bluuebunny/crossref_metadata_2025 huggingface dataset:
Genotyping of pantophysin I (Pan I) of Atlantic cod (Gadus morhua L.) by allele‐specific PCR
Authors: STENVIK JØRGEN , WESMAJERVI METTE SERINE , DAMSGÅRD BØRGE , DELGHANDI MADJID
Published: October 2005

The two main allelic variants of the Atlantic cod (Gadus morhua L.) pantophysin I (Pan I) locus have different frequencies within different cod stocks. The Dra I polymorphism which distinguishes the two alleles can thus be used for discrimination of coastal and offshore cod populations. We present a new method for Pan I genotyping using fluorescent allele‐specific duplex polymerase chain reaction (PCR). This method is more rapid, reliable and cost‐effective than the previously published method and it is not affected by DNA source and quality. This improvement is important for studies demanding high throughput and accuracy of Pan I genotyping
Cold hardiness of diapausing and non‐diapausing pupae of the European grapevine moth, Lobesia botrana
Authors: Andreadis Stefanos S. , Milonas Panagiotis G. , Savopoulou‐Soultani Mathilde
Published: October 2005

Lobesia botrana (Denis & Schiffermüller) (Lepidoptera: Tortricidae) is a key pest of grapes in Europe. It overwinters as a pupa in the bark crevices of the plant. Supercooling point (SCP) and low temperature survival was investigated in the laboratory and was determined using a cool bath and a 1 °C min−1 cooling rate. Freezing was fatal both to diapausing and non‐diapausing pupae. SCP was significantly lower in diapausing male (−24.8 °C) and female (−24.5 °C) pupae than in non‐diapausing ones (−22.7 and −22.5 °C, respectively). Sex had no influence on SCP both for diapausing and non‐diapausing pupae. Supercooling was also not affected by acclimation. However, acclimation did improve survival of diapausing pupae at temperatures above the SCP. Survival increased as acclimation period increased and the influence was more profound at the lower temperatures examined. Diapausing pupae could withstand lower temperatures than non‐diapausing ones and lethal temperature was significantly lower than for non‐diapausing pupae. Freezing injury above the SCP has been well documented for both physiological stages of L. botrana pupae. Our findings suggest a diapause‐related cold hardiness for L. botrana and given its cold hardiness ability, winter mortality due to low temperatures is not expected to occur, especially in southern Europe.
Distribution, timing of attack, and oviposition of the banana weevil, Cosmopolites sordidus, on banana crop residues in Uganda
Authors: Masanza M. , Gold C.S. , van Huis A.
Published: October 2005

Crop sanitation (removal and chopping of residue corms and pseudostems following plant harvest) has been recommended as a ‘best bet’ means of reducing banana weevil, Cosmopolites sordidus (Germar) (Coleoptera: Curculionidae), populations. However, it has been unclear when such practices should be carried out and what types of residues should be destroyed. Therefore, trials were conducted in Uganda to determine C. sordidus distribution, timing of attack, and oviposition on crop residues and growing plants. Assessments were performed in on‐station trials on different aged standing and prostrate residues by destructive sampling. Similar data were collected from farmers’ fields maintained at low, moderate, and high levels of sanitation. In the on‐station trial, oviposition occurred on up to 120‐day‐old residues, although most occurred within 30 days of harvest. In a second on‐station experiment, oviposition on standing residues was not significantly affected by residue age. By contrast, oviposition on prostrate residues was two times higher on 4‐week‐old than on 2‐week‐old residues, while the number of larvae on 8‐week‐old residues was three times higher than on 2‐week‐old residues. The number of adults was twice as high on 16‐week‐old residues as that on 2‐week‐old residues for both prostrate and standing residues. Farmers’ fields maintained at high sanitation had 50% fewer eggs per residue than farms with low sanitation levels. In general, the number of immatures per residue was 50% higher on banana corms than on pseudostems. Numbers of larvae per residue were three times more abundant at low than at high sanitation levels. Residues in fields with high sanitation supported 50% fewer adults than residues in low sanitation fields. The results suggest that removal and splitting of corms after harvest is effective and practical in destroying immature growth stages of the pest and that such practices should be carried out soon after harvest.
Photoperiodic response of diapause induction in the pine caterpillar, Dendrolimus punctatus
Authors: Huang Lili , Xue Fangsen , Wang Guohong , Han Ruidong , Ge Feng
Published: October 2005

