bluuebunny/crossref_metadata_2025 huggingface dataset:
1,1,2-Trifluoroethane (HFC-143):Zero-ODP Blowing Agent for Rigid Polyurethane Foams Using Conventional Dispensing Equipment
Authors: Barthelemy P. P. , Leroy A. , Franklin J. A. , Zipfel L. , Krücke W.
Published: July 2017

For the time being, it is indisputable that the prime blowing agent for rigid polyurethane foams is HCFC-141b. Nevertheless, this transitional substance is already subject to growing political pressure which will lead to restriction of its use early in the 21st century.

Additional efforts are needed to identify zero-ODP blowing agents. Solvay has undertaken a thorough screening of 1,1,2-trifluoroethane (HFC-143), a compound which probably represents the best compromise among zero-ODP fluorocarbons for blowing rigid PUR foams. In this contribution we present evidence for the environmental acceptability of HFC-143, and we discuss its suitability as a PUR blowing agent; in both cases advantages over other possible alternatives are stressed.

Results more specifically pertinent to rigid polyurethane foam blowing indicate that under given conditions and for a given formulation, HFC-143 can be processed much more easily than HFC-134a. In this regard, whilst HFC-134a requires a completely new technology, HFC-143 can be considered to be a practically drop-in substitute for HCFC-22/HCFC-142b blends.
Cyclopentane Blown Foam Systems for Domestic Appliances Application
Authors: Bazzo W. , Cappella A. , Talbot S.
Published: July 2017

During the last year all major European Appliance Manufacturers have chosen the cyclopentane options as blowing agent for polyurethane insulation as the optimum solution for the phase-out of CFCs. The reason for this choice is due to several factors, including: zero-ODP, environmental acceptance, reasonable low initial thermal conductivity, appropriate boiling point and proven availability. These factors outweighed the disadvantage of cyclopentane flammability and the related safety problems.

This paper presents the results of ICI Polyurethanes studies with cyclopentane foam in terms of: • processing and safety, including engineering advice for the modification of existing equipment, storage facilities and handling procedures • the VOC emission during handling and foaming process • the exothermicity of the reaction, overpack and pressure generation • the initial properties of the foam: thermal conductivity and thermal insulation efficiency on the cabinets, mechanical properties, dimensional stability, blowing efficiency and foam flowability • anticipation of long term performances, including diffusion and condensation phenomena, identification of accelerated method for the prediction of aged foam physical properties • the performances in domestic appliances in terms of the aging phenomena, the solubility of the cyclopentane in the PU foam and compatibility with plastic liners • the plasticizing effect on the PU matrix • the aspect related to the environmental impact

This paper also addresses the further developments being carried out with leading appliance manufacturers towards the improvement of key requirements, such as thermal conductivity, foam morphology and mechanical properties.
Determination of the Blowing Agent Distribution in Rigid Polyurethane Foam
Authors: Svanstrom Magdalena , Ramnas Olle
Published: July 2017

The amount and distribution of blowing agent in rigid polyurethane foam were determined by several methods, which are described and compared. A method for solvent extraction with subsequent gas chromatographic analysis was developed and found to be advantageous for CFC-blown foam along with a combustion method (the Schoniger method), where the chloride ions formed were determined by titration. The solvent extraction method was successfully applied to blowing agents in CFC-free foams as well. Three methods involving heating and weight-loss determination were evaluated. They are easy to use, but corrections for thermal decomposition of the polymer are needed. About half of the total amount of CFC-11 in the investigated polyurethane foams from district heating pipes was found to be dissolved in the polymer matrix.
Influence of the Void Fraction on the Mechanical Compression Properties of Foams
Authors: Bledzki A. K. , Gassan J. , Kurek K.
Published: July 2017

Epoxy and polyurethane foams with different content of voids were tested under compression.

Thereby, the epoxy foam showed a simple correlation between the fraction of the foaming agent and the density and void fraction. In contrast to this foam, the density and void fraction of the polyurethane system is additionally dependent on the position in the body of the foam.

The empirical classic correlation and the mechanical modified Gent-Thomas model as models for the calculation of the compression properties of foams showed good agreement between the measured and the calculated values. The empirical model with its materials parameters showed a bigger flexibility.
Load Bearing Response of HR Molded Foam as a Function of Processing and Testing Parameters
Authors: Cavender K. D. , Kinkelaar M. R.
Published: July 2017

There are critical processing and testing parameters which have major impacts upon the apparent firmness of HR molded polyurethane foam. Inadequate control of these parameters hinders the ability of the molder to meet narrow IFD specifications. This paper addresses five of these parameters and defines model equations which are useful in predicting load response to specific control parameters. In addition, the data are presented in a format that should be useful to the molder in better understanding the criticality of each parameter, singularly and in unison. The study was made possible by utilizing specialized equipment which allows accurate determination of IFD measurements under controlled and variable environments.

