bluuebunny/crossref_metadata_2025 huggingface dataset:
Photochemistry of Bacteriochlorophylls in Human Blood Plasma: 2. Reaction Mechanism Investigated by Product Analysis and Deuterium Isotope Effect
Authors: Dandler Jörg , Wilhelm Brigitte , Scheer Hugo
Published: January 2010

Transmetalated (Pd) bacteriochlorophyll derivatives are currently being clinically tested as sensitizers for photodynamic therapy. Protocols using short delay times between injection and irradiation generate interest in the photochemistry of these pigments in the blood. Using near‐infrared irradiation where these pigments absorb strongly, we have studied the mechanism of photo‐oxidation in two lipoprotein fractions, low‐ and high‐density lipoproteins, derived from human blood plasma that preferentially accumulate these pigments (Dandleret al.[2009]Photochem. Photobiol.,85, in press). Using quenchers of reactive oxygen species, and chemical reporters, in particular peroxides generated from cholesterol as an inherent component of the lipoproteins, a Type II mechanism generating singlet oxygen has been demonstrated for Pd‐ and Zn‐bacteriopheophorbides. In homogeneous systems, accelerated bleaching in D2O, compared with H2O, supports this mechanism. An unusual deuterium isotope effect was observed, by contrast, in heterogeneous amphiphilic‐water systems. In the early phase, and under high oxygen concentrations, again a positive D‐isotope effect is observed which later, in a second phase, is reversed to a negative D‐isotope effect. The latter cannot be explained by heterogeneous pigment populations in the amphiphilic system; we, therefore, conclude a mechanistic switch, and discuss a possible mechanism.
Solar UV Geometric Conversion Factors: Horizontal Plane to Cylinder Model†
Authors: Pope Stanley J. , Godar Dianne E.
Published: January 2010

Most solar UV measurements are relative to the horizontal plane. However, problems arise when one uses those UV measurements to perform risk or benefit assessments because they do not yield the actual doses people get while they are outdoors. To better estimate the UV doses people actually get while outdoors, scientists need geometric conversion factors (GCF) that change horizontal plane irradiances to average irradiances on the human body. Here we describe a simple geometric method that changes unweighted, erythemally weighted and previtamin D3‐weighted UV irradiances on the horizontal plane to full cylinder and semicylinder irradiances. Scientists can use the full cylinder model to represent the complete human body, while they can use the semicylinder model to represent the face, shoulders, tops of hands and feet. We present daily, monthly and seasonally calculated averages of the GCF for these cylinder models every 5° from 20 to 70°N so that scientists can now get realistic UV doses for people who are outdoors doing a variety of different activities. The GCF show that people actually get less than half their annual erythemally weighted, and consequently half their previtamin D3‐weighted, UV doses relative to the horizontal plane. Thus, scientists can now perform realistic UV risk and benefit assessments.
Reducing Photoyellowing of Wool Using Nano TiO2
Authors: Montazer Majid , Pakdel Esfandiar
Published: January 2010

Wool is the most important animal fiber used in textile industries, but its photostability is very low. Scientists have searched for new ways to increase the photostability of wool. As TiO2 nano particles have features suitable for new applications, the UV‐blocking power of nano TiO2 may be used for protecting fabrics against UV rays. Treatment of wool with TiO2 can be effective for controlling photodegradation. This study focused on protecting wool fabric against UV rays using nano TiO2. To this end, oxidized and raw wool were treated with citric acid as the cross‐linking agent and different concentrations of nano TiO2. The whiteness and yellowness of wool fabric samples were reported. XRD patterns proved the existence of TiO2 nano‐particles on the wool surface. Finally, the results revealed that nano TiO2 is a suitable UV absorber on wool fabric and its effect depends on concentration.
Vibrio vulnificus genome suggests two distinct ecotypes
Authors: Rosche Thomas M. , Binder Eric A. , Oliver James D.
Published: January 2010

The genus Vibrio contains several of the most important pathogens known. One member of this group, Vibrio vulnificus, is an estuarine bacterium which is the causative agent of both food‐borne disease and wound infection. Vibrio vulnificus is ubiquitous in estuarine waters and occurs in molluscan shellfish in high numbers. However, the incidence of disease is relatively low and it has been suggested that not all strains of V. vulnificus are equally virulent. We have previously shown that there is a dimorphism present in the vcg (virulence correlated gene) locus of V. vulnificus, with the vcgC (clinical) and vcgE (environmental) alleles strongly correlating with either clinical or environmental isolation source. In this study, an examination of eight V. vulnificus genes for which there is sufficient data showed that such a C/E dimorphism is present in each gene examined, including housekeeping genes. Additionally, we found that the C and E genotypes of V. vulnificus respond in markedly different ways to environmental conditions. These findings lead us to hypothesize that the C and E genotypes also represent different ecotypes, possibly in the process of diverging into separate species.
Long-Range Pipeline Monitoring by Distributed Fiber Optic Sensing
Authors: Inaudi Daniele , Glisic Branko
Published: January 2010