The pine caterpillar, Dendrolimus punctatus (Walker) (Lepidoptera: Lasiocampidae), is a multivoltine pest of pine trees in China, overwintering as larvae. Winter diapause was induced by short day length. The critical night length was about 10 h 40 min at 25, 28, and 31 °C in the field, showing a temperature‐compensated diapause induction. Transfer experiments from a short night (L16:D8) to a long night (L12:D12) or vice versa at different times after hatching showed that sensitivity to day length was restricted to the first 14 days; the required day number for a 50% response at 25 °C was about 3.5 days for short nights but 7.5 days for long nights, indicating that short nights are photoperiodically more effective. When four successive short nights (L16:D8) were used to interrupt the long‐night regime (L12:D12) at different development stages and vice versa, the results showed that the highest sensitivity to photoperiod occurred on the 4th−8th day, corresponding to the second larval instar. Experiments of alternating short‐night (L16:D8) and long‐night (L12:D12) cycles during the larval period showed that the information of short nights as well as long nights could be accumulated. By rearing the larvae under conditions other than 24‐h light–dark cycles, we clearly showed that the dark period (scotophase) played a major role in the determination of diapause. The Nanda‐Hamner and Bünsow experiments failed to reveal rhythmic fluctuations with a period of about 24 h in the occurrence of diapause. Therefore, the photoperiodic clock in D. punctatus is an hourglass timer or a damped circadian oscillator.
Life Events in Older Adults with Intellectual Disabilities: Differences Between Adults with and Without Down Syndrome
Authors: Patti Paul J. , Amble Karen B. , Flory Michael J.
Published: October 2005

Abstract  Life events can have a negative impact on older adults with intellectual disabilities (ID) and are associated with depression and functional decline. Research on life events in people with ID revealed few reports that investigated life events exposure in people with Down syndrome (DS). The number and types of life events experienced in a cohort of 211 adults with ID (108 with DS, and 103 without DS) older than 50 years of age were studied. Data on life events exposure were collected from clinical records and informant interviews. The findings revealed that persons with DS in the sixth decade of life experienced a significantly greater number of life events and changes than adults without DS of similar or older ages. The number of relocations and medical events were found to be significantly greater in those with DS, whereas adults without DS experienced a significantly lower number of occurrences in all the life events categories studied. Adults with DS 50–59 years of age experienced a greater number of life events than did a group of adults without DS 50 years of age and older. Of the categories of life events investigated, changes in environment, experienced losses/separations, and medical events appear to be a common occurrence in the lives of older adults with DS. Functional decline, which commonly occurs during the dementia process, was seen as directly related to the prevalence and types of life events that adults with DS experience.
Investment Attractiveness of Afforestation in Canada Inclusive of Carbon Sequestration Benefits
Authors: Yemshanov Denys , McKenney Daniel W. , Hatton Terry , Fox Glenn
Published: October 2005

Afforestation is one of several possible mechanisms available to sequester carbon and help reduce greenhouse gas concentrations. We have developed a spatial Monte Carlo‐based simulation model, Canadian Forest Service—Afforestation Feasibility Model (CFS‐AFM) to help assess the financial attractiveness of afforestation as a means of carbon storage in Canada. The model tracks five carbon pools and simulates costs and benefits of plantation investments. In this paper we simulate three afforestation scenarios that could be used in Canada; plantations using hybrid poplar, hardwoods, and softwoods with average growth rates of 14 and 6–7 m3/ha/year, respectively. The attractiveness of afforestation is driven by regional cost and plantation productivity variation and carbon price expectations. The results indicate that afforestation would be an attractive investment in many areas of the country at carbon prices of $10 per metric ton of CO2 or higher. However, with a zero carbon price, very little afforestation would be financially viable. Thus, with low carbon price expectations, other co‐benefits may be required to make afforestation more attractive to Canadian investors.
The Consequences of Cobenefits for the Efficient Design of Carbon Sequestration Programs
Authors: Feng Hongli , Kling Catherine L.
Published: October 2005

In this paper, we study the social efficiency of private carbon markets that include trading in agricultural soil carbon sequestration when there are significant cobenefits (positive environmental externalities) associated with the practices that sequester carbon. Likewise, we investigate the efficiency of government run conservation programs that are designed to promote a broad array of environmental attributes (both carbon sequestration and its cobenefits) for the supply of carbon. Finally, policy design and efficiency issues associated with the potential interplay between a private carbon market and a government conservation program are studied. Empirical analyses for an area that represents a significant potential source of carbon sequestration and its associated cobenefits illustrate the magnitude and complexity of these issues in real world policy design.
The discovery of X-ray binaries in the Sculptor dwarf spheroidal galaxy
Authors: Maccarone Thomas J. , Kundu Arunav , Zepf Stephen E. , Piro Anthony L. , Bildsten Lars
Published: October 2005

We report the results of a deep Chandra survey of the Sculptor dwarf spheroidal galaxy. We find five X-ray sources with LX of at least 6 × 1033 ergs−1 with optical counterparts establishing them as members of Sculptor. These X-ray luminosities indicate that these sources are X-ray binaries, as no other known class of Galactic point sources can reach 0.5–8 keV luminosities this high. Finding these systems proves definitively that such objects can exist in an old stellar population without stellar collisions. Three of these objects have highly evolved optical counterparts (giants or horizontal branch stars), as do three other sources whose X-ray luminosities are in the range which includes both quiescent low-mass X-ray binaries and the brightest magnetic cataclysmic variables. We predict that large area surveys of the Milky Way should also turn up large numbers of quiescent X-ray binaries.
SENSITIVITY OF SUBLETHALLY INJURED GRAM‐NEGATIVE BACTERIA TO PEDIOCIN P
Authors: OSMANAĞAOĞLU ÖZLEM
Published: October 2005

