bluuebunny/crossref_metadata_2025_split huggingface dataset:
Air Volume Change Measurement in Unsaturated Soil Testing Using a Digital Pressure-Volume Controller
Authors: Adams BA , Wulfsohn D , Fredlund DG 
Published: February 2009

AbstractOne of the challenges associated with the testing of unsaturated soils is the measurement of air volume change induced by stress changes. This paper reports the results of an evaluation of a digital pressure-volume controller as an air volume change indicator. Effects of temperature, confined volume, and precompression of the measurement medium on the p-V characteristics and the device response were determined. The device was also used to measure air volume changes of unsaturated soil specimens undergoing isotropic consolidation and axial loading in constant water content tests in a triaxial cell. The results show that the controller performs satisfactorily as an air volume change measurement device. It also permits measurement of air volume change simultaneously with the implementation of the axis-translation technique, making it a versatile device in the testing of unsaturated soils.
Ultrasonic Method for Evaluation of Annular Seals for Wells and Instrument Holes
Authors: Yesiller N , Edil TB , Benson CH 
Published: February 2009

Abstract
An ultrasonic testing method employing the pulse-echo inspection technique was developed to assess the integrity of annular seals surrounding casings (i.e., instrument tubes or well casings). This nondestructive testing method permits testing a seal from inside a casing without disturbing the casing, seal, or formation. Seals constructed with cement-based and bentonite-based sealants surrounding various types and sizes of casings can be evaluated using the method. An evaluation is conducted by sending and receiving ultrasonic waves using a single piezoelectric transducer and commercially available hardware (a pulser receiver and a waveform analyzer). A probe was designed and constructed for downhole testing. Differences in the ultrasonic responses of the materials in contact with a casing are analyzed to determine the presence of different materials (seal or defects filled with air or water in a seal) outside a casing.
Measurement of Volume Changes in Triaxial Tests Using Digital Imaging Techniques
Authors: Macari EJ , Parker JK , Costes NC 
Published: February 2009

Abstract
Conventional procedures for the determination of volume changes in triaxial tests are based on the amount of pore fluid changes into or out of the fully saturated cylindrical specimen. As a triaxial soil specimen shears, the total volume may increase or decrease depending on the soil density, current state of stress, and the stress history. The measurement of these changes in volume are of great importance in the characterization of the soil's mechanical properties. This paper presents an innovative or alternative technique that has been used for measuring the volumetric deformation that cylindrical specimens experience during the shearing stages of a triaxial test. This method incorporates digital imaging techniques and computer-aided analysis to assess the changes in volume throughout a test. A detailed description of the hardware and other equipment is provided along with the data analysis methodology used to simplify the operation. Comparisons are made between the observed results and those obtained from conventional measurement techniques.
Interpreting Stream Physical Characteristics in Index of Biotic Integrity Classifications: General Similarities and Specific Differences
Authors: Goldstein Robert M. 
Published: February 2009

Abstract
Fish assemblage-based indices of biotic integrity (IBIs) are commonly used by many states. These IBIs contain a core of common metrics and a few metrics that are specific to the local environmental setting and fish assemblage. This implies a consistency of responses as degradation increases, but the responses are modified by the local environmental setting. These implications lead to two hypotheses: (1) stream physical characteristics, such as substrate composition, geomorphologic composition, and hydraulic characteristics, will differ among integrity classes regardless of geographic location or environmental setting and (2) the differences in stream physical characteristics among integrity classes change due to the environmental setting. To test these hypotheses, fish assemblages and stream physical characteristics were examined across a priori defined degradation gradients in four diverse environmental settings by comparing species traits (preferences for substrate, preferences for geomorphic channel units, and locomotion morphology) and stream physical characteristics (substrate composition, geomorphic channel unit abundance, and stream hydraulic characteristics) among three IBI classes (high, moderate, and low). Across all environmental settings combined, Euclidean distances of species traits normalized to local reference conditions indicated differences in substrate preferences among each of the three integrity classes: substrate particle size preferences differed among all three integrity classes, geomorphic channel unit preference differed between the high-integrity sites and the other sites, and locomotion morphology differed between low-integrity sites and the other sites. These results indicate that degradation occurs in each of the three physical stream characteristics regardless of environmental setting. Within the individual environmental settings, there were some specific differences in the changes in substrate preferences, geomorphic unit preference, and locomotion morphology among integrity classes. Within individual environmental settings, differences in stream physical characteristics among integrity classes generally reflected the same differences as indicated by differences in fish assemblage composition.
Variation in Growth and Survival of Bluegills and Redbreast Sunfish in Georgia Rivers
Authors: Sammons Steven M. , Maceina Michael J. 
Published: February 2009