Distributed fiber optic sensing presents unique features that have no match in conventional sensing techniques. The ability to measure temperatures and strain at thousands of points along a single fiber is particularly interesting for the monitoring of elongated structures such as pipelines, flow lines, oil wells, and coiled tubing. Sensing systems based on Brillouin and Raman scattering are used, for example, to detect pipeline leakages, to verify pipeline operational parameters and to prevent failure of pipelines installed in landslide areas, to optimize oil production from wells, and to detect hot spots in high-power cables. Recent developments in distributed fiber sensing technology allow the monitoring of 60 km of pipeline from a single instrument and of up to 300 km with the use of optical amplifiers. New application opportunities have demonstrated that the design and production of sensing cables are a critical element for the success of any distributed sensing instrumentation project. Although some telecommunication cables can be effectively used for sensing ordinary temperatures, monitoring high and low temperatures or distributed strain presents unique challenges that require specific cable designs. This contribution presents advances in long-range distributed sensing and in novel sensing cable designs for distributed temperature and strain sensing. This paper also reports a number of significant field application examples of this technology, including leakage detection on brine and gas pipelines, strain monitoring on gas pipelines and combined strain and temperature monitoring on composite flow lines, and composite coiled tubing pipes.
On the Mach Number Invariance of Gas Jets Expanding Into Hot or Cold Environments
Authors: Sambasivam R. , Durst F.
Published: January 2010

Gas jet flows expanding into a space containing the same medium but at a significant temperature difference are of concern in many fields of engineering. One such example is the expansion of supersonic oxygen jets in the basic oxygen furnace (BOF) steelmaking process. While studying the characteristics of such gas jets, an interesting invariance of the local Mach number with the change in the surrounding temperature was found. The velocity and temperature of the jet at any given location increased with the increasing ambient temperature. However, the local Mach number remained the same for all ambient temperatures. This interesting result was further studied since there is no mention of it in any published literature. The reasons for these characteristics of the jet are analyzed in this paper. It is stressed that this finding is of practical importance and can be used in experimental studies of submerged gas jets expanding into environments with different ambient temperatures.
Optimization of a Pin Fin With Variable Base Thickness
Authors: Kang H. S.
Published: January 2010

A pin fin with variable fin base thickness is optimized using a two-dimensional analytic method. The values of the inner wall temperature and fin volume are given as constants. The fin base temperature varies with variation in the fin base thickness, fin outer radius, fin length, and convection characteristic number. Under these conditions, the optimum heat loss, the corresponding optimum fin effectiveness, fin length, and fin outer radius are presented as functions of the fin base thickness, fin volume, and convection characteristic number. One of the results shows that both the optimum heat loss and optimum fin length decrease linearly with increase in the fin base thickness.
Comparison of Neutron and Synchrotron Diffraction Measurements of Residual Stress in Bead-on-Plate Weldments
Authors: Paradowska Anna M. , Price John W. H. , Finlayson Trevor R. , Lienert Ulrich , Ibrahim Raafat
Published: January 2010

This paper explores the use of neutron and synchrotron diffractions for the evaluation of residual stresses in welded components. It has been shown that it is possible to achieve very good agreement between the two independent diffraction techniques. This study shows the significance of the weld start and end sites on the residual strain/stress distribution. Quantitative evaluation of the residual stress development process for multibead weldments has been presented. Some measurements were also taken before and after postweld stress relieving to establish the reduction and redistribution of the residual stress. The detailed measurements of residual stress around the weld achieved in this work significantly improve the knowledge and understanding of residual stress in welded components.
Crack Geometry Effect on Stress-Strain Fields for Crack Under Biaxial Loading
Authors: Minami Fumiyoshi , Ohata Mitsuru , Watanabe Daisuke , Igi Satoshi , Kubo Takahiro , Suzuki Nobuhisa
Published: January 2010

With increasing demand of high-strength and high-pressure pipelines in gas transmission industries, the fracture control design of pipelines has been a driving factor to ensure the integrity of the pipeline. This paper addresses the stress and strain fields for a crack in a wide plate component under biaxial loading, which simulates a large-diameter pipe subjected to inner pressure coupled with axial loading. Attention is focused on the initiation of brittle fracture (stress controlled type) as well as ductile fracture (strain controlled type). Three-dimensional finite element-analyses are conducted. It was found that biaxial loading has a significant effect on the stress fields of through-thickness crack; the near-crack-tip stress is elevated to a large extent by biaxial loading. By contrast, the stress field for a surface crack is not sensitive to biaxial loading, while the near-crack-tip stress at the crack corner is increased locally by biaxial loading. The Weibull stress criterion was applied to discuss the biaxial loading effect on the brittle fracture strength of the wide plate. Ductile crack initiation properties are also discussed with two-parameter (plastic strain and stress triaxiality) diagram. The ductile damage is increased by biaxial loading for a through-thickness crack, whereas a surface crack has little effect of biaxial loading on the ductile damage.
Improved Prediction Method for Estimating Notch Elastic-Plastic Strain
Authors: Adibi-Asl R. , Seshadri R.
Published: January 2010

