bluuebunny/crossref_metadata_2025 huggingface dataset:
Localization of Two Loci that Confer Resistance to Soybean Cyst Nematode from Glycine soja PI 468916
Authors: Kabelka E. A. , Carlson S. R. , Diers B. W.
Published: October 2005

Two quantitative trait loci (QTL) that confer resistance to the soybean cyst nematode (SCN, Heterodera glycines Riggs and Niblack) isolate PA3 (HG Type 0, Race 3) were previously mapped in a population of F2–derived lines developed from a cross with the Glycine soja Sieb. and Zucc. plant introduction (PI) 468916. These two QTL represent new resistance genes as they reside in genetic locations that differ from where SCN‐resistance QTL in soybean [Glycine max (L). Merr.] cultivars map. The objectives of this research were to confirm the G. soja SCN‐resistance QTL in a domestic soybean background and to localize, or better define, the positions of these QTL. Additional molecular markers were identified within the regions containing the SCN‐resistance QTL by using amplified fragment length polymorphism (AFLP) markers and bulked segregant analysis (BSA). Each QTL was localized by developing and testing several backcross populations that segregated for different genomic regions where the resistance QTL map. The SCN‐resistance QTL on LG E was localized to a 13.2‐cM interval with an average marker distance of 0.6 cM. The SCN‐resistance QTL on LG G was localized to an 18.5‐cM interval with an average marker distance of 3.1 cM. The AFLP‐BSA technique proved to be beneficial for adding molecular markers to the two regions from G. soja that confer resistance to SCN. These closely linked markers will assist in map‐based cloning of the G. soja PI 468916 SCN resistance genes which could potentially uncover genes involved in the soybean–SCN interaction and aid with their continued exploration.
Tillage Effects on Corn Emergence, Silage Yield, and Labor and Fuel Inputs in Double Cropping with Wheat
Authors: Lithourgidis Anastasios S. , Tsatsarelis Constantinos A. , Dhima Kico V.
Published: October 2005

Conservation tillage systems can be an important part of a sustainable agricultural system providing benefits for the farmers in terms of labor and fuel consumption; however, yield variability may discourage and slow adoption. Field experiments were conducted for four consecutive growing seasons in northern Greece to investigate the effect of three tillage systems (no‐tillage, reduced tillage, and conventional tillage) on corn (Zea mays L.) establishment and silage yield and to compare human labor and fuel consumption required for corn production under these tillage systems in double cropping with winter wheat (Triticum aestivum L.). The effect of tillage system on wheat grain yield was also evaluated. No significant differences in the emergence of corn plants were found between no‐tillage and conventional tillage in two out of the 4 yr of the experimentation; however, in 2 yr, the number of the emerged corn plants was lower by 26 and 16% with no‐tillage than with conventional tillage apparently because of dry soil conditions at sowing. In all years, the number of emerged corn plants in reduced tillage did not differ significantly from the other two tillage systems. No significant differences in corn silage yield were found among tillage systems, with the exception of 1 yr where a reduction in corn biomass by 13% was recorded with no‐tillage compared with conventional tillage. There were on average 35.9 and 5.6% total time saving and 36.0 and 7.2% total fuel saving with no‐tillage and reduced tillage, respectively. Despite significant differences among years, wheat yield was not affected by tillage practices. No‐tillage or reduced tillage corn following winter wheat could be successfully implemented under favorable soil conditions at sowing with the advantage of reducing labor and fuel consumption compared with conventional tillage.
Identification of Male‐Specific AFLP Markers in Dioecious Texas Bluegrass
Authors: Renganayaki K. , Jessup R. W. , Burson B. L. , Hussey M. A. , Read J. C.
Published: October 2005

Dioecy is a breeding system that promotes cross‐pollination in plants. The transfer of this trait into economically important self‐pollinated cereal crops would revolutionize the production of hybrids in these species and provide a means for increasing yields because of heterosis. Texas bluegrass (Poa arachnifera Torr.) (2n = 8x = 56) is a polymorphic dioecious species that provides an opportunity to genetically map the dioecy locus. In this study, amplified fragment length polymorphism (AFLP)‐based linkage maps were constructed for both the maternal and paternal plants used to develop a mapping population of Texas bluegrass. The maternal map contained 126 single dose restriction fragments (SDRFs), 31 linkage groups, 1744 cM, and an average marker spacing of 13.8 cM. The paternal map contained 210 SDRFs, 46 linkage groups, 2699 cM, and an average marker spacing of 12.9 cM. Approximately 76 to 81% of the Texas bluegrass genome was covered. Two AFLP markers (txbg7 and txbg154) mapped equidistantly (9.5 cM) on opposite sides of the dioecy locus (PDio1) on the paternal map. These markers provide a preliminary tool for studying sex determination and a framework for further characterization of the genomic region conferring dioecy in Texas bluegrass.
Nondestructive Estimates of Leaf Area in White Clover Using Predictive Formulae: The Contribution of Genotype Identity to Trifoliate Leaf Area
Authors: Gamper Hannes
Published: October 2005