All Gram‐negative bacteria tested were normally resistant to the bactericidal action of pediocin P of Pediococcus pentosaceous Pep1, which had been isolated from vacuum‐packaged sausages. However, when they were subjected to sublethal stress (exposure to physical and chemical stresses such as freezing, heating and acid treatment) and were treated with pediocin P, gram‐negative bacterial cells that were normally resistant to pediocin P developed sensitivity to it and pediocin P reduced the viability of bacterial cells surviving sublethal stresses, although the extent of reduction varied with strain and type of treatment. When the combined effect of ethylenediaminetetraacetic acid (EDTA), sublethal heat and pediocin P was studied by adding EDTA and pediocin P to cell suspensions right before heating them, there was a considerable reduction in the number of viable cells, even at the lowest concentration of pediocin P tested. The results of our preliminary studies showed that sublethal injury can make the gram‐negative bacterial cells sensitive to pediocin P.
EFFECT OF PEDIOCIN DT10 ON LEUCONOSTOC MESENTEROIDES OZ‐N3 CELLS
Authors: OSMANAĞAOĞLU ÖZLEM , KIRAN FADIME , GÜL NURSEL
Published: October 2005

Pediococcus pentosaceous DT10, isolated from ready‐to‐eat fish products, produced a bacteriocin active against Gram‐positive bacteria, many of which are associated with food spoilage and food‐related health hazards. The bacteriocin, named pediocin DT10, was partially purified and was observed to kill sensitive Leuconostoc mesenteroides cells by acting on their cytoplasmic membrane. Exposure of cell suspensions of L. mesenteroides to pediocin DT10 produced cell‐viability loss, as shown by the reduction in colony‐forming units after treatment. The activity of pediocin DT10 against L. mesenteroides cells was bactericidal in nature, and also induced an important efflux of intracellular material. The transmission electron microscopy of ultrathin sections of L. mesenteroides cells confirmed the way pediocin DT10 causes lysis of the sensitive L. mesenteroides cells.
Basic Concepts for the Linear Model of Ground Water Level Recession
Authors: Rutledge Albert T.
Published: October 2005

Basic concepts are illustrated for the display of ground water level recession as a linear plot on a semilog graph, as first described by Rorabaugh. This exponential decay function can be achieved if there is a definable outflow boundary such as a lake or river and if water levels are expressed relative to the altitude of the boundary. The model can be used to estimate aquifer hydraulic diffusivity. Concepts are illustrated using three finite‐difference simulations. One represents the ideal case as described by Rorabaugh, in which the altitude of the outflow boundary is uniform along its length. Another simulation includes a sloping boundary with simple geometry and demonstrates that the model can be used accurately. Based on this simulation, it appears that the ground water level must be expressed relative to the closest point on the outflow boundary. The third simulation includes a sloping boundary and complex boundary shape, and demonstrates departures from the linear model of recession and errors in the estimate of hydraulic diffusivity. Another cause of nonlinearity is the instability of the ground water head profile soon after a recharge event. The nature of these early‐time departures will vary depending on the location of the water level observation site relative to the outflow boundary and the hydrologic divide of the ground water flow system.
Correlation for Flow Boiling Heat Transfer at Low Liquid Reynolds Number in Small Diameter Channels
Authors: Zhang Weizhong , Hibiki Takashi , Mishima Kaichiro
Published: October 2005

In view of significance of a heat transfer correlation of flow boiling under the conditions of low liquid Reynolds number or liquid laminar flow, and very few correlations in principle suitable for such flow conditions, this study is aiming at developing a heat transfer correlation of flow boiling at low liquid Reynolds number for small diameter channels. The correlation is developed based on superimposition of two main flow boiling mechanisms, namely nucleate boiling and forced convection. In the correlation, two terms corresponding to nucleate boiling and forced convection are obtained from the pool boiling correlation by Forster and Zuber and the analytical annular flow model by Hewitt and Hall-Taylor, respectively. An extensive comparison with a collected database indicates that the developed correlation works satisfactorily with mean deviation and rms errors of 19.1% and 24.3%, respectively, under many experimental conditions such as different channel geometries (circular and rectangular) and flow orientations (vertical and horizontal) for some test fluids (water, R11, R12, and R113). A detailed discussion reveals that existing correlations for turbulent flow boiling such as Chen’s correlation, Schrock and Grossman’s correlation, and Dengler and Addoms’s correlation may be derived from a generalized form of the newly developed correlation.
Effective Dewetting in a Microporous Particle
Authors: Qiao Yu , Kong Xinguo
Published: October 2005

