bluuebunny/crossref_metadata_2025 huggingface dataset:
Kinetics of Phenol Removal from Aqueous Solution by Adsorption onto Peanut Shell Acid-Activated Carbon
Authors: Gonzo Elio E. , Gonzo Luis F.
Published: August 2005

A pseudo-second-order rate equation describing the kinetic adsorption of phenol onto peanut shell acid-activated carbon at different initial concentrations, carbon dosages and particle sizes has been developed. The adsorption kinetics were followed on the basis of the amount of phenol adsorbed at various time intervals at 22°C. The rate constant and the equilibrium adsorption capacity were calculated. From these parameters, empirical correlations for predicting the equilibrium adsorption capacity as a function of the C0/D ratio, and for estimating the rate constant as a function of the relation D/(C0dp)0.5, were derived.

This allowed a general rate expression for design purposes to be obtained which was valid for C0/D ≤ 1.5. The operation line for each case studied was constructed and the equilibrium adsorption capacity obtained. A comparison was undertaken with the experimental adsorption isotherm as previously determined. The effect of the initial phenol concentration, the carbon dose and the particle size on the initial adsorption rate was also analyzed.
Adsorption of Heavy Metal Ions on Virgin and Chemically-Modified Lignocellulosic Materials
Authors: Saliba R. , Gauthier H. , Gauthier R.
Published: August 2005

Amidoximated wood sawdust (Am-WS) and wood flour (Am-WF) were prepared using the same procedure as described recently for amidoximated cellulose (Am-Cell). The modified supports thus obtained were characterized by IR, TGA and DSC methods. In comparison to the untreated material, such treatment led to a considerable increase in adsorption capacity towards heavy metal ions from aqueous solution. The quantity adsorbed increased with pH, initial metal ion concentration and immersion time. The formation of a 1:1 complex between the amidoxime group and Cu(II), Cr(III) and Cd(II) ions and a 2:1 complex with the Ni(II) ion was demonstrated by the adsorption limit values. Overall, Am-WS and Am-WF exhibited similar behaviour to Am-Cell and are suitable for the treatment of wastewaters containing heavy metal ions.
Experimental Investigation of Self-Sustained Oscillations on the Spike-Tipped Cylinder in Supersonic Flow
Authors: Zapryagaev V.I. , Kavun I.N.
Published: August 2005

A study of the self-sustained quasi-periodic flows near the spike-tipped body at free-stream Mach number M∞ = 6 is carried out. The influence of length and spike cone angle on a flow structure is shown. The character of the pulsation flow mode depending on the geometry of the model is defined.
Noise Prediction for Increasingly Complex Jets. Part II: Applications
Authors: Shur Michael L. , Spalart Philippe R. , Strelets Michael Kh.
Published: August 2005

The numerical system described in Part I (Ref. 1) is applied to a variety of cases which increase difficulty, and progress in the direction of the complete simulation of an airliner engine. The grids have on the order of 1 million points. In many cases, the system meets the 2–3 dB accuracy target both in terms of directivity and of spectrum, up to a Strouhal number of about 1.5. The jet Mach number is varied from 0.3 to slightly supersonic with under-expansion, generating shock cells and greatly increasing side-line noise. For heated jets, the cross-effect between the acoustic Mach number and the temperature is correctly reproduced. Jets placed in a co-flowing stream with velocity up to 60% of the jet's are studied and found to sustain natural transition without unsteady forcing; the noise trends are correct. Finally, “synthetic chevrons” are added by altering the inflow conditions, and found to reduce low-frequency noise while increasing mid-frequency noise. In total, about fifteen meaningfully different cases are presented, and subjected to quantitative comparisons over the direction/frequency space without major failure. The principal limitation of the large-eddy-simulation approach remains its upper limit on frequency.
Experimental Study of Aeroacoustic Characteristics of Screens with an Orifice
Authors: Lebedeva Irina V. , Grushin Alexei E. , Kravtsov Yaroslav U.
Published: August 2005

We present a study of acoustic jets occurring in the vicinity of an orifice in a screen mounted at the end of a waveguide which conducts intense sound. The velocity field is measured by a cooling-power anemometer. We have used an impedance matching principle and demonstrated the ability to generate a strong acoustic jet and to create efficient resonant sound absorbers.
The Financial Impact of ISO 9000 Certification in the United States: An Empirical Analysis
Authors: Corbett Charles J. , Montes-Sancho María J. , Kirsch David A.
Published: August 2005

The ISO 9000 series of quality management systems standards, introduced in 1986, has been adopted at over 560,000 locations worldwide. Anecdotal evidence suggests that firms can achieve internal benefits such as quality or productivity improvements or that certification can help firms maintain or increase their market share, or both. Others argue that the standard is too generic to cause performance improvement but can be seen as a signal of good management. In this paper, we track financial performance from 1987 to 1997 of all publicly traded ISO 9000 certified manufacturing firms in the United States with SIC codes 2000–3999, and test whether ISO 9000 certification leads to productivity improvements, market benefits, and improved financial performance. We employ event-study methods, matching each certified firm to a control group of one or more noncertified firms in the same industry with similar precertification size and/or return on assets. We find that firms’ decision to seek their first ISO 9000 certification was indeed followed by significant abnormal improvements in financial performance, though the exact timing and magnitude of this effect depend on the specification of the control group. Three years after certification, the certified firms do display strongly significant abnormal performance under all control-group specifications. The degree to which the precise results vary across control-group specifications indicates that event studies should always include extensive sensitivity analysis, for instance matching by size and performance separately and jointly, using both single firms and portfolios as controls.
Soybean Inventory and Forward Curve Dynamics
Authors: Geman Hélyette , Nguyen Vu-Nhat
Published: August 2005