Studies on plant development in ecology and agriculture typically assess the formation of leaf area. Plants studied here were clonal propagates of nine genets of Trifolium repens cv. Milkanova (white clover), a common species of grasslands and an important forage legume. A simple predictive mathematical relationship is introduced that can be used to estimate the area of trifoliate leaves nondestructively from the lengths of the corresponding middle leaflets. Since differences in the correlative relationship between area and length were found among all nine investigated plant genets, genet‐specific coefficients are reported. Our findings suggest that before nondestructive growth analyses are undertaken on the leaf area of clonal propagates of white clover, appropriate genet‐specific coefficients for individual predictive formulae should be determined. However, for studies in the field or mathematical modeling on a larger scale, where ecological factors may have much greater influence on leaf development than genotypes, the common predictive equation calculated for all nine genets appears to be a reasonable approximation.
Biomass Production of Switchgrass in Central South Dakota
Authors: Lee D. K. , Boe A.
Published: October 2005

Switchgrass (Panicum virgatum L.) has potential as feedstock for a cellulose‐based biofuels industry in temperate steppe regions of the northern Great Plains. Therefore, our objectives were to determine: (i) patterns of biomass accumulation and optimum harvest times for an early maturing cultivar, Dacotah (origin 46° N, 100° W), and a later maturing cultivar, Cave‐In‐Rock (origin 37° N, 88° W), in central South Dakota (44° N, 100° W) and (ii) if variation in patterns of biomass accumulation were associated with variation in patterns of precipitation. Dacotah and Cave‐In‐Rock were no‐till planted near Pierre, SD, on 6 Dec. 1999. Harvest dates were once per year during July, August, September, or October 2001 through 2004. Morphological development was determined in early, mid, and late summer 2004. Maximum biomass yields for Dacotah were obtained during July or August. Optimum harvest time for Cave‐In‐Rock was as late as September depending amount of summer precipitation. Biomass production of both cultivars was highly plastic, fluctuating > fivefold over a 4‐yr period. Maximum annual biomass yields were from >9 Mg ha−1 to <2 Mg ha−1 for both cultivars. Variation in April through May precipitation explained >90% of variation in maximum annual biomass production. The superior biomass yield potential of the putatively unadapted Cave‐In‐Rock compared with the putatively adapted Dacotah was only expressed during years when precipitation was >75% of average.
Tillage Method and Sowing Rate Relations for Dryland Spring Wheat, Barley, and Oat
Authors: Schillinger William F.
Published: October 2005

Some farmers in the Inland Pacific Northwest (PNW) have reported lower grain yield of spring cereals with no‐till (NT) compared with conservation tillage (CT). A 4‐yr field study was conducted in a 300‐mm annual precipitation zone to determine tillage method and sowing rate effects on seed‐zone water, seed‐zone temperature, plant stand, grain yield, grain yield components, and straw production for three spring‐sown cereal species. Wheat (Triticum aestivum L.), barley (Hordeum vulgare L.), and oat (Avena sativa L.) were sown at 120, 200, and 280 seeds m−2 in a split plot design with NT and CT as main plots and sowing rate × cereal species combinations as subplots. Factors other than tillage method (i.e., drill, sowing date, fertilizer rate, sowing depth) were held constant. There were no differences in plant stand between NT and CT, but grain yield was reduced by 5% in NT in part because of less water in the seed zone compared with CT during early plant development. Disruption of capillary continuity with CT appeared to restrict upward movement of water, resulting in greater retention of water in the seed zone underlying the depth of tillage. Grain yield was not affected by sowing rate for any crop species because increased number of heads per unit area (HPU) and kernels per head (KPH) consistently compensated for reduced plant stand density. With precise seed placement, sowing rate of spring cereals can be reduced by 50% or more from rates commonly used.
Soil Resources of the Ancient Maya at Piedras Negras, Guatemala
Authors: Fernández Fabián G. , Johnson Kristofer D. , Terry Richard E. , Nelson Sheldon , Webster David
Published: October 2005

The ancient Maya thrived for centuries in the Petén rain forest of Guatemala. Their impressive architecture and the evidence of highly populated centers attest that the Maya farmers were capable of producing food surpluses. In the eighth to ninth centuries CE the Classic Maya civilization collapsed. The processes leading to its decline are still debated, but unsustainable agricultural practices and exhaustion of natural resources may have contributed. This paper reports on soil formation rates, soil taxonomy, phytolith analysis, and δ13C values of soil organic matter in a rural area near the ancient city of Piedras Negras. Our objective was to understand ancient Maya rural life by linking soil characteristics to ancient agricultural resources and anthropogenic activities. We found that these soils formed at a rate of approximately 0.09 mm yr−1All 15 soil profiles belonged to the order Mollisols. The soils of the back‐slope locations were shallow (<25 cm) and were probably severely eroded at the time of abandonment (ninth century CE). The soils located at the valley's floor were deep, well developed, and potentially good for sustainable agriculture. Phytolith analysis indicated that in ancient times panacoid grasses were dominant in these soils and provided evidence that the forest was cleared for maize (Zea maysL.) agriculture. Stable C isotopes provided evidence that the vegetation shifted from forest (C3) to C4vegetation during the time of Maya occupation. The toe‐slope soils were observed to be less enriched in13C in profiles closer to Piedras Negras than in those farther away.
Modeling Soil Temperatures and the Mesic‐Frigid Boundary in the Central Great Lakes Region, 1951–2000
Authors: Schaetzl Randall J. , Knapp Bruce D. , Isard Scott A.
Published: October 2005