It is well known that the load bearing responses of HR polyurethane foam are influenced by ambient temperature and humidity. These load bearing responses are generally reversible, and are not the permanent effects often seen as a function of environmental conditions at time of pour and post mold cure of the polyurethane. The idealized cushioning material would be unaffected by either temperature or humidity. Subsequent experimental designs exploring variables in polyol structures were conducted which have resulted in the definition of new high performance polyol systems that demonstrate less sensitivity to the reversible effects of temperature and humidity.
Compression Creep and Long-Term Dimensional Stability in Appliance Rigid Foam
Authors: Yourd Raymond A.
Published: July 2017

Diffusion of gases and condensation of blowing agents can cause the formation of lower-than-ambient pressures inside the cells of closed-cell rigid foam. The net result is a shrinkage force which can cause partial collapse of the cells and dimensional instability of the foam. Computer modeling of the cell gas pressures inside the cells of a typical appliance foam formulation shows that a loss of 1-3 psi of pressure can be due to the loss of carbon dioxide through diffusion out of the cells. An additional 6-9 psi loss of pressure can be due to the condensation of the blowing agent (141b in the present example). This total loss of pressure of 7-12 psi can represent 30-40% of the compression yield strength of the foam, enough to cause dramatic shrinkage in the foam over a period of time. This deformation at low loads and long times is known as creep and is a phenomena common to viscoelastic materials such as polymers.

In the present paper, compression creep experiments were used to study the effects of varying external loads on the deformation behavior of samples of rigid polyurethane foam. A model similar to that used by other researchers to predict the creep behavior of polyurethane foams and thermoplastics was found to agree very closely to the creep data that was obtained. Using this model, the creep behavior could be extrapolated to longer times than those used in the actual creep experiments. HCFC 141b foams showed poorer creep performance than CFC 11 foams when all important parameters, such as density, index and water content, were held constant. This result would agree with evidence from other researchers that HCFC 141b is soluble in the foam polymer causing a loss in mechanical properties.
Low Density Disc Shape Microcellular Polymeric Foams
Authors: Falconer John W. , Nazarov Wigen , Baker Michael J. , Sutton Douglas W.
Published: July 2017

Porous metal oxides discs were used as moulds to produce low density microcellular disc shape foams. The oxide discs were produced by calcination of pressed hydroxide discs in vacuum at 500°C. The porous oxide discs were then impregnated with an appropriate amount of the required polymer solution. By placing the impregnated discs in a "non-solvent," the polymer inside the discs can be precipitated. Subsequent removal of the oxide produced disc shape microcellular foams. Foams made were in the density range of 100-400 mg cm-3, and cell sizes of 1-2 μm were observed. The foams were dried by a critical point drying apparatus, using super critical carbon dioxide, and the shrinkage during drying was small (3-5%).
Improved Aging CO2 Blown Foam for Refrigerators/Freezers
Authors: Grünbauer H. J. M. , Cikut L. , Haworth G. J. , Beerwart A.
Published: July 2017

An industrial trial has been conducted to evaluate aging and energy consumption performance of a new, slow-aging CO2 blown PU foam. A PETG barrier film laminated on the liner sheet and plastic encapsulated powder vacuum panels (PVP's) were included in the trial matrix to measure their impact on aging and energy consumption, respectively.

The CO2 foams produced at 2.31 pounds per cubic foot (2.31 pcf) minimum fill density (37 kg/m3 in metric units) showed excellent structure, lower k-factor and a 10-fold retarded aging effect with respect to conventional CO2 foams. Using current HCFC-141b technology as a reference, initial energy consumption was 15% to 20% higher without vacuum panels but nearly 10% lower with vacuum panels. Within the one year measurement period available so far, aging effects are virtually negligible for the new CO2 foam which is attributed to the combined action of barrier liner and slow aging CO2 foam.

The underlying mechanism for the observed excellent performance is attributed to a lack of condensation effects under service conditions which are always associated with the use of the usual high-boiling blowing agents, such as HCFC-141b and cyclopentane.
New Determination Method of Flowability and Demolding Properties in Polyurethane Rigid Molded Foams
Authors: Kodama K. , Ryoshi H. , Okamura M. , Fujita S. , Fujita J.
Published: July 2017

This paper describes a method of determinating the flowability and demolding property of molded polyurethane rigid foams by the dynamic viscoelasticity spectrometer. In response to periodic stimulations, the dynamic viscoelasticity gives us much physical information of polymers, including flowability and demolding properties. The flowability and demolding property can be determined from viscoelasticities and blowing pressures during the foaming process, which are measured with the newly developed apparatus. With this newly developed apparatus we show measurement examples on many kinds of systems, such as variation of base polyols (different functionalities) and blowing agent (CFC-11, HCFC-141b and cyclopentane), etc..
Commercial Potential for Recycling of Finely Ground Foam in Flexible Polyurethane Foam: A Project of the Polyurethane Recycle and Recovery Council—SPI
Authors: Stone H. , Lichvar S. , Sweet F.
Published: July 2017