We present two results concerning soybean prices. First, we exhibit a simple relationship between stocks and price volatility. The observation of an increasing price volatility with decreasing inventory is often mentioned in the literature, but has so far been documented using a proxy for inventory (see Fama and French 1987, 1988; Litzenberger and Rabinowitz 1995). Instead, we reconstruct a yearly, quarterly, and monthly database of worldwide soybean inventories using aggregate data from the United States, Brazil, and Argentina. We show that under all time scales, price volatility is an increasing linear function of inverse inventory, which we term “scarcity.” Second, we show how the addition of the factor scarcity in a state-variable approach to the dynamics of the term structure of soybean forward prices improves the quality of the fit. We document this property on a 25-year database of CBOT futures contracts and show that the superior accuracy also affects long-maturity futures contracts, an important property for the valuation of long-term origination contracts between producing countries and the agrifood industry.
Pricing Diagnostic Information
Authors: Arora Ashish , Fosfuri Andrea
Published: August 2005

Diagnostic information allows an agent to predict the state of nature about the success of an investment project better than the prior. We analyze the optimal pricing scheme for selling diagnostic information to buyers with different, privately known, ex ante success probability. Investment costs and returns of successful projects are assumed to be the same for all buyers. The value of diagnostic information is the difference in expected payoffs with and without it, and we show that the willingness to pay for diagnostic information is nonmonotonic in the ex ante success probability. When the information seller can offer only one quality level, and negative payments are not allowed, we find that the optimal menu of (linear) contracts is remarkably simple. A pure royalty is offered to buyers with low ex ante success probability, and a pure fixed fee is offered to buyers with high ex ante success probability.
Global Production Planning Under Exchange-Rate Uncertainty
Authors: Kazaz Burak , Dada Maqbool , Moskowitz Herbert
Published: August 2005

Motivated by an aggregate production-planning problem in an actual global manufacturing network, we examine the impact of exchange-rate uncertainty on the choice of optimal production policies when the allocation decision can be deferred until the realization of exchange rates. This leads to the formulation of the problem as a two-stage recourse program whose optimal policy structure features two forms of flexibility denoted as operational hedging: (1) production hedging, where the firm deliberately produces less than the total demand; and (2) allocation hedging, where due to unfavorable exchange rates, some markets are not served despite having unused production. Our characterization of the optimal policy structure leads to an economic valuation of production and allocation hedging. We show that the prevalence of production hedging is moderated by the degree of correlation between exchange rates. A comprehensive examination under the following four generalized settings provides the depth, scope, and relevancy that our proposed operational hedges play to facilitate aggregate planning: (1) multiple periods, (2) demand uncertainty, (3) price setting or monopolistic pricing, and (4) price setting under demand uncertainty. We show that production and allocation hedging are robust for these generalizations and should be integrated into the overall aggregate planning strategy of a global manufacturing firm.
Research Note—Price Discrimination After the Purchase: Rebates as State-Dependent Discounts
Authors: Chen Yuxin , Moorthy Sridhar , Zhang Z. John
Published: August 2005

Promotional tools such as rebates and coupons are usually seen as different ways of price discriminating among consumers. We focus on a different property of rebates: their ability to price discriminate within a consumer among her postpurchase states. Unlike price discrimination between consumers, this property is unique to rebates because, by design, they are redeemed after the purchase. (Coupons, by contrast, are redeemed with the purchase.) The consumer redeems the rebate only in postpurchase states in which her marginal utility of income is high. This selective redemption behavior provides an opportunity for the seller to “utility arbitrage,” directing discounts to when they matter most, resulting in an increase in the consumer’s up-front willingness to pay. In turn, this enables an increase in the regular price. Of course, rebates can still price discriminate among consumers. Indeed, their ability to deliver state-dependent discounts may enhance their overall price discrimination ability, as we show in an example comparing them to coupons.
Protrusion of the Valvular Intestine in Captive Smalltooth Sawfish and Comments on Pristid Gastrointestinal Anatomy and Intestinal Valve Types
Authors: Henningsen Alan D. , Whitaker Brent R. , Walker Ian D.
Published: August 2005

We report on three separate instances of protrusion of the valvular intestine in the smalltooth sawfish Pristis pectinata, compare pristid gastrointestinal anatomy and intestinal valve structure with those of other elasmobranchs, and discuss the relevance of anatomy and valve structure to the husbandry of captive specimens. Protrusion of the valvular intestine, or intestinal eversion, has been documented in carcharhinid sharks with scroll-type intestines. All three cases of protrusion in smalltooth sawfish in this report involved specimens in multispecies display facilities and ultimately resulted in mortality. These are the first documented cases of intestinal eversion in any species of elasmobranch with a conicospiral valvular intestine. The valvular intestine of sawfishes (family Pristidae) is of the conicospiral type, which is similar to that described in other batoid species. However, unlike many other sharks and batoids, which possess short, stout pyloric stomachs, the pyloric stomachs in the pristids we examined were long and similar to those of carcharhinid sharks. The ability to protrude the valvular intestine in elasmobranchs may depend upon both valve morphology and the length of the pyloric stomach. The details of the gastrointestinal anatomy may be useful for systematics but also may be relevant to the captive husbandry of carcharhinids and sawfishes.
Comparisons of Two Statistical Models for Evaluating Boll Retention in Cotton
Authors: Wu Jixiang , Jenkins Johnie N. , McCarty Jack C. , Watson Clarence E.
Published: August 2005