In this paper, the kinetics of the outflow in a microporous particle infiltrated by a nonwetting liquid is analyzed in context of effective phase transformation. The “dewetting” process is considered as the nucleation, growth, and coalescence of empty pore clusters (EPCs) that starts from the interior and eventually involves the whole particle. Initially, the EPC nucleation is dominant while the influence of EPC coalescence becomes increasingly important as the EPC volume fraction increases. The dependence of the dewetting time on the pore size distribution is discussed in detail.
Residential acoustics—A European perspective
Authors: Kihlman Tor
Published: October 2005

For a long time European building codes have included requirements on sound insulation between dwellings as well as noise levels from indoor and outdoor sources. Minimum requirements on sound insulation in finished buildings are based on the ISO documents 140 and 717. Typical minimum requirements lie in the range Rw′≥52−55 dB and Lnw′≤53−58 dB. Today’s trend is to extend the frequency range down to 50 Hz and to sharpen the minimum requirements somewhat, which creates some problems. In response to increasing demands from consumers, different classification systems for the sound insulation have been developed. The highest class demands insulation values up to 10 dB better than the legal requirements. A-weighted levels from building installations may not exceed 30–35 dB. To limit low-frequency ventilation noise C-weighted levels are specified in addition to A-weighted levels. Traffic noise levels are based on Leq as a Ldn or as separate values for day and night. Typical demand is LAeq<55 dB outdoors and 30 dB indoors. In existing situations, these levels are often exceeded. Effort is now being spent in the European community to deal with this problem.
Acoustical defects in multifamily construction
Authors: Van Houten John J. , Wieland David L.
Published: October 2005

Defects in multifamily construction have plagued the building industry in recent years. These defects are elements of the completed building which do not meet building code standards and/or may not conform to the architectural details or specifications. Additionally, defects in construction may involve contractual considerations and the homeowner complaint history. The identification of acoustical defects in multifamily construction requires a comprehensive review of the project documentation and field tests of a representative number of the floor–ceiling and/or party wall separations. The noise level of air handling equipment, elevator systems, and plumbing installations are also obtained. The findings of these tests are compared to noise insulation standards, established guidelines, and in some cases, home buyer expectations. Marketing information and disclosures conveyed at the time of sale are factors which may influence the evaluation of defects. Additional investigation usually involves destructive inspections of the actual assemblies, plumbing and equipment installations. These inspections are vital to the identification of recommended repairs. The various defects observed in multifamily construction within California will be indicated and the conflicting interests of homeowners, builders, and subcontractors will be discussed.
Acoustical characterization of straw bales as structural elements
Authors: Mas Carl J. , Everbach E. Carr
Published: October 2005

For several thousand years, straw has been used mainly as bedding for horses and cattle. This inexpensive, thermally insulating, and environmentally renewable material has been used increasingly in the southwestern United States as a structural element in the construction of residential houses, storage facilities, and restaurants. An understanding of the acoustical properties of straw bales is therefore required if this medium is to be used appropriately. The transmission loss (TL) of wheat and rye-grass straw bales was measured for bales placed in different configurations, and for the stucco-covered wall of a straw bale house. The TL for the straw bale house wall was 59.4 dB (A-weighted). The coefficient of acoustic absorption of the straw bales was also measured at 125, 250, 500, 1000, 2000, and 4000 Hz. [Work supported by an NSF PFF.]
Acoustical behavior of a new lightweight partition made with gypsum board and cork
Authors: Carvalho António Pedro O.
Published: October 2005

The building construction development in Portugal has been changed by the gradual move to a general use of residential partitions made with increasingly light materials from the traditional heavy interior walls. A socioeconomic analysis of the Portuguese situation as it is concerned with the lodging policies and building construction industry, is briefly presented. An international comparison on this matter is shown using some economic parameters. The Portuguese situation is compared to 36 other countries. The main goal of this paper is to present a study of the acoustical behavior of lightweight partitions, especially those usually called ‘‘sandwich-type’’ and its experimental application to a new and very specific kind of partition made of gypsum board and cork, a traditional material in Portugal. This newly developed sandwich lightweight partition is presented and acoustically characterized. A new and simple mathematical model is presented to evaluate the sound isolation of this kind of partition. The results obtained in reverberant chamber tests are presented as well as the comparisons with the predicted values using the new model proposed. Different single and double wall types were tested giving STC values up to 44 dB. [Work supported by LNEC and Univ. of Porto—Portugal.]
Getting the most out of acoustic data: Linking acoustics with spatially explicit ecological models
Authors: Brandt Stephen B.
Published: October 2005