Understanding the spatial and temporal variation in soil temperatures is important to classification, land use, and management. To that end, mean annual soil temperature (MAST) data for Wisconsin and Michigan were modeled to (i) determine the effects of the Great Lakes and their snowbelts on soil temperatures, and (ii) better estimate the location of the boundary between the mesic and frigid soil temperature regimes in this region. The location of the mesic‐frigid (M‐F) line is particularly difficult to determine where east‐west gradients in air temperature cross north‐south trends in snowfall due to Lake Michigan. Additionally, the soil temperature regime of several Great Lakes' peninsulas near the M‐F line is in question. To determine the accuracy of our soil temperature model, soil temperature data output from it were compared with data derived from thermocouples implanted in soils at 39 sites in northern Michigan that had been collecting data several times daily for more than 6 yr. Error statistics for the model show that it has essentially no mean bias when examined on an annual basis or for winter, and only a bias of 0.1°C for the warm season. The M‐F line in Wisconsin and Michigan is slightly north of most previously estimated locations, and is strongly influenced by the snowbelt in southern Michigan. Soils in deep snow areas stay warmer in winter than do soils inland, increasing their MAST and forcing the M‐F line north of where air temperatures alone might have placed it. Lake‐effect areas also stay cold longer into the spring season, and cool down more slowly in fall. Soil temperatures in these areas are, therefore, more moderated on an annual basis, as indicated by coefficients of variation.
Application of Spin Counting to the Solid‐State31P NMR Analysis of Pasture Soils with Varying Phosphorus Content
Authors: Dougherty Warwick J. , Smernik Ronald J. , Chittleborough David J.
Published: October 2005

Solid‐state31P NMR spectroscopy has the potential to identify forms of soil P without the need for extractions or pretreatment. We used both cross polarization (CP) and direct polarization or Bloch Decay (DP) solid‐state31P NMR to examine the forms of P in a set of soil samples that vary widely in their total P contents and proportions of organic and inorganic P. Using the technique of spin counting, we found that the31P NMR observability (Pobs) of P in our soils was poor. Average Pobswas 9% by CP and 22% by DP. We attributed the poor observability to paramagnetic iron in close association with both organic and inorganic P. Using a series of selective extractions, we assigned the broad resonances of whole soil31P NMR spectra to organic P and prominent, sharp resonances to inorganic P. Pretreatment of soils with HF, as commonly used in13C and15N NMR analyses, resulted in Pobsof >70% by both CP and DP. However, organic P recovery in this fraction was poor. Our findings highlight the risks of trying to quantify different P types by integrating NMR spectra without taking into the account possible differences in their NMR sensitivity. Furthermore, we believe that significant improvements in the information garnered from solid‐state31P NMR analysis of soil will come not from improving resolution—there are fundamental limitations here—but in using information contained in nonfrequency parameters, such as observability, chemical shift anisotropy, and relaxation rates.
Application and Evaluation of the SWAP Model for Simulating Water and Solute Transport in a Cracking Clay Soil
Authors: Crescimanno Giuseppina , Garofalo Paolo
Published: October 2005

In Sicily, the increasing scarcity of quality water is leading to irrigation with saline water in soils having a considerable susceptibility to cracking. Irrigation systems involving high application rates are used in these irrigated areas, and bypass flow during irrigation is thus prevalent. Adoption of management practices accounting for cracking is therefore necessary to prevent salinization and land degradation. In this paper, water flow and solute transport in a Sicilian cracking soil irrigated with saline water was simulated by using the soil‐water‐atmosphere‐plant environment (SWAP) model, and the simulated results compared with measured values of soil moisture and salinity. The soil hydraulic parameters were obtained by inverse method based on multi‐step outflow experiments, adopting two different sets of hydraulic parameters/functions, that is, (i) the van Genuchten‐Mualem, (VGM model) and (ii) the Brutsaert retention equation coupled with the hydraulic conductivity model proposed by Gardner (B‐G model). The results obtained using field measurements from four soil profiles of a cracking clay soil showed that SWAP provided accurate predictions of water content, θ, when the soil hydraulic properties were expressed according to the B‐G model. Using the B‐G hydraulic parameters/functions, the model was calibrated with reference to the dispersivity (Ldis). A calibration value of about 20 cm was found for the four different profiles. In the conditions occurring in the Sicilian area where we are focusing our attention, the predictive errors associated with the simulated ECsat, can be considered acceptable if the purpose of application is to predict the influence of salinity on crop yield.
Sampling Device to Extract Intact Cores in Saturated Organic Soils
Authors: Caldwell P. V. , Adams A. A. , Niewoehner C. P. , Vepraskas M. J. , Gregory J. D.
Published: October 2005