Boll number is one of the most important traits related to yield of upland cotton (Gossypium hirsutum L.). Evaluation of boll retention properties at different fruiting sites would provide useful information for cotton breeding and cotton growth management. The presence or absence of a boll at each fruiting position can be considered as binomially distributed. In this study, 188 upland cotton recombinant inbred (RI) lines, two parental lines, and a control cultivar, Stoneville 474, were used. These lines were planted at Mississippi State, MS in 1999. The data set was analyzed by the mixed linear model and logistic regression model. The results showed that the boll retention for the first position was significantly different among nodes but expressed similar total numbers from the first position among RI lines. Estimates for boll retention were similar for both models; however, the logistic regression model gave smaller confidence intervals for each estimate than the mixed linear model.
Spinodal dewetting–A simple method to prepare conjugated polymer array
Authors: Yan Lifeng
Published: August 2005

A novel, simple method was developed to prepare conjugated polymer array in a large scale by using a spinodal dewetting technique. Mica, silicon, and glass were selected as substrates. The results show that with a suitable concentration of poly(9,9‐dihexylfluorene) (PF) in volatile organic solvent the polymer forms different sizes of array on the substrates. Atomic force microscopy measured the three‐dimensional structure of the arrays, and the relative FFT and PSD analyses reveal the detail information of the dewetting process and the array formation mechanism. The size of spots in the arrays is controlled by the evaporation speed of solvent and concentration of the PF solutions. The photoluminescence of PF arrays were also measured. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1412–1417, 2005
Atom transfer radical polymerization of styrene using a copper catalyst with a pseudohalogen anion
Authors: Singha Nikhil K. , German A. L.
Published: August 2005

Atom transfer radical polymerization has been a very useful method in the recent advances in controlled radical polymerization. It needs an activated alkyl halide as an initiator and a copper halide as a catalyst. This investigation reports the successful application of copper thiocyanate, a catalyst with a pseudohalide anion, in the presence of different ligands such as N,N,N=,N″,N‴,N‴‐hexamethyltriethylenetetramine (HMTETA), pentyl‐2‐pyridylmethaneimine, and substituted bipyridine in the atom transfer radical polymerization of styrene. Among the three ligands used, HMTETA was found to be very efficient. The polymers were characterized with 13C‐NMR, matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry, and gel permeation chromatography analysis. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1418–1426, 2005
Control and development of crystallinity and morphology in poly(β‐hydroxybutyrate‐co‐β‐hydroxyvalerate)/poly(propylene carbonate) blends
Authors: Li J. , Lai M. F. , Liu J. J.
Published: August 2005

Two different methodologies (reactive blending and mechanical blending) for preparing blends of poly(β‐hydroxybutyrate‐co‐β‐hydroxyvalerate) (PHBV) and poly(propylene carbonate) (PPC) were used. The miscibility, chemical structure, thermal behavior, crystallinity, morphology, and mechanical properties of the blends were investigated with Fourier transform infrared spectroscopy, differential scanning calorimetry, polarized optical microscopy, scanning electron microscopy, and tensile tests. A certain extent of hydrogen‐bonding interactions between PHBV and PPC took place in the blends. The graft copolymerization was confirmed in the reactive system. The incorporation of PPC hampered the crystallization process of PHBV and evidently altered the morphology, and the effect was enhanced in the reactive blend. The mechanical properties of PHBV could be changed by 1–2 orders of magnitude by blending modification. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1427–1436, 2005
Kraft lignin/poly(ethylene oxide) blends: Effect of lignin structure on miscibility and hydrogen bonding
Authors: Kubo Satoshi , Kadla John F.
Published: August 2005

Blends of poly(ethylene oxide) (PEO) with softwood kraft lignin (SKL) were prepared by thermal blending. The miscibility behavior and hydrogen bonding of the blends were investigated by differential scanning calorimetry (DSC) and Fourier transform infrared (FTIR) spectroscopy. The experimental results indicate that PEO was miscible with SKL, as shown by the existence of a single glass‐transition temperature over the entire composition range by DSC. In addition, a negative polymer–polymer interaction energy density was calculated on the basis of the melting point depression of PEO. The formation of strong intermolecular hydrogen bonding was detected by FTIR analysis. A comparison of the results obtained for the SKL/PEO blend system with those previously observed for a hardwood kraft lignin/PEO system revealed the existence of stronger hydrogen bonding within the SKL/PEO blends but weaker overall intermolecular interactions between components; this suggested that more than just hydrogen bonding was involved in the determination of the blend behavior in the kraft lignin/PEO blends. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1437–1444, 2005
Effect of the elastomer type on the microstructure and mechanical properties of polypropylene
Authors: Öksüz Mustafa , Eroğlu Mehmet
Published: August 2005

In this study, the effects of the elastomer type—ethylene–propylene–diene monomer (EPDM), three kinds of ethylene vinyl acetate (EVA 9, EVA 18, and EVA 28, where the number is the vinyl acetate concentration), and styrene–butadiene–styrene—and content on the microstructure and mechanical and thermal properties of isotactic polypropylene (i‐PP) blends were investigated. Five different elastomer concentrations (3, 6, 9, 12, and 15 wt %) were added to i‐PP to produce polypropylene/elastomer blends. The yield and tensile strengths, elastic modulus, impact strength, hardness, melt flow index (MFI), and structural properties of the blends were investigated. The tensile and yield strengths, elastic modulus, and hardness decreased gradually, whereas the impact strength and MFI increased as the elastomer content increased. As a result, with respect to the impact strength, the most effective elastomers were EPDM with 15 wt % and EVA 28 with 15 wt % for higher impact strength values. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1445–1450, 2005
Polyurethanes and polyesters from lignin
Authors: Bonini Carlo , D'Auria Maurizio , Emanuele Lucia , Ferri Rachele , Pucciariello Rachele , Sabia Anna Rita
Published: August 2005

