bluuebunny/crossref_metadata_2025_split huggingface dataset:
Investigation of the elastic properties of UNI2Si2 as a function of temperature, magnetic field, and pressure
Authors: Quirion G , Kelly A , Newbury S , Razavi F S , Garrett J D 
Published: September 2003

It is now well-established that the strong anisotropy in the magnetic properties of the intermetallic compounds UT2Si2, where T stands for a transition metal, is responsible for their rich magnetic phase diagram. However, within that series of compounds, UNi2Si2 is one that shows an unusual sequence of magnetically ordered states. Thus, to better understand its unusual properties, we have investigated the elastic properties of UNi2Si2 as a function of temperature, magnetic field, and pressure. In all three magnetic phases, our measurements indicate that the sound-velocity temperature dependence is dominated by the magnetoelastic coupling. Moreover, the analysis of the temperature dependence for the incommensurate longitudinal spin-density wave phase is consistent with a critical exponent β = 0.38 ± 0.01. We also present the magnetic phase diagram for UNi2Si2 obtained at 0 and 8 kbar. Our investigation reveals that the triple-point coordinates (Tp, Hp) decrease with pressure at a rate of dTp/dP = 0.1 K/kbar and dHp/dP = 0.1 T/kbar, respectively. PACS Nos.: 75.30.kz, 62.20.Dc, 62.50.+p, 75.40.Cx
Reply to the comment by M. Denny on "The motion of a curling rock"
Authors: Shegelski Mark RA , Niebergall Ross 
Published: September 2003

We present experimental results for purely rotating curling rocks and show that these results are easily accounted for by "wet" friction and cannot be explained in terms of "dry" friction. We also list other observed motions of curling rocks that can be understood in terms of wet friction and not dry friction. PACS Nos.: 01.80.+b, 45.40.f
Comment on "The motion of a curling rock"
Authors: Denny Mark 
Published: September 2003

We investigate the model adopted in a recent paper in which the authors seek to explain the observed trajectory of a curling rock. We question the basis upon which the model is built, namely, frictional asymmetry arising from kinematic melting of the ice, and establish that the forms assumed for fluid friction motion are incorrect. Analytical and experimental results show that the force acting upon curling rocks is dominated by dry friction. PACS Nos.: 01.80.+b, 45.40.f
On uniqueness and reciprocity theorems for generalized thermo-viscoelasticity with thermal relaxation
Authors: Ezzat Magdy A , El-Karamany Ahmed S 
Published: September 2003

The equations of generalized thermo-viscoelasticity for an isotropic medium are given. Using Laplace transforms, a uniqueness theorem for these equations is proved. Also, a reciprocity theorem is obtained and some applications are given. PACS No.: 46.35.+z
Reply to the comment by A. Aste on "A simple explanation of the nonappearance of physical gluons and quarks"
Authors: Hansson Johan 
Published: September 2003

This is the reply to a comment by Andreas Aste on a previous article of mine in the Canadian Journal of Physics The counter-arguments used by Aste utilize a mathematical limit without physical meaning. We still contend that in QCD, the particles "gluons" and "quarks" are merely artifacts of an approximation method (the perturbative expansion) and are simply absent in the exact theory. PACS Nos.: 12.38.Aw, 03.70.+k, 11.15.q
Unification of Newton's laws of motion
Authors: Antippa A F 
Published: September 2003

Newton's three laws of motion are unified into one law (a slightly modified second law), valid in generalized inertial frames (defined by a slightly modified first law), invariant under mass scaling (guaranteed by the third law), and having important implications for the concept of force and the problem of self-energy. PACS Nos.: 45.20.Dd, 45.50.Jf, 45.05.+x
Nitrogen fixation in coarse woody debris of Thuja plicata and Tsuga heterophylla forests on northern Vancouver Island
Authors: Brunner Andreas , Kimmins J P 
Published: September 2003