Physical property data on organic soils are lacking due to difficulty in collecting undisturbed samples from these frequently saturated and weakly consolidated soils. A sampling device was constructed to extract undisturbed cores from saturated organic soils in a forested setting. The sampler consists of a 100‐cm‐long, 7.6‐cm‐diam. schedule 40 PVC pipe that was fitted with female threaded adapters on either end. A cutting head was constructed to cut through the fibric root mat and other woody debris in the profile by gluing a 7.6‐cm‐diam. hole‐saw to a male threaded adaptor that was attached to the PVC pipe. The sampler was rotated by hand into the organic soil with gentle downward pressure. When the desired depth was reached, the remaining air space in the PVC pipe was filled with water and a threaded cap was used to seal the top of the sampler. A 1.3‐cm‐diam. galvanized pipe was inserted next to the sampler to add water to the bottom of the core, relieving the suction created as the core was pulled from the soil. The sampler and vent pipe were pulled from the soil either by hand or with a tripod–winch arrangement. Before the cutting head was raised above the water table, it was removed and replaced with another threaded PVC cap. The 100‐cm‐long pipe containing the soil core was then cut into 7.6‐cm‐long sections using a wheel‐type PVC pipe cutter. Saturated hydraulic conductivity and soil water characteristics were then measured in the laboratory using the resulting 7.6‐cm‐long samples encased in the PVC cylinders.
Prediction of transient bed height in batch sedimentation at large times
Authors: Usher Shane P. , Scales Peter J. , White Lee R.
Published: October 2005

Sedimentation of particulate slurries in industrial sedimentation ponds and laboratory‐based batch settling tests is difficult to describe analytically. Understanding long‐time settling behavior is of particular importance when extrapolating existing sedimentation data to predict the final extent and how long it will take. A simple analytical equation has been derived to describe the final stage of compression in batch settling. In addition, numerical methods for determining the equation parameters have been proposed and demonstrated. The validity of the analytical equation and the parameters determined has been verified by comparison with finite element predictions. This new knowledge has the potential to significantly reduce the computational time requirements of predicting long‐time batch settling behavior. © 2005 American Institute of Chemical Engineers AIChE J, 2006
Producing chromium carbide using reduction of chromium oxide with methane
Authors: Khoshandam B. , Kumar R. V. , Jamshidi E.
Published: October 2005

In the present work, reduction of chromium oxide using methane is investigated. The thermogravimetric method was used to obtain kinetic parameters of the reaction in the temperature range of 870‐975°C under atmospheric pressure. The experimental data was analyzed using the grain model. The reaction product, chromium carbide, was observed to be produced at a temperature of about 140°C lower than by other conventional methods. Carbon deposition, which is highly undesirable in the synthesis of chromium carbide, was negligible in the present experiments. The experiments were conducted in two modes, either under the conditions of reaction control or under the conditions of diffusion control for determining reaction rate constants and diffusion rates to study pore diffusion, respectively. The pore diffusion studies were carried out with and without considering the bulk flow effect. The gas phase diffusion coefficient through the product layer around the grains was calculated with an approximate method. © 2005 American Institute of Chemical Engineers AIChE J, 2006
Density functional theory for chemical engineering: From capillarity to soft materials
Authors: Wu Jianzhong
Published: October 2005

Understanding the microscopic structure and macroscopic properties of condensed matter from a molecular perspective is important for both traditional and modern chemical engineering. A cornerstone of such understanding is provided by statistical mechanics, which bridges the gap between molecular events and the structural and physiochemical properties of macro‐ and mesoscopic systems. With ever‐increasing computer power, molecular simulations and ab initio quantum mechanics are promising to provide a nearly exact route to accomplishing the full potential of statistical mechanics. However, in light of their versatility for solving problems involving multiple length and timescales that are yet unreachable by direct simulations, phenomenological and semiempirical methods remain relevant for chemical engineering applications in the foreseeable future. Classical density functional theory offers a compromise: on the one hand, it is able to retain the theoretical rigor of statistical mechanics and, on the other hand, similar to a phenomenological method, it demands only modest computational cost for modeling the properties of uniform and inhomogeneous systems. Recent advances are summarized of classical density functional theory with emphasis on applications to quantitative modeling of the phase and interfacial behavior of condensed fluids and soft materials, including colloids, polymer solutions, nanocomposites, liquid crystals, and biological systems. Attention is also given to some potential applications of density functional theory to material fabrications and biomolecular engineering. © 2005 American Institute of Chemical Engineers AIChE J, 2006
Global optimization of a combinatorially complex generalized pooling problem
Authors: Meyer Clifford A. , Floudas Christodoulos A.
Published: October 2005

Global optimization strategies are described for a generalization of the pooling problem that is important to the petrochemical, chemical, and wastewater treatment industries. The problem involves both discrete variables, modeling the structure of a flow network, and continuous variables, modeling flow rates, and stream attributes. The continuous relaxation of this mixed integer nonlinear programming problem is nonconvex because of the presence of bilinear terms in the constraint functions. We propose an algorithm to find the global solution using the principles of the reformulation‐linearization technique (RLT). A novel piecewise linear RLT formulation is proposed and applied to the class of generalized pooling problems. Using this approach we verify the global solution of a combinatorially complex industrial problem containing 156 bilinear terms and 55 binary variables, reducing the gap between upper and lower bounds to within 1.2%. © 2005 American Institute of Chemical Engineers AIChE J, 2006
The use of alumatrane for the preparation of high‐surface‐area nickel aluminate and its activity for CO oxidation
Authors: Utchariyajit K. , Gulari E. , Wongkasemjit S.
Published: October 2005

