The mechanism of formation and the damaging effect of each pattern is discussed.There is evidence that, for given similar soil conditions, local geomorphic characteristics have a decisive effect on the macrofeatures of liquefaction and damage on the ground. This might provide a new basis for the avoidance of liquefaction-prone areas.
Drynoch landslide, British Columbia – a history
Authors: VanDine D. F.
Published: May 2008

Drynoch landslide, located along the Thompson River, British Columbia, is a large volume, slow-moving earthflow. Geotechnically, it is classified as a zonal, infinite slope soil failure. Geological evidence indicates that it began to move approximately 3000–6000 years ago. Until the early 1800's, movement of the slide only affected the lifestyle of the early Interior Salish Indians, the inhabitants of the area. Since that time the landslide has had a direct influence upon the Cariboo Road built in the 1860's (which later became British Columbia Highway 1 and more recently the Trans-Canada Highway) and the Canadian Pacific and Canadian National railway lines. The history of Drynoch landslide is entwined with the geographic and geologic exploration of British Columbia and the development of the interior of the province. Over the past hundred years many geologists and engineers, some quite eminent, have recorded a number of theories on the possible cause and failure mechanism of this notable slide. Suggested and attempted methods of controlling the movement of Drynoch landslide have been numerous, and have met with various degrees of acceptance and success.
Extensions to the generalized method of slices for stability analysis
Authors: Chen Zu-Yu , Morgenstern N. R.
Published: May 2008

Extensions are suggested to the generalized method of slices that is commonly used in slope stability analysis. It is shown that restrictions exist on the assumptions used to make the problem statically determinate. In addition, a numerical procedure has been developed to find the bounds to the factor of safety, subject to additional requirements of physical admissibility. As a result of these developments it has been possible to produce a revised computer program that appears to overcome the problems of convergence experienced by other programs in current use. Results obtained with this new analysis confirm the reliability of several methods of analysis used in practice.
Foundations for shock-producing machines
Authors: Novak M.
Published: May 2008

The principal criteria for the design of hammer foundations are specified and the methods of defining stiffness and damping constants for shallow foundations and pile foundations are reviewed. An analytical approach to the prediction of damped vibration is presented. The incorporation of damping is based on an energy consideration and verified by comparison with results obtained using the complex eigenvalue approach. The inclusion of damping makes the response prediction more realistic and may prevent considerable overestimation of the response and overdesign of the foundation. Keywords: damping, dynamics, foundations, hammers, shock, vibration.
Floating piles in soft, highly plastic clays
Authors: Bengtsson Per-Evert , Sällfors Göran
Published: May 2008

In Sweden the bearing capacity of axially loaded floating piles in soft clay is calculated using the undrained shear strength of the clay (often determined by the field vane test). In this study several load tests, compression as well as tension tests, have been made on well-instrumented piles. The results from these tests, in combination with thorough investigations of the field vane test, have led to a well-documented understanding of the behaviour of floating piles in soft clay.In the article, a method is presented that makes it possible to calculate the load–displacement variation in the permissible load range, as well as the bearing capacity. Results from several load tests are presented and predictions are compared with performance. Keywords: soft clay, time dependence, floating piles, bearing capacity, load tests, method of calculation, case histories.
Egypt's Aswan High Dam: Dinner address presented on December 17, 1956
Authors: Terzaghi Karl
Published: May 2008

The following note is the summary of an address given by the late Dr. Karl Terzaghi at the dinner meeting of the 10th Soil Mechanics Conference in Ottawa on December 17, 1956. The summary originally appeared in Technical Memorandum 46 of the Associate Committee on Geotechnical Research, National Research Council of Canada.The final Aswan dam was quite different from that described here. Reference should be made to the paper by Kinawy et al. which describes the development of the design in some detail and from which Fig. 1 has been prepared. The major modification in the final design related to measures taken to control piping both in the cofferdams and in the completed embankment. An innovative technique was developed of filling voids in rock fill underwater with sluiced sand thus minimizing the need for filters. This is discussed in the papers by Evdokimov et al. and by Abu-Wafa and Hanna Labib. The address by Dr. Terzaghi is a valued record to the profession in that it provides essential background to the evolution of design for this major dam structure. The Canadian Geotechnical Journal would be very pleased to receive discussions from readers familiar with its final design and performance. (R. M. Quigley, editor, and V. Milligan)
Deep foundation design in the new Ontario Highway Bridge Design Code
Authors: Fellenius Bengt H. , Meyerhof Geoffry G.
Published: May 2008