Asymbiotic nitrogenase activity in coarse woody debris was measured using the acetylene reduction assay under ambient conditions in three different stand ages (5, 53, and 88 years old) of an unmanaged second-growth Tsuga heterophylla (Raf.) Sarg.  Abies amabilis (Dougl. ex Loud.) Dougl. ex J. Forbes forest type and a Thuja plicata Donn. ex D. Don  Tsuga heterophylla old-growth forest on northern Vancouver Island, British Columbia, Canada. Four different decay classes of coarse woody debris, different species in the early decay stages, and sapwood and heart wood were sampled separately. Mean nitrogenase activity ranged between 1.3 and 19.5 nmol C2H4·d1·(g dry mass)1, with an overall mean of 5.7. High variability of the activity rates between logs and within logs was observed in all four stands. Mean activity rates were, in most cases, significantly different between decay classes, with generally increasing nitrogenase activity with the progress of decay. Moisture content of the samples was a good predictor of nitrogenase activity and could explain differences between decay classes. Only minor differences in nitrogenase activity were found between the different stands. Estimates of nitrogen fixation ranged from 1.0 to 2.1 kg N·ha1·year1, the magnitude of these values depending more on the mass of coarse woody debris substrate available for asymbiotic nitrogen-fixing bacteria (103158 t·ha1 in this study) than on differences in nitrogenase activity rates. The measured nitrogenase activity and the resultant estimates of nitrogen fixation are among the highest values reported in the literature.
Bcl-xL antagonism of BCR-coupled mitochondrial phospholipase A2 signaling correlates with protection from apoptosis in WEHI-231 B cells
Authors: Katz Elad , Lord Caroline , Ford Catriona A. , Gauld Stephen B. , Carter Natalie A. , Harnett Margaret M. 
Published: September 2003

AbstractCrosslinking of the antigen receptors on the immature B-cell lymphoma, WEHI-231, leads to growth arrest and apoptosis. Commitment to such B-cell receptor (BCR)–mediated apoptosis correlates with mitochondrial phospholipase A2 activation, disruption of mitochondrial function, and cathepsin B activation. CD40 signaling has been reported to rescue WEHI-231 B cells from BCR-driven apoptosis primarily via up-regulation of the antiapoptotic protein Bcl-xL. Coupling of the BCR to the mitochondrial phospholipase A2–dependent apoptotic pathway can be prevented by rescue signals via CD40. We now show that overexpression of Bcl-xL can prevent mitochondrial phospholipase A2 activation, disruption of mitochondrial potential, and postmitochondrial execution of BCR-mediated apoptosis via cathepsin B activation. Moreover, overexpression of Bcl-xL protects WEHI-231 B cells from mitochondrial disruption and apoptosis resulting from culture with exogenous arachidonic acid, the product of phospholipase A2 action, suggesting that Bcl-xL may act to antagonize arachidonic acid–mediated disruption of mitochondrial integrity. However, although Bcl-xL expression can mimic CD40-mediated rescue of BCR-driven apoptosis, it cannot substitute for CD40 signaling in the reversal of BCR-mediated growth arrest of WEHI-231 B cells. Rather, CD40 signaling additionally induces conversion of arachidonic acid to prostaglandin E2 (PGE2), which promotes WEHI-231 B-cell proliferation by restoring the sustained, cycling extracellular signal–regulated/mitogen-activated protein kinase (ErkMAPkinase) signaling required for cell cycle progression.
Kinetics of Mixed Adsorbent Systems in Gas–Solid Adsorption
Authors: Webley Paul A. , Todd Richard S. 
Published: September 2003

Mixtures of solid adsorbents often occur in the process industries through either accident or design. To model such systems, a common approach is to define a pseudo-adsorbent with equilibrium properties equal to the mass fraction weighted average of the components in the mixture. The selection of an appropriate mass-transfer rate constant for the mixture is, however, more complicated. In this study, we have derived simple relationships between the linear driving force rate constants for a pseudo-mixture in terms of the rate constants, equilibrium parameters and mass fractions of the components of the mixture. The reciprocal rate constant for a mixture of adsorbents was shown to be related to the mass fraction weighted average reciprocal rates of the components of the mixture for the case of equal equilibrium isotherms. Expressions of greater complexity resulted for non-linear and non-equal isotherms. Experimental testing was undertaken of the breakthrough behaviour in adsorbent mixtures using the air system with mixtures of CaX and NaX in an adiabatic packed column. The mass-transfer behaviour of the solid mixtures was in good agreement with that predicted by the simple models.
Chemisorption of Hydrogen Ions on Aminosilica Surfaces at Different Temperatures
Authors: Kholin Yuriy V. , Myerniy Sergiy A. , Shabaeva Yutta V. , Khristenko Inna V. , Samoteikin Anton A. , Sumskaya Nina R. 
Published: September 2003