Abstract
Growth and survival of bluegills Lepomis macrochirus and redbreast sunfish L. auritus (N = 5,664) were examined in 13 river sections located in the southern half of Georgia. Bluegills tended to grow faster than redbreast sunfish within rivers where the two species were collected together. Annual survival of redbreast sunfish (range = 18–52%; mean = 38%) was greater than that of bluegills (range = 21–34%; mean = 29%). For both species, growth of males was generally greater than females, though annual survival did not differ significantly between sexes for either species. Growth of redbreast sunfish and bluegills appeared to increase along a northwest to southeast gradient across the state of Georgia. Growth variation of these sunfishes was likely mediated by prey availability, habitat, and physicochemical variables within each river section.
Instream Evaluation of Passive Integrated Transponder Retention in Brook Trout and Brown Trout: Effects of Season, Anatomical Placement, and Fish Length
Authors: Dieterman Douglas J. , Hoxmeier R. John H. 
Published: February 2009

Abstract
We examined effects of tagging season, anatomical placement of tags, and fish total length (TL) at tagging on 2-month retention of passive integrated transponder (PIT) tags in 181 brook trout Salvelinus fontinalis (99–302 mm TL) and 709 brown trout Salmo trutta (122–511 mm TL) in small streams of southeastern Minnesota. A lower percentage of brown trout retained their tags in spring (56%) than in fall (68%), but season did not affect tag retention in brook trout. Retention rates varied with anatomical placement for both species. For brook trout, retention was 70% when the PIT tag was placed into the body cavity using an insertion point that was posterior to the pelvic fins and 100% when the tag was placed into the dorsal musculature. Among brown trout, PIT tag retention was 56% for body cavity placement (posterior insertion) and 95% for dorsal musculature placement. Tag retention was not associated with fish TL for brown trout and was only weakly associated with TL of brook trout. Although reported retention rates of PIT tags implanted into the body cavity of salmonids have often exceeded 90%, our retention estimates were considerably lower. This discrepancy can be partially attributed to differences in laboratory versus field studies. However, most previous studies of salmonids have used body cavity insertion points that were anterior to the pelvic fins, whereas we used a posterior insertion point; this was probably the primary factor responsible for the difference in results. We caution against the assumption that retention of PIT tags is universally high, and we recommend the estimation of PIT tag retention before or during marking studies. We also provide a list of factors that should be considered and evaluated when designing PIT tag studies, especially tag retention studies.
Implications of Recreational Fishing on Juvenile Masu Salmon Stocked in a Hokkaido River
Authors: Miyakoshi Yasuyuki , Sasaki Yoshitaka , Fujiwara Makoto , Tanaka Keiko , Matsueda Naokazu , Irvine James R. , Kitada Shuichi 
Published: February 2009

Abstract
Freshwater recreational anglers in northern Japan sometimes catch significant numbers of juvenile masu salmon Oncorhynchus masou, thereby reducing the effectiveness of enhancement activities aimed at increasing marine catches of adult masu salmon. We stocked 66,500 juvenile masu salmon in the Shirai River, a major tributary of the Yoichi River in Hokkaido, northern Japan, during October 2005. Surveys conducted during the month after stocking revealed that approximately 65 fish/angler-day were caught, and catch varied between fishing gears (bait or fly) and locations (upper or lower reach). Estimated total number (mean ± SE) of fish harvested was 5,647 ± 2,394, equivalent to 8.5 ± 3.6% of the fish stocked. The estimated number of fish remaining in the river at the end of the angler survey was 57,246 ± 8,595, and survival rate during this month was 86.1 ± 12.9%. While releasing hatchery-reared masu salmon in late fall can reduce fishing mortality in rivers compared with earlier releases, mortality could be further reduced by dispersing fish over large areas that contain locations with suitable overwintering habitat.
Self‐Supporting, Double Stimuli‐Responsive Porous Membranes From Polystyrene‐block‐poly(N,N‐dimethylaminoethyl methacrylate) Diblock Copolymers
Authors: Schacher Felix , Ulbricht Mathias , Müller Axel H. E. 
Published: February 2009