Lignin, obtained through steam explosion from straw, was completely characterized via elemental analysis, gel permeation chromatography, ultraviolet and infrared spectroscopy, and 13C and 1H nuclear magnetic resonance spectrometry. Polyurethanes were obtained by treating steam‐exploded lignin from straw with 4,4′‐methylenebis(phenylisocyanate), 4,4′‐methylenebis(phenylisocyanate) –ethandiol, and poly(1,4‐butandiol)tolylene‐2,4‐diisocyanate terminated. The obtained materials were characterized by using gel permeation chromatography, infrared spectroscopy, and scanning electron microscopy. Differential scanning calorimetry analysis showed a Tg at −6°C, assigned to the glass transition of the poly(1,4‐butandiol) chains. The presence of ethylene glycol reduced the yields of the polyurethanes. The use of the prepolymer gave the best results in polyurethane formation. Steam‐exploded lignin was used as the starting material in the synthesis of polyesters. Lignin was treated with dodecanoyl dichloride. The products were characterized by using gel permeation chromatography, infrared spectroscopy, 13C and 1H nuclear magnetic resonance spectrometry, and scanning electron microscopy. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1451–1456, 2005
Graft polymerization of styrene on soy protein isolate
Authors: Xi Donglei , Yang Cheng , Liu Xiaoya , Chen Mingqing , Sun Chao , Xu Yulan
Published: August 2005

The grafting of styrene on soy protein isolate (SPI) in an 8 moL/L urea aqueous solution initiated by ammonium cerous nitrate and potassium persulfate was studied. The grafted copolymers were characterized by IR spectroscopy and DSC. The results indicated that styrene was grafted on the SPI. The influence of the reaction conditions on the grafting and efficiency percentages was investigated. The grafting and efficiency percentages initially increased and then decreased with the increase of the initiator concentration, monomer concentration, and reaction temperature. With the increase of reaction time, the grafting and efficiency percentages increased. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1457–1461, 2005
Polymerization‐induced phase separations in branched poly(methyl methacrylate) synthesis
Authors: Kwok Alan Y. , Neo Su Ann , Qiao Greg G. , Solomon David H.
Published: August 2005

Methyl methacrylate and ethylene glycol dimethacrylate or 1,6‐hexanediol dimethacrylate (HDDMA) were copolymerized in the presence of a nonsolvent (heptane) for poly(methyl methacrylate) (PMMA) to examine the phenomenon of polymerization‐induced phase separations (PIPS) in branched PMMA synthesis. The process was dependent upon the amount of nonsolvent and crosslinker in the reaction mixture. Gel particles were obtained in the majority of phase‐separated systems, and their formation was promoted by the preferential partition of monomer and crosslinker into the precipitated polymer phase during the phase separation process. Experimental data showed that, because of its lower solubility parameter, HDDMA can be used as crosslinker to minimize gel particle formation in systems where PIPS is present. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1462–1468, 2005
Zinc hydroxystannate and zinc stannate as flame‐retardant agents for flexible poly(vinyl chloride)
Authors: Xu Jianzhong , Zhang Chunyan , Qu Hongqiang , Tian Chunming
Published: August 2005

The flame‐retardant and smoke‐suppressant properties of inorganic tin compounds such as zinc hydroxystannate (ZHS) and zinc stannate (ZS) were investigated in a comparison with alumina trihydrate, magnesium hydroxide, and Sb2O3 through the limiting oxygen index test and smoke density test. The flame‐retardant mechanisms were studied through the char yield test, SEM, quantitative analysis, thermogravimetry and differential thermal analysis. The thermal degradation in air of flexible PVC treated with the above compounds was studied by thermal analysis from ambient temperature to 800°C. The results showed that tin compounds such as ZHS and ZS could be used as a highly effective flame retardant for flexible PVC, and it appears that the tin compound may exert its action in both the condensed and vapor phases, but mainly in condensed phases as a Lewis acid. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1469–1475, 2005
Fluorinated segmented polyurethane anionomers for water–oil repellent surface treatments of cellulosic substrates
Authors: Trombetta Tania , Iengo Paolo , Turri Stefano
Published: August 2005

Three model structures of linear segmented anionomeric polyurethanes based on perfluoropolyether dimethylol‐terminated oligomers, isophorone diisocyanate, and dimethylol propionic acid were synthesized and obtained in the form of aqueous dispersions. The structures differed from each other in the chemical nature of the chain extender (diol or diamine) and in the content of carboxylic acid. Dispersions and polymer films were characterized by dynamic light scattering, dynamic mechanical analysis, differential scanning calorimetry, and contact angle measurements. Diluted aqueous dispersions were also evaluated as protective sizing agents in paper treatment, both as bulk modifiers and as surface treatments. Paper sheets characterized by high water and oil repellence were obtained. The results showed that performance is mainly related to the ionic group content of the polymer and to its molecular architecture. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1364–1372, 2005
Microstructure and mechanical properties of poly(L‐lactide) scaffolds fabricated by gelatin particle leaching method
Authors: Zhou Qingliang , Gong Yihong , Gao Changyou
Published: August 2005

