bluuebunny/crossref_metadata_2025 huggingface dataset:
A culture system enabling in situ determination of net and gross photosynthesis, O2 evolution, N assimilation, and C2H2 reduction in cyanobacteria
Authors: Turpin David H. , Layzell David B.
Published: May 2008

A chemostat culture system is described in which measurements of rates associated with carbon and nitrogen assimilation may be made in in situ steady-state cultures of N2-fixing cyanobacteria. Net C and N assimilations were determined from the steady-state cellular carbon and nitrogen contents and the steady-state growth rate of the cultures. O2 evolution in the light and short-term 14C assimilation were measured simultaneously in unperturbed culture cuvettes. 14C assimilation was linear with time through the origin over the 20-min sampling period, thereby providing a measure of gross photosynthesis. C2H2 reduction was measured within the culture cuvette using an open gas analysis system. Steady-state rates of C2H2 reduction were obtained within 10 min and remained constant for up to 1 h. Preliminary results showed that at similar growth rates (0.018–0.019 h−1) cultures grown on [Formula: see text] and N2 contained heterocysts, were smaller, and had higher chlorophyll contents than cells grown on NH3. Corresponding gross photosynthesis was 1.6 to 1.8 times higher than net photosynthesis in [Formula: see text] and N2-grown cells; however, for NH3-grown cells the ratio of gross photosynthesis:net photosynthesis was close to unity. These results are discussed with reference to the energetic costs associated with N assimilation in cyanobacteria.
Development of a treed bog island in a minerotrophic fen
Authors: Zoltai S. C. , Johnson J. D.
Published: May 2008

The development of a heavily treed bog island situated in a wooded fen was investigated. Macrofossils indicate that the central part of the island has supported oligotrophic treed bog vegetation almost since the beginning of its formation. Three volcanic ash layers allow the reconstruction of the position of the wetland surface at different times. The treed island was initiated on a slight rise and it was always slightly higher than the surrounding fen, maintaining oligotrophic conditions above the fen level. On the treed island, the peat above the fen level is low in such nutrients as calcium, magnesium, and sulfur, but below the fen level the chemical characteristics of the peat are similar to those of the fen peat.
Ultrastructural aspects of Pyrola mycorrhizae
Authors: Robertson Diane C. , Robertson Jack A.
Published: May 2008

The mycorrhizae of six species of Pyrola were examined with light and electron microscopes. The hyphae on the root surface varied from a loose weft to an abundant mass with numerous strands, but no organized sheath was observed. Infection began with the formation of a Hartig net several millimetres behind the root tip. Hyphae from this net subsequently grew into each epidermal cell, forming masses of intracellular hyphae. These hyphae were surrounded by the host plasmalemma and a matrix material, presumably of host origin. During the stage of mature infection the host cytoplasm was finely granular and filled with organelles. The host vacuoles often had tanninlike deposits along their tonoplasts. Senescence of the symbiosis began with the gradual degeneration of the host cytoplasm, which became dark and vesiculated with loss of its organelles. The fungal hyphae and matrix material appeared essentially unchanged at this stage but eventually degenerated and collapsed. The fungal partners were normally basidiomycetes with dolipore septa, but one ascomycetous infection (distinguished by simple septa and Woronin bodies) was found to have a similar mycorrhizal organization. It differed in having an intermittent Hartig net. The presence of both the Hartig net and intracellular hyphae indicates that these are arbutoid mycorrhizae.
Effect of aluminum on potassium uptake by red spruce seedlings
Authors: Cumming J. R. , Eckert R. T. , Evans L. S.
Published: May 2008

Potassium uptake by roots of intact red spruce seedlings exposed to 0, 1, and 4 mg∙L−1 Al3+ was determined using kinetic analysis. Uptake parameters Vmax and Km were estimated by nonlinear least-squares analysis of K+ absorption data fitted to a combined active and linear uptake model. Roots treated with 1 mg∙L−1 Al exhibited enhanced potassium uptake for up to 72 h of aluminum exposure. K+ uptake in the presence of 4 mg∙L−1 Al also increased but was influenced by the duration of exposure to Al in solution. Comparison of kinetic parameters revealed an increase in Vmax in roots treated with aluminum. Km in both 1 and 4 mg∙L−1 aluminum treatments varied consistently with duration of exposure, characterized by an initial decrease in apparent carrier-site affinity followed by Km values trending toward control levels. These changes are hypothesized to result from a combination of physical and physiological changes in red spruce seedling roots induced by Al3+ in solution.
Nimbospora octonae, a new marine ascomycete from Hawaii
Authors: Kohlmeyer Jan
Published: May 2008

Nimbospora octonae was collected on drift and intertidal wood in Hawaii and Kauai. It is compared with the other two species of Nimbospora Koch.
New Ecuadorian species in Calathea series Nudiscapae (Marantaceae)
Authors: Kennedy Helen
Published: May 2008

Four Ecuadorian species in Calathea series Nudiscapae (Petersen) Schumann s.l. are described as new. Calathea tinalandia occurs on the Pacific slope of the Cordillera in Pichincha and Esmeraldas provinces, while C. lanicaulis, C. anderssonii, and C. clivorum occur in northeastern Ecuador in the Amazonian lowlands of Napo and Pastaza provinces.
Artificial inoculation of young seedlings of lodgepole pine with Endocronartium harknessii
Authors: Allen E. , Hiratsuka Y.
Published: May 2008