AbstractAsymmetric membranes are prepared via the non‐solvent‐induced phase separation (NIPS) process from a polystyrene‐block‐poly(N,N‐dimethylaminoethyl methacrylate) (PS‐b‐PDMAEMA) block copolymer. The polymer is prepared via sequential living anionic polymerization. Membrane surface and volume structures are characterized by scanning electron microscopy. Due to their asymmetric character, resulting in a thin separation layer with pores below 100 nm on top and a macroporous volume structure, the membranes are self‐supporting. Furthermore, they exhibit a defect‐free surface over several 100 µm2. Polystyrene serves as the membrane matrix, whereas the pH‐ and temperature‐sensitive minority block, PDMAEMA, renders the material double stimuli‐responsive. Therefore, in terms of water flux, the membranes are able to react on two independently applicable stimuli, pH and temperature. Compared to the conditions where the lowest water flux is obtained, low temperature and pH, activation of both triggers results in a seven‐fold permeability increase. The pore size distribution and the separation properties of the obtained membranes were tested through the pH‐dependent filtration of silica particles with sizes of 12–100 nm.
Doping of the Metal Oxide Nanostructure and its Influence in Organic Electronics
Authors: Park Mi‐Hyae , Li Juo‐Hao , Kumar Ankit , Li Gang , Yang Yang 
Published: February 2009

AbstractSynthesizing metal oxides through the sol–gel process provides a convenient way for forming a nanostructured layer in wide band gap semiconductors. In this paper, a unique method of introducing dopants into the metal oxide semiconductor is presented. The doped TiO2 is prepared by adding a Cs2CO3 solution to a nanocrystalline TiO2 solution that is synthesized via a non‐hydrolytic sol–gel process. The properties of the TiO2:Cs layer are investigated and the results show stable nanostructure morphology. In addition to providing morphological stability, Cs in TiO2 also gives rise to a more desirable work function for charge transport in organic electronics. Polymer solar cells based on the poly(3‐hexylthiophene) (P3HT): methanofullerene (PC70BM) system with the addition of a TiO2:Cs interfacial layer exhibit excellent characteristics with a power conversion efficiency of up to 4.2%. The improved device performance is attributed to an improved polymer/metal contact, more efficient electron extraction, and better hole blocking properties. The effectiveness of this unique functionality also extends to polymer light emitting devices, where a lower driving voltage, improved efficiency, and extended lifetime are demonstrated.
Synthesis and structural peculiarities of 1,1‐dimethylhydrazine‐based polyurethanes
Authors: Savelyev Y. V. , Veselov V. Y. , Kharitonova V. K. , Savelyeva O. A. , Shtompel V. I. , Perekhrest A. I. , Travinskaya T. V. , Kanapitsas A. , Pissis P. 
Published: February 2009

AbstractNovel polyurethanes (PUs) based on poly(oxytetramethylene glycol), 4,4′‐methylenediphenyl diisocyanate, and 1,1‐dimethylhydrazine (DMH) were prepared. Stoichiometric (1 : 1) and nonstoichiometric (2 : 1 to 20 : 1) prepolymer/DMH ratios were studied. The number‐average molecular masses and possible structures of the obtained polymers were evaluated by potentiometric nonaqueous titration analysis of terminal groups, the Kieldal method (the evaluation of the nitrogen atom content), the aminolysis method, viscosimetry, IR spectroscopy, rheology, and small‐angle X‐ray scattering. Only in the case of the stoichiometric (1 : 1) ratio was a low‐molecular‐mass PU with a linear structure formed, whereas for all studied nonstoichiometric ratios, PUs with branched structures were formed. The level of hard and flexible block segregation increased with the increase in the prepolymer/DMH ratio. Dielectric results for the dynamic glass transition and water sorption measurements provided additional support to the structural studies. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Enhanced hydrolytic stability of poly(p‐dioxanone) with polycarbodiimide
Authors: Liu Zhong‐Ping , Ding Song‐Dong , Sui Ying‐Jia , Wang Yu‐Zhong 
Published: February 2009