Notch stress-strain conversion (NSSC) rules are widely used to estimate nonlinear and history-dependent stress-strain behavior of the notch components or structures. This paper focuses on the estimation of stress and strain using the conventional NSSC rules and linear elastic analysis by considering the entire relaxation locus of the component during inelastic action. On the basis of local effects, net-section collapse, and reference stress, a simple method for estimating inelastic strain in the vicinity of stress concentrations is proposed. The accuracy of the method is compared with elastic-plastic finite element analysis for several notch configurations exhibiting two-dimensional and three-dimensional effects.
Flow-Excited Acoustic Resonance in Industry
Authors: Ziada Samir
Published: January 2010

The excitation mechanism of acoustic resonances has long been recognized, but the industry continues to be plagued by its undesirable consequences; manifested in severe vibration and noise problems in a wide range of industrial applications. This paper focuses on the nature of the acoustic resonance excitation mechanism for the case of closed side branches because of its relative importance to industrial applications. Design charts are presented for the Strouhal number at the onset of acoustic resonance and for the acoustic source strength representing the integral effect of the shear layer at the mouth of the side branch. Because these design charts are developed from tests of cylindrical pipes conveying turbulent flow at high Reynolds numbers, they can be used in industrial applications to predict the onset flow velocity and the intensity of acoustic resonances in side branches. Two industrial examples involving flow-excited acoustic resonance of closed side branches are presented. The first example deals with acoustic fatigue failure of the steam dryer in a boiling water reactor due to acoustic resonance in the main steam piping system, whereas the second example considers acoustic resonances in the roll posts of the short take-off vertical lift (STOVL) joint strike fighter. In both examples, effective means to alleviate the acoustic resonance mechanism are discussed.
Fluid Pressures on Unanchored Rigid Rectangular Tanks Under Action of Uplifting Acceleration
Authors: Taniguchi Tomoyo , Ando Yoshinori
Published: January 2010

Although uplift motion of flat-bottom cylindrical shell tanks has been considered to contribute toward various damages to the tanks, the mechanics were not fully understood. As well as uplift displacement of the tanks, fluid pressure accompanying the uplift motion of the tanks may play an important role in the cause of the damage. An accurate estimate of the fluid pressure induced by the uplift motion of the tanks is indispensable in protecting the tanks against destructive earthquakes. As a first step of a series of research, this study mathematically derives the fluid pressure on a rigid rectangular tank with a unit depth accompanying angular acceleration, which acts on a pivoting bottom edge. The rectangular tank employed herein is equivalent to a thin slice of the central vertical cross section of a rigid flat-bottom cylindrical shell tank. Assuming a perfect fluid and velocity potential, a continuity equation is given by the Laplace equation in Cartesian coordinates. The fluid velocities accompanying the motions of the walls and bottom plate constitute the boundary conditions. Since this problem is set as a parabolic partial differential equation of the Neumann problem, the velocity potential is solved with the Fourier-cosine expansion. The derivative of the velocity potential with respect to time gives the fluid pressure at an arbitrary point inside the tank. A mathematical solution for evaluating the fluid pressure accompanying the angular acceleration acting on the pivoting bottom edge of the tank is given by an explicit function of a dimensional variable of the tank, but with the Fourier series. The proposed mathematical solution well converges with a few first terms of the Fourier series. Values of the fluid pressure computed by the explicit finite element (FE) analysis well agrees with those by the proposed mathematical solution. For the designers’ convenience, diagrams that depict the fluid pressures normalized by the maximum tangential acceleration given by the product of the angular acceleration and diagonals of the tank are also presented. Consequently, the mathematical solution given by the Fourier series converges easily and provides accurate evaluation of the fluid pressures on a rigid rectangular tank accompanying the angular acceleration acting on the pivoting bottom edge. Irregularity in the fluid pressure distribution increases as the tank becomes taller.
Propagation of narrow-band-high-frequency clicks: Measured and modeled transmission loss of porpoise-like clicks in porpoise habitats
Authors: DeRuiter Stacy L. , Hansen Michael , Koopman Heather N. , Westgate Andrew J. , Tyack Peter L. , Madsen Peter T.
Published: January 2010

Estimating the range at which harbor porpoises can detect prey items and environmental objects is integral to understanding their biosonar. Understanding the ranges at which they can use echolocation to detect and avoid obstacles is particularly important for strategies to reduce bycatch. Transmission loss (TL) during acoustic propagation is an important determinant of those detection ranges, and it also influences animal detection functions used in passive acoustic monitoring. However, common assumptions regarding TL have rarely been tested. Here, TL of synthetic porpoise clicks was measured in porpoise habitats in Canada and Denmark, and field data were compared with spherical spreading law and ray-trace (Bellhop) model predictions. Both models matched mean observations quite well in most cases, indicating that a spherical spreading law can usually provide an accurate first-order estimate of TL for porpoise sounds in porpoise habitat. However, TL varied significantly (±10 dB) between sites and over time in response to variability in seafloor characteristics, sound-speed profiles, and other short-timescale environmental fluctuations. Such variability should be taken into account in estimates of the ranges at which porpoises can communicate acoustically, detect echolocation targets, and be detected via passive acoustic monitoring.
The role of suppression in psychophysical tone-on-tone masking
Authors: Rodríguez Joyce , Neely Stephen T. , Patra Harisadhan , Kopun Judy , Jesteadt Walt , Tan Hongyang , Gorga Michael P.
Published: January 2010