Seedlings of lodgepole pine (Pinus contorta Dougl.) as young as 11 days old were successfully inoculated with Endocronartium harknessii (J. P. Moore) Y. Hiratsuka, and recognizable discolored areas were observed on these as early as 7 days after inoculation.
Data mining for miRNAs and their targets in the Triticeae
Authors: Dryanova Ani , Zakharov Arseny , Gulick Patrick J.
Published: May 2008

MicroRNAs (miRNAs) and the mRNA targets of miRNAs were identified by sequence complementarity within a DNA sequence database for species of the Triticeae. Data screening identified 28 miRNA precursor sequences from 15 miRNA families that contained conserved mature miRNA sequences within predicted stem-loop structures. In addition, the identification of 337 target sequences among Triticeae genes provided further evidence of the existence of 26 miRNA families in the cereals. MicroRNA targets included genes that are homologous to known targets in diverse model species as well as novel targets. MicroRNA precursors and targets were identified in 10 related species, though the great majority of them were identified in bread wheat, Triticum aestivum , and barley, Hordeum vulgare , the two species with the largest EST data sets among the Triticeae.
Contractor selection: fuzzy-control approach
Authors: Bendaña Ricardo , del Caño Alfredo , Pilar de la Cruz M.
Published: May 2008

This paper presents a fuzzy-logic-based system for selecting contractors. This tool, which was based on the fuzzy control technique, was created for the private sector client in traditional design–bid–build projects with one-step selection processes, but its philosophy can also serve other types of clients, industries, contracts, and selection processes. The system develops an assessment of different qualitative and quantitative issues that influence a contractor’s suitability for constructing a specific design in a specific environment (client’s needs and objectives, objectives prioritization, etc.), taking into account the risk of not achieving the client’s objectives. A computer application was developed and validated, including a Delphi analysis with professionals who are experts in contractor selection. The application covers the possibility of using different selection policies, when the essential project objective is cost, time or quality. As part of the validation process, a neural network was developed to prove that the fuzzy-control tool has a behavior that can be recognized by a neural network.
Analytical probabilistic flood routing for urban stormwater management purposes
Authors: Guo Yiping , Zhuge Zhengji
Published: May 2008

The main purpose of flood routing calculations conducted in urban stormwater management studies is to determine the flood frequency distribution at a downstream location knowing the upstream catchments, channel reaches, and detention ponds. As the current state of practice, the design storm approach is widely used for this purpose and for the planning and design of related stormwater management facilities. Building upon previous work, methods and procedures are proposed here so that flood routing for stormwater management purposes can be completed probabilistically using analytical equations. Results from the proposed methods and procedures are compared with design storm modeling results for a number of routing scenarios. The comparison study not only establishes the credibility of the proposed methodology, but also highlights potential problems associated with the application of the design storm approach.
Validation of forest height–age models
Authors: Nigh Gordon D. , Sit Vera
Published: May 2008

Forest height–age models are used in forest management to estimate height and (or) site index. It is useful to know the bias and precision of these models in order to evaluate their applicability. Methods are available for validating the models; however, many problems exist with the methods because of a lack of independence in the data and nonconstant error variance across a range of ages. A validation procedure is presented that overcomes these problems by using a multivariate technique (random coefficients) to model the structure of the errors associated with the models. Confidence intervals for bias and precision can then be constructed based on the error structure. This method of validation was demonstrated on the white spruce (Piceaglauca (Moench) Voss) height–age model for British Columbia, Canada. The preliminary validation showed the model to be unbiased for estimating both height and site index; however, its precision was poor.
Why Engelmann spruce does not have a persistent seed bank
Authors: Johnson E.A. , Fryer G.I.
Published: May 2008

Piceaengelmannii Parry ex Engelm. becomes established after fire by dispersing seeds into a burn, not through the maintenance of a persistent soil seed bank. The objective here was to determine causes of spruce seed loss from the bank to understand its lack of a persistent seed bank. One hundred seeds placed in soil cores were enumerated for 2.5 years and divided into three treatments: (i) varying the amount of protection from predators, (ii) keeping litter intact or removing it, and (iii) placing seeds on top of litter or between litter and mineral soil. For all treatments, fewer than 5% of seeds remained at the end of the study. Predation caused the greatest loss to the seed bank, much greater than germination in all treatments. Removal of litter increased germination, but predation occurred at the same rate; therefore, the total rate of loss to the seed bank increased. Seeds placed between litter and mineral soil experienced greater germination and less predation than seeds placed above the litter layer. However, increased germination balanced the reduced predation so there was little difference in the total rate of loss to the seed bank from seeds placed in either location. Further, seeds appeared to lose viability within two seasons. Thus, there is no persistent seed bank because of high predation and a rapid loss of viability.
Ecological factors affecting the abondance of advance regeneration in Quebec's southwestern boreal forest
Authors: Kneeshaw Daniel D. , Bergeron Yves
Published: May 2008