The chemisorption of hydrogen ions by silicas chemically modified with aliphatic amines was discussed. The sorption kinetics followed the model of sorption from a semi-infinite solution, with sorption being of a two-stage nature. The first stage, involving the overwhelming majority of sorption centres, was very fast. In contrast, the second stage was rather slow and diffusion-controlled. A proper description of the protolytic equilibria on the aminosilica surface required account to be taken not only of the protonization of the grafted amino groups but also of their homoconjugation. The latter reaction resulted from interactions between neighbouring groups and led to the non-random (islandlike) coverage of the surface by amino groups. Both the nature of the background electrolyte in the solution and its concentration had no effect on the model structure. The thermodynamic equilibrium constants for the heterogeneous protonization reaction were determined from the dependencies of the mixed equilibrium constants on the concentration of the background electrolyte in solution. Chemisorption of H+ ions, accompanied by penetration of the counterions into the subsurface layer, was of an endothermic nature and associated with increasing entropy.
Adsorption of Biologically Active Compounds from Aqueous Solutions on to Commercial Unmodified Activated Carbons. Part IV. Do the Properties of Amphoteric Carbon Surface Layers Influence the Adsorption of Paracetamol at Acidic pH Levels?
Authors: Terzyk Artur P. 
Published: September 2003

Three previously characterised, unmodified commercial activated carbons (D43/1, WD and AHD), differing in porosity and surface layer composition, were further examined using some additional methods of surface chemical description (electrochemical studies, acid–base site distribution, pHPZC and resistance measurements). Paracetamol adsorption isotherms (as well as kinetic curves) were measured on these carbons at acidic pH (1.5) and three temperatures, i.e. 300, 310 and 320 K. Measurements of the enthalpies of immersion in HCl and paracetamol solutions were also performed at 310 K, and diffusion coefficients and energies calculated. The results of measurements at acidic pH were compared with those obtained under neutral pH conditions. Some new correlations between the properties of the carbon surface and the constants characterising the process of paracetamol adsorption suggested recently were extended from data measured initially for six carbons. The mechanism of adsorption at both pH values was elaborated with the importance of surface carbonyls and basic groups being emphasised. The adsorption of the polymerisation product of paracetamol at acidic pH was determined using FT-IR and UV–vis spectroscopic measurements.
Smart Panel Technology for Broadband Noise Reduction
Authors: Kim Jaehw an 
Published: September 2003

The possibility of a broadband noise reduction by piezoelectric smart panels is demonstrated. A smart panel is basically a plate structure on which piezoelectric patches with electrical shunt circuits are mounted and sound absorbing material is bonded on the surface of the structure. Sound absorbing material can absorb the sound transmitted at the mid frequency region effectively while the use of piezoelectric shunt damping can reduce the transmission at resonance frequencies of the panel structure. To be able to reduce the sound transmission at low panel resonance frequencies, piezoelectric damping is adopted. A resonant shunt circuit for piezoelectric shunt damping is composed of resistor and inductor in series, and they are determined by maximizing the dissipated energy through the circuit. The transmitted noise reduction performance of smart panels was tested in an acoustic tunnel. Sound absorbing material and air gap reduces the sound transmitted at the mid-frequency region effectively while the use of piezoelectric shunt damping works at the low frequency region. As a result, a remarkable noise reduction of 9-15dB was achieved in broadband frequency. Double panel exhibits better noise reduction than other panels. This approach was also applied to the structural acoustic problem of turbulent boundary layer (TBL) induced sound radiated from a panel, and the possibility of TBL noise reduction was demonstrated. The hybrid approach of smart panels is a promising technology for noise reduction over broad frequency band.
Synthesis, characterization, and electroluminescent properties of a novel perylene‐containing copolyimide
Authors: Yang Mujie , Xu Shengang , Wang Jianpu , Ye Hui , Liu Xu 
Published: September 2003