This study tested the hypothesis that suppression contributes to the difference between simultaneous masking (SM) and forward masking (FM). To obtain an alternative estimate of suppression, distortion-product otoacoustic emissions (DPOAEs) were measured in the presence of a suppressor tone. Psychophysical-masking and DPOAE-suppression measurements were made in 22 normal-hearing subjects for a 4000-Hz signal/f2 and two masker/suppressor frequencies: 2141 and 4281 Hz. Differences between SM and FM at the same masker level were used to provide a psychophysical estimate of suppression. The increase in L2 to maintain a constant output (Ld) provided a DPOAE estimate of suppression for a range of suppressor levels. The similarity of the psychophysical and DPOAE estimates for the two masker/suppressor frequencies suggests that the difference in amount of masking between SM and FM is at least partially due to suppression.
Prediction of noise reduction through vehicle path rerouting
Authors: Makarewicz Rufin
Published: January 2010

Traffic noise, produced by moving vehicles, is described in terms of the day-night average sound level Ldn and the day-evening-night level Lden. Both levels depend on the path of noise sources, such as road vehicles or aircraft. Usually, noise source path is rectilinear. Substituting a circle arc of radius R for the straight path segment yields noise reduction ΔL=ΔLdn=ΔLden. Assuming that noise propagation is governed by geometrical spreading, air absorption, and ground effect, relationship between ΔL and R is derived. For example, replacement of a straight road at the distance of 100 m with the road of radius R=270 m and the angle Φ=68° yields the noise reduction of 4 dB. In the case of road traffic noise, the presented results seem to be a viable alternative to barrier construction.
Utilizing dual frequency band transmit pulse complexes in medical ultrasound imaging
Authors: Hansen Rune , Måsøy Svein-Erik , Johansen Tonni F. , Angelsen Bjørn A.
Published: January 2010

A method of acoustic imaging that potentially can improve the diagnostic capabilities of medical ultrasound is presented. The method, given the name SURF (Second order UltRasound Field) imaging, is achieved by processing the received signals from transmitted dual frequency band pulse complexes with at least partly overlapping high frequency (HF) and low frequency (LF) pulses. The transmitted HF pulses are used for image reconstruction, whereas the transmitted LF pulses are used to manipulate the elastic properties of the medium observed by the HF imaging pulses. The present paper discusses fundamental concepts in relation to the use of dual frequency band pulse complexes for medical ultrasound imaging.
Excitation and focusing of Lamb waves in a multilayered anisotropic plate
Authors: Chapuis Bastien , Terrien Nicolas , Royer Daniel
Published: January 2010

The radiation of Lamb waves by an axisymmetric source on the surface of an anisotropic plate is investigated. An analytical expression of the Green’s function, valid in the far field domain, is derived. This approximation shows that the anisotropy of the propagation medium induces a focusing of Lamb modes in some directions, which correspond to minima of the slowness. Numerical simulations and experiments demonstrate that for the fundamental A0 and S0 modes, this phenomenon, analog to the phonon focusing effect, can be very strong in materials such as composite fiber-reinforced polymers. This effect due to the plate anisotropy must be correctly taken into account, for example, in order to develop systems for in situ structural health monitoring. The choice of the most appropriate Lamb mode, the excitation frequency, and the design of the array of piezoelectric disks used as transmitters and receivers depends on such considerations.
On the importance of preserving the harmonics and neighboring partials prior to vocoder processing: Implications for cochlear implants
Authors: Hu Yi , Loizou Philipos C.
Published: January 2010

Pre-processing based noise-reduction algorithms used for cochlear implants (CIs) can sometimes introduce distortions which are carried through the vocoder stages of CI processing. While the background noise may be notably suppressed, the harmonic structure and/or spectral envelope of the signal may be distorted. The present study investigates the potential of preserving the signal’s harmonic structure in voiced segments (e.g., vowels) as a means of alleviating the negative effects of pre-processing. The hypothesis tested is that preserving the harmonic structure of the signal is crucial for subsequent vocoder processing. The implications of preserving either the main harmonic components occurring at multiples of F0 or the main harmonics along with adjacent partials are investigated. This is done by first pre-processing noisy speech with a conventional noise-reduction algorithm, regenerating the harmonics, and vocoder processing the stimuli with eight channels of stimulation in steady speech-shaped noise. Results indicated that preserving the main low-frequency harmonics (spanning 1 or 3kHz) alone was not beneficial. Preserving, however, the harmonic structure of the stimulus, i.e., the main harmonics along with the adjacent partials, was found to be critically important and provided substantial improvements (41 percentage points) in intelligibility.
Finite amplitude method for measuring the nonlinearity parameter B∕A in small-volume samples using focused ultrasound
Authors: Saito Shigemi
Published: January 2010