Acoustic data are rich in information but models or other data (e.g., sound speed) need to be applied to the raw, time-dependent voltages to extract information on fish sizes, abundances, and distribution. Information extraction is hierarchical in that the more models (or assumptions) used, the more information obtained from the data. Recent research combines spatially explicit acoustic data with other environmental measurements to provide a template for ecological modeling of fish feeding and growth. This modeling links the physical and biological structure of the habitat in a way that maintains the spatial integrity of the system. Data visualization, geographic information systems, and data animation are used to display model output. The approach makes more full use of the spatial information inherent in acoustic data and can be used to predict fish growth and production, predator–prey interactions, the potential success of species introductions, and the effects of environmental perturbations. [Work supported by NSF, Biological Oceanography.]
Dominant scattering mechanisms and associated scattering models for several zooplankton types
Authors: Stanton Timothy K. , Chu Dezhang , Wiebe Peter H.
Published: October 2005

The shape and material properties of zooplankton can vary widely from species to species and, as a result, the acoustic scattering properties vary accordingly. Because of the great complexity of the boundary conditions of the animals, determination of the conditions is difficult, if not impossible, by direct measurement. Through a series of controlled laboratory measurements of acoustic backscatter by live individual animals, the boundary conditions of several different types of animals have been inferred. Dominant scattering mechanisms of the animals have been identified and incorporated into approximate scattering models. Data and models are presented for live individual euphausiids (weakly scattering fluidlike), gastropods (hard elastic shelled), and siphonophores (gas-bearing). In particular, relative scattering efficiency (echo energy per unit biomass) and patterns of target strength versus frequency for both single echoes from individuals as well as averages from many echoes will be shown. [Work supported by ONR and NSF.]
Acoustic classification of zooplankton
Authors: Martin Linda V. , Stanton Timothy K. , Wiebe Peter H. , Lynch James F.
Published: October 2005

Accurate acoustic characterization of zooplankton species is essential if reliable estimates of zooplankton biomass are to be made from acoustic backscatter measurements of the water column. Work on the forward problem has resulted in the identification of three categories of scatterers, represented by theoretical scattering models [Stanton etal., ICES J. Marine Sci. 51, 505–512 (1994)]: gas-bearing (e.g., siphonophores), fluidlike (e.g., euphausiids), and hard elastic-shelled (e.g., pteropods). If there are consistent differences in the characteristic acoustic signatures of each of these classes of zooplankton, it should be possible to solve the inverse problem by using acoustic backscatter data to mathematically infer the class of scatterer. Two different inversion techniques are applied to a dataset of several hundred pings collected from broadband insonifications (∼350–750 kHz) of live zooplankton tethered and suspended in a large tank filled with filtered seawater. The model-based classifiers depend on comparison of the data with theoretical scattering models, whereas the feature-based classifiers are independent of the models and exploit only the inherent characteristics of the acoustic returns. Preliminary results indicate that the acoustic classification of zooplankton insonifications into categories representing distinct scatterer-types is feasible.
An overview of the completely-in-the-canal hearing aid
Authors: Agnew Jeremy
Published: October 2005

As the ability to miniaturize electronic circuitry and components has progressed, modern hearing aids have become smaller and smaller. This trend has resulted in the completely-in-the-canal (CIC) hearing aid, which is the smallest hearing aid available today. This paper will provide an overview of the background, technology, and acoustics of CIC hearing aids. Topics to be covered include the origins and evolution of the CIC, miniaturization of components, and allied advances in enabling technology. Emphasis will be placed on the acoustic advantages of placing the CIC hearing aid deep in the auditory canal, including the effects on gain and distortion, the resulting frequency response in the ear, the significance of localization, the use of natural pinna cues, and the reduction of the occlusion effect. These topics will also be related to normal binaural hearing. The results of objective and subjective testing in these areas will be included. The paper will conclude with examples of challenging patient fittings that are possible with CIC hearing aids.
Directional hearing aid based on array technology
Authors: Soede Wim , Killion Mead C. , Roberts Matthew J.
Published: October 2005

Hearing-impaired listeners often have great difficulty understanding speech in surroundings with background noise or reverberation. Directional-microphone hearing aids can often reduce background noise in relation to the desired speech signal. To this end at the Delft University of Technology in The Netherlands, microphone systems were developed with strongly directional characteristics, using array techniques. Considerable attention was paid to optimization and stability. Free-field simulations of several robust models showed that a directivity index of 9 dB can be obtained. Simulations were verified with a laboratory model. The results of the measurements agreed well with the measurements, and based on these two, portable models were developed. The benefit of these microphone arrays for the hearing impaired was tested in a measurement setup with eight noise sources, simulating a true cocktail party. The results of the listening tests with 44 hearing-impaired subjects will be presented showing an average improvement of the S/N ratio of 7.0 dB for monaural fitting. The first results of research on another array type will be discussed.
Improvements in hearing aid transducers
Authors: Geddes Earl R.
Published: October 2005