Supported nickel has been used in a wide range of applications for industrial reactions, such as steam reforming, hydrogenation and methanation. In this work, nickel aluminate was prepared by the sol–gel process using alumatrane as the alkoxide precursor, directly synthesized from the reaction of inexpensive and available compounds, aluminum hydroxide and TIS (triisopropanolamine) via the oxide one pot synthesis (OOPS) process. Various conditions of the sol–gel process, such as pH, calcination temperature, hydrolysis ratio and ratio of nickel to aluminum, were studied. All samples were characterized using FTIR, TGA, XRD, TPR, DR‐UV and BET. The BET surface area was in the range of 340–450 m2/g at the calcination temperature of 500 °C with a mesoporous pore size distribution. Catalyst activity testing in CO oxidation reaction depended on Ni:Al ratio and calcination temperature. Higher activity was obtained from higher Ni content and lower calcination temperature. In addition, catalysts prepared using alumatrane precursor had higher percentage conversion than those prepared using aluminum hydroxide precursor. Copyright © 2005 John Wiley & Sons, Ltd.
Formation of thermosensitive copolymer beads having phosphinic acid groups and adsorption ability for metal ions
Authors: Nonaka Takamasa , Yasunaga Atsushi , Ogata Tomonari , Kurihara Seiji
Published: October 2005

Hydrophilic thermosensitive copolymer beads having phosphinic acid groups were prepared by suspension copolymerization of acryloyloxypropyl n‐octylphosphinic acid (APPO), N‐isopropyl acrylamide (NIPAAm), and tetraethyleneglycol dimethacrylate (4G). The thermosensitivity and the adsorption ability of the copolymer beads for metal ions beads were studied. The APPO‐NIPAAm‐4G copolymer beads were obtained in a good yield by suspension copolymerization of monomers (APPO, NIPAAm, and 4G) dissolved in chloroform, in a saturated Na2SO4 aqueous solution in the presence of surfactant and MgCO3. The APPO‐NIPAAm‐4G copolymer beads had higher adsorption ability for lanthanide metal ions (Eu3+, Sm3+, Nd3+, or La3+) than for main transition metal ions (Cu2+, Ni2+, or Co2+). Furthermore, it was also found that the APPO‐NIPAAm‐4G copolymer beads had selective adsorption ability between lanthanide metal ions, and the order of adsorption ability for lanthanide metal ions was as follows: Eu3+ > Sm3+ > Nd3+ > La3+. The selective adsorption for these metal ions from their mixed solutions was performed by both a batch method and a column method. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 449–460, 2006
Preliminary investigation of poly(ether sulfone)/poly(aryl ether ketone) containing 1,4‐naphthalene blends
Authors: Jiang Dong , Chen Xing‐Bo , Niu Ya‐Ming , Zhang Yun‐He , Jiang Zhen‐Hua , Ma Rong‐Tang
Published: October 2005

The blends of poly(ether sulfone) and poly(aryl ether ketone) containing 1,4‐naphthalene were prepared by melt mixing in a Brabender‐like apparatus. The specimens for measurements were made by compression molding under pressure and then were water‐quenched at room temperature. The tensile strength, tensile modulus, elongation at break, thermal analysis, and scanning electron microscopy were each measured. The dependence of tensile strength, tensile modulus, and elongation at break on blend systems was obtained. The effects of composition and miscibility on the mechanical properties are discussed. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 472–476, 2006
Morphology studies of multilayered HDPE/PS systems
Authors: Bernal‐Lara T. E. , Masirek R. , Hiltner A. , Baer E. , Piorkowska E. , Galeski A.
Published: October 2005

Films with alternating layers of high density polyethylene (HDPE) and polystyrene (PS) were prepared by layer‐multiplying coextrusion, using two HDPEs differing in molecular weight. The crystal structure of extremely thin PE layers confined between PS layers was studied by small angle X‐ray scattering (SAXS), wide angle X‐ray diffraction (WAXS), and also by atomic force microscopy (AFM) and differential scanning calorimetry (DSC) technique including MDSC. The morphology of HDPE in the systems studied is greatly affected by the presence of HDPE/PS interfaces. In the HDPE layers, the texture component was observed with lamellae with their basal planes normal to the interface and (200) crystallographic planes parallel to the interface. Thus, the polymer chains in this texture component are parallel to the interface between both polymers. The small fraction of lamellae parallel to the interface in thicker HDPE layers disappears with the thinning of the layers beyond 100 nm. AFM images show in these samples straight, long lamellae positioned edge‐on at HDPE/PS interface. The thickness and perfection of lamellae decrease with the decrease of individual HDPE layer thickness. Those thinner and less perfect lamellae are more susceptible to reorganization during heating as it is observed by MDSC. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 597–612, 2006
Electrical and mechanical behaviors of carbon nanotube‐filled polymer blends
Authors: Wu Man , Shaw Leon
Published: October 2005

Four carbon nanotube (CNT)‐filled polymer blends, i.e., CNT‐filled polyethylene terephthalate (PET)/polyvinylidene fluoride, PET/nylon 6,6, PET/polypropylene, and PET/high‐density polyethylene blends, have been injection‐molded and characterized in terms of their microstructures, electrical conductivities, and mechanical properties. The distribution of CNTs in the polymer blends has been examined based on their wetting coefficients and minimization of the interfacial energy. The electrical conductivity and mechanical properties have been related to the cocontinuous polymer blends, the conductive path formed by CNTs, the CNT distribution, and the intrinsic properties of the constituent polymers. It is found that to obtain a CNT‐filled polymer composite with both high electrical conductivity and good mechanical properties, it is preferred that most CNTs distribute in one polymer phase, while the other polymer phase(s) remain neat. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 477–488, 2006
Structure‐property relations in UV‐curable urethane acrylate oligomers
Authors: Khudyakov Igor V. , Swiderski Kenneth W. , Greer Robert W.
Published: October 2005