On the basis of finite amplitude and comparative methods, the acoustic nonlinearity parameter B∕A of a liquid sample of as small as 0.1ml is measured using an 18.6-MHz focused Gaussian beam. The sample fills the space between a polystyrene plate and a tungsten reflector set about 1mm apart from each other within the focal region. The sound speed c and attenuation coefficient α are determined using the time of flight and the insertion loss of the sound passing through the sample, respectively. The density ρ is estimated from the reflection coefficient at the interface between the polystyrene plate and the sample, where the transformation from longitudinal to transverse waves is considered. To compensate for the effect of velocity dispersion on the second harmonic generation, the relative phase of the second harmonic sound is also measured using dual-frequency sound. By summarizing all the linear properties and amplitude data of the second harmonic component in the sound transmitted through the sample, the B∕A value is finally determined. The measurement is validated through the experiments on nondispersive liquids and weakly dispersive biological samples with known B∕A values.
Optimum absorption and aperture parameters for realistic coupled volume spaces determined from computational analysis and subjective testing results
Authors: Bradley David T. , Wang Lily M.
Published: January 2010

This project utilizes computational modeling to study the effects of varying two architectural parameters, absorption ratio and aperture size, in a realistic coupled volume concert hall. Coupled volumes have been shown to exhibit non-exponential sound energy decay profiles, referred to as double slope effect. A number of objective metrics (T30/T15, LDT/T10, decay ratio, and ΔL) have been used to quantify the double slope effect of the profiles generated in the virtual hall. T30/T15 and LDT/T10 showed similar trends across all hall configurations, indicating decreasing double slope effect with increasing coupled volume absorption ratio for each aperture size, and producing highest values at a specific aperture size for each absorption ratio. Generally, LDT/T10 provides finer resolution than T30/T15 when analyzing the decay profiles in this study. Results from the two metrics derived from Bayesian analysis, decay ratio and ΔL, seem less consistent. Subjective testing has also been conducted to determine the effect of varying the two architectural parameters in the hall, and multidimensional scaling analysis shows that, in general, listener preference is inversely proportional to the level of double slope effect, with the highest levels of preference occurring at low and medium levels of double slope effect. Recommended design guidelines for coupled volume halls are provided based on these computational and subjective results.
A different approach to use narrowband super-resolution multiple signal classification algorithm on wideband sources
Authors: Asgari Mohammad , Soltani Nasim Yahya , Riahi Ali
Published: January 2010

There are varieties of wideband direction-of-arrival (DOA) estimation algorithms. Their structure comprises a number of narrowband ones, each performs in one frequency in a given bandwidth, and then different responses should be combined in a proper way to yield true DOAs. Hence, wideband algorithms are always complex and so non-real-time. This paper investigates a method to derive a flat response of narrowband multiple signal classification (MUSIC) [R. O. Schmidt, IEEE Trans. Antennas Propag., 34, 276–280 (1986)] algorithm in the whole frequencies of given band. Therefore, required conditions of applying narrowband algorithm on wideband impinging signals will be given through a concrete analysis. It could be found out that array sensor locations are able to compensate the frequency variations to reach a flat response of DOAs in a specified wideband frequency.
The ensemble variance of pure-tone measurements in reverberation rooms
Authors: Jacobsen Finn , Rodríguez Molares Alfonso
Published: January 2010

Reverberation rooms are often used for measuring the sound power emitted by sources of sound. At medium and high frequencies, where the modal overlap is high, a fairly simple model based on sums of waves from random directions having random phase relations gives good predictions of the ensemble statistics of measurements in such rooms. Below the Schroeder frequency, the relative variance is much larger, particularly if the source emits a pure-tone. The established theory for this frequency range is based on ensemble statistics of modal sums and requires knowledge of mode shapes and the distribution of modal frequencies. This paper extends the far simpler random wave theory to low frequencies. The two theories are compared, and their predictions are found to compare well with experimental and numerical results.
Multiple instances of vocal sensorimotor adaptation to frequency-altered feedback within a single experimental session
Authors: Hawco Colin S. , Jones Jeffery A.
Published: January 2010

Vocal sensory-motor adaptation is typically studied by introducing a prolonged change in auditory feedback. While it may be preferable to perform multiple blocks of adaptation within a single experiment, it is possible that a carry-over effect from previous blocks of adaptation may affect the results of subsequent blocks. Speakers were asked to vocalize an /a/ sound and match a target note during ten adaptation blocks. Each block represented a unique combination of target note and shift direction. The adaptation response was found to be similar for all blocks, indicating that there were no carry-over effects from previous blocks of adaptation.
Elafin Is a Biomarker of Graft-Versus-Host Disease of the Skin
Authors: Paczesny Sophie , Braun Thomas M. , Levine John E. , Hogan Jason , Crawford Jeffrey , Coffing Bryan , Olsen Stephen , Choi Sung W. , Wang Hong , Faca Vitor , Pitteri Sharon , Zhang Qing , Chin Alice , Kitko Carrie , Mineishi Shin , Yanik Gregory , Peres Edward , Hanauer David , Wang Ying , Reddy Pavan , Hanash Samir , Ferrara James L. M.
Published: January 2010

Plasma elafin concentrations correlate with graft-versus-host disease of the skin and long-term survival.
A numerical method for static and free-vibration analysis of non-uniform Timoshenko beam–columns
Authors: Girgin Z Canan , Girgin Konuralp
Published: January 2010