A review is presented of some aspects of deep foundation design in the new Ministry of Transportation and Communications of Ontario, ultimate limit states Bridge Design Code. The design of axial pile capacity distinguishes between structural capacity limit and geotechnical capacity limit. The geotechnical capacity of a driven pile is governed by the dynamic impedance of the pile cross section. Higher geotechnical capacity, for instance due to soil setup, can only be utilized if proven to exist. Different capacity modification factors are used for routine load tests and high level test loading. Modern methods of dynamic monitoring are included and capacity determination by such methods is accepted as equivalent to determination from routine load tests. Lateral capacity of single piles and group piles, downdrag, and inclined loading of pile groups are considered, as are details such as splicing and use of pile shoes. Pile spacing is given as a function of expected pile length.
Dewatering optimization using a groundwater flow model at the Whitewood open-pit coal mine, Alberta
Authors: Sumer S. M. , Elton J. J. , Tapics J. A.
Published: May 2008

By 1980, coal production and coal recovery at the Whitewood mine, Alberta, were unacceptably low as a result of poor groundwater and surface water control at the mine. A feasibility study conducted to determine the most cost-effective method to reduce groundwater inflows into the mine pit and reduce pore-water pressures in the mine walls concluded that a vertical well dewatering system, which would be located behind the highwall, was the most suitable. A finite difference computer model was constructed and successfully applied to design the dewatering system. The flexibility and ease of application of the model made it possible to determine the optimum number, production schedules, and locations of the dewatering wells, in conjunction with evolving mine plans. The implementation of the dewatering well program and improvements in surface water and in-pit drainage have resulted in increased coal recovery, a significant decrease in mine wall failures, and improved coal quality. Key words: dewatering, modelling, groundwater, open-pit mining, hydrogeology, pumping wells, optimization, monitoring, coal recovery.
Field measurements of stresses and deformations in a first-year ice cover adjacent to a wide structure
Authors: Sayed M. , Frederking R. , Wessels E.
Published: May 2008

Ice cover movements and stresses were measured near Adams Island from November 1984 to May 1985. The average horizontal movement rate was 0.1 m/day. Global compressive and tensile strains were less than 1 and 4%, respectively. Strain rates (measured over 1 – 2 month periods) were of the order of 10−9 s−1. Maximum stresses and forces in the ice cover were 500 kPa and 400 kN/m, respectively. Key words: ice movements, ice stresses, ice forces, Canadian Arctic Ocean.
Eleventh Canadian Geotechnical Colloquium: Contaminant migration through groundwater—the role of modelling in the design of barriers
Authors: Rowe R. Kerry
Published: May 2008

The role of analysis in the evaluation and design of barriers is discussed. Factors considered include (i) the mechanisms controlling contaminant migration through barriers; (ii) the determination of diffusion and distribution coefficients; (iii) leachate mounding and the effect of clogging of leachate collection systems upon contaminant migration through barriers; (iv) the importance of considering the finite mass of contaminant available for transport into the soil and a method of modelling the effect of finite mass of contaminant; and (v) examples of how analysis may improve the geotechnical engineer's feel for the effectiveness of potential contaminant attenuation mechanisms in both glacial till deposits and fractured rock. Key words: contaminant migration, analysis, diffusion, advection, clays, groundwater, fractured rock, design, barriers.
Large-diameter bored and grouted piles in marine sediments of the Red Sea
Authors: Ghazali Fouad M. , Sotiropoulos Elias , Mansour Osama A.
Published: May 2008