Boreal forest disturbance regimes have changed during the past century, in turn changing regeneration and stand dynamics of these forests. This is occurring at the same time that the forest industry is emphasizing operations that take advantage of pre-established natural regeneration. This study has therefore investigated the effect of various ecological factors on the abundance of Abiesbalsamea (L.) Mill., Piceaglauca (Moench) Voss, Piceamariana (Mill.) BSP, Thujaoccidentalis L., Betulapapyrifera Marsh., and Populustremuloides Michx. natural regeneration in some boreal stands in the Abitibi region of Quebec. Abiotic ecological site classification variables were found to be poorly correlated with seedling densities for most species. Parent trees, as a seed source, and stand type, for its influence on the quality of the seedbed, were strongly correlated with abundant conifer regeneration. As expected, time since fire was positively correlated with seedling abundance for late successional species, whereas it was not related to the abundance of early successional species. Post-fire disturbances, such as those due to spruce budworm (Choristoneurafumiferana (Clem.)) outbreaks, accounted for the variations in seedling densities observed with respect to stand age. The presence of budworm-caused gaps was positively correlated with regeneration abundance, whereas shrub competition, which was greatest in large gaps, was negatively correlated with advance regeneration density. Forest management based on abundance of pre-established regeneration should focus mainly on mixed stands because seedling density is very low in hardwood stands and because of the strong competition found in large gaps of resinous forests. The low number of seedlings observed, especially in coniferous stands, may limit the effectiveness of operations that take advantage of advance regeneration. The large variability observed among site and stand types limits their operational use in predicting seedling densities.
Effect of artificial defoliation on biomass allocation in ectomycorrhizal Pinussylvestris seedlings
Authors: Markkola Anna Mari
Published: May 2008

Ectomycorrhizal seedlings of Scots pine (Pinussylvestris L.) were subjected to repeated artificial defoliation (0, 25, 50, and 75%) to demonstrate the effect of a reduced amount of photosynthates on the allocation of biomass between the tree and its fungal symbionts. Defoliation reduced shoot biomass in the seedlings significantly, and belowground parts adjusted to the same growth level. Biomass parameters of seedlings that had undergone the mildest defoliation treatment did not differ significantly from control seedlings, while the two most intensive treatments reduced growth and biomass of seedlings in a similar way. Defoliation did not reduce mycorrhizal colonization or fungal biomass calculated per unit weight of fine roots. Actual needle biomass in seedlings correlated positively with stem biomass, total root biomass, fungal biomass both in roots and in soil, and the number of mycorrhizal root tips per seedling. Root/shoot ratio and total allocation pattern were relatively constant.
Classification of montane forest community types in the Cedar River drainage of western Washington, U.S.A.
Authors: Moral Roger Del , Long James N.
Published: May 2008

Vegetation of the Cedar River watershed, located in the Cascade Mountains of western Washington, was analyzed by an agglomerative clustering method followed by discriminant analysis. Stepwise mutliple discriminant analysis provided a means to reallocate stands and assists in the production of a classification scheme and a key to the vegetation types. Ten types are recognized, six from upper-elevation older-growth stands, and four seral types from lower elevation stands logged since 1900. Each type can be identified in the field with a simple key based on cover percentage. The key provides a means for large-scale vegetation mapping with a limited amount of effort.
Stump injections with soil fumigants to eradicate Armillariellamellea from young-growth ponderosa pine killed by root rot
Authors: Filip Gregory M. , Roth Lewis F.
Published: May 2008

Root rot caused by Armillariellamellea (Vahl ex Fr.) Karst. creates unproductive disease centers in young-growth ponderosa pine (Pinusponderosa Laws.) after removal of the old-growth timber. The fungus persists in stumps in these centers keeping the land unproductive indefinitely. Armillariellamellea was effectively eradicated from infected stumps by insitu fumigation with methyl bromide, Vorlex, chloropicrin, carbon disulfide, and Vapam. The fungal antagonist Trichoderma appeared to be unaffected by the fumigants except for methyl bromide, which resulted in a significant increase in the incidence of Trichoderma over control stumps.
Initiation and development of subterminal buds in Abiesbalsamea
Authors: Powell G.R.
Published: May 2008

On mature, sapling, and seedling trees of balsam fir (Abiesbalsamea (L.) Mill.) cataphyll production on shoot apices began 3 to 4 weeks before vegetative bud burst. Subterminal bud primordia were initiated in the axils of two or three of the first-formed cataphylls at about the time of vegetative bud burst. A week later, prophylls were evident on the subterminal bud apices. Cataphylls were subsequently produced until mid-July. Most buds then initiated needle primordia and increased in size until late September. Some, on weaker shoots, failed to produce needles and remained latent. Throughout their development, the subterminal buds were never dissociated from the terminal bud and, together, the buds formed a terminal bud unit, ultimately encased in a continuous layer of resin. The subterminal buds produce the nodal branches which are distinctly more vigorous than internodal branches, which are produced in lateral buds which have a different origin.
Sampling oak foliage by the randomized-branch method
Authors: Valentine Harry T. , Hilton Susan J.
Published: May 2008

Foliage in mature Quercus spp. crowns was sampled by using a two-phase procedure. The first phase provided estimates of the total count of leaf clusters in the tree crowns. The second-phase sample provided information about the clusters such as dry weight, surface area, and leaf count.
Biomass and nutrient distribution patterns in a young Pseudotsugamenziesii ecosystem
Authors: Webber B. D.
Published: May 2008