Biodegradable poly(L‐lactide) (PLLA) scaffolds with well‐controlled interconnected irregular pores were fabricated by a porogen leaching technique using gelatin particles as the porogen. The gelatin particles (280–450 μm) were bonded together through a treatment in a saturated water vapor condition at 70°C to form a 3‐dimensional assembly in a mold. PLLA was dissolved in dioxane and was cast onto the gelatin assembly. The mixtures were then freeze‐dried or dried at room temperature, followed by removal of the gelatin particles to yield the porous scaffolds. The microstructure of the scaffolds was characterized by scanning electron microscopy with respect to the pore shape, interpore connectivity, and pore wall morphology. Compression measurements revealed that scaffolds fabricated by freeze‐drying exhibited better mechanical performance than those by room temperature dying. Along with the increase of the polymer concentration, the porosity of the scaffolds decreased whereas the compressive modulus increased. When the scaffolds were in a hydrated state, the compressive modulus decreased dramatically. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1373–1379, 2005
Emulsion copolymerization of vinyl acetate and 2‐ethyl hexyl acrylate using nonionic emulsifiers in loop reactor
Authors: Sarac Ayfer , Keklik Mehmet , Yildiz Özgür , Yildirim Huseyin
Published: August 2005

Batch emulsion copolymerization of vinyl acetate and 2‐ethyl hexyl acrylate (VAc/2EHA = 90 : 10) was initiated by the thermal initiators ammonium persulfate and potassium persulfate at 70°C in the presence of nonylphenol ethoxylates with varying chain lengths and poly(vinyl alcohol). VAc–2EHA copolymer latexes were synthesized as two different series in a loop reactor. The first series was initiated by ammonium persulfate, and the second series was initiated by potassium persulfate. The influence of the counterions or initiators and chain lengths of a nonionic emulsifier on the properties of VAc–2EHA copolymer latexes were determined by measuring the viscosities, weight‐average molecular weights, number‐average molecular weights, molecular weight distribution, and surface tension of latexes to air. The results for the copolymer latexes indicated that some of their physicochemical properties increased with increasing chain length of the nonionic emulsifier, but some of them followed a different trend for the two initiators. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1380–1384, 2005
Acoustic analysis of composite soft materials III: Compressibility of boundary layers around particles of mica and calcium carbonate
Authors: Maebayashi Masahiro , Otsuka Shinya , Matsuoka Tatsuro , Koda Shinobu
Published: August 2005

The velocities of longitudinal, transverse, and leaky surface skimming compressional waves (LSSCW) of polyvinylchloride composite materials were measured as a function of the particle concentration. The mica and calcium carbonate (CC) particles were used as additives. The longitudinal and transverse velocities for the PVC/mica composite increased with the concentration of the mica. In the case of the PVC/CC composite, the transverse velocity increased with the concentration of the CC particle, but the longitudinal velocity was independent of the concentration. The LSSCW velocity for the polyvinylchloride matrix did not change in each composite. The partial specific volume and the partial specific adiabatic compressibility of each particle dispersed in polyvinylchloride were evaluated from sound velocity and density data. The compressibility of the boundary layer around the particles was estimated. The thickness of the boundary layer around the mica particle was estimated. For the PVC/CC composite, on the other hand, a softer phase than the PVC matrix was formed around the CC particle because the compressibility of the boundary layer was larger than that of the PVC matrix. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1385–1392, 2005
Dynamically vulcanized PP/EPDM blends by multifunctional peroxides: Characterization with various analytical techniques
Authors: Datta S. , Naskar K. , Jelenic J. , Noordermeer J. W. M.
Published: August 2005

The characterization of peroxide‐cured PP/EPDM TPVs using various spectroscopic techniques is difficult. These techniques are most suited for analysis of solutions, while the PP‐phase does not dissolve in common organic solvents at room temperature. To obtain more insight into the chemistry and reactivity involved between the multifunctional peroxides and EPDM rubber, several characterization techniques were employed. In the present investigation, FTIR, GC‐(FID + MS), HP‐SEC, and element analysis were used to characterize the multifunctional peroxides TBIB and DTBT, before and after the dynamic curing of the EPDM phase. The decomposition products obtained from these multifunctional peroxides are most likely grafted onto the EPDM‐rubber, thereby reducing their volatility and avoiding the common unpleasant smell. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1393–1403, 2005
The effects of zwitterionic and anionic charge densities in polymer chains on the viscosity behavior of a pH‐responsive hydrophobically modified ionic polymer
Authors: Umar Yunusa , Abu‐Sharkh B. F. , Ali Sk. Asrof
Published: August 2005

Sulfur dioxide, N,N‐diallyl‐N‐carboethoxymethylammonium chloride, and the hydrophobic monomer N,N‐diallyl‐N‐octadecylammonium chloride were cyclocopolymerized in dimethyl sulfoxide using azobisisobutyronitrile (AIBN) as the initiator to afford water‐soluble cationic polyelectrolytes (CPE) having a five‐membered cyclic structure on the polymeric backbone. The CPE on acidic hydrolysis of the pendent ester groups gave the corresponding cationic acid salts (CAS), which, on treatment with sodium hydroxide, were converted to polybetaines (PB) and anionic polyelectrolytes (APE), as well as polymers PB/APE containing various proportions of zwitterionic (PB) and anionic fractions (APE) in the polymer chain. The solution properties of the CPE, APE, and PB/APE systems containing varying amounts of the hydrophobic monomers in the range 0–4 mol % were investigated by viscometric techniques. Treating the pH‐responsive CAS polymers 4 with different equivalents of NaOH varied the zwitterionic and anionic charge densities in the polymer chain. It was found that the PB/APE polymer with a ratio of 33 : 67 for the zwitterionic and anionic fractions in the polymer chain, respectively, gave the highest viscosity value. The polymers showed that concentration (C*HA) of around 1 g/dL was required for the manifestation of significant hydrophobic associations. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1404–1411, 2005
Schalldämpfer für raumlufttechnische Anlagen in Niedrigenergiehäusern
Authors: Ackermann Ulrich
Published: August 2005