This work presents the construction procedures and pile load test results of large-diameter bored and grouted cast-in-place concrete piles in coral formations and carbonate sediments in the Red Sea. Construction details and difficulties involved in the process of site preparation, borings, reinforcement, concrete casting, and grouting are described and discussed. Geotechnical engineering considerations that led to the selection of this type of foundation and the conditions of the site are included. Key words: pile foundations, bored and grouted, marine sediments, construction methodology, load testing.
Semi-synthesis and proteasome inhibition of D-ring deoxy analogs of (–)-epigallocatechin gallate (EGCG), the active ingredient of green tea extract
Authors: Huo Congde , Shi Guoqing , Lam Wai Har , Chen Di , Cui Quizhi Cindy , Dou Q Ping , Chan Tak Hang
Published: May 2008

A semi-synthetic route to the D-ring analogs of (–)-epigallocatechin gallate (EGCG) from the relatively abundant (–)-epigallocatechin (EGC), isolated from green tea leaves, is described. A natural product (13), found in Cistus salvifolius, its acetate (14) and analog (17) were synthesized by this method. Their inhibitory activities against proteasomes were investigated.Key words: green tea, (–)-epigallocatechin gallate (EGCG), (–)-epigallocatechin (EGC), proteasome inhibition.
Partitioning of charged and neutral dextran-dye derivatives in biphasic cellulose nanocrystal suspensions
Authors: Beck-Candanedo Stephanie , Viet David , Gray Derek G
Published: May 2008

The partitioning behaviour of dye-labeled dextrans of high molecular weight in aqueous suspensions of native cellulose nanocrystals was studied. Cellulose concentrations lie in the isotropic–nematic coexistence region. Blue dextrans of various molecular weights and degrees of substitution of dye molecules (anionic Cibacron blue 3G-A) were investigated. Increasing the total concentration of blue dextran and degree of dye substitution led to increasing partition coefficients. Increasing dextran molecular weight resulted in higher partition coefficients, in agreement with theory. Partition coefficients were larger than predicted theoretically using a second virial coefficient approximation. Electrostatic and entropic contributions to the partition coefficient of blue dextran are discussed. Dextrans labeled with neutral fluorescein isothiocyanate did not partition preferentially in this system.Key words: partition coefficient, cellulose nanocrystals, dextrans, degree of substitution, polyelectrolyte.
Dumbbell-shaped dendrimers — Synthesis and self-assembly
Authors: Vassilieff Tatiana , Kakkar Ashok
Published: May 2008

We report on the synthesis and detailed characterization of dendrimers that evolve symmetrically from a linear core of 2-butyne-1,4-diol with 3,5-dihydroxybenzyl alcohol based dendron arms. The divergent layer-by-layer build-up of the dumbbell-shaped dendrimers is based on simple acid–base hydrolytic chemistry of bis(dimethylamino)dimethylsilane with OH-terminated molecules. The self-assembly of these dendrimers in THF and water is significantly influenced by their generation number, the backbone structure, and the solvent.Key words: dendrimers, divergent synthesis, macromolecules, self-assembly
Diffusion of molecular probes and the effects of their interactions with polymer matrices as studied by pulsed-field gradient NMR spectroscopy
Authors: Thérien-Aubin Héloise , Baille Wilms E , Zhu X X
Published: May 2008

Pulsed-field gradient NMR spectroscopy was used to study the interactions between small molecular probes and polymers bearing interacting groups. The self-diffusion coefficients of ethylene glycol and its oligomers and their methyl ester derivatives in poly(vinyl alcohol) gels were measured to study the effect of hydrogen bonding. The self-diffusion coefficients of small molecular probes containing hydroxyl, amine, and carboxylic acid groups were determined in several polymer matrices including poly(vinyl alcohol), poly(allylamine), and poly(acrylic acid) bearing lateral hydroxyl, amine, and carboxylic acid groups, respectively. The ionic interactions between the functional groups of the diffusants and of the polymers exhibited a marked effect on the diffusion of the molecular probes. For example, the reduced self-diffusion coefficients measured for a diffusant with a carboxylic acid group in a poly(allylamine) matrix were shown to be lower even though the molecular masses of the diffusants are similar.Key words: pulsed-field gradient NMR spectroscopy, self-diffusion, intermolecular interactions.