bluuebunny/crossref_metadata_2025_split huggingface dataset:
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.
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.
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 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.
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.
A Comparison of the Carding and Processing Performance of 2.25 with 1.5-Denier Cotton/Polyester Opening-Room Blends
Authors: Simpson Jack , Fiori Louis A. 
Published: July 2017

Various levels of cotton and polyester fibers blended during opening and picking were investigated to determine their effect on carding efficiency and processing performance. A medium staple cotton of average fiber properties and a high-modulus polyester (2.25 denier) were used in the blends. Shear friction and compression recovery of the blends increased as the percent polyester increased. For the 2.25-den polyester blends, shear friction was slightly lower and compression recovery practically the same as for 1.5-den polyester/cotton blends. Higher polyester content increased friction and cylinder load, thereby reducing carding action so that the short-term sliver variability and neps of the cotton component in the card web increased. Cylinder load and neps in the card web were lower for the 2.25 than the 1.5-den polyester blends. Higher polyester contents slightly improved yarn grade, and the grades for the 2.25-den were higher than those for the 1.5-den polyester blends. Increased friction and length uniformity of the polyester improved drafting so that second-drawing sliver, roving, and yarn uniformity improved when polyester was added to the blend. Carding waste was practically the same whether using 2.25 or 1.5-den polyester; very little polyester was lost in the waste. At constant end breakage, spinning production increased up to a 50/50 blend and then decreased as the percent of 2.25-den polyester was increased. These findings indicate that for cotton and polyester blended in the opening room, one with a high percentage of cotton can be processed more efficiently than the reverse.
Alcohol Consumption Patterns of Two Cohorts of Italian Men Today and at their Moment of Maximum Consumption
Authors: Guidoni Odillo Vidoni 
Published: July 2017

This article describes the alcohol consumption patterns of a sample of 114 males aged 40–45 and 65–70, and analyzes their alcoholic habits today and in the peak consumption periods they identified. The habits we looked at included a study of the behavior, social and personal context and details that characterized alcohol consumption at any particular moment. This part of the study was conducted by first asking the participants to fill in a questionnaire of closed-ended questions, and then by submitting the participant to a semi-structured open-ended interview where his lifetime use of alcohol was discussed. The data illustrated how the sample diminished its alcohol consumption from the period of maximum consumption up until today, due to a change in drinking habits. A stronger impact on consumption seems to be the drop in drinking regularity, with a reduction in daily consumption and a rise in occasional drinking. The two age groups seem to manifest two different drinking models: the elder one, though having diminished the quantity of alcohol consumed, has largely maintained its drinking patterns of wine and, to a lesser extent, beer. The younger age group has shifted from a pattern in which the prevalent beverage was beer with occasional consumption of high-strength alcohol, which had a largely social role, with relatively frequent episodes of excessive consumption with friends in non-family contexts, to a classic Mediterranean style of consumption very similar to that of the elder age group.
Changes in the Social Meaning of Alcohol Consumption in Italy: A “Privileged” Look
Authors: Beccaria Franca 
Published: July 2017

Explanations of the social mechanisms behind the consumption decline have been discussed and studied with several key informants who, for professional reasons occupied positions allowing them to observe the phenomenon under study: people from the world of alcoholic beverages production, representatives of the union of public facility operators, journalists, dieticians, and physicians. Our “specialist” interview panel members not only confirmed the conclusions that emerged from the individual interviews, but they also introduced partly or entirely new ideas. The experts confirmed that in Italy, wine often held a function of prestige for the younger age group (40–45 years old): wine consumption fell, while favouring more costly and prestigious products, and more attention was given to wine's quality. The attention given to quality was often a signal to others of the social class to which one belonged or aspired. Often it permitted the public to integrate new consumption styles with values established over time. The alimentary-hedonistic style seems compatible with the greater importance being given to health issues that emerged from the interviews with the consumers and key informants. Despite the belief of experts on alcohol that the attention given to alcoholic-related problems in Italy is insufficient, this research has revealed that the mass media, and general practitioners as well, have been paying increasing attention to citizens' overall health.
Studies on the Effect of Waste Dipped and Calendered Nylon Short Fibre on Farm/Tractor Tyre Tread Formulation
Authors: Chandra A. K. , Nizar K. M. A. , Mukhopadhyay R. 
Published: July 2017

The effective utilisation of waste and dipped calendered Nylon fabric in Farm/Tractor tyre tread to improve the tearing and chunking resistance has been studied. Short fibres are made from the waste dipped and calendered nylon fabric and mixed with a standard Farm/Tractor tyre tread formulation in different concentrations. Physical and mechanical properties of the mixes in the longitudinal as well as in the transverse directions, i.e., mill direction and perpendicular to mill direction, were studied. Abrasion resistance, hardness and modulus increase while the tensile strength and fatigue life decreased on increasing the fibre concentration. Tear strength and crack growth resistance are found optimum at 5 phr of fibre loading. A laboratory Banbury trial with 5 phr of calendered fabric, which substituted an equal amount of carbon black, has been found to enhance most of the physical properties without affecting the processability. The positive results obtained in this study point to the potential utilization of this waste fabric, generated by the rubber industry, thereby, providing a substantial improvement in the economy of the industry.