Attempts to include ground foam by cryogenic grinding of scrap foams in the production of new flexible polyurethane foams started more than ten years ago. Current work, sponsored by PURRC (Polyurethane Recycle and Recovery Council-SPI), reports on pilot plant and full scale demonstration of the use of foams from a variety of sources, including plant fall off and post consumer foams. Ground foams were produced by cryogenic and mechanical grinding. New foams were produced at two densities and different loading levels while maintaining equal density and IFD to unfilled control foams. The study includes data on dispersion properties of the powders, foam performance and estimated economics.
Five-Year Field Study Confirms Accelerated Thermal Aging Method for Polyisocyanurate Insulation
Authors: Christian Jeffrey E. , Desjarlais André , Graves Ron , Smith Thomas L.
Published: July 2017

In 1989, industry produced some experimental, permeably-faced polyisocyanurate (PIR) laminated board insulation blown with HCFC-141b and a second batch blown with CFC-11, which has undergone continuous field thermal performance monitoring for 5.5 years (June 1989 until February 1995). From these boards, several thin-sliced specimens were prepared and laboratory k-factors periodically measured on these core foam specimens. This work was conducted as part of a six-year joint research project between The Society of the Plastics Industry, Inc. (SPI). Polyisocyanurate Insulation Manufacturers Association (PIMA), National Roofing Contractors Association (NRCA), and the U.S. Department of Energy (DOE) Oak Ridge National Laboratory (ORNL). One of the major research products from this cooperative research effort was the development of an accelerated method for predicting full thickness lifetime thermal conductivities ("in-service R-values") of permeably-faced polyisocyanurate products. This paper compares the prediction of the field installed permeably-faced boards generated from the accelerated aging procedure to the actual measured field performance. The field applications consist of loose-laid boards under ethylene propylene diene terpolymer (EPDM) membranes in a low-sloped roof installed in the ORNL Roof Thermal Research Apparatus (RTRA). For the 5.5 years, each test roof was monitored hourly for temperature and heat flux. This data provides a time series of boundary conditions for a computer program PROPOR ( Properties— Oak Ridge) to compute weekly thermal conductivities. PROPOR is an application of one-dimensional inverse heat transfer analysis. Every six months the test specimens were pulled from the roof and tested under steady state conditions in the laboratory according in American Society of Testing Materials (ASTM) C 518-91. This field validation of an accelerated aging procedure concludes that the thin slicing and laboratory k-factor measurements, within the first six months, accurately predict five years of full thickness, in-situ thermal performance of HCFC-141b permeably-faced polyisocyanurate insulation boards. A computer program was developed which uses the thin slice data set of a specific manufacturer's insulation. The design service life and full product thickness is input, and the in-service R-value is estimated. This value will vary depending on results from the thin slice testing. This work is leading toward an acceptable industry standard to determine the in-service R-value, which is defined as the design thermal resistance of insulation over the normal life of a roof system containing foams which thermally age. At the National Roof Contractors Association 110th Annual Convention Feb. 4, 1997 in Orlando, Florida, the Polyisocyanurate Insulation Manufacturers announced that by January 1, 1998 each PIMA member-insulation manufacturer would have available aged thermal performance data.
Improved Low Thermal Conductivity Fine Cell HCFC-141b Appliance Foam
Authors: Venegas Mauricio H. , Doerge Herman P.
Published: July 2017

The issue of global warming is receiving more attention on the world stage. Carbon dioxide emission from the burning of fossil fuels is suspected of being a major contributor in the phenomena of global warming. In the U.S.A., the National Appliance Energy Conservation Act of 1987 (NAECA) was passed into law, in part to reduce the demand for electrical power, thereby decreasing carbon dioxide emissions from power generating plants. Under the provisions of NAECA, the U.S. Dept. of Energy (DOE) has received authority to further restrict the amount of electricity used by household refrigerators and freezers sold in the U.S.A. The U.S. DOE will probably exercise that authority at some future date. Consequently, the continued development of better insulating HCFC-141b blown polyurethane foams is necessary to meet the future needs of the domestic refrigeration industry.

Initial fine-cell HCFC blown foam systems having low thermal conductivity were first reported by Mobay Corporation (now Bayer Corporation) at the SPI in 1990. These early systems had high densities and long demolding times. Then, in 1991, at the SPI, Mobay Corporation reported a foam system with reduced demolding times comparable to commercial CFC-11 blown foams. But the high density of this foam still impeded it from becoming a commercially viable system. In 1992, at the SPI, Miles Inc. (now Bayer Corporation) reported a polymeric MDI HCFC-141b foam system with an initial core k-factor of 0.115 Btu-in./hr. ft2°F, a freeze stable density of 2.23 pcf, and an improvement in demolding properties over commercial CFC-11 blown foam systems. This system, in spite of its good k-factor and density, did not pass a cabinet freeze stability test due to foam cracks. Further improvements led to commercial HCFC-141b foam systems in 1994 which had initial core k-factors of approximately 0.117 Btuin./hr. ft2°F and densities of approximately 2.15 pcf. Cell diameters were around 194 microns.

