bluuebunny/crossref_metadata_2025_split huggingface dataset:
Polyurethane: The Material of Choice for Occupant Protection and Energy Management
Authors: Yu-Hallada Lorraine C. , Kuczynski Edward T. , Weierstall Mark 
Published: July 2017

National Highway Traffic Safety Administration (NHTSA) is mandated to promote improvements in automotive occupant protection by specifying vehicle crash-worthiness regulations in terms of forces and accelerations measured during test crashes. A primary focus of these Federal Motor Vehicle Safety Standards (FMVSS) has been in the area of energy-management during the "second collision"—the collision between the occupant and the automotive interior. As relevant to energy-absorbing materials, regulations are continuously being revised and upgraded: FMVSS 201, head impact [HIC(d)] for pillars, roof rails, visors and instrument panels; FMVSS 208, passive restraint for head, upper-thorax and upper-leg protection; FMVSS 213, for child safety seats; FMVSS 214, for side impact protection; and FMVSS 218, for motorcycle helmets. In addition, manufacturers need to be concerned about the potential product liability for enhanced injuries due to the "second collision" when superior alternate materials are technologically available and commercially practical. As a result of these demands to improve occupant protection through energy-management materials, it was necessary to examine those that may find use in these applications, including: expanded polypropylene (EPP), expanded polystyrene (EPS), expanded polyphenylene oxide/polystyrene (EPPE/PS), and polyurethanes (PU). The areas of examination and analysis are dynamic impact and static compression testing; -physical properties; flammability; dimensional stability and energy-absorption as a function of temperature; and chemical resistance. The advantages of polyurethane technology are in its versatility, diversity and adaptability to customer and application needs. Energy-absorbing polyurethanes have properties (e.g., low weight, moldability, relative temperature insensitivity) which allow the automobile manufacturers greater design flexibility at lower cost. Whereas thermoplastics have the one-dimensional ability to vary energy-absorption profiles only through density adjustment, polyurethanes can be customized to meet an infinite variety of energyabsorption profiles and performance characteristics through adjustments in either density and/or polymer structure. Energy-management polyurethanes can be produced as: rigid foams, friable or crushable; recoverable semi-rigid foams; or visco-elastic foams. The object of this paper is to compare the physical properties and impact performance characteristics of EPP, EPS, EPPE/PS, and rigid and recoverable polyurethane foams. The results will show that energy-management polyurethane foams have performance properties which make them particularly suitable for occupant protection applications.
Polyurethane-Based Aerogels for Use as Environmentally Acceptable Super Insulants in the Future Appliance Market
Authors: Biesmans G. , Randall D. , Francais E. , Perrut M. 
Published: July 2017

ICI Polyurethanes has talked extensively about the introduction of VACPAC* panels (polyurethane-based vacuum insulation panels) into the appliance market. Details have been presented at previous SPI and Utech meetings. In the meantime, extensive field tests have been carried out and, recently, several commercial models have been launched based on "VACPAC" panel technology. Researchers all over the world are now working on a next generation super-insulation material called aerogels. Aerogels are lightweight, air-filled materials with a low thermal conductivity. The microporosity of these materials greatly reduces the air conductivity. Most of these materials are silica based and rather brittle in nature. Some work has been reported on organic polymeric aerogels. We have now completed the laboratory development work of polyurethane- and polyisocyanurate-based organic aerogels. These materials offer a thermal conductivity of 7 mW/mK at a modest vacuum of 10 mbar. When no vacuum is applied, and the aerogel is completely filled with air, the thermal conductivity is 22 mW/Mk. This paper describes the factors that have been optimized to develop an aerogel material which, in the long term, it is believed, will be a viable filler material in moderate vacuum technology. The project has been focused towards the appliance industry where energy requirements are becoming more and more stringent.
Tailoring the Performance of Molded Flexible Polyurethane Foams for Car Seats
Authors: Casati F. M. , Herrington R. M. , Broos R. , Miyazaki Y. 
Published: July 2017

The automobile seat is a major element of contact between the occupant, the vehicle and ultimately the road surface. Flexible polyurethane foams are the material of choice for this application, not only because of the economies offered by large scale operations, but also because the cushioning characteristics of the foam/seat assembly can be adjusted. Commercially useful foams can be made from a variety of polyurethane molding chemistries. Recent advances in polyol and copolymer polyol technology, together with multiple isocyanate choices and even new foam manufacturing technologies, present the foam producers, seat assemblers and seat designers with a myriad of options. The automotive original equipment manufacturers (OEM's) worldwide are looking for optimization of the balance between foam weight and foam specifications, with more emphasis than ever on comfort and durability. This goes with specific requirements for the various foam pads, i.e., front cushion, rear cushion, front back-rest and rear back-rest. This paper presents new data showing how the choice of molding chemistry impacts not only foam processing and physical properties, but also the comfort and durability that can be expected from the final seat assembly. Results from recent studies carried out by The Dow Chemical Company on a global basis and concentrating on static and dynamic fatigue, resiliency, vibration damping characteristics and humid aging, are presented in an effort to provide foam producers and users worldwide with up-to-date information useful in helping them to meet their present and future performance targets.
Hydrocarbon Blown Rigid Polyurethane Foam for the Boardstock Industry—A Novel Approach
Authors: Berrier R. E. , Singh S. N. , Costa J. S. , Bonapersona V. 
Published: July 2017