Calculations are presented giving biomass and quantities of nitrogen, phosphorus, potassium, calcium, and magnesium contained in soil, understory vegetation, and standing arboreal components of a low-site, immature Pseudotsugamenziesii (Mirb.) Franco ecosystem on southern Vancouver Island. For the standing arboreal crop, biomass and elemental content of the foliage, live and dead branches, wood, bark, and total tree were estimated, using the formula logeY = a + b logeD2H, where D = diameter breast height and H = total tree height.The soil component contained over 70% each of the total organic matter biomass and nitrogen, calcium, and magnesium content in the ecosystem. Although the soil also contained large quantities of potassium and phosphorus, the vegetative component significantly increased in importance with regard to these two elements. Biomass and nutrient distribution patterns within the standing arboreal crop are discussed in terms of elemental concentrations and distribution between components over the diameter range encountered. The distribution of biomass and the total elemental content among the various ecosystem components are discussed and comparisons are made with related studies.
Quantitative relationships among some Plnusbanksiana – Piceamariana forests subjected to wildfire and postlogging treatments
Authors: Noble Mark G. , DeBoer Linda K. , Johnson Kenneth L. , Coffin Barbara A. , Fellows Lucia G. , Christensen Neil A.
Published: May 2008

Numerical classifications are used to compare vegetation and soil characteristics at virgin, logged, slash-burned, wildfire burned, and rock-raked sites in northeastern Minnesota and western Ontario. Virgin sites are dominated by Pinusbanksiana Lamb. and Piceamariana (Mill.) BSP. and adjacent disturbed sites were previously dominated by these species. The vegetation of each study site is related to regional upland community types by discriminant and canonical analysis.A relationship between predisturbance and postdisturbance vegetation is indicated, regardless of the type of disturbance. Sites disturbed by logging or logging followed by slash burning are more similar to virgin sites than to wildfire or rock-raked sites, which are generally more similar to one another than to any of the other sites. The wildfire and rock-raked sites have undergone significant vegetational changes, but the difference in invader species indicates that the types of changes have not been the same. The number of invader species present is influenced by the type of disturbance experienced by a site. An important consequence of rock-raking is the movement of nutrients from timber producing areas to windrows.
Conelet abortion in longleaf pine
Authors: White Timothy L. , Harris Jr. H. G. , Kellison R. C.
Published: May 2008

Conelet abortion in longleaf pine (Pinuspalustris L.) ranged from 85 to 100% in 4 of 5 years in a clonal seed orchard in southeastern North Carolina. Investigation of the cause of the malady was inconclusive, but freeze damage, seed bugs, and inadequate pollen supply were excluded as principal causes. Where combinations of balanced fertilizers and ammonium nitrate had been used in the orchard, abortion was variable by clone, with some clones showing more abortion under higher fertilizer regimes.
A simulation of water relations of white oak based on soil moisture and atmospheric evaporative demand
Authors: Thompson D. R. , Hinckley T. M.
Published: May 2008

A model was described which simulated xylem pressure potential and leaf surface resistance for a white oak (Quercusalba L.) tree and several saplings in central Missouri. The simulation was accomplished using a deterministic approach and was applicable from after leaf maturation in the spring to leaf senescence in the fall. Soil moisture content, vapor pressure deficit, and solar radiation were the required driving variables. The Ohm's law analogy describing water potentials and fluxes in the soil–plant–atmospheric continuum served as the basis for the model. The model was tested with data not used in the original parameter estimation, and very close agreement between observed and predicted values was found. The patterns of xylem pressure potential and leaf surface resistance obtained from simulation runs imply that white oak has a significant amount of stress tolerance and an ability to avoid severe dehydration.
Insect juvenile hormone analogs in conifers. III. Variability of Douglas-fir wood extractives with geographical location
Authors: Manville John F. , Rogers Ian H.
Published: May 2008

Cores, branch wood, and foliage samples were taken from five healthy Douglas-fir trees at each of 20 sites across southern British Columbia, ranging from central Vancouver Island to the western slopes of the Rocky Mountains. Hybridization values for each tree were established by von Rudloff, based on the composition of the foliage essential oil. Branch wood samples and cores from bole wood were analyzed for lipophilic extractives content; the presence of juvabione-type insect juvenile hormone analogs (IJHA) was noted. A strong negative correlation was noted between lignin content and a hybrid index and a strong positive association between lignin content and diameter. There was a strong positive relationship between extractive content and age. Juvenile hormones were most commonly found in trees of the coastal and coastal intermediate subvariants. Branch wood and bole wood samples usually gave comparable results for the presence of the juvenile hormones.
Freezing injury and shoot elongation in balsam fir
Authors: Lester D. T. , Lindow S. E. , Upper C. D.
Published: May 2008

Three-year-old seedlings of balsam fir (Abiesbalsamea (L.) Mill.) representing provenances with different rates of shoot growth initiation were exposed to four temperatures between −3.3 and −8.5 °C at two different times during shoot elongation. Exposure at −3.3 °C resulted in no bud, shoot, or leaf injury. Exposure at −8.5 °C resulted in injury to 53% of 2000 buds and shoots tested. Differences in provenance and in timing of exposure were significant at lower temperatures. Freezing injury was largely a function of the developmental stage of buds and shoots at each temperature of −4.5 °C or lower. One-year-old leaves were severely damaged at lower temperatures and effects of provenance and timing of exposure were present.
Dwarf mistletoe seed dispersal and germination in southwestern Alberta
Authors: Muir John A.
Published: May 2008