Hearing aid transducers have been around for nearly 50 years and have reached a significant level of maturity. Recent improvements have been made primarily in the areas of robustness, size, and integration of subsystems. This presentation will describe several recent improvements in hearing aid transducers. The author will also discuss areas where future improvements are likely to be made. A discussion of the noise levels in microphones, which are felt to be a concern of the industry, will be made in an attempt to present a manufacturer’s view of this issue.
Micromachined silicon microphones and hearing aids: Performance and potential
Authors: Nedzelnitsky Victor
Published: October 2005

Small size, good frequency response characteristics, wide dynamic range, low cost, low sensitivity to external influences such as vibration, and low power requirements (extended battery life) of associated electronics have long been recognized as desirable properties of microphones used in hearing aids. New technologies of micromachined silicon capacitive microphones show promise not only for present hearing aid applications, but also for evolving array-based ones that may become practical for improving speech reception in the presence of noise and reverberation. Stability of microphone sensitivity can be particularly important in maintaining the designed directionality of arrays during their service lifetime. Designers of new microphones need reliably measured performance data to develop these new technologies and to optimize designs for specific applications. NIST measurement services long available to the public have been extended to obtain these data. Examples, including free-field sensitivity level versus frequency characteristics, are discussed for some experimental prototype omnidirectional microphones recently designed by J. Bernstein of Draper Laboratory, a customer of these services. Some possible lines of research and development of micromachined silicon transducers for hearing aid applications are suggested and discussed.
Open audiometric reporting standard (OARS)
Authors: Delage David J. , Dean Brenda , Yanz Jerry L.
Published: October 2005

Communicating data and/or graphs from hearing test instruments to hearing-aid-fitting systems or office management systems which are typically produced by different manufacturers has proved an impediment to the use of programmable hearing aids. In an attempt to resolve this difficulty, a flexible standard software protocol for communicating data and graphs between PC-based systems has been developed by Qualitone and has been offered royalty-free to the hearing health community. Called the open audiometric reporting standard (OARS), it is based on the existing Windows open database connectivity (ODBC) standard. The purpose of OARS is to allow systems to store or transfer data or graphical information in an open and standardized way, independent of the database language. Effort has been made to insure compatibility with all Windows-based systems (including test instruments, hearing aid programmers, and office management systems) and to provide a method whereby all possible system configurations and their data and graphic needs can be supported.
Feedforward compression algorithm to compensate for the loudness recruitment in hearing-impaired people
Authors: Ribic Zlatan , Yang Jun
Published: October 2005

In the proposed compression algorithm, Hilbert transform and vector sum generator are used to obtain the Hilbert envelope AM which is the input signal of the following attack/release network (ARN). ARN is simulated by a first-order, low-pass filter with a variable time constant. Signal AM is also processed by a first-order high-pass filter (its time constant is about 10 ms) to provide a signal B for controlling the time constant of the ARN in such a way that the time constant is the attack time with the recommended range from 0.1 to 10 ms when B is positive, and the release time with the recommended range from 10 to 100 ms when B is negative. Finally, a voltage-controlled amplifier is used to amplify the original signal with the gain inversely proportional to the power function of the signal at the output of ARN. The desired compression ratio can be obtained by changing the power. Simulation results have shown that the proposed compression algorithm is simple and applicable for not only the wideband channel, but also multiband channels. In addition, the compression parameters can be adjusted according to the designer’s requirement.
Effects of installation for computer cooling fans
Authors: Bezemek Jacklyn D. , Mongeau Luc
Published: October 2005

The aerodynamic performance and the noise emissions of computer cooling fans are influenced by the design of the computer enclosure and its internal components. Moreover, the coupling between the spatially distributed source and the acoustic response of the system hampers the use of most linear electroacoustic source filter models. Employing a method derived from acoustic similarity laws [Neise and Barsikow, ‘‘Acoustic Similarity Laws for Fans,’’ Trans. ASME 104 (May 1982)], the installation effects of three small axial cooling fans mounted in various computer-power supply assemblies have been determined by combining measurements insitu and standardized fan sound power measurements. It was found that flow performance may be reduced, additional sound may be generated due to inflow inhomogeneities, and the fan itself may affect the fundamental Helmholtz resonance of the computer and power supply cavities.
Measurements of third-order elastic constants in rocks
Authors: Winkler Kenneth W. , Liu Xingzhou
Published: October 2005

Third-order elasticity successfully describes a variety of acoustic phenomenon in many materials, and measurements exist of third-order elastic constants in metals, plastics, and crystals. A key feature of third-order elasticity theory is that acoustic velocities vary with the stress in a material. In spite of the fact that velocities in rocks are extremely stress dependent, no measurements have previously been published of third-order elastic constants in sedimentary rocks. This experimental technique is based on measuring changes in velocity with applied stress, both uniaxial stress and hydrostatic stress. By measuring five acoustic modes there is an overdetermined system of five equations and three unknowns. Measurements are reported of the three third-order elastic constants for nine rocks (sandstones, limestones, granite) and a few synthetic materials at ambient room conditions. Along with velocity, porosity, density, and uniaxial strength, these data constitute a unique database of rock properties.
High amplitude, bifrequency experiments in porous rocks
Authors: Plona Thomas J. , Sinha Bikash , D’Angelo Ralph , Kimball Chris , Landsberger B. J. , Hamilton Mark F.
Published: October 2005