A challenge facing rigid polyurethane foam insulation today is the development of foam formulations and processing technologies that use blowing agents which are environmentally acceptable and produce foam having an excellent balance of properties. Rigid polyurethane foams are known for their outstanding combination of density, thermal resistivity, structural and fire performance, and cost-effectiveness. Such attributes are essential for, maintaining a competitive edge over alternate insulation materials. Currently, hydrocarbons and HFCs are the two leading classes of blowing agents under consideration to replace HCFCs. The benefits and challenges for each of the viable blowing agents are well known. This study focuses on hydrocarbon blown foam where the primary challenge is to meet the required regulatory firetests together with providing superior aged thermal resistance and structural performance at low densities. Learning from the ongoing commercial production with pentanes in Europe as well as from prior published works, this study systematically looks at the effects of selected polyurethane formulation and processing variables on the key polyurethane foam and laminate board performance characteristics. Formulation variables examined include pentane composition, index, and fire retardant. Processing variables examined include temperature, laydown, and the physical state of the blend. Physical properties of the laminate board and foam are discussed. ASTM E84 and Factory Mutual Calorimeter test results are presented. The results are analyzed keeping in perspective findings from years of experience with CFC-11 and HCFC-141b blown foam. Based on these evaluations, this paper outlines the key material and processing requirements for the successful use of hydrocarbon blowing agents in the North American boardstock industry.
HFC-365mfc: A Versatile Blowing Agent for Rigid Polyurethane Foams
Authors: Zipfel L. , Börner K. , Krücke W , Barthélemy P , Dournel P 
Published: July 2017

HFC-365mfc and HFC-245fa are now well documented as promising blowing agents, and their production will come on stream in a few years. However, none has the same ideal boiling point as CFC-11 or HCFC-141b. Blends may offer the best compromise to customize the different end-use requirements. Two different directions for further developments have emerged from our work: Two binary, non-azeotropic blends of HFC-365mfc with HFC-245fa or HFC-134a open the door to non-flammable blowing agents with a convenient boiling point in the range of 20 to 25°C (depending on actual composition) and a very good gas phase thermal conductivity. These new blowing agents could be safely used in the same manner as CFC-11 or HCFC-141b, but would be the most expensive option in the series of blowing agents currently under examination. It would fit the needs of foamers looking especially for non flammability (ease of handling, low investments) and optimized foam thermal conductivity. Three low boiling, binary azeotropes have been found with HFC-365mfc and the three pentane isomers (n-, iso-, and cyclo-pentane). Although these azeotropes are flammable, they open the door to more cost effective formulations with improved properties over formulations blown with straight pentane. It is anticipated that each mixed blowing agent now under investigation will find applications in specific end-uses. HFC-365mfc appears to be a key building block to design a full range of blowing agents which offers a wide flexibility to system houses and polyurethane foamers, both in the direction of non flammable or flammable blowing agents. Semi industrial trials with the blends and industrial trials with straight HFC-365mfc are reported as a practice related example of the suitability of these blowing agents.
Liquid Carbon Dioxide Foaming in Flexible Slabstock Foam Production—A Challenge to be Met with New Structural Building Blocks
Authors: Burkhart G. , Langenhagen R. , Weier A. 
Published: July 2017

The introduction of liquid carbon dioxide foaming into the production of polyurethane foams a few years ago created a challenge for the whole industry. That is true for the equipment as well as for the raw material suppliers-and especially so for any additive supplier. The new foaming technology created a demand for processing conditions and ingredients that would meet the challenge of providing the additional nucleation required without sacrificing other important performance aspects. The important role of the surfactant used has been recognized even with the start of this future-shaping technology. This alone justified a higher interest in the questions "How do the different structural parts of a surfactant molecule influence its performance?" and "Which structural pattern is useful for the controlled design of surfactant performance for the new level of nucleation needs?" To keep other vital performance aspects, these structural patterns then have to be combined with the polydimethylsiloxane-polyether-copolymer structure of foam surfactants commonly utilized today which are mainly based on a combination of just three structural units: the methyl substituted siloxane backbone as well as a sophisticated combination of ethylene oxide and/or propylene oxide forming the attached polyethers. This paper will describe our work in the liquid carbon dioxide field and the resulting structure-performance relationships of flexible slabstock polyurethane foam surfactants. It will also link those structure-performance relationships to different possible applications like fr-or non-fr-foams. A number of building blocks will be introduced for the novel design of these performance additives. Especially in view of further industrial trends, these novel structural units should open up the possibility for new foam surfactants with adjusted and improved performance profiles.
A Review of Some Alternative Approaches to Drug Management of Hyperactivity in Children
Authors: Walden Everett L. , Thompson Sheila A. 
Published: July 2017