AbstractThe effect of polycarbodiimide (PCD) on hydrolytic stability of poly(p‐dioxanone) (PPDO) was investigated by hydrolytic degradation of PPDO and PPDO added with PCD (PPDOCD) in phosphate buffer solution (pH = 7.4) at 37°C. The variation of weight, water absorption, pH, molecular weight, tensile properties, surface morphologies, and thermal properties with degradation time were evaluated. After 11 weeks, the weight loss and water absorption of PPDO was 24 and 30%, respectively, but the corresponding values were only 3 and 5% for PPDOCD5, where 5 represents the weight percentage of PCD added; the molecular weight of PPDO decreased much faster than that of PPDOCD. The pH of the solution was monitored for 15 weeks and a final pH value of the solution involving PPDOCD5 was 6.81 whereas that of PPDO solution was 3.77, indicating that more acid fragments from PPDO samples migrate into the buffer solution. Surface morphological changes showed a better physical integrity for PPDOCD samples and they also kept their mechanical properties for a longer time than PPDO samples. These results revealed that PCD can retard the hydrolysis degradation of PPDO and enhance its hydrolytic stability. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Effects of pretreatment reagents on the hydrolysis and physical properties of PET fabrics
Authors: Kim Eun Seon , Lee Chang Hwan , Kim Seong Hun 
Published: February 2009

AbstractThe effects of pretreatment reagents on the hydrolysis and physical properties of PET fabrics were investigated under various alkaline hydrolysis treatment and pretreatment conditions. Before alkaline hydrolysis, solvent treatment with pretreatment reagents, including benzyl alcohol (PET‐b) or 2‐phenyl ethanol (PET‐p), modified the structure of the PET fabric, thus affecting the hydrolysis and physical properties of the PET fabrics. Fabric weight loss increased with increasing hydrolysis time. The rate constant (k) increased markedly with increasing methyl groups in the pretreatment reagents. The activation energy (Ea) of untreated fabrics was higher than those of the treated fabrics. The crystallinity of the PET fabrics increased with increasing hydrolysis times (t) and methyl groups in the pretreatment reagents. The weight loss of PET‐b increased with increasing pretreatment temperature (T). However, the weight loss of PET‐p increased up to 100°C but decreased above 120°C. The shrinkage of all samples increased with increasing hydrolysis times (t). Shrinkage of PET‐b and PET‐p was greater than that of untreated fabrics. PET‐b displayed greater shrinkage than PET‐p because byproducts polluted the PET fibers. Both the initial and maximum water absorption of the fabrics increased with increasing hydrolysis times (t). © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Physicochemical characterization of poly(ethylene glycol) plasticized poly(methyl vinyl ether‐co‐maleic acid) films
Authors: Singh Thakur Raghu Raj , McCarron Paul A. , Woolfson A. David , Donnelly Ryan F. 
Published: February 2009

AbstractThe influence of the poly(ethylene glycol) (PEG) plasticizer content and molecular weight on the physicochemical properties of films cast from aqueous blends of poly(methyl vinyl ether‐co‐maleic acid) (PMVE/MA) was investigated with tensile mechanical testing, thermal analysis, and attenuated total reflectance/Fourier transform infrared spectroscopy. Unplasticized films and those containing high copolymer contents were very difficult to handle and proved difficult to test. PEG with a molecular weight of 200 Da was the most efficient plasticizer. However, films cast from aqueous blends containing 10% (w/w) PMVE/MA and either PEG 1000 or PEG 10,000 when the copolymer/plasticizer ratio was 4 : 3 and those cast from aqueous blends containing 15% (w/w) PMVE/MA and either PEG 1000 or PEG 10,000 when the copolymer/plasticizer ratio was 2 : 1 possessed mechanical properties most closely mimicking those of a formulation we have used clinically in photodynamic therapy. Importantly, we found previously that films cast from aqueous blends containing 10% (w/w) PMVE/MA performed rather poorly in the clinical setting, where uptake of moisture from patients' skin led to reversion of the formulation to a thick gel. Consequently, we are now investigating films cast from aqueous blends containing 15% (w/w) PMVE/MA and either PEG 1000 or PEG 10,000, where the copolymer/plasticizer ratio is 2 : 1, as possible Food and Drug Administration approved replacements for our current formulation, which must currently be used only on a named patient basis as its plasticizer, tripropylene glycol methyl ether, is not currently available in pharmaceutical grade. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Morphology‐related packetlike space‐charge behavior in linear low‐density polyethylene doped with Al2O3 nanoparticles
Authors: Zheng Feihu , Hao Shujuan , Wang Wenyan , Xiao Chun , An Zhenlian , Zhang Yewen 
Published: February 2009