A generalized numerical method is proposed to derive the static and dynamic stiffness matrices and to handle the nodal load vector for static analysis of non-uniform Timoshenko beam–columns under several effects. This method presents a unified approach based on effective utilization of the Mohr method and focuses on the following arbitrarily variable characteristics: geometrical properties, bending and shear deformations, transverse and rotatory inertia of mass, distributed and (or) concentrated axial and (or) transverse loads, and Winkler foundation modulus and shear foundation modulus. A successive iterative algorithm is developed to comprise all these characteristics systematically. The algorithm enables a non-uniform Timoshenko beam–column to be regarded as a substructure. This provides an important advantage to incorporate all the variable characteristics based on the substructure. The buckling load and fundamental natural frequency of a substructure subjected to the cited effects are also assessed. Numerical examples confirm the efficiency of the numerical method.Key words: non-uniform, Timoshenko, substructure, elastic foundation, geometrical nonlinearity, stiffness, stability, free vibration.
Suivi et validation des mesures pour un déversoir d'orage latéral à seuil court
Authors: Crobeddu Éric , Bennis Saad
Published: January 2010

This work proposes an original approach for monitoring and validating discharge measurements on a lateral storm weir. The approach is based on the combined use of a measuring device and a discharge formula. The developed validation procedure first identifies the erroneous measurements and, consequently, the faulty sensor, using information redundancy on the discharged flow. The erroneous measurements are identified using statistical tests on the relative gap between the measured and simulated discharged flows. Secondly, the erroneous discharge flow measurements are corrected by following the correction rules stated for each type of error. The validation procedure has been tested in a laboratory on a test bench equipped with sensors currently used in wastewater systems. The tests helped demonstrate the validity and robustness of the Dominguez formula used to simulate discharge flows. These tests also helped substantiate the validation procedure developed through identification and correction of erroneous discharged flows introduced in the measurement samples.Key words: storm overflow, lateral storm weir, discharge formula, instrumentation, validation, measurements.[Journal translation]
Behaviour of perfobond rib shear connectors: push-out tests
Authors: Veldanda M. R. , Hosain M. U.
Published: January 2010

This paper summarizes the results of tests performed on 48 push-out specimens to investigate the feasibility of using perfobond rib type shear connectors in composite beams with ribbed metal decks placed parallel to the steel beams. The perfobond rib shear connector is a flat steel plate containing a number of holes. The results indicate that perfobond rib connectors can be effectively used in composite beams with ribbed metal decks placed parallel to the steel beams. An appreciable improvement in performance was observed in test specimens when additional reinforcing bars were passed through the perfobond rib holes. Shank shear was the principal mode of failure in specimens with headed studs. In specimens with perfobond rib, failure was triggered by the longitudinal splitting of the concrete slab, followed by the crushing of concrete in front of the perfobond rib. Key words: composite beam, shear connector, perfobond rib, headed stud, push-out test, metal deck.
Optimization of cold formed steel C-sections using standard Can/CSA-S136-M89
Authors: Dinovitzer Aaron S.
Published: January 2010

The lip dimension of cold formed steel C-sections (channels) is optimized according to the provisions of CSA Standard CAN/CSA-S136-M89 "Cold formed steel structural members." The provisions in the 1989 edition of S136 are compared with those of the 1984 edition. Due to changes in design criteria, previously optimal sections are no longer optimal. The interaction of many of the elements is described and the manner in which the design standard takes the interaction into account is discussed. The lip sizes of C-sections are optimized in order to maximize flexural resistance and minimize cross-sectional area. An optimal C-section is one in which the flange is nearest to being fully effective. The optimal geometry generally has a lip-to-flange ratio of 3/8, which is restricted by a maximum lip flat width of 14 times the steel thickness. An optimal section based on the 1989 edition of S136 has a lower flexural resistance and a longer lip than an optimal C-section based on the 1984 edition of S136. Due to certain changes in the 1989 edition of S136, cold work of forming is now applicable in fewer cases than previously allowed by the 1984 edition of S136. Key words: cold formed steel, effective width, stiffener, lip, C-section, channel, optimization.
Câbles à base de fibres pour la précontrainte
Authors: Chabert A. , Picard A.
Published: January 2010

Successful use of high performance composite materials was first made in the aircraft industry and, to a lesser extent, in the automobile industry. The use of these materials in civil engineering is now a reality, particularly for prestressing applications. This state-of-the-art paper deals with composite materials used for cables. It describes the composition of fiber prestressing cables and presents their mechanical properties. The anchorages, the advantages and disadvantages of these cables, their field of applications, and three successful applications in structural engineering are also discussed. Key words: composite materials, prestressing, fiber cables, concrete.
Balanced and unbalanced welds for angle compression members
Authors: Temple Murray C. , Sakla Sherief S. S.
Published: January 2010

Angles used as web members in trusses are often welded to the chords with unbalanced welds. This is necessary because of space limitations. It is not known what effect such a weld has on the compressive load carrying capacity of an angle. The standards and specification examined allow an unbalanced weld for an angle. The justification for using such a weld is based on research conducted on angles in tension. For these members, it was concluded that an unbalanced weld does not affect the tensile load carrying capacity of the angle. Research results for angles with different weld patterns subjected to compressive loads are not available in the literature. Eighteen tests were conducted on angle compression members with various weld patterns. It was determined that an unbalanced weld is detrimental to the load carrying capacity of an intermediate length angle but is beneficial for a slender angle. Key words: angles, column (structural), compressive resistance, effective length, standards, welds.
Aeration and deaeration at bottom aeration devices on spillways
Authors: Chanson Hubert
Published: January 2010