This paper will describe a new system of finer cell polymeric MDI-based HCFC-141b blown foam. It has been tested commercially on cabinets and doors, showing a 3.4% reduction in initial core k-factor and a 2.8% reduction in reverse heat leak as compared with a standard MDI/HCFC-141b blown foam system. The system has an initial core k-factor of 0.113 Btu-in./hr. ft2°F and a freeze stable density of 2.25 pcf. The cell diameter was reduced by 15%, which lowered the radiative heat transfer. Also, lower water levels produced less carbon dioxide, further reducing the thermal conductivity due to less heat transfer by cell gas conduction.

This development is of particular interest for appliance manufacturers who may need an extra boost to lower refrigerator energy consumption to be in compliance with the energy consumption regulations established for the products sold in the U.S.A. It can also help manufacturers' products qualify for energy efficiency rebate programs sponsored by the utility companies.
HFC-245fa as a Blowing Agent for the Appliance Industry
Authors: Logsdon P. B. , Parker R. C. , Williams D. J.
Published: July 2017

HFC-245fa (1,1,1,3,3-pentafluoropropane) has been under development by AlliedSignal since 1994 as a potential replacement for HCFC-141b in blowing agent applications. During 1996, a great deal of work took place that compared the physical properties of appliance foams prepared with HFC-245fa versus other blowing agents. During 1997, it is anticipated that ongoing performance optimization work will enable appliance manufacturers to conduct plant trials using HFC-245fa as the blowing agent.

The domestic refrigerator appliance industry is under a time constraint to make a transition to a third generation blowing agent, such as HFC-245fa, by January 2003. In addition to the phase out of HCFCs, Department of Energy regulations will mandate an increase in the energy efficiency of refrigerators effective July 1, 2001. Needless to say, the development time for the appliance industry is short.

Further optimization studies will enhance the insulation value and physical properties of foams blown with HFC-245fa. Development work is also being performed that examines the overall system, that is, the interaction of HFC-245fa foam blown into the walls of a refrigerator. This paper will discuss the results of a freeze stable density study using HCFC-141b and HFC-245fa as blowing agents. Results from a surfactant screening study that examines flowability will be reviewed. In addition, modeling of blowing agent diffusion into a refrigerator will be discussed. This work is part of a continuing effort by AlliedSignal to develop a blowing agent replacement for HCFC-141b that meets the needs of our customers well into the future.
Chemical Recycling of Polyurethanes and Applications for the Recyclates
Authors: You K. K. , Durocher D. T. , Kierkus P. Ch. , Fishback T. L.
Published: July 2017

The recycling of thermoset materials, including polyurethane, has always posed unique challenges. Traditional approaches to recycling such materials include mechanical regrinding and the use of the regrind as filler. Chemical recycling of polyurethanes by such means as hydrolysis, aminolysis, and glycolysis, is for the most part considered economically uncompetitive compared to formulating with virgin raw materials. To protect our environment and avoid land filling with polyurethanes, BASF has invested resources and technology to develop what are believed to be practical approaches to the chemical recycling of polyurethane process and end-of-life waste. Initially, we employed the well-established glycolysis technology developed at BASF Schwarzheide, Germany. BASF Corporation's Wyandotte, MI, Laboratory has continued research and development in this area, concentrating on modifying the chemistry and process to suit our polyurethane customers in North America. Our second generation chemistry results in homogeneous recycled polyols with residual amine content of less than 0.1% in a "one-pot" process operating at ambient pressure and moderate temperatures. Further, it eliminates the need for installing sophisticated control mechanisms and minimizes the separation and disposal of any hazardous materials. Recyclate products made from RIM waste streams were to be available commercially in the fall, 1997.

The properties of the recyclate are generally dependent on the properties of the polyurethane waste stream. A glycolysate from a high density non-cellular rigid polyurethane, made using the second generation technology, can be reformulated into a variety of rigid and semi-rigid foams at up to 100% polyol loading while providing excellent mechanical and physical properties in the finished product. Examples include polyisocyanurate foam, insulation non-critical foam, structural foam, friable energy absorbing foam, low density void filling foam, elastomeric coatings, rigid non-cellular polyurethane, and molded semi-flexible foam. This paper describes our efforts in chemical recycling of polyurethane waste streams and our success in incorporating the resultant glycolysates into a wide variety of polyurethane products.
Evaluation of HFC-245fa and Pentanes in Polyisocyanurate and Polyurethane Laminated Panel Rigid Foam Formulations
Authors: Rossitto F. C. , Adam N.
Published: July 2017

The laminated panel industry in both the United States and Europe has successfully converted from chlorofluorocarbons (CFC) to alternative blowing agents. The U.S. markets championed HCFC-141b, while the European markets concentrated on pentane. Since the production and use of HCFCs will be phased out worldwide by the year 2020, all alternative non-chlorinated blowing agents with zero ozone depletion potential (ODP) and low global warming potential (GWP) need to be evaluated to determine which blowing agent candidates are best suited for the different rigid foam applications. It is crucial for researchers in this field to develop products which meet these stringent criteria to ensure the continued growth of the polyurethane rigid foam industry.