Numerous theories concerning the etiology of hyperkinesis have been proposed in recent years, adding to the mystery of this syndrome. But, regardless of causation, the most outstanding symptom of hyperkinesis-hyperactivity-remains a problem for educators and parents. The most common treatment for hyperactivity has been the use of psychotropic drugs, and is seen by many as a panacea for resolving hyperactive behavior problems. The rationale for their use is that if drugs can help decrease the symptoms of hyperactivity and increase the benefits of educational exposure, then drug therapy has served a useful purpose. Since some children experience negative side effects, and the long-term consequences of chemical management have not been thoroughly investigated, drug therapy should be considered a more extreme alternative to nonmedical management. Available intervention techniques for treating the hyperactive child include a wide range of alternatives to chemical management and should be used whenever possible prior to the initiation of chemical intervention.
Segment Inventories for Speech Synthesis
Authors: Sivertsen Eva 
Published: July 2017

Speech synthesis may be based on a segmentation of the speech continuum either into simultaneous components or into successive time segments. The time segments may be of varying size and type: phonemes, phoneme dyads, syllable nuclei and margins, half-syllables, syllables, syllable dyads, and words. In order to obtain an estimate of the size of the segment inventory for each type of segment, a phonological study was made of the particular phoneme sequences which occur in English, particularly in relation to the immediate constituents of the syllable (nucleus and margin) and to the syllable. An estimate was also made of the number of prosodic conditions required for each type of phoneme sequence. It was found that in general there is a direct relationship between the length of the segment and the size of the inventory. However, when the borders of the proposed segments do not coincide with the borders of linguistic units, the inventory has to be relatively large. The value of using the various types of segment for speech synthesis is discussed, both for basic research on speech and for practical application to a communication system with high intelligibility.
Effect of Zonal Structure of Some Fibers on the Penetration Thermokinetics
Authors: Balcerzyk Edward , Kozlowski Wojciech , Wlodarski Gabriel 
Published: July 2017

Studies have been carried out on the thermokinetics of penetration of suitable selected liquids into cellulose, protein and polyvinyl alcohol fibers. The selection of penetrants was made on the basis of a previous finding that some liquids penetrate slowly into the accessible regions of particular types of fibers. The thermokinetics of the action of these liquids on fibers of mono- and bizonal structures has been studied. It has been found that, in the case of monozonal fibers the shape of thermogram is a result of, at least, two penetration processes which proceed at different rates, namely, a relatively quick penetration of liquid into interfibrillar spaces (micropores) and a slow penetration into intermolecular regions (intermolecular diffusion). As a result, “head-tail” and “two-maxima” type composite thermograms are obtained. The former is mostly common for monozonal fibers. In the case of bizonal fibers, the shape of the thermograms is dependent, first of all, on the fiber group. The thermograms have mostly two maxima. However, it is difficult to find a relation between the zonal structure of fiber and the shape of thermograms on the basis of a quality assessment. Examination of changes in the thermogram shape in the case of annealed samples or analysis of thermograms of the action of concentrated NaOH solution on fibers allow to find a closer relationship between the shape of thermograms and the zonal structure of fibers.
The Horizontal Flame-Propagation Rate of Undyed Cotton Fabrics
Authors: Segal Leon , Drake G. L. 
Published: July 2017

Differentiation of the flammabilities of nonflame-retardant, all-cotton fabrics cannot be accomplished by the usual test procedures, as these merely provide the means for determining when a fabric exceeds a certain set standard. The desired differentiation, however, can be obtained by measurement of the flame-propagation rate using the Ahiba Flammability Tester with the sample in the horizontal position. Eight nonflame-retardant, undyed cotton fabrics of different constructions were studied. The weights of the fabrics fell into four groups: 3.1, 3.6–3.8, 4.1–4.4, and 7.5 oz/yd2. Specimens were cut from the warp and filling directions of the fabrics; one set of specimens was oven-dried prior to testing, while another set was conditioned to equilibrium moisture content at 65% relative humidity and 70°F. Burning was different in the warp and filling directions. Differences in flame-propagation rates were found that were not weight dependent. In general, flame-propagation rate was not constant over the length of the specimen; in the warp direction the rates increased with distance from point of ignition, while in the filling direction constant and decreasing rates were also found. Flame-propagation rate was not effected to the extent expected by changing from oven drying to conditioning to equilibrium moisture content; only four of the eight fabrics showed significant changes. Burning in the filling directions of two fabrics was markedly changed; smaller differences were found in the warp direction only of a third fabric and in both the warp and filling directions of a fourth fabric.
Mechanical Properties of Cotton Yarns Mercerized in Liquid Ammonia and Sodium Hydroxide
Authors: Nelson M. L. , Hassenboehler C. B. , Andrews F. R. , Markezich A. R. 
Published: July 2017