AbstractPacketlike space‐charge behavior and the isothermal decay processes of the injected charge in neat linear low‐density polyethylene (LLDPE) and LLDPE doped with Al2O3 nanoparticles were investigated by the pressure wave propagation method. The 1‐mm sheet samples, sandwiched by semiconductive electrodes, were submitted to 40 kV/mm of direct current field at various temperatures for 3 h. The charge‐injecting rate and the apparent mobility of packetlike space charge under direct‐current stress were compared among the samples subjected to different blending processes with or without nanoparticles. The slight doping concentration showed a significant influence on the space‐charge dynamics, with a lower injecting rate and apparent mobility for higher doped samples. The isothermal decay processes of the injected charge indicated trap‐modulated features. The phenomena were considered to be related to the changing morphology of the matrix material. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Double‐network hydrogel with high mechanical strength prepared from two biocompatible polymers
Authors: Zhang Xiaoyan , Guo Xinglin , Yang Shuguang , Tan Shuaixia , Li Xiaofeng , Dai Hongjun , Yu Xiaolan , Zhang Xiaoli , Weng Ning , Jian Bin , Xu Jian 
Published: February 2009

AbstractNovel double‐network (DN) hydrogels with high mechanical strength have been fabricated with two biocompatible polymers, poly(vinyl alcohol) (PVA) and poly(ethylene glycol) (PEG), through a simple freezing and thawing method. Some properties of the obtained hydrogels, such as the mechanical strength, rheological and thermodynamic behavior, drug release, and morphology, have been characterized. The results reveal that in sharp contrast to most common hydrogels made with simple natural or synthetic polymers, PVA/PEG hydrogels can sustain a compressive pressure as high as several megapascals, highlighting their potential application as biomedical materials. In addition, a model for describing the structural formation of PVA/PEG DN hydrogels is proposed: the condensed PVA‐rich phase forms microcrystals first, which bridge with one another to form a rigid and inhomogeneous net backbone to support the shape of the hydrogel, and then the dilute PEG‐rich phase partially crystallizes among the cavities or voids of the backbone; meanwhile, there are entanglements of molecular chains between the two polymers. Moreover, a mechanism is also proposed to explain the high mechanical strength of PVA/PEG DN hydrogels. It is suggested that the free motion of PEG clusters in the cavities of PVA networks can prevent the crack from growing to a macroscopic level because the linear PEG chains in the cavities effectively absorb the crack energy and relax the local stress either by viscous dissipation or by large deformation of the PEG chains. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Preparation and characterization of LDPE and PP—Wood fiber composites
Authors: Taşdemır Münir , Biltekin Hasan , Caneba Gerald T. 
Published: February 2009

AbstractNatural fiber reinforced composites is an emerging area in polymer science. These natural fibers are low cost fibers with low density and high specific properties. These are biodegradable and nonabrasive. The natural fiber composites offer specific properties comparable to those of conventional fiber composites. However, in development of these composites, the incompatibility of the fibers and poor resistance to moisture often reduce the potential of natural fibers, and these draw backs become critical issue. Wood‐plastic composites (WPC) are a relatively new class of materials and one of the fastest growing sectors in the wood composites industry. Composites of wood in a thermoplastic matrix (wood–plastic composites) are considered a low maintenance solution to using wood in outdoor applications. WPCs are normally made from a mixture of wood fiber, thermoplastic, and small amounts of process and property modifiers through an extrusion process. In this study, Wood–plastic composites (WPC) are produce by adding a maleic anhydride modified low density polyethylene coupling agent to improve interfacial adhesion between the wood fiber and the plastic. Mixing is done with twin screw extruder. Subsequently, tensile strength, the modulus of elasticity, % elongation, hardness, Izod impact strength, melt flow index (MFI), and heat deflection temperature (HDT) are determined. Thermal transition temperatures and microstructure are determined with DSC and SEM, respectively. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009