Fluid-filled, porous, sedimentary rocks have the general characteristic that the sound speeds are strongly dependent on the state of stress and therefore, the third-order elastic coefficients (i.e., A, B, C) are generally much larger than for normal solids. However, the linear attenuation can also be very large such that in nonlinear wave propagation, the Gol’dberg number is small. Experiments studying harmonic generation in porous rocks have been made using an ultrasonic immersion system (i.e., water/solid/water) where a high amplitude (e.g., 500 kPa), bifrequency (0.95 and 1.05 MHz), tone burst is emitted and then sum and difference frequencies are detected after propagation through the water/solid/water system. A frequency domain numerical implementation of the KZK (Khokhlov–Zabolotskaya–Kuznetsov) nonlinear parabolic wave equation is used to describe the nonlinear propagation in the three layer system. Experiments on solids with well-known acoustic properties (linear and nonlinear) were used to validate the model. Measurements were then made on several sandstones and limestones and the model used to derive the nonlinear propagation parameter, β=f(A,B,C). Finally, these results are compared with independent measurements of A, B, C for these rocks.
Nonlinear vibroacoustic properties of rocks
Authors: Ostrovsky Lev A.
Published: October 2005

This is a summary of recent theoretical and experimental work performed by the Nonlinear Acoustic Group (L. Ostrovsky, A. Sutin, V. Nazarov, I. Belyaeva, Yu. Zaitsev) at the Institute of Applied Physics, N. Novgorod, Russia. Experiments show that Earth materials can have anomalously strong mechanical nonlinearity. However, in many cases there is a lack of clear understanding of specific mechanisms responsible for these nonlinear effects. Some theoretical models of structurally inhomogeneous media have been constructed and experimentally verified. These models include: (1) porous waterlike media characterized by small (but finite) shear modulus; (2) grainy media where nonlinearity is caused by the intergrain contacts (Hertz model); (3) some nonlinear models of cracks. Laboratory experiments have demonstrated a good agreement with theoretical results, and in all three cases the values of the nonlinearity parameter (defined similarly to that used in nonlinear acoustics for gases and liquids) could achieve the values of the order of 103–104 and even more. Some estimates for real rocks are also given. They show that nonlinear parameters may prove to be much more sensitive to the details of the material structure than the usual linear ones (e.g., sound velocity). This can serve as a base for developing new methods of seismic surveillance.
New developments in loudspeaker materials
Authors: Klasco Michael A.
Published: October 2005

Perhaps the drive behind a number of important new materials developments for speakers was the compact disc. The CD brought wide dynamic range with extended bass response into the home and car and ‘‘digital-ready speakers’’ have become more than just a marketing pitch. How are speaker engineers increasing excursion, thermal power handling, and maintaining performance characteristics at higher sound levels, while improving reliability? Specific solutions such as carbon fiber and Kevlar woven and nonwoven composite cones, new cone forming technologies, injection molded adhesiveless suspension surrounds, thermally conductive adhesives, thermally (but nonelectrically) conductive voice coil formers, high-temperature voice coil wire insulation and adhesives, a new magnetic geometry for high-excursion linear travel, ferrofluids for woofers, high-heat emmisivity plating techniques, and other fabriction and materials solutions will be briefly discussed. Advances in materials extend to enclosure materials, and a brief survey of developments in this related field will be mentioned. Additionally, test and measurement procedures to objectively quantify these enhancements will be touched upon.
Time AlignR loudspeaker crossovers
Authors: Long Edward M.
Published: October 2005

A Time AlignR loudspeaker system must produce an acoustical output at the listening position such that the fundamental and overtones of a complex, transient signal have the same relationships that they have at the electrical transient signal have the same relationships that they have at the electrical input to the system. natural time offset between the acoustical outputs of the l must be corrected. This time offset is caused by the natural low-pass filter characteristics of the drivers and the electrical crossover filters. The time offsets between the acoustical output of each of the drivers must be corrected and the electrical crossover filters must be designed to produce an acoustical output from adjacent drivers that is 6 dB down from its passband level. When the coherent acoustical outputs of adjacent drivers are combined, the result is a uniform acoustical output. The polarity of the acoustical outputs is also a Time AlignR crossover. A Time AlignR loudspeaker system must be able to produce acoustical square waves and have a short impulse response. Time AlignR design techniques are shown by practical examples.
Practical considerations in the use of the boundary element method
Authors: Cunefare Kenneth A.
Published: October 2005