In 1966, numbers of seeds of dwarf mistletoe (Arceuthobiumamericanum Nutt. ex Engelm.) dispersed from two transplanted lodgepole pine (Pinuscontorta Dougl. var. latifolia Engelm.) decreased logarithmically with increasing distance from the trees. In two study areas in 1967–1969. dispersal of seeds from individual plants began in late August and was completed in 2–3 weeks. Differences of up to 2 weeks in the beginning and duration of dispersal were apparent between the areas. On one occasion, a difference in seed dispersal was noted between plants originating from seed collected at the two study areas and growing on a single tree at another location. Seed germination began in middle to late April, and in 4–6 weeks, 10–50% of the seeds had germinated.
Characteristics of stomatal diffusion resistance in a Douglas fir forest exposed to soil water deficits
Authors: Tan C. S. , Black T. A. , Nnyamah J. U.
Published: May 2008

As part of a 2-year study of the effect of thinning on evapotranspiration in Douglas fir (Pseudotsugamenziesii (Mirb.) Franco), the relationship between stomatal diffusion resistance (rs) and environmental variables were studied. Research was conducted in an unthinned stand (1840 stems ha−1) with negligible undergrowth and a thinned stand (840 stems ha−1) with substantial salal (Gaultheriashallon Pursh) undergrowth. During the daytime rs was mainly related to the soil water potential (ψs) and the vapour pressure deficit (v.p.d.) of the canopy air. Daytime values of rs for Douglas fir ranged from 2 to 60 s cm−1 for values of v.p.d. between 4 and 24 mb (4 and 24 × 102 Pa) and values of ψs between 0 and −12.5 bars (0 and −12.5 × 105 Pa). Although increasing rs was usually associated with decreasing pressure potential of the twig xylem (ψt), increasing rs appeared to be associated with increasing ψt when the v.p.d. was high. Stress history was found to cause a shift in the relationship of rs to ψt, but had little effect on the relationship of rs to v.p.d. and ψs. Daytime values of rs for salal ranged from 2 to 45 s cm−1. This stomatal behaviour suggests that as the soil dried out, salal transpiration accounted for an increasing fraction of the total water loss by the thinned stand.
Cone induction in yellow cypress (Chamaecyparisnootkatensis) by gibberellin A3 and the subsequent development of seeds within the induced cones
Authors: Owens John N. , Molder Marje
Published: May 2008

Gibberellin A3 (GA3) induced prolific pollen cones and seed cones in 1- and 3-year-old yellow cypress (Chamaecyparisnootkatensis (D. Don) Spach) trees. In the first experiment, the GA3-induced cones developed normally and the viable pollen was allowed to pollinate the GA3-induced seed cones. Embryo development was normal and mature seeds were produced, of which 55% were filled and 93% of all filled seed germinated. In a second experiment 1-year-old potted seedlings grown in cold frames were treated with GA3 in June and July under natural long days (about 18 h of light) or short days (8 h of light). Under the long days, 4 and 5 weeks of GA3 treatment produced the maximum number of pollen cones and seed cones, respectively. Treatment with GA3 under short days induced fewer cones and gave inconsistent results.Thus, induction of cones in yellow cypress by a foliar spray can be accomplished easily and economically in seedlings or in young trees in a seed orchard under natural long days. When compared with cones which develop under natural conditions, GA3-induced cones produced a higher percentage of filled seed with a high germination percentage.
Overstory spread and intensification of hemlock dwarf mistletoe
Authors: Smith R. B.
Published: May 2008

Development of dwarf mistletoe (Arceuthobiumtsugense (Rosendahl) G.N. Jones) on 51 western hemlock (Tsugaheterophylla (Raf.) Sarg.) trees planted in 1963 at varying distances from an infected residual tree is described. Distribution of infections in the planted trees related directly to seed-dispersal patterns, i.e., it was influenced mainly by distance and direction from the infected residual. Factors controlling the numbers of infections produced included the amount of throughfall and winter depredation of seed, germination, and infection success. From an initial dispersal of 100 seeds, an average of 37 attached firmly and were retained on the branches the next spring, 23 germinated, and 13 caused infection. The influence of early autumn frosts, death of established infections, and variation in resistance levels in the trees on the ultimate number of functioning infections is documented. It was concluded that with early removal of the overstory source, levels of infection sufficiently high to cause significant early damage on all intervening regeneration would result with about 86 evenly scattered, severely infected residuals per hectare.
LEAD BARIUM POTASSIUM SODIUM NIOBATE CERAMICS FOR PIEZOELECTRIC APPLICATIONS
Authors: SAMBASIVA RAO K. , VALLISNATH N. , PRASAD T. N. V. K. V. , CH. VARADA RAJULU K. , TILAK B. , LEE JOON HYUNG
Published: May 2008

This paper reports a systematic study of tungsten bronze morphotropic phase boundary (MPB) system Pb 2-2X-3Y/2 Ba 2x RE y K 1-x Na x Nb 5 O 15, where, x = 0.20, 0.25, 0.30, RE = Pr and Bi and y = 0.05 and their structure, microstructure, hysteresis, dielectric, piezoelectric, and Pyroelectric properties. Enhanced piezoelectric constants kp, kt, k31, d31, d33, g31, g33, [Formula: see text] as 30.8%, 47.6%, 18.9%, 57 × 10-12 C/N , 159 × 10-12 C/N , 6.89 × 10-3 mV/N , 19.23 × 10-3 mV/N , and 13.88 × 10-12 m 2/ N respectively are observed in the composition for which y = 0, and x = 0.30, which is above MPB. Also, a change in thickness, 0.0159 μm has been developed for a thickness of the sample 1.2 mm, d33 = 159 × 10-12 C/N and for an applied voltage of 100 V. The same material produces a length extension, 0.0475 μm for d31 = 57 × 10-12 C/N , l = 10 mm , t = 1.2 mm , for an applied voltage of 100 V. Thus the material may be useful for a piezoelectric transducer. Enhanced piezoelectric coefficients, d31 = 96 × 10-12 C/N and g33 = 12.95 × 10-3 mV/N are also observed in the composition for which RE = Pr and x = 0.25.
TRACKING CONTROL FOR A CLASS OF CHAOTIC SYSTEMS
Authors: WANG XINGYUAN , WANG MINGJUN
Published: May 2008