Four urethane acrylate oligomers were synthesized by a reaction of an excess of isophorone diisocyanate (D) with polypropylene glycol Acclaim 4200N (P) with a subsequent reaction of nonreacted D with a hydroxy acrylate Tone M100 (A). The latter has a common name caprolactone acrylate. Oligomers were prepared by different ways of addition of P to D or D to P and at different ratio of [D]/[P]. The fifth oligomer ADA was prepared as an individual compound. Viscosities, GPC traces, Tg's of oligomers were taken alongside with other physical properties of cured oligomers. It was demonstrated that oligomers with P consist of ADPDA, ADA, and of a chain‐extended product A… Pn… A, which has two or more Ps in a molecule. Additive contributions of these three components essentially determine properties of the liquid and cured oligomers. Structure‐property relations of urethane acrylate oligomers are discussed. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99:489–494, 2006
New fluorescent monomers and polymers displaying an intramolecular proton‐transfer mechanism in the electronically excited state. III. Thermogravimetric stability study of the benzazolylvinylene derivatives
Authors: Campo Leandra Franciscato , Rodembusch Fabiano Severo , Stefani Valter
Published: October 2005

Six fluorescent benzazolylvinylene derivatives were studied by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and related molecular parameters. The thermal stability was determined in terms of the steps of degradation and its fitting parameters, such as maximum degradation rate (Rmax), maximum degradation rate temperature (TRmax), degradation temperature range, which is related to the half‐width at half‐height values (Γ), and the kinetic parameters: activation energy (Ea), pre‐exponential factor (A), and reaction order (n) obtained by Barrett's method. Different organic substitutes and heteroatoms do not play a fundamental role in the thermal behavior of the studied dyes. The compensation effect between pre‐exponential factor and activation energy was confirmed. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 495–500, 2006
Abs/iron nanocomposites prepared by cryomilling
Authors: Zhu Y. G. , Li Z. Q. , Zhang D. , Tanimoto T.
Published: October 2005

Acrylonitrile‐Butadiene‐Styrene (ABS)/iron nanocomposites have been prepared by cryomilling (high‐energy ball milling under cryogenic temperature), and a microstructure of iron network in ABS matrix was obtained. The blending scale and homogenization of ABS/iron nanocomposites are observed by Atomic Force Microscope (AFM). The morphology and structure of cryomilled composite powders are characterized by means of Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM), and X‐ray Diffraction (XRD). The results indicate that upon cryomilling for 20 h, ABS and Fe are intimately blended with the single composite particle size less than 100 nm, the Fe phase domains less than 50 nm, and Fe grain size reduced to 20 nm. Both the fast rate of homogenization and size reduction are mainly attributed to the introduction of cryogenic temperature and comilling. The evidences suggest that cryomilling is a capable and promising technique for the production of polymer/metal nanocomposites. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 501–505, 2006
Interpolymer complex microparticles based on polymethacrylic acid‐chitosan for oral insulin delivery
Authors: S. Sajeesh , Sharma Chandra P.
Published: October 2005

In the present study, microparticles composed of polymethacrylic acid‐chitosan (PMAA‐CS) were prepared by a novel interionic gelation method. Free‐radical polymerization of methacrylic acid was carried out in the presence of CS, using a water‐soluble initiator, and application of these microparticles toward oral insulin delivery was evaluated. Microparticles obtained were characterized by scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) studies. From SEM studies, it was observed that microparticles had an aggregated morphology with size ∼20 μm, while FTIR confirmed the presence of ionic interaction between PMAA and CS chains. Protein loading was done by diffusion filling method, and from in vitro release study, it was observed that insulin‐loaded microparticles displayed a pH depended release profile at alkaline/acidic pH. Microparticles exhibited sustained release of insulin for 3–4 h at neutral pH, and enzyme linked immunosorbent assay (ELISA) proved that encapsulated protein maintained 100% biological activity at neutral pH. Preliminary study suggests that these microparticles can serve as good candidate for oral protein delivery. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 506–512, 2006
Effect of heat‐sealing temperature on the properties of OPP/CPP heat seals. Part II. Crystallinity and thermomechanical properties
Authors: Tetsuya Tsujii , Hashimoto Yasuo , Ishiaku U. S. , Mizoguchi M. , Leong Y. W. , Hamada Hiroyuki
Published: October 2005