Die gute Isolation von Niedrigenergiehäusern erhöht die Gefahr von Schimmelbildung, da der Wasserdampf nicht entweichen kann. Um das Wasser zu entfernen, muß eine raumlufttechnische Anlage installiert werden. Die Strömungskanäle verbinden alle Räume und erzeugen einen akustischen Kurzschluß. Um diese sog. Telefonie zu unterdrücken, müssen Schalldämpfer in die Strömungskanäle eingebaut werden. Die Schalldämpfer erzeugen einen zusätzlichen Druckverlust, der Energie kostet. Die Schalldämpfer wurden deshalb aerodynamisch und akustisch optimiert. Die entwickelten Kulissenschalldämpfer sind aus verhautetem Kunststoff aufgebaut und dadurch gegen Verschmutzung geschützt. Die beste Dämpfung wird zwischen 1000 und 5000 Hz erreicht. In diesem Frequenzbereich ist das menschliche Gehör am empfindlichsten.
Europäische Dämmstoffnormen der 2. Generation: Prüfmethoden zur Ermittlung flüchtiger organischer Komponenten (VOC)
Authors: Gellert Roland , Horn Wolfgang
Published: August 2005

Die im Oktober 2001 erschienenen Dämmstoffnormen der 1. Generation DIN EN 13162 (Mineralwolle), DIN EN 13163 (EPS) und folgende (bis DIN EN 13171) verlangen vom Hersteller einen “initial type test (ITT)” von einer notifizierten Prüfstelle – nicht nur für bauphysikalische Eigenschaften wie den Wärmedurchgangswiderstand – sondern auch für die Freisetzung gefährlicher Substanzen. In den Normen wird allerdings noch auf nationale Regelungen verwiesen, da entsprechende Erfahrungen mit europäischen Prüfverfahren nicht vorliegen – auch nationale Erfahrungen liegen nur sehr eingeschränkt vor. Deshalb ist die Entwicklung eines kostengünstigen und praxisrelevanten Prüfverfahrens zur Bestimmung der Emissionen aus Dämmstoffen von normativem Interesse. Es konnte gezeigt werden, daß das Emissionsprüfzellenverfahren (FLEC mit Subunit) gemäß DIN V ENV 13419‐2 vergleichbare Ergebnisse wie das aufwendigere 1‐m3‐Prüfkammerverfahren gemäß DIN V ENV 13419‐1 liefert und damit als Erstprüfverfahren fungieren könnte.
Zur Ermittlung des Energiebedarfs für Kunstlicht in Bürogebäuden – Diskussion von Meßresultaten
Authors: Hoffmann C. , Voss Karsten
Published: August 2005

Im Rahmen des Förderkonzeptes Energieoptimiertes Bauen werden Forschung und Demonstration auf dem Gebiet energiesparender Gebäude des Nichtwohnungsbaus gefördert. Das Förderkonzept und die Gebäude wurden 2003 u. a. in dieser Zeitschrift [1, 2] und in einer Buchpublikation [3] vorgestellt. Der vorliegende Beitrag konzentriert sich auf die Auswertung des Bereichs Tageslicht und elektrische Beleuchtung. Neben einer vergleichenden Gegenüberstellung der Projekte wird untersucht, wie wirklichkeitsnah sich der Energiebedarf für elektrische Beleuchtung anhand von Rechenverfahren voraussagen läßt.
Bemessung von Holzdecken aus Hohlkastenelementen im Brandfall
Authors: Frangi Andrea , Fontana Mario
Published: August 2005

Der vorliegende Aufsatz stellt eine vereinfachte Berechnungsmethode zur Bemessung von Holzdecken aus Hohlkastenelementen bei Normbrandbeanspruchung vor. Die vereinfachte Berechnungsmethode orientiert sich an der vereinfachten Bemessungsmethode mit reduziertem Querschnitt für Holzbauteile im Brandfall gemäß Eurocode 5 und berücksichtigt zwei unterschiedliche Brandphasen, und zwar vor und nach der vollständigen Verkohlung der unteren, direkt dem Feuer ausgesetzten Holzlamelle. Es wird angenommen, daß die Abbrandgeschwindigkeit während der ersten bzw. zweiten Brandphase konstant über die Zeit ist. Im ersten Teil wird die vereinfachte Berechnungsmethode vorgestellt, der zweite Teil vergleicht die Resultate von Brandversuchen mit der Bemessungsmethode.
Hochschalldämmende Leichtbau‐Trennwände für ein Kino
Authors: Fischer Christian
Published: August 2005

Mit hochschalldämmenden Trennwänden hat sich die DS‐Plan Ingenieurgesellschaft vor allem in den 1990er Jahren intensiv beschäftigt, als eine große Zahl von Multiplexkinos geplant wurde. Kinobetreiber orientierten sich damals an dem THX‐Manual der Lucasfilm Ltd, in dem unter anderem schallschutztechnische Standards formuliert waren. Zahlreiche Erfahrungen bei der Übertragung der amerikanischen Begrifflichkeiten auf deutsche Kenntnisse und Bauweisen erwiesen sich als hilfreich dabei, einen Kinokomplex in der geforderten Qualität in Leichtbauweise zu erstellen.
Schalldämmung von Gipskarton‐Einfachständerwänden: Einfluß von Veränderungen der Unterkonstruktion
Authors: Wildoer Jörg
Published: August 2005