Aeration devices are introduced along chute spillways and at bottom outlets to prevent cavitation damage in high velocity flows. Bottom aerators are characterized by large quantities of air entrained along the jet interfaces and also by a strong deaeration process near the impact of the water jet with the spillway bottom. In this paper, the aeration and deaeration occurring respectively in the aeration region and in the impact region are reviewed. A reanalysis of air concentration data obtained on models provides information on the flow characteristics at the end of the impact region. These results enable an accurate initialization of the downstream flow calculations using the method developed by Chanson. Key words: bottom aeration devices, aerators, spillways, air entrainment, detrainment.
Effects of construction cracks on the design of asphalt pavements
Authors: Halim A. O. Abd El , Razaqpur A. G. , Kashef A. H. El
Published: January 2010

Compaction of asphalt mix has been recognized as one of the most important factors that affect the long-term performance of the pavement. Problems experienced in compacting asphalt mixes have generally been ascribed to the mix. Roller "checking," the result of compaction with steel rollers, has been disregarded or considered as irrelevant. Compaction based on a new concept, using a soft plate, avoids roller checking, as demonstrated by a series of side-by-side field tests with steel and pneumatic rollers. The surface cracks initiated by the steel wheel roller may provide an explanation for the often reported phenomenon of early deterioration of asphalt pavements. Finite element analyses of pavement structures with roller-induced cracks have shown significantly higher tensile stresses than the corresponding stresses in otherwise identical uncracked pavements. The analytical findings are supported by indirect tensile and stress fatigue tests results obtained in the laboratory from asphalt samples compacted in the field. The test samples were recovered from pavements compacted either by existing compaction equipment and technique or by the new soft plate method. Key words: asphalt, crack, compaction, fatigue, finite element, tensile strength testing, pavement.
Properties of modified Alberta fly ash in relation to utilization in waste management applications
Authors: Joshi R. C. , Hettiaratchi J. P. A. , Achari Gopal
Published: January 2010

This paper presents the results of a laboratory investigation on hydraulic conductivity (k, also known as coefficient of permeability), compressive strength, and contaminant leachability of self-cementitious fly ash produced by two different coal-fired thermal power plants in Alberta. Hydraulic conductivity data are presented for fly ash and lime-modified fly ash samples with tap water and brine as permeants. The tap water k values of fly ash samples are almost two orders of magnitude higher than 1 × 10−7 cm/s, the usually required k value for a landfill bottom liner material. Addition of lime to fly ash increased the unconfined compressive strength and decreased the k value. The effect was directly proportional to the curing time and the percentage of lime added to the ash. The pozzolanic reactions between lime, water, and alumino-siliceous glass in the fly ash give rise to insoluble cementitious calcium alumino silicate hydrates. These pozzolanic reaction products contribute to strength gain and decrease in k value. It is also quite possible that salt precipitation during brine permeation blocked pore spaces and resulted in decreased k value. Nonetheless, the permeabilities of lime-modified fly ash samples are significantly lower than those of fly ash samples.In general, the amount of trace elements leached from test samples during tap water permeation decreased with increasing curing time and percentage of lime in samples. Exception was lead (Pb). Leachability of Pb increased with increasing lime content and curing time. Leachate pH held constant with time, which indicates that the removal of Ca(OH)2 in pozzolanic reactions did not have a significant impact on the pore solution pH. Key words: fly ash, hydraulic conductivity, contaminants, lime, leachability, liners, waste management, compressive strength, heavy metals.
ENTANGLEMENT CONCENTRATION AND DILUTION REVISITED
Authors: FUJITA HACHIRO
Published: January 2010

In this paper, we revisit the entanglement concentration protocol of Bennett et al. and the entanglement dilution protocol of Lo and Popescu via the method of types and provide a simple upper bound on the coefficient of the [Formula: see text] bound on the classical communication cost of the Lo-Popescu protocol.
NON-HERMITIAN ADIABATIC QUANTUM OPTIMIZATION
Authors: BERMAN GENNADY P. , NESTEROV ALEXANDER I.
Published: January 2010

We propose a novel non-Hermitian adiabatic quantum optimization algorithm. One of the new ideas is to use a non-Hermitian auxiliary "initial" Hamiltonian that provides an effective level repulsion for the main Hamiltonian. This effect enables us to develop an adiabatic theory which determines ground state much more efficiently than Hermitian methods.
A novel photochromic and electrochromic europium tetraazaporphyrinato and phthalocyaninato heteroleptic double-decker for information storage
Authors: Zhang Ying , Qi Dongdong , Jiang Jianzhuang , Sun Xuan
Published: January 2010