This paper presents a tracking control strategy for a class of chaotic systems. A general tracking controller is designed. It is proved theoretically that the error signal can exponentially converge to zero. Numerical simulations show that the controller can make the output signal track all kinds of reference signals. Besides, a better effect can be obtained via changing the control parameters properly.
PROFESSOR C. N. YANG AND STATISTICAL MECHANICS
Authors: WU F. Y.
Published: May 2008

Professor Chen Ning Yang has made seminal and influential contributions in many different areas in theoretical physics. This talk focuses on his contributions in statistical mechanics, a field in which Professor Yang has held a continual interest for over sixty years. His Master's thesis was on the theory of binary alloys with multi-site interactions, some 30 years before others studied the problem. Likewise, his other works opened the door and led to subsequent developments in many areas of modern day statistical mechanics and mathematical physics. He made seminal contributions in a wide array of topics, ranging from the fundamental theory of phase transitions, the Ising model, Heisenberg spin chains, lattice models, and the Yang–Baxter equation, to the emergence of Yangian in quantum groups. These topics and their ramifications will be discussed in this talk.
TRANSIENT SCALING OF THE KINETIC SPHERICAL MODEL
Authors: HE C. S. , LI Z. B. , PANG W.
Published: May 2008

The dynamical equation for the kinetic spherical model of a system of spins that is initially in an arbitrary equilibrium state of a given temperature and an external magnetic field is solved. The properties of the non-equilibrium process which ensues when the temperature and field are suddenly changed are studied. The scaling hypotheses by introducing three characteristic functions are generalized. It is found that the process is scale invariant in the low temperature phase while finite-scale invariant in the high temperature phase. The characteristic functions governing the renormalization group trajectories are obtained. The diagram of renormalization group flow reveals a scaling violating point at 3Tc.
A FAILURE ANALYSIS OF INTRAMUSCULAR RIGID IMPLANTS FOR MUSCLE CONTRACTIONS
Authors: KIM YOUNG-HO , LOEB GERALD E. , PECK RAYMOND A. , SINGH JASSPREET , DESHPANDE SUDEEP , BAKER LUCINDA L. , BRYANT J. TIMOTHY
Published: May 2008

Several studies have been made to develop different versions of new leadless, permanently implanted small electronic devices that allow to be injected into muscles (BIONs™). Their circuitry should be protected from body fluids by thin-walled hermetic capsules of rigid and brittle materials such as glass or ceramic to include feed through for their electrodes. These packages experience repetitive stresses due to the muscle contraction from their excitations. This study provides a worst-case analysis of such stresses and methods to test and validate devices intended for such usage, along with the failure analysis and remediation strategy for a design that experienced unanticipated failures in vivo.
APPLICATION OF LASER GENERATED ULTRASOUND FOR EVALUATION OF INTERNAL DEFECTS IN CARBON/PPS COMPOSITES
Authors: HA YOUNG-JOON , LEE JOON-HYUN , LEE SEUNG-JOON , BYUN JOON-HYUNG
Published: May 2008

The aim of this study is to develop non-contact and real time inspection technique based on laser generated ultrasound for evaluating defects such as void, delamination in CFRP composite fabricated from recently developed 3-dimensional fiber placement system (FPS). Fiberized Nd ;YAG pulse laser is used to generate ultrasonic guided wave in the unidirectional Carbon/PPS specimen. The laser generation of narrowband ultrasound is achieved through a linear slit array. Receiving angle of air-coupled transducer is optimized by changing angle of it. The system has proven sensitive to defects in composite materials, and is well suited for on-line process control applications, with standoff distance for the transmitter and receiver, while retaining single-shot operation.
CONTINUOUS MONITORING OF STRESS CORROSION CRACKING GROWTH IN TYPE 316L STAINLESS STEEL WELDMENT USING INDUCED CURRENT POTENTIAL DROP TECHNIQUE AT ELEVATED TEMPERATURE
Authors: SATO YASUMOTO , ATSUMI TAKEO , SHOJI TETSUO
Published: May 2008

In this study, induced current potential drop (ICPD) technique was applied to monitor SCC crack growth. The SCC crack monitored was introduced on the internal wall of a pipe specimen in which simulated BWR water flows. The measurement was performed on the external wall of the pipe specimen. It was shown that the ICPD technique permits continuous monitoring of the SCC growth, which initiates from the inner wall of the pipe specimen under elevated temperature.
DETERMINATION OF MECHANICAL PROPERTIES WITH GEOMETRICAL FACTORS OF CLOSED CELL ALUMINUM FOAMS USING X-RAY TOMOGRAPHY PROCESSING
Authors: KIM YOUNG , GIMM HAKIN , KANG DONG-HWAN , KIM TAE-WON
Published: May 2008