AbstractA novel diphenylfluorene‐based Cardo copolyimide containing perylene (PFB5) was designed and synthesized by polycondensation of a diamine 4,4′‐(9H‐fluoren‐9‐ylidene)bisphenylamine with perylene dianhydride and another dianhydride in m‐cresol with isoquinoline as a catalyst at 200°C. PFB5 was characterized by FTIR, EA, GPC, TGA, DSC, UV‐vis, and PL. Because of the existence of the bulky diphenylfluorene units in the backbone, PFB5 showed high thermal stability and good solubility in common solvents such as chloroform. Solubility of PFB5 in low boiling point solvents allows direct spin coating of the polymer films, which exhibit intense photo‐ and electroluminescence (EL) in the visible range. This nonconjugated polymer could be used as emitting and electron‐hole transporting layers in polymer electroluminescent devices (PELDs). EL properties of the unilayer ELDs based on PFB5 are discussed. The device emitted a greenish yellow light. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 786–791, 2003
Transport and solubility of fluids into polyphenylene sulfide (PPS)
Authors: Wolf Clarence J. 
Published: September 2003

AbstractThe solubility and transport of toluene and carbon disulfide into amorphous and crystalline polyphenylene sulfide (PPS) was investigated. The rates of sorption, desorption, and resorption of both fluids were measured as a function of temperature. The sorption of these fluids into amorphous PPS produces a semi‐crystalline material by solvent induced crystallinity (SIC). Although the rate of diffusion of carbon disulfide (CS2) into crystalline PPS, (produced either thermally or by SIC), is several orders of magnitude slower than that observed in amorphous PPS, the solubility is only slightly reduced, by approximately 10%. The PPS films exhibit highly stressed surface regions that rapidly sorb the penetrant. Thermal annealing at temperatures as high as 100°C (note Tg of PPS is 85°C) has little or no effect on the surface stress, the diffusion process or the solubility of toluene into PPS. In addition to SIC, PPS undergoes cold crystallization at 130°–140°C; however, the degree of crystallinity induced by cold crystallization is approximately 60% of that formed by cooling from the melt. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 615–625, 2003
Effect of interfacial crosslinking on miscibility behavior between isocyanate‐functionalized poly(n‐butyl methacrylate) particles and carboxylic alkali‐soluble resin
Authors: Yoon Chul‐Hyun , Shin Jin‐Sup , Cheong In‐Woo , Lee Doug‐Youn , Park Young‐Jun , Kim Jung‐Hyun 
Published: September 2003

AbstractThe effect of interfacial crosslinking on miscibility behavior in blend systems of isocyanate‐functionalized poly(n‐butyl methacrylate) (PBMA) and a carboxylic alkali‐soluble resin, poly(styrene/alpha‐methylstyrene/acrylic acid) (SAA), was studied with different dimethyl meta‐isopropenyl benzyl isocyanate (TMI) concentrations. For the blend films of pure PBMA and SAA, both theoretical analysis and direct observation showed immiscibility between PBMA and SAA. For the blend systems of isocyanated PBMA and SAA, Fourier transform infrared spectra and gel permeation chromatography analyses qualitatively showed the crosslinking between the isocyanate group in isocyanated PBMA and the carboxylic group in SAA. Two tan δ peaks were shown in the blend system of SAA and isocyanated PBMA containing low concentrations of TMI (from 0 to 5 wt %), and the span of the two peaks became shorter as the TMI concentration increased. For a high TMI concentration (7 wt %), only one tan δ peaks was observed. This result means the interfacial crosslinking between isocyanated PBMA and SAA occurred fully, and thus the miscibility between two polymers was significantly improved. As these results showed, the tensile strength of the blend film of isocyanated PBMA and SAA was higher than that of pure PBMA and SAA. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 792–798, 2003
Synthesis and properties of hydrophilic polymers. IX. Synthesis, biodegradability, and metal complexation of copolymers of ethylenediaminetetraacetic acid dianhydride and lactose
Authors: Choi S. J. , Geckeler K. E. 
Published: September 2003