Our current emphasis focuses on HFC-245fa and the normal, iso-, and cycloisomers of pentane. As was experienced with the conversion from CFC-11 to HCFC 141b, there are many potential technical challenges associated with blowing agent conversion. These challenges need to be explored by experimentation to ensure a smooth transition into the next generation of blowing agents. At the 1995 and 1996 SPI conferences, work from handmix and full-scale panel evaluations, respectively, was presented which compared properties of foams processed with HFC-245fa to those processed with HCFC-141b. The next phase of our evaluation is to compare foams processed with HFC-245fa to those processed with normal, iso-, and cyclo-pentanes. This paper details a comparative study of these blowing agents in polyisocyanurate and polyurethane rigid-foam systems which currently use HCFC-141b. Full-scale panels were processed on a pilot-scale laminator and were tested for end-use properties.
The Mechanical Properties of Conventional and Auxetic Foams. Part I: Compression and Tension
Authors: Chan N. , Evans K. E.
Published: July 2017

Auxetic foams exhibit the unusual property of a negative Poisson's ratio and hence expand laterally when stretched. In this, the first of two papers, a systematic study is made of the mechanical properties of a range of foams fabricated to have different negative Poisson's ratios. The stress-strain behaviour, in both tension and compression, is compared with conventional foams. Values for the Young's moduli and Poisson's ratios in the three principal directions, in both tension and compression, are obtained. Negative Poisson's ratios ranging between -0.2 and -0.9 in tension, and between -0.1 and -0.8 in compression have been obtained. The effect of densification, during loading is significantly enhanced in auxetic foams, and this significantly affects the stress-strain curves. The creep resistance of the foams is also examined.
A Non-Isothermal Model to Study the Influence of Blowing Agent Concentration on Polymer Viscosity and Gas Diffusivity in Thermoplastic Foam Extrusion
Authors: Ramesh N. S. , Malwitz Nelson
Published: July 2017

This fundamental study focuses on the influence of blowing agent on bubble growth during thermoplastic foam extrusion. The extruded molten mixture expands and cools simultaneously when exposed to ambient conditions. The bubble growth is influenced by the concentration-dependent blowing agent diffusion coefficient, transient cooling of the expanding foam, influence of blowing agent on polymer viscosity, and the escape of blowing agent from the surface of the foam. Previous models in the literature do not consider these significant influences. A model is presented accounting for those more subtle effects. In addition, a new experimental technique is described to collect experimental bubble growth data. Predictions of the new model reasonably agree with the experimental data.
Modeling of Diffusion in Closed Cell Polymeric Foams
Authors: Alsoy Sacide
Published: July 2017

Closed-cell foams made of polymers have the lowest thermal conductivity of any currently available insulation material other than vacuum insulation systems. The increase of foam conductivity with age occurs as air diffuses into the foam while the blowing agent diffuses out, thus modifying the cell gas composition. Also, the change in cell gas composition influences the dimensional stability of the foams. To predict the long term aging behavior and dimensional stability of these foams, the diffusion characteristics of the different components need to be known. Several models exist in the literature which describe diffusion in foams. The most popular of these models are reviewed, and effective diffusivities predicted from one model are compared with experimental data. An unsteady state model is then proposed and solved numerically using a finite difference scheme. The numerical solution algorithm is developed to efficiently solve the large number of coupled equations resulting from this model. The uptake curves predicted from both the unsteady-state model and a discrete model (Bart and Du Cauze De Nazelle, 1993) are compared with available experimental data for the polystyrene-nitrogen system. From the analysis of uptake curves generated for different numbers of cells, the effective diffusivity of the PS/N2 system is predicted. Also, the effect of initial cell gas composition and cell size on both the long term aging profile and dimensional stability of polyurethane foam is considered. The proposed model can easily be extended to include the influence of blowing agent concentration on diffusivity in the polymer phase and the isotherm describing the distribution of blowing agent between the gas and polymer phases.
The Next Generation Blowing Agents: From One Single Product to a Product Range
Authors: Zipfel L. , Barthtlemy P , Dournel P
Published: July 2017

In the context of the HCFC-141b phase out, the two candidates HFC-365mfc and HFC-245fa have been selected over the last few years, as reported in previous papers.

Since our last presentation, a lot of work has been performed to increase our knowledge of these new products and to study their behavior in various applications.

Although HFC-365mfc and HFC-245fa are promising candidates, a single HFC blowing agent cannot match all the outstanding characteristics of traditional fluorocarbon blowing agents: right boiling point, non flammability, cost effectiveness..., to name but a few. It is very unlikely that a single blowing agent will cover all the future needs of the polyurethane industry. Such a trend is already seen today with at least seven physical blowing agents finding commercial applications in the different sectors of the industry (HCFC-141b, HCFC-22/HCFC-142b, HFC-134a, cyclopentane, pentane or isopentane).