The crystalline structure of the heat‐sealed part of oriented polypropylene (OPP) and cast polypropylene (CPP) films was investigated by differential scanning calorimetry, Fourier transform infrared spectroscopy, and thermal mechanical analysis (TMA). The relationship between the crystalline structure and the mechanical properties was analyzed. It was found that the high total crystallinity of both OPP and CPP gave rise to good mechanical properties and that the orientation of the crystalline structure in the OPP film also was an important factor. The optimum condition for heat sealing was the temperature at which total crystallinity was highest while still retaining the crystalline orientation of OPP. The assessment of crystalline orientation by TMA is an innovation initiated by the authors. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 513–519, 2006
Silicon‐29 and carbon‐13 nuclear magnetic resonance identification of intermediates developed during the formation of a hybrid based on tetraethoxysilane (TEOS) and 4‐[(5‐dichloromethyl)(silyl)pentyloxy]cyanobenzene (DCN)
Authors: Trejo‐Duran Mónica , Martínez‐Richa Antonio , Vera‐Graziano Ricardo , Mendoza‐Diaz Guillermo , Castaño‐Meneses Victor M.
Published: October 2005

During the formation of organic–inorganic hybrid materials by the sol–gel process, the observation of multiphase systems at different stages of the reaction is not uncommon. An assessment of the chemical species formed before and after gelation is not an easy task because complex mixtures are generally found in these systems. In this study, the identification of intermediates developed during the formation of a hybrid obtained from tetraethoxysilane (TEOS) and 4‐[(5‐dichloromethylsilyl)pentyloxy]cyanobenzene monomer has been undertaken. Solution and solid‐state29Si‐ and13C‐NMR spectra, recorded at different degrees of conversion, allow the elucidation of the mechanism of hybrid formation. 4‐[(5‐dichloromethylsilyl)pentyloxy]cyanobenzene, (DCN), DCN–TEOS cyclosiloxanes and low‐molecular‐weight linear copolysiloxanes are formed in the early stages of the process and before gelation occur. Before the gel is formed, cyclic species undergo an acid‐catalyzed ring‐opening copolymerization with silica to produce a random copolymer. Other intermediates of the Qijtype (where Q indicates a four‐functional silicon, the first subscript indicates the number of siloxane bridges connected to the silicon site, and the second subscript indicates the number of silanol groups) that develop before the gel is formed have also been identified. Spectral peak patterns of the final hybrid, observed in solid‐state29Si and13C‐NMR spectra, are also discussed. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 520–531, 2006
Effect of an epoxy‐based bonding agent on the cure characteristics and mechanical properties of short‐nylon‐fiber‐reinforced acrylonitrile–butadiene rubber composites
Authors: Seema A. , Kutty S. K. N.
Published: October 2005

The cure characteristics and mechanical properties of short‐nylon‐fiber‐reinforced acrylonitrile–butadiene rubber composites with and without an epoxy resin as a bonding agent were studied. The epoxy resin was a good interfacial‐bonding agent for this composite system. The minimum torque showed a marginal increase with the resin concentration. The maximum–minimum torque showed only a marginal change with the resin. The scorch time decreased with the fiber concentration and resin content. The tensile strength and abrasion resistance were improved and the tear resistance and resilience were reduced with the resin concentration. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 532–539, 2006
Viscosity of polystyrene solutions expanded with carbon dioxide
Authors: Whittier Rachel E. , Xu Dawei , van Zanten John H. , Kiserow Douglas J. , Roberts George W.
Published: October 2005

The viscosity of solutions of polystyrene (PS) in decahydronaphthalene (DHN) was measured in the presence of carbon dioxide (CO2) with a moving‐piston viscometer. The effects of the CO2 pressure (0–21 MPa), polymer concentration (1–15 wt %), temperature (306–423 K), and polymer molecular weight (126 and 412 kDa) on the viscosity were investigated. In the absence of CO2, the increase in the viscosity with increasing polymer concentration was approximately exponential in concentration and was well described by the Martin equation. All the data fell on a single line when the relative viscosity was plotted against cM0.50 (where c is the concentration of the polymer in solution and M is the molecular weight of the polymer). The viscosity of the polymer solution decreased with increasing CO2 pressure under otherwise constant conditions. For a given CO2 pressure, the viscosity reduction was greatest when the relative viscosity was high in the absence of CO2, that is, for high‐molecular‐weight polymer, high polymer concentrations, and low temperatures. Reductions in the relative viscosity of almost 2 orders of magnitude were observed in some cases. The viscosity of solutions of PS in DHN also was measured in the presence of sulfur hexafluoride (SF6). At a given pressure, SF6 was about as effective as CO2 in reducing the solution viscosity. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 540–549, 2006
DSC study of the cure kinetics during nanocomposite formation: Epoxy/poly(oxypropylene) diamine/organically modified montmorillonite system
Authors: Ivankovic Marica , Brnardic Ivan , Ivankovic Hrvoje , Mencer Helena Jasna
Published: October 2005

The effect of an organically modified montmorillonite (OMMT) on the curing kinetics of a thermoset system based on a bisphenol A epoxy resin and a poly(oxypropylene)diamine curing agent were studied by means of differential scanning calorimetry (DSC) in isothermal and dynamic (constant heating rate) conditions. Montmorillonite and prepared composites were characterized by X‐ray diffraction analysis (XRD) and simultaneous differential scanning calorimetry–thermogravimetric analysis (DSC–TGA). Analysis of DSC data indicated that the presence of the filler has a very small effect on the kinetics of cure. A kinetic model, arising from an autocatalyzed reaction mechanism, was applied to the DSC data. Fairly good agreement between experimental and modeling data was obtained. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 550–557, 2006
Synthesis and characterization of fluoropolymer modified polyacrylate in emulsion polymerization
Authors: Chen Zhengxia , Cui Xuejun , Jiang Wenyong , Cheng Xiuli , Wang Hongyan
Published: October 2005