Factors affecting non-uniform structures of cellular materials include wrinkled morphology, foam shape, and irregular solid structures. These factors result in different mechanical properties. The effect of different cell structure of aluminum foam on mechanical properties has been investigated in terms of several geometrical factors such as foam surface, foam volume, solid surface and solid volume. Uniaxial compression/tension tests have been performed by using a batch of various relative density foams. A 2-D micro-scan data of the foam structure with high spatial resolution was obtained by a Micro-CT through a digital processing technique of X-ray Tomography. The foam structures were then reconstructed as a set of flat cross-sections to interpret the 3-D morphological parameters. As shown by the results, the ratio of foam volume to solid volume has been substituted for the relative density well enough, and thus the higher of the relative density showed the greater of the total cell volume within the solid volume. The ratio of foam surface to solid volume also represented a degree of the total cell surface within a unit solid volume. Energy absorption has been changed with the ratio of foam surface to foam volume. The ratio of foam surface to foam volume in a specific morphology therefore can correctly characterize the complexity of the cell structures for the determination of mechanical properties of closed cell foams.
A STUDY ON THE FATIGUE ANALYSIS OF HEAVY DUTY DIESEL ENGINE
Authors: LEE YOUNG-SHIN , KONG JEONG-PYO , LEE JAE-OK , LEE HYUN-SEUNG , KIM JAE-HOON , JUN JOON-TAK , KIM CHUL-GOO
Published: May 2008

The heavy duty diesel engine must have a large output for maintaining excellent mobility. The compacted graphite iron (CGI) is a material currently under study for the engine demanded for high torque, durability and stiffness. In this study, structural analysis of heavy duty engine was carried out with ABAQUS, and the fatigue analysis was executed with FEMFAT using the result of structural analysis. We considered about three loading condition; pre-fit load, assembly load, gas load. Safety factors were investigated by assuming the engine was operated until 2 · 106 cycles with cyclic gas loading condition.
FAST DETECTION OF SEEDS AND FREEZE DAMAGE OF MANDARINES USING MAGNETIC RESONANCE IMAGING
Authors: KIM SEONG MIN , MILCZAREK REBECCA , MCCARTHY MICHAEL
Published: May 2008

Fast detection of seeds and freeze damage in mandarine citrus fruit was performed using magnetic resonance imaging. A 1 T industrial grade permanent magnet was used to acquire the image data. The spatial resolution of the image was 550 μm. A fast spin echo pulse sequence was used to detect freeze damage and seeds. The signal intensity of seeds and freeze damaged regions was weaker than normal tissue. Threshold based image analysis has proven successful in detecting seeds and quantifying freeze damage.
ONLINE MULTITASKING LINE-SCAN IMAGING TECHNIQUES FOR SIMULTANEOUS SAFETY AND QUALITY EVALUATION OF APPLES
Authors: KIM MOON SUNG , LEE KANGJIN , CHAO KAUNGLIN , LEFCOURT ALAN , CHO BYUNG-KWAN , JUN WON
Published: May 2008

We developed a push-broom, line-scan imaging system capable of simultaneous measurements of reflectance and fluorescence. The system allows multitasking inspections for quality and safety attributes of apples due to its dynamic capabilities in simultaneously capturing fluorescence and reflectance, and selectivity in multispectral bands. A multitasking image-based inspection system for online applications has been suggested in that a single imaging device that could perform a multitude of both safety and quality inspection needs. The presented multitask inspection approach in online applications may provide an economically viable means for a number of food processing industries being able to adapt to operate and meet the dynamic and specific inspection and sorting needs.
DETECTING DEFECTS IN OR BEHIND TUNNEL LINING CONCRETE USING ELECTROMAGNETIC WAVE RADAR WITH CHANGE OF ANTENNA TYPE AND FREQUENCY DOMAIN
Authors: KYUN PARK SEOK
Published: May 2008

The presence of defects (including cavities et al.) in or behind tunnel lining of concrete is likely to result in collapse. One method of detecting such cavities by non-destructive means is radar. By the way, the cavity of small size and deep depth can't be detected easily by the present radar technology when it applies to civil structures. To overcome these problems and limitations, this study aims to propose and develop a fitting frequency of radar and analysis method for detecting cavities in or behind tunnel lining concrete. Study for a fitting frequency of radar and analysis method is based on the experiments with various types of cavities and change of radar frequencies. As the results, it is clarified that a proposed fitting frequency and analysis method has a possibility of detecting various types of cavitations in or behind tunnel lining concrete.
DETECTION OF ANOMALIES IN PARTICULATE MATERIALS USING ELECTRICAL RESISTIVITY SURVEY-ENHANCED ALGORITHM
Authors: RYU HEE-HWAN , CHO GYE-CHUN , SIM YOUNG-JONG , LEE IN-MO
Published: May 2008

In viewpoint of geotechnical engineering, the prediction of anomaly presence in subsurface and the estimation of its position, size and state play an important role in designing structural foundations and characterizing their overall mechanical behaviors. The present study develops an enhanced algorithm for detecting anomalies in particulate materials effectively using an electrical resistivity survey. The algorithm was analytically derived using Gauss' law and Laplace's equation. A series of experimental tests was performed on anomalies that were different in terms of size, location, and type in order to verify the developed algorithm. The location, size, and characteristics of the anomalies in particulate materials are predicted from measured resistances through proper inversion processing. A comparison of the predicted and measured values shows that anomalies can be detected effectively using the electrical resistivity–based enhanced algorithm developed in this study.
DEVELOPMENT OF 3-DIMENSION CONTROLLABLE CATHETER TO SHOW THE IMMEDIATE RESPONSE USING BOTH THE THERMOELECTRIC MODULE AND THE SHAPE MEMORY ALLOY (SMA)
Authors: KIM CHEOL-WOONG , OH DONG-JOON , LEE SANG-HEON , WANG JOON-HO , KANG KI-WEON
Published: May 2008