The main reason why HFC blowing agents will be used in the future is their ability to give foams with optimized thermal conductivity. However, because of possible condensation phenomena at low temperature for relatively high boiling blowing agents, the rating of different blowing agents is a function of temperature.

We have now measured foam thermal conductivity over the temperature range between -20°C and +45°C for several blowing agents, including HFC-245fa, HFC-365mfc, pentane isomers and blends thereof. Included in this study are the newly discovered low boiling azeotropes of HFC-365mfc with all three pentane isomers.

In this paper, we will especially show that the evolution of thermal conductivity with temperature can be a very good selection criteria to find the most appropriate blend for a specific application.
Adhesive behaviour of carbon fibre reinforced plastic panels manufactured using woven and unidirectional tape after ultraviolet laser surface treatment
Authors: Botana-Galvín Marta , Blanco Ginesa , González-Rovira Leandro , Rodríguez Miguel A , Botana Francisco J
Published: July 2017

This paper describes the results obtained when ultraviolet laser treatment was performed as a surface treatment prior to adhesive bonding for two aeronautical carbon fibre-reinforced plastics based on an epoxy resin prepreg. Different laser-processing parameters were employed, and their effect on the surfaces was analysed through morphological characterisation and wettability studies. X-ray photoelectron spectroscopy measurements were performed to determine the cleaning and activation effects of the treatment. The strength of the bonded joint was studied for laser-treated and manually ground samples. Samples processed under the selected laser conditions exhibited better adhesive behaviour than the manually treated samples, thereby suggesting that ultraviolet laser treatment could be used as an alternative method for surface activation of aeronautical composites based on epoxy resins.
Judicial Studies Board Specimen Directions and the Enforcement of Orthodoxy: A Modest Case Study
Authors: Munday Roderick
Published: July 2017

Judges summing up to juries in criminal cases must deliver directions on a wide range of issues, substantive and evidential. The Crown Court Bench Book, issued by the Judicial Studies Board, publishes specimen directions, designed to ensure that juries are correctly directed on the legal rules that they must apply to the facts. Judges were never meant to follow these directions ‘mechanistically’. Several decisions of the Court of Appeal would suggest otherwise. This article offers a critique of two recent decisions, involving good character directions, where the Court of Appeal has again enforced strict adherence, and argues for a greater degree of judicial autonomy.
A Comparative Study of two Hesitation Phenomena
Authors: Goldman-Eisler Frieda
Published: July 2017

The durations of hesitation devices such as the sounds /α, ∊, æ, r, ∂, m/, also called filled pauses, were measured and compared with the durations of silent hesitations or unfilled pauses. Their individual consistency and psychological significance were also investigated and the relation to uncertainty of filled pauses and unfilled pauses respectively was compared. It appears that under certain conditions of speech production the two hesitation phenomena reflect different internal processes.
The Identification and Discrimination of Synthetic Vowels
Authors: Fry D. B. , Abramson Arthur S. , Eimas Peter D. , Liberman Alvin M.
Published: July 2017

A series of thirteen two-formant vowels was synthesized and used as the basis of labelling and discrimination tests with a group of English-speaking listeners. The sounds varied only in F1/F2 plot and the resulting vowel qualities were such that listeners found no difficulty in assigning each sound to one of three phonemic categories, those of the vowels in bid, bed and bad. The results of the tests were compared with those previously obtained in experiments involving the consonant phonemes /b, d, g/.

It appears from the data that the phoneme boundaries in the case of the three vowel phonemes are less sharply defined than in the case of the stop consonants. The labelling functions for the vowels show a gradual slope and the discrimination functions do not show any marked increase in sensitivity to change in the region of the phoneme boundaries. It is clear also that the listeners were able to discriminate differences very much smaller than would need to be distinguished simply in order to place vowels in the appropriate category. The results show further that the effect of sequence or acoustic context in the perception of vowels is very considerable.

In all the aspects examined in these experiments, the perception of synthetic vowels is found to be different from that of synthetic stop consonants. These differences lend some support to the hypothesis that the degree of articulatory discontinuity between sounds may be correlated with the sharpness of the phonemic boundaries that separate them.
Hesitation Pauses and Juncture Pauses in Speech
Authors: Boomer Donald S. , Dittmann Allen T.
Published: July 2017

A psychophysical comparison of speech pause perception thresholds for juncture and hesitation pauses yielded significantly lower thresholds for the latter. On the basis of these and other data, a functional and methodological distinction between these two types of pause is proposed.
Preferences of Phonetic Stimuli
Authors: Enkvist N. E. , Lindman R.
Published: July 2017