Beim Einsatz von leichten Gipskarton(GK)‐Ständerwänden mit Schallschutzanforderungen ist neben exakter schalltechnischer Planung und Systemauswahl besondere Sorgfalt bei der Ausführung erforderlich. Abweichende Materialparameter oder Systemeigenschaften sind vorab praktisch schwer erkennbar, können jedoch erheblichen Einfluß auf die schalltechnischen Eigenschaften haben. Anhand meßtechnischer Untersuchungen an Trennwänden mit nicht systemkonformer Unterkonstruktion werden die Auswirkungen auf die erreichbare Schalldämmung dargestellt und diskutiert.
Kalibrierung eines Ingenieurmodells zur hygrothermischen Materialcharakterisierung
Authors: Scheffler Gregor , Grunewald John , Häupl Peter
Published: August 2005

Im vorliegenden Beitrag wird ein Materialmodell vorgestellt, mit welchem die Verknüpfung komplexer, aus thermodynamischen Grundlagen abgeleiteter Funktionen mit einfachen, in der Ingenieurpraxis bekannten Kennwerten hergestellt wird. Das Modell besitzt dadurch die Vorteile der einfachen Handhabung und der Erweiterbarkeit auf andere Problemstellungen, da es keinen prinzipiell einschränkenden Voraussetzungen bzgl. der Modellierung von Transportvorgängen unterliegt. Im Ergebnis steht ein im gesamten Feuchtebereich kalibriertes, auf thermodynamischen Grundlagen basierendes Transportmodell für gekoppelten Flüssigwasser‐, Wasserdampf‐ und Wärmetransport. Das Modell ist für die wissenschaftliche Weiterentwicklung offen, z. B. auf den Salztransport und Salzkristallisationsprozesse erweiterbar.
Effects of neck exposure to 5.5 mT static magnetic field on pharmacologically modulated blood pressure in conscious rabbits
Authors: Okano Hideyuki , Ohkubo Chiyoji
Published: August 2005

Static magnetic fields (SMF) in the millitesla (mT) range have been reported to modulate microcirculatory hemodynamics and/or blood pressure (BP) under pharmacologically modified state in mammals. This study was designed to investigate the acute effects of local application of a SMF to neck or pelvic region under pharmacologically modulated BP; norepinephrine (NE)‐induced hypertension as well as an L‐type voltage‐gated Ca2+ channel blocker, nicardipine (NIC)‐induced hypotension in conscious rabbits. Magnetic flux densities were up to 5.5 mT and the spatial magnetic gradient peaked in neck (carotid sinus baroreceptor) region at the level of ∼0.06 mT/mm. The duration of exposure was 30 min (including 10 min of pretreatment) and the effects on BP were investigated up to 100 min postexposure. Baroreflex sensitivity (BRS) was estimated from invasive recordings of systolic BP and pulse interval. Neck exposure to 5.5 mT significantly attenuated the pharmacologically induced vasoconstriction or vasodilation, and subsequently suppressed the increase or decrease in BP compared with sham exposure. In contrast, pelvic exposure to 5.5 mT did not significantly antagonized NE‐elevated BP or NIC‐reduced BP. The neck exposure to 5.5 mT has a biphasic and restorative effect on vascular tone and BP acting to normalize the tone and BP. The neck exposure to 5.5 mT caused a significant increase in BRS in NE‐elevated BP compared with sham exposure. The buffering effects of the SMF on increased hemodynamic variability under NE‐induced high vascular tone and NIC‐induced low vascular tone might be, in part, dependent on baroreflex pathways, which could modulate NE‐mediated response in conjunction with Ca2+ dynamics. Bioelectromagnetics 26:469–480, 2005. © 2005 Wiley‐Liss, Inc.
Study of subgridding in SAR computation for the cochlea
Authors: Kopecký Rudolf , Hamnerius Yngve , Persson Mikael
Published: August 2005

A 3D subgridding technique is used to model the specific absorption rate (SAR) distribution in the isolated cochlea exposed to mobile phone radiation at 1750 MHz using the FDTD method. The cochlea is modeled using an increasing spatial resolutions of 1, 1/3, 1/5, and 1/7 mm. First simulations were performed at 1 mm spatial resolution. The numerical resolution was then increased to 1/3, 1/5, and 1/7 using subgridding without changing the spatial resolution. A second set of simulations was then performed when both the spatial and numerical resolution were increased together. From the obtained results, we conclude that subgridding is important only when both the numerical resolution of the computational grid and the spatial resolution of the model are increased together. Bioelectromagnetics 26:520–522, 2005. © 2005 Wiley‐Liss, Inc.
Boris Balinsky: transition from embryology to developmental biology
Authors: Korzh Vladimir
Published: August 2005

This is the story of a textbook that students of developmental biology have used for 45 years. “An Introduction to Embryology” was released soon after a role for genes in the control of development became finally recognized but not yet well documented. Thus this book manifested the transition from embryology to developmental biology. The story of its author, Boris Balinsky, who against all odds survived to write this book, is remarkable on its own. He started his scientific career in the USSR, but due to 20th century social and political upheavals, ended it in South Africa. This article will shed light on the life of Boris Balinsky, a scientist and writer and will explore the origins of his book. BioEssays 27:970–977, 2005. © 2005 Wiley Periodicals, Inc.
Evolution of early development of the nervous system: a comparison between arthropods
Authors: Stollewerk Angelika , Simpson Pat
Published: August 2005