A novel method to produce fluorine‐containing polyacrylate emulsion is presented. It is prepared by the copolymerization of n‐methyl methacrylate, n‐styrene, n‐butyl acrylate, and α‐methacrylic acid in the presence of swollen particles of PTFE. The structure and properties of the polymers are characterized by GPC, PSD, SEM, and XPS. The number‐average molar mass (Mn) 51,332, and the polydispersity 5.8688 are obtained. The mean diameter of latex particles is 300nm. Scanning electron microscopy reveals that particles of the emulsion are well dispersed. Meanwhile, the F1S content of the surface on the latex membrane is 8.99%. It is shown that the method of mixing micron and nanometer‐sized particles should be made the next step of research. It is also proved that inertia polymers can be used in emulsion property modification. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 558–562, 2006
Optical monitoring of polyesters injection molding
Authors: Marinelli Alessandra Lucas , Farah Marcelo , Elida Rosario , Bretas Suman
Published: October 2005

An optical fiber sensor similar to the one developed by Thomas and Bur1 was constructed for the monitoring of the crystallization of three polyesters during the injection molding process. The polyesters studied were: polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), and polyethylene terephthalate (PET). With this optical system it was possible to obtain, in real time, some essential parameters of the polyester crystallization kinetics at different processing conditions. Thus, a study of the influence of injection molding variables on the nonisothermal crystallization kinetics of these polyesters was done. The processing variables were: mold wall and injection temperatures, Tw and Ti, respectively; flow rate, Q; and holding pressure, Ph. The experiments were done following a first order central composite design statistical analysis. The morphology of the samples was analyzed by polarized light optical microscopy, PLOM. The signal of the laser beam during the filling and the crystallization stages of the injection molding of these materials was found to be reproducible. The measurements showed that this system was sensitive to variations of the crystallization of different types of polymers under different processing conditions. The system was not able, however, to monitor the crystallization process when the crystallinity degree developed by the sample was very low, as in the PET resin. It was also observed that Tw and Ti were the most influential variables on the crystallization kinetics of PBT and PTT. Due to its slower crystallization kinetics, PTT was found to be more sensitive to changes in these parameters than the PBT. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 563–579, 2006
Effects of composition of hardener on the curing and aging for an epoxy resin system
Authors: Wu Lixin , Hoa Suong V. , Minh‐Tan  , Ton‐That
Published: October 2005

Different mixture ratios of Shell Epon 828 (based on diglycidyl ether of bisphenol A, DGEBA) and Shell EPI‐CURE 3046 (based on triethylenetetramine, TETA) were evaluated under different environments of isothermal curing at 80°C in DSC, room temperature curing in air, and aging in water at 45°C. The curing reactions were monitored using differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and infrared spectroscopy (IR). It was shown that the initial curing rate increased with the amount of hardener. However, the epoxy groups in samples with excess hardener were prone to reaction with primary amines located at the ends of TETA molecules, resulting in a less dense epoxy network. During aging in water at 45°C, significant effects of water on the postcure and the increased water absorption with an increase of hardener amount were observed. The DMA results show that the samples with hardener around stoichiometric composition have the greatest storage modulus while curing in air environment. However, the samples with hardener much less than stoichiometric composition have greater storage modulus under aging in water at 45°C. in water at 45°C. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 580–588, 2006
Momentary relationship between cortisol secretion and symptoms in patients with fibromyalgia
Authors: McLean Samuel A. , Williams David A. , Harris Richard E. , Kop Willem J. , Groner Kimberly H. , Ambrose Kirsten , Lyden Angela K. , Gracely Richard H. , Crofford Leslie J. , Geisser Michael E. , Sen Ananda , Biswas Pinaki , Clauw Daniel J.
Published: October 2005

Objective

To compare the momentary association between salivary cortisol levels and pain, fatigue, and stress symptoms in patients with fibromyalgia (FM), and to compare diurnal cycles of cortisol secretion in patients with FM and healthy control subjects in a naturalistic environment.

Methods

Twenty‐eight patients with FM and 27 healthy control subjects completed assessments on salivary cortisol levels and pain, fatigue, and stress symptoms, 5 times a day for 2 consecutive days, while engaging in usual daily activities. Only those participants who adhered to the protocol (assessed via activity monitor) were included in the final analyses.

Results

Twenty FM patients and 16 healthy control subjects adhered to the protocol. There were no significant differences in cortisol levels or diurnal cortisol variation between FM patients and healthy controls. Among women with FM, a strong relationship between cortisol level and current pain symptoms was observed at the waking time point (t = 3.35, P = 0.008) and 1 hour after waking (t = 2.97, P = 0.011), but not at the later 3 time points. This association was not due to differences in age, number of symptoms of depression, or self‐reported history of physical or sexual abuse. Cortisol levels alone explained 38% and 14% of the variation in pain at the waking and 1 hour time points, respectively. No relationship was observed between cortisol level and fatigue or stress symptoms at any of the 5 time points.

Conclusion

Among women with FM, pain symptoms early in the day are associated with variations in function of the hypothalamic–pituitary–adrenal axis.