Eight types of recorded phonetic stimuli were presented to Finnish-speaking and Swedish-speaking students of Finnish universities. Four of these stimulus types consisted of wholly artificial, partly controlled and partly randomized sequences of Finland-Swedish speech sounds; two were more similar to Finnish and two to Swedish, having been obtained by scrambling either the vowels or the consonants of samples of Finnish and Swedish texts, respectively. It was found that (1) the ratings of Finnish and Finland-Swedish listeners were relatively consistent when the stimuli differed radically from Finnish and Finland-Swedish, but tended to vary more when stimuli were more similar to these two natural languages; and that (2) the consonant/vowel ratio and syllabic structure had a greater influence on aesthetic preference than the front vowel/back vowel ratio.
Supraglottal Air Pressure in the Production of English Stops
Authors: Lisker Leigh
Published: July 2017

Generally higher levels of intra-oral air pressure during occlusion are regularly reported for English /p,t,k/ as compared with /b,d,g/, and considerable significance has been attached to such observations, particularly by phonologists. Many of the published bodies of data, however, represent quite limited speech samples, consisting in the main of short nonsense utterances which contain stops in only a few contextual situations. In the present study ten readings of a list of twenty short English phrases were recorded for a single speaker. The phrases contained stops in initial, medial and final positions, and under various conditions of stress. A pressure transducer mounted at the end of a nasal catheter was introduced into the pharynx, and variations in intra-oral pressure were recorded on a multi-channel penwriter. From the pressure records obtained it appeared that /p,t,k/ and /b,d,g/ differ in their mean peak pressures, but that this difference is not equally significant in all contexts. Both initially and medially before a stressed vowel the two categories show peak pressures that overlap very extensively. This makes questionable the view that such differences more regularly co-exist with the /p,t,k/:/b,d,g/ distinction than any difference in voicing or mode of laryngeal operation, and that they demonstrate the " fortis ":" lenis " nature of the distinction.
General Language Deficits in Children With Articulation Problems
Authors: Whitacre Janet D. , Luper Harold L. , Pollio Howard R.
Published: July 2017

Sixteen 7 year-old children with normal articulation, and sixteen 7 year-old children with defective articulation were compared as to their performance on series of language tests designed to assess the child's knowledge of form class, sentence structure, and phonological composition in English. Results showed that children in the defective articulation group gave significantly fewer paradigmatic responses in a word-association test, were less able to discriminate possible from impossible phoneme sequences in English, and were able to repeat fewer sentences correctly than children in the normal articulation group. These results are discussed in terms of their implications for present articulation therapy, which stresses the production of individual sounds and often provides little or no remedial experience in the wider aspects of language usage such as would seem required by results of the present study.
Pitch, Politeness and Sexual Role: An Exploratory Investigation into the Pitch Correlates of English and Japanese Politeness Formulae
Authors: Loveday Leo
Published: July 2017

This paper reports a preliminary investigation into the pitch correlates of politeness formulae produced by Japanese and English informants of both sexes. Significant pitch differences in the expression of politeness occur between the two language communities: The Japanese female subjects adopt an extremely high pitch clearly separating themselves acoustically from Japanese males in the same circumstances, while English male pitch is considerably less differentiated from English female pitch. These pitch differences arise, it is suggested, because of a contrasting sociosemiotic function assigned to pitch in the two speech communities whereby Japanese high pitch is typically reserved for the enactment of female roles while English high pitch is adopted by both sexes to express politeness.
Simultaneous Measurements of Vowels Produced by a Hearing-Impaired Speaker
Authors: Mcgarr Nancy S. , Gelfer Carole E.
Published: July 2017

Perceptual judgments, acoustic measurements and electromyographic (EMG) records were obtained for one deaf speaker producing the vowels [i, I, æ, a, u, u] in an [hVd] frame. Overall listener judgments were consistent with spectral measurements. In general, front vowels were perceived as more similar to targets than back vowels, and high vowels were perceived correctly more often than low vowels. Experienced and inexperienced listeners were found to differ significantly in their categorization of the point vowels [i, æ, a, and u] but not for [I and u] . The vowel space, as determined by the formant frequency measures, was reduced with respect to normal values particularly in the region appropriate to high back vowels. However, EMG records of genioglossus and orbicularis oris do not entirely account for the perceptual and acoustic data. In particular, genioglossus activity is relatively undifferentiated across all vowels when compared to data from normals. The results of this study generally support the widespread notion of reduced vowel space secondary to a reduced range of tongue movement in this deaf speaker. The physiological records were also characterized by a significant degree of variability from token to token. In this regard, these data are different from acoustic and physiological patterns that have been previously reported for vowels produced by deaf speakers.
Basic Colour Terms in Literature
Authors: McManus I.C.
Published: July 2017

It is shown that the use of colour words in poetry and literature correlates closely with the order of evolution of colour words, as described by Berlin and Kay. This relationship is independent of the overall frequency of colour word usage. A review of other literature suggests that a number of the psychological aspects of colour naming correlate closely with the Berlin and Kay ordering.
Multiple Determinants of a Stigmatized Speech Style: Women's Language, Powerless Language, or Everyone's Language?
Authors: Rubin Donald L. , Nelson Marie Wilson
Published: July 2017