Large numbers of cells with unique neuronal specificity are generated during development of the central nervous system of animals. Here we discuss the events that generate cell diversity during early development of the ventral nerve cord of different arthropod groups. Neural precursors are generated in a spatial array in the epithelium of each hemisegment over a period of time. Spatial cues within the epithelium are thought to evolve as embryogenesis proceeds. This spatiotemporal information might generate diversity among the neural precursors in all arthropod groups, although the mechanisms regulating the positioning of individual precursors have diverged. However, distinct strategies for the generation of neuronal diversity have evolved in the different arthropod lineages that appear to correlate with specific modes of ontogenesis. We hypothesize that an evolutionary trend towards reduced cell numbers and possibly rapid embryogenesis in insects has culminated in the appearance of stereotyped neuroblast lineages. BioEssays 27:874–883, 2005. © 2005 Wiley Periodicals, Inc.
Regulation of BRCA1, BRCA2 and BARD1 intracellular trafficking
Authors: Henderson Beric R.
Published: August 2005

The subcellular location and function of many proteins are regulated by nuclear–cytoplasmic shuttling. BRCA1 and BARD1 provide an interesting model system for understanding the influence of protein dimerization on nuclear transport and localization. These proteins function predominantly in the nucleus to regulate cell cycle progression, DNA repair/recombination and gene transcription, and their export to the cytoplasm has been linked to apoptosis. Germ‐line mutations in the BRCA1/BRCA2 and BARD1 genes predispose to risk of breast/ovarian cancer, and certain mutations impair protein function and nuclear accumulation. BRCA1 and BARD1 shuttle between the nucleus and cytoplasm; however heterodimerization masks the nuclear export signals located within each protein, causing nuclear retention of the BRCA1–BARD1 complex and potentially influencing its role in DNA repair, cell survival and regulation of centrosome duplication. This review discusses BRCA1, BRCA2 and BARD1 subcellular localization with emphasis on regulation of transport by protein dimerization and its functional implications. BioEssays 27:884–893, 2005. © 2005 Wiley Periodicals, Inc.
The structure of photosystem I and evolution of photosynthesis
Authors: Nelson Nathan , Ben‐Shem Adam
Published: August 2005

Oxygenic photosynthesis is the principal producer of both oxygen and organic matter on earth. The primary step in this process—the conversion of sunlight into chemical energy—is driven by four multi‐subunit membrane protein complexes named photosystem I, photosystem II, cytochrome b6f complex and F‐ATPase. Photosystem I generates the most negative redox potential in nature and thus largely determines the global amount of enthalpy in living systems. The recent structural determination of PSI complexes from cyanobacteria and plants sheds light on the evolutionary forces that shaped oxygenic photosynthesis. The fortuitous formation of our solar system in a space plentiful of elements, our distance from the sun and the long time of uninterrupted evolution enabled the perfection of photosynthesis and the evolution of advanced organisms. The available structural information complements the knowledge gained from genomic and proteomic data to illustrate a more precise scenario for the evolution of life systems on earth. BioEssays 27:914–922, 2005. © 2005 Wiley Periodicals, Inc.
Evolution of the neural basis of consciousness: a bird–mammal comparison
Authors: Butler Ann B. , Manger Paul R. , Lindahl B.I.B. , Århem Peter
Published: August 2005

The main objective of this essay is to validate some of the principal, currently competing, mammalian consciousness–brain theories by comparing these theories with data on both cognitive abilities and brain organization in birds. Our argument is that, given that multiple complex cognitive functions are correlated with presumed consciousness in mammals, this correlation holds for birds as well. Thus, the neuroanatomical features of the forebrain common to both birds and mammals may be those that are crucial to the generation of both complex cognition and consciousness. The general conclusion is that most of the consciousness–brain theories appear to be valid for the avian brain. Even though some specific homologies are unresolved, most of the critical structures presumed necessary for consciousness in mammalian brains have clear homologues in avian brains. Furthermore, considering the fact that the reptile–bird brain transition shows more structural continuity than the stem amniote–mammalian transition, the line drawn at the origin of mammals for consciousness by several of the theorists seems questionable. An equally important point is that consciousness cannot be ruled out in the absence of complex cognition; it may in fact be the case that consciousness is a necessary prerequisite for complex cognition. BioEssays 27:923–936, 2005. © 2005 Wiley Periodicals, Inc.
ECM degrading proteases and tissue remodelling in the mammary gland
Authors: Green Kirsty A. , Lund Leif R.
Published: August 2005

Matrix degradation and tissue remodelling directed by matrix‐degrading proteases are activated in physiological situations such as wound healing and involution of the prostate, ovaries and uterus. Recently, other activities, in addition to the cleavage of matrix proteins, have been attributed to matrix proteases including the release of growth factors from the extracellular matrix and roles in the maturation of adipocytes. This review describes extracellular proteases, including MMPs, plasminogen and cathepsins involved in the tissue remodelling processes that occur in the breast during pubertal mammary development and the mammary cycle of pregnancy, lactation and weaning. It particularly focuses on development and weaning, termed mammary gland involution, when the majority of remodelling occurs. It also brings together recent findings on the exciting new functions of matrix‐degrading proteases. BioEssays 27:894–903, 2005. © 2005 Wiley Periodicals, Inc.