A novel tetraazaporphyrinato and phthalocyaninato mixed heteroleptic double-decker sandwich rare-earth compound with photochromic and electrochromic features has been facilely synthesized by one-pot reaction using Eu(acac)3 ·n H2O , metal-free phthalocyanine H2Pc′ ( Pc′ = 2,3,9,10,16,17,23,24-octakis(decyloxy)phthalocyanine), and the photochromic precursor 1,2-dicyano-l,2-bis(2,3,5-trimethyl-3-thienyl)ethane as starting materials. The compound was well characterized by elemental analysis and various spectroscopic methods including UV-vis, IR, 1H NMR, and mass spectroscopies. The electrochemical behavior of this compound was studied by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) methods, which showed up to three one-electron oxidation and four one-electron reduction processes, demonstrating an electro-active compound for high-density information storage. The photochromic performance of the compound was detected by electronic absorption spectra, suggesting the compound to be a good candidate for non-destructive readout by means of UV-vis spectroscopy.
Synthesis and photophysical properties of zinc phthalocyanines substituted with quinolinoxy group
Authors: Xue Jinping , Cai Lixuan , Chen Naisheng , Huang Jinling
Published: January 2010

The synthesis of tetrasubstituted zinc phthalocyanines bearing quinolinoxy groups are reported for the first time. The new compounds have been characterized by elemental analysis, IR, MS and electronic spectroscopy. The photophysical properties, such as the electronic absorption spectra and fluorescence spectra, have also been investigated and discussed together with the influence of substituent position and organic solvents on these properties. The introduction of quinolinoxy group to the Pc ring was found to affect these photophysical properties to some extent.
First industrial-scale biomimetic oxidation of hydrocarbon with air over metalloporphyrins as cytochrome P-450 monooxygenase model and its mechanistic studies
Authors: Guo Can-Cheng , Liu Xiao-Qin , Liu Qiang , Liu Yang , Chu Ming-Fu , Lin Wei-Ying
Published: January 2010

A novel industrial-scale trial for cyclohexane oxidation with air over metalloporphyrins as cytochrome P-450 monooxygenase model was reported. Upon addition of extremely low concentrations (1–5 ppm) of simple cobalt porphyrin to the commercial cyclohexane oxidation system, and decrease of the reaction temperature and pressure about 20 °C and 0.4 MPa respectively, the conversion rate of the cyclohexane oxidation increased from 4.8% to 7.1%, the yield of cyclohexanone raised from 77% to 87%, and a 70,000-ton cyclohexanone equipment set yielded an output of 125,000 tons cyclohexanone. Furthermore, a novel biological-chemical-cycle coupling mechanism was proposed to rationalize the aerobic oxidations of hydrocarbons catalyzed by the metalloporphyrins.
COMPUTING STEINER POINTS AND PROBABILITY STEINER POINTS IN ℓ1 AND ℓ2 METRIC SPACES
Authors: WENG J. F. , MAREELS I. , THOMAS D. A.
Published: January 2010

The Steiner tree problem is a well known network optimization problem which asks for a connected minimum network (called a Steiner minimum tree) spanning a given point set N. In the original Steiner tree problem the given points lie in the Euclidean plane or space, and the problem has many variants in different applications now. Recently a new type of Steiner minimum tree, probability Steiner minimum tree, is introduced by the authors in the study of phylogenies. A Steiner tree is a probability Steiner tree if all points in the tree are probability vectors in a vector space. The points in a Steiner minimum tree (or a probability Steiner tree) that are not in the given point set are called Steiner points (or probability Steiner points respectively). In this paper we investigate the properties of Steiner points and probability Steiner points, and derive the formulae for computing Steiner points and probability Steiner points in ℓ1- and ℓ2-metric spaces. Moreover, we show by an example that the length of a probability Steiner tree on 3 points and the probability Steiner point in the tree are smooth functions with respect to p in d-space.
Identification of Compounds That Inhibit IGF-I Signaling in Hyperglycemia
Authors: Maile Laura A. , Allen Lee B. , Veluvolu Umadevi , Capps Byron E. , Busby Walker H. , Rowland Michael , Clemmons David R.
Published: January 2010

Increased responsiveness of vascular cells to the growth factor IGF-I has been implicated in complications associated with diabetes. Here we describe the development of an assay and screening of a library of compounds for their ability to accelerate cleavage of the transmembrane protein integrin-associated protein (IAP) thereby disrupting the association between IAP and SHPS-1 which we have shown as critical for the enhanced response of vascular cells to IGF-I. The cell-based ELISA utilizes an antibody that specifically detects cleaved, but not intact, IAP. Of the 1040 compounds tested, 14 were considered active by virtue of their ability to stimulate an increase in antibody-binding indicative of IAP cleavage. In experiments with smooth muscle and retinal endothelial cell cultures in hyperglycemic conditions, each active compound was shown to accelerate the cleavage of IAP, and this was associated with a decrease in IAP association with SHPS-1 as determined by coimmunoprecipitation of the proteins from cell lysates. As a consequence of the acceleration in IAP cleavage, the compounds were shown to inhibit IGF-I-stimulated phosphorylation of key signaling molecules including Shc and ERK1/2, and this in turn was associated with a decrease in IGF-I-stimulated cell proliferation. Identification of these compounds that utilize this mechanism has the potential to yield novel therapeutic approaches for the prevention and treatment of vascular complications associated with diabetes.