Previous research identifies a number of factors associated with a socially stigmatized speech style known initially as "women's language" and subsequently as "powerless language." This study examines the effects of speaker sex, socio-economic status, ability, communication apprehension, rigidity, and question type on the incidence of 16 style markers and on verbosity in simulated job interviews. Results reveal limited evidence of the impact of social and psychological factors, but pervasive potency for question type. Open questions constitute an element of interaction structure that engenders expressions of tentativeness and uncertainty. Under these circumstances, it is more reasonable to change dysfunctional linguistic stereotypes than common, contextually induced language behaviors.
The Use of Threats in Children's Discourse
Authors: Benoit Pamela J.
Published: July 2017

This study investigates the nature of threats and their responses as collaborative units in children's discourse. Coding of conversations between preschool children yields frequency data that suggest that assertions provoke threats while offensive threats are produced more than defensive threats. Analyses of types of threats indicate a preference for expressing harm to the interactional partner or intending to withhold an object or action from the partner. The partner most frequently responds to the threat with a rejection thereby countering the speaker's attempt to control. The sex of the interactant does not influence the frequency of threats, but it does affect the type of threat as female children show a clear preference for withhold-object or action and harm-threats while male children focus exclusively on harm-threats. Younger children produce more threats than older children and threats occur more frequently in child-directed settings compared to adult-directed settings.
Cognition and Talk: The Relationship of Semantic Units to Temporal Patterns of Fluency in Spontaneous Speech
Authors: Greene John O. , Cappella Joseph N.
Published: July 2017

This paper reports two studies concerning the relationship of temporal rhythms in speech fluency to the ideational content of the discourse. Action assembly theory is employed to advance the prediction that when subjects are not allowed to prepare speech in advance of actual production, there will be a tendency for ideational boundaries to be associated with a decrease in speech fluency. This relationship was hypothesized to be attenuated, however, when the structure of the discourse (as opposed to the content) has been prepared in advance. The first prediction was borne out in Experiment 1 in that five of seven ideational boundaries were found to be associated with a decrease in speech fluency (at p < 0.10). Experiment 2 showed that this relationship was, indeed, attenuated under conditions of structural preparation in advance of speech.
Viewing The Development of Speech Perception As An Innately Guided Learning Process
Authors: Jusczyk Peter W. , Bertoncini Josiane
Published: July 2017

The present paper examines the issue of how speech sounds may be treated by infants as special signals relative to other kinds of acoustic stimuli. Consideration is given to the view that the mechanisms underlying the infant's perception of speech are specialized for this purpose. Some of the difficulties of providing definitive evidence for or against this position are noted. Then the thesis is advanced that special processing of speech may lie in the inherent salience which such sounds have for infants. in particular, it is suggested that the development of speech perception follows the course of an innately guided learning process. One key assumption of this view is that speech sounds may be more apt to attract attention or have a higher priority for further processing than other types of acoustic signals. Recent evidence from a number of new paradigms for studying infant speech perception is reviewed in light of this position. The paper concludes with a discussion of how findings concerning the development of speech perception during the first year of life fit with the innately guided learning view.
Prosody as a Marker of Information Flow in Spoken Discourse
Authors: Swerts Marc , Geluykens Ronald
Published: July 2017

This study concerns the role of prosody in the structuring of information in monologue discourse, from the point of view of production as well as perception. Two prosodic variables were investigated: speech melody and pauses. Melodically, it was found that local intonation features (falling vs. rising tones) are employed to indicate discourse boundaries. On a more global level, speakers appear to use relative height of pitch peaks and of average pitch values as markers of information units. Furthermore, speakers manipulate both the distribution of pauses and their relative length to mark information flow. A perception experiment was carried out to evaluate the perceptual impact of both speech melody and pauses. It was found that, in the absence of semantic cues, both melodic and pausal information is used by listeners to process the incoming signal in terms of discourse structure.
Syllabification of Bisyllabic Nonwords: Evidence from Short-Term Memory Errors
Authors: Treiman Rebecca , Straub Kathleen , Laver Patrick
Published: July 2017

Do errors in short-term memory for spoken stimuli sometimes combine one syllable from one to-be-remembered item with one syllable from another to-be-remembered item? If so, can the errors shed light on how the stimuli are syllabified? We report three experiments in which college students tried to recall five-item lists containing two CVCVC (consonant-vowel-consonant-vowel-consonant) nonwords and three filler digits. When the second vowel of the nonword was stressed, recombination errors tended to blend the initial CV of one nonword with the final CVC of another, especially if the middle consonant was an obstruent. When the first vowel was stressed, the error pattern depended on the type of vowel. CV/CVC recombinations were more common for tense vowels than for lax vowels. In general, CV/CVC recombinations tended to be more frequent relative to CVC/VC recombinations when the middle consonant was an obstruent than when it was a sonorant. The findings are discussed in relation to linguistic theories of syllabification and the results of previous experiments using metalinguistic tasks.