AbstractThe synthesis and characterization of poly(ethylenediaminetetraacetic acid‐co‐lactose) with pendant carboxylic groups of high molar mass (132 kg mol−1) is described. The polycondensate was hydrolytically and microbiologically degradable with conventional microbiological methods. The metal‐complexing properties of the polyester were studied for Cr(III), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Sr(II), Cd(II), Pb(II), and Al(III) ions in aqueous solution with the liquid‐phase polymer‐based retention (LPR) method. In addition, the complexing capacity of the Cu(II)‐saturated copolymer was determined by thermogravimetric analysis to be 182 mg g−1 of polymer. According to the retention profiles determined as a function of the filtration factor with LPR in conjunction with inductively coupled plasma spectrometry, Cr(III) and Fe(III) showed a strong interaction with this polymer under these conditions, as indicated by retention values of about 100% at pH 5. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 650–657, 2003
Role of a chelating agent in the formation of polyaniline films on aluminum
Authors: Huerta‐Vilca D. , Moraes Sandra R. , Motheo Artur J. 
Published: September 2003

AbstractA chelating agent, alizarin, was used to pretreat an aluminum surface before the electrochemical synthesis of polyaniline. Alizarin had two main effects on the process: (1) it suppressed the hydrogen evolution reaction and increased the current efficiency and (2) it stabilized the open‐circuit potential in a corroding environment, such as in 0.1M NaCl. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 819–823, 2003
Styrene‐assisted free‐radical graft copolymerization of maleic anhydride onto polypropylene in supercritical carbon dioxide
Authors: Dong Qingzhi , Liu Ying 
Published: September 2003

AbstractThe free‐radical graft copolymerization of maleic anhydride (MAH) onto polypropylene (PP) with the assistance of styrene (St) in supercritical carbon dioxide (CO2) was studied. The effects of the St concentration and initiator concentration on the functionality degree of the grafted PP in supercritical CO2 were investigated. The addition of St drastically increased the MAH functionality degree, which reached a maximum when the molar ratio of MAH and St was 1:1. St, an electron‐donating monomer, could interact with MAH through charge‐transfer complexes to form the St–MAH copolymer (SMA), which could then react with PP macroradicals to produce branches by termination between radicals. There was SMA in the grafting reaction system characterized by Fourier transform infrared and differential scanning calorimetry. Furthermore, the highest MAH functionality degree was obtained when the concentration of 2,2′‐azobisisobutyronitrile (AIBN) was 0.6 wt % based on PP. The effects of the temperature and pressure of supercritical CO2 on the functionality degree of the grafted PP were analyzed. An increase in the temperature accelerated the decomposition rate constant of AIBN, thereby promoting the grafting reaction. In addition, an increase in the temperature increased the diffusion of monomers and radicals in the disperse reaction system of supercritical CO2. The highest degree of functionality was found at 80°C. Also, the functionality degree of grafted PP decreased with an increase in the pressure of supercritical CO2 within the experimental range. The morphologies of pure PP and grafted PP were significantly different under polarizing optical microscopy. The PP spherulites were about 38 μm in size, and the grafted PP spherulites were significantly reduced because of heterogeneous nucleation. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 853–860, 2003
Thermal memory of polyethylenes analyzed by temperature modulated differential scanning calorimetry
Authors: Amarasinghe G. , Chen F. , Genovese A. , Shanks R. A. 
Published: September 2003

AbstractTemperature modulated differential scanning calorimetry (TMDSC) was employed to study the melting and crystallization behavior of various polyethylenes (PEs). Samples of high density PE (HDPE), low density PE (LDPE), linear low density PE (LLDPE), and very low density PE (VLDPE) with different crystal structures and morphologies were prepared by various thermal treatments (isothermal crystallization and slow, fast, and dynamic cooling). The reversing and nonreversing contributions, measured on the experimental time scale, were varied, depending on the crystal stability. A relatively large reversing melt contribution occurs for unstable crystals formed by fast cooling compared to those from slow cooling treatments. All samples of highly branched LDPE, LLDPE, and VLDPE showed a broad exotherm before the main melting peak in the nonreversing curve, suggesting crystallization and annealing of crystals to more stable forms. Other samples of HDPE, except when cooled quickly, did not show any significant crystallization and annealing before melting. The crystallinity indicated that dynamically cooled polymers were much more crystalline, which can be attributed to crystal perfection at the lamellar surface. A reversible melting component was also detected during the quasiisothermal TMDSC measurements. Melting is often accompanied by large irreversible effects, such as crystallization and annealing, where the crystals are not at equilibrium. Such phenomena during a TMDSC scan provide information on the polymer thermal history. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 681–692, 2003