Today, the highlighted actuators such a Shape Memory Alloy (hereafter, it is called SMA), will change greatly the next medical device market since their energy integration, lightness and simple structure are superior to those of the conventional electromechanical actuator. Especially, the reason why the SMA actuator system becomes the most important technique for the medical device market of the next generation is that the minimally invasive technique can be applied to the in-vivo lesion due to the superior flexibility of SMA actuator system such a hand. In spite of this advantage, the current SMA actuator is not widespread. The reason is that the non-linear dynamic characteristics of the SMA original hysteresis have not yet been solved. Therefore, to evaluate the thermoelectric characteristics of our developed thermoelectric module for our first basic study, we investigated the temperature variation by stage 1) according to the current increase of the consecutive current and 2) according to the countercurrent of the discontinuous static current.
A CALIBRATION METHOD OF MECHANICAL STRAINS FROM A TEMPERATURE-COMPENSATING FBG SENSOR
Authors: CHOI NAK-SAM , JUNG DAL-WOO
Published: May 2008

The sensitivity of a temperature-compensating fiber Bragg grating (FBG) sensor which has different FBGs in one fiber line was analyzed for the real time measurement of mechanical normal strain in structures. Measurement of mechanical strains of the aluminum beam surface by the double FBG sensor was performed under various heating rates and temperature range. The results were compared with those of an electrical resistance strain gage. A considerable delay in the strain measurement by the double FBG sensor during the heating process was shown, which could be quantified for the strain compensation by the introduction of a strain retardation factor to the FBG sensor.
ANALYSIS OF ULTRASONIC SIGNALS FOR MEASURING BURNING RATES OF SOLID PROPELLANTS
Authors: OH HYUN-TAEK , KIM HAK-JOON , SONG SUNG-JIN , KO SUN-FEEL , KIM IN-CHUL , YOO JI-CHANG , JUNG JUNG-YONG
Published: May 2008

To measure burning rates of solid propellants, the strand burner method is widely adopted as a standard method. The strand burner method measures burning rates under the constant pressure, so it requires a number of measurements to determine the burning rates over all pressure range. However, ultrasonic technique can measure burning rates as a function of pressure in single test, since it performed under a constant volume condition. But, we measured that burning rates by ultrasonic technique have deviation that is bigger than 3% from average one. In this study, to reduce the deviation, we have investigated variation in material property of solid propellants. And then we analyze the relation between variations of the burning rates and material property. Also, we have predicted effects of non-linear burning surface using simulated ultrasonic signals.
A LIFE ASSESSMENT FOR STEAM TURBINE CASING USING INELASTIC ANALYSIS
Authors: CHOI WOOSUNG , HYUN JUNGSEOB
Published: May 2008

An important characteristic of a fossil power plant is its ability to maintain reliability and safety of the plant against frequent start-ups and load changes. Unstable states arising during start-ups, shutdowns and load changes give rise to unsteady temperature distribution with time in steam turbine innercasing (HP/IP), which results in non-uniform strain and stress distribution. The rapid increase of temperature during starts-ups, especially, causes susceptible to failure and reduction of expected life for steam turbine components. Thus accurate knowledge of thermal stresses is required for the integrity and lifetime assessment for the turbine components. In this paper, the fatigue damage is calculated of steam turbine inner casing was calculated by combining the stress analysis based procedure and Neuber's rule. By substituting the material cyclic stress-strain relationship into the Neuber equation, the inelastic total strain range was obtained. Using this study, life consumption of steam turbine inner-casing can be obtained and a guideline for effective maintenance was proposed.
NOISE SOURCE IDENTIFICATION IN A REVERBERANT FIELD USING SPHERICAL BEAMFORMING
Authors: CHOI YOUNG-CHUL , PARK JIN-HO , YOON DOO-BYUNG , KWON HYU-SANG
Published: May 2008

Identification of noise sources, their locations and strengths, has been taken great attention. The method that can identify noise sources normally assumes that noise sources are located at a free field. However, the sound in a reverberant field consists of that coming directly from the source plus sound reflected or scattered by the walls or objects in the field. In contrast to the exterior sound field, reflections are added to sound field. Therefore, the source location estimated by the conventional methods may give unacceptable error. In this paper, we explain the effects of reverberant field on interior source identification process and propose the method that can identify noise sources in the reverberant field.
AN IMPACT SOURCE IDENTIFICATION TECHNIQUE FOR A SHELL TYPE STRUCTURE
Authors: YOON DOO-BYUNG , PARK JIN-HO , CHOI YOUNG-CHUL , KWON HYU-SANG
Published: May 2008

A time-frequency analysis technique is proposed to enhance the estimation capability for an impact mass for a shell type structure. The validity of the proposed method is verified through an experiment. The experimental result demonstrates that the proposed method is valid for estimating the center frequency of an impact response signal easily, even in a noisy environment. It is expected that the proposed method can be used to enhance the accuracy of an impact mass estimation for a shell type structure.