The use of the acoustic boundary element method (BEM) is gaining widespread acceptance in industrial applications. This paper will present practical considerations for successful application of the BEM. The major issues which require attention for accurate and reliable modeling of a particular structure, whether existing or under design, include proper mesh selection, geometric modeling, the so-called ‘‘nonuniqueness’’ problem and the methods for its solution and intergration with other modeling programs (e.g., coupled FEM/BEM approaches). Mesh selection relates to the choice of element interpolation order and integration order. Geometric modeling issues include determination of the level of detail required for accurate modeling. The nonuniqueness issue addresses the well-known failure of the unmodified acoustic BEM at certain discrete frequencies. Program integration relates to some potential difficulties that could arise when coupling FEM and BEM programs. Finally, the paper will review some of the particular applications of the acoustic BEM.
Finite element applications in acoustics
Authors: Eversman Walter
Published: October 2005

A review of finite element methods in acoustics is presented. General concepts of FEM such as weighted residual and variational formulations, element types and interpolation within elements, the assembly of elements, continuity of the solution at element boundaries, requirements placed on FEM meshes by high frequencies, the imposition of boundary conditions on rigid, flexible, and absorbing surfaces, the representation of sources, and the approximation of far-field radiation conditions are discussed. The application of FEM to several types of problems in acoustics is demonstrated by reference to published results. Specific examples include: (1) interior problems such as resonant frequencies and forced response in enclosures such as car bodies, aircraft cabins, auditoria, and combustors; (2) sound propagation in moving media in ducts and propagation and radiation in and around aircraft turbofan engines; (3) structure and acoustic interatction such as transmission of sound through aircraft fuselages; (4) acoustic radiation problems which are related to (2) and (3). Emphasis is placed on the physical content of the various problems, mesh generation, the choice of elements, solution procedures, accuracy, and computer resource requirements.
Developing acoustic models for boundary and finite element methods
Authors: Browell James T.
Published: October 2005

The software needed to develop meshes for acoustic boundary element methods (BEMs) and finite element methods (FEMs) are the ones commercially available for structural finite element codes. However, creating a mesh is only the first step to acoustic model development. The analyst must also consider meshing guidelines required and simplifying assumptions allowed by the various solution methods. The density of acoustic analysis meshes is primarily defined by the geometry of the domain boundary and the maximum frequency of the analysis. Accurately describing the distribution of boundary conditions and coupling interfaces also plays a role. While BEMs have distinct modeling advantages over FEMs, BEMs have specialized modeling requirements. In addition, BEM requires the creation of data recovery meshes to display results, because the surface of the model is not usually the point of interest. Simplifying assumptions are made in acoustic analyses to decrease the time for model development. For example, symmetry is used to simplify a problem. In addition, assumptions are made to simulate fully reflective or pressure release infinite planes, such as highways or ponds, sources are used to represent excitation boundary conditions in the far field, and acoustic damping is considered as surface impedance or complex speed of sound.
Numerical methods for gas turbine silencer design
Authors: Ramakrishnan Ramani , Wilson Eric D.
Published: October 2005

Gas turbines are becoming common power producers in small to medium scale power plants. However, the environmental noise impact due to the proximity of these plants to urban centers has become a critical concern and large amounts of silencing are required. Passive and/or reactive elements are commonly used to silence the noise propagating from the turbine exhaust stack. Two factors, namely temperature and low-frequency dominance of the sound spectrum, must be properly accounted for in the silencer design. Simple conventional designs must include the effects of the above two parameters so that appropriate modifications can be incorporated to provide the necessary insertion loss. In this paper, performance evaluation of a passive silencer as well as a reactive silencer using numerical methods will be presented. Finite-element methods (FEM) have been successfully used to predict the performance of passive silencers. Details of the FEM procedure and the necessary temperature modifications will be highlighted. Boundary element methods (BEM) were applied to evaluate the performance of a reactive silencer. Simple tests to verify the results of the multidomain BEM methods were conducted. The results of the BEM procedure and the temperature modifications will also be presented in this paper.
Acoustic radiation prediction of an engine block using a combined finite element method and boundary element method technique integrated with test data
Authors: Garcea Ralph
Published: October 2005

The project discussed in this paper was undertaken to validate the acoustic radiation prediction of engine block noise using a combined FEM and BEM technique, integrated with experimental data. Using a strictly analytical technique, the acoustic results from a BEM analysis will be limited by the accuracy of the velocity boundary conditions generated from structural FEM data. Experimentally determined velocity boundary conditions are more accurate, but they may not be available at every node of the BEM mesh. A new tool has been developed that combines the calculated structural modes of vibration with a limited set of measurement data, to extrapolate velocity boundary conditions on the entire BEM model. A FEM technique is used for the structural analysis and an indirect BEM technique is used to predict noise at some distance from the engine block. Very good correlation is obtained with measured sound-pressure levels. The modal expansion procedure combines experimental and numerical data to provide more velocity boundary conditions for the BEM acoustic analysis. Incorporating the test data helps to define a more realistic excitation and damping in the model, leading to more accurate noise predictions.