Yarns spun from high- and low-maturity cottons were mercerized in liquid ammonia in a continuous process, and in liquid ammonia and sodium hydroxide in skein form under various tensions. Both swelling agents produced similar changes in mechanical properties (breaking strength, tenacity, elongation-at-break, and initial modulus) under comparable conditions. Mercerization under high tension increased breaking strength and tenacity and decreased elongation-at-break. Slack mercerization in caustic resulted in elongations-at-break substantially higher than did ammonia treatment. A major difference between reagents was noted during treatment. When skeins were swollen slack and then restretched, much greater force was required to restretch ammonia-swollen skeins, and they could not be stretched as much as those that were caustic-swollen. Measurements of length changes in yarns during swelling, tensioning, and deswelling gave quantitative data to substantiate this observation. Differences in mechanism of swelling are discussed in relation to these findings.
Giving up on Drugs: Homeless Young People and Self-Reported Problematic Drug Use
Authors: Keys Deborah , Mallett Shelley , Rosenthal Doreen 
Published: July 2017

Numerous studies have revealed high levels of drug-taking among young people experiencing homelessness. This article draws upon 40 in-depth interviews carried out as part of a five-year longitudinal study of homeless young people (Project i). It is noteworthy that almost all of those who identified their drug use as problematic gave up or reduced their level of use without treatment or professional assistance during the period of the study. The interviews provided insight into the way in which some young people experiencing homelessness view their drug use and the actions they take in light of these understandings. Here we report their stated reasons for giving up or reducing usage and identify some commonalities that may have impacted on the outcomes.
Consumption Patterns of Alcoholic Beverages in Two Cohorts of Italian Men
Authors: Scarscelli Daniele 
Published: July 2017

From individual interviews with Italian men aged 40–45 and 65–70 three prevailing models of consumption pattern can be categorized: the use of alcohol gradually increases and remains a constant in the subject's life until the adult phase is reached, when it decreases; alcohol consumption rises gradually until reaching a peak that characterizes a phase of elevated consumption, after which it decreases; alcohol consumption varies considerably over the years—a pattern which is characterized by different phases. The traditional model, adopted by most of the members of the group aged 65–70, was a pattern of consumption in which alcohol use grew gradually (the period of adolescence/youth) and then remained constant for a long period over a person's lifetime. Instead, the consumption pattern of the members of the group now aged 40–45 illustrated an interesting “action-oriented learning mechanism”: the traditional model of consumption, taught by the family, was what the subjects adopted after abandoning the socializing/intoxicating model, once their situations changed due to different life transitions. The historical-social process of “the internationalization of consumption styles” did not seem to have reduced the influence of the traditional model typical of a “wet” culture: if anything, those who were adolescents in the 1970s, as previously documented, were exposed to several consumption models.
A Novel Series of Corrosion Inhibitive Polymers for Steel Protection
Authors: El-Ghaffar M. A. Abd , Youssef E. A. M. , Darwish W. M. , Helaly F. M. 
Published: July 2017

Poly(o-aminophenol), poly(o-aminothiophenol), poly(m-anisidine) and polyaniline have been prepared by chemical oxidation of their monomers using ammonium persulfate at 0°C. The polymers were characterized and their structures confirmed using elemental analysis and spectrophotometric measurements (FTIR, UV-VIS, 1HNMR, MS, XRD and TGA). The polymers were evaluated as corrosion inhibitors for steel protection by measuring their corrosion rates in comparison with the previously prepared polyaniline and the control sample. The polymers show a high performance as efficient corrosion inhibitors, and promising results were achieved when the polymers were incorporated in various paint formulations to replace a major part of the inhibitive pigments and to replace the classical toxic corrosion inhibitors of low molecular weights and low melting points. These results are very important from an economic and safety points of view.
Regeneration of Facial Nerve after Hypoglossal Facial Anastomosis: An Animal Study
Authors: Chen Yuh‐Shyang , Yanagihara Naoaki , Murakami Shingo 
Published: July 2017

Hypogiossal‐facial nerve anastomosis was carried out in 20 adult guinea pigs. Electromyographic responses of orbicularis oculi muscle evoked by blink reflex were recorded 2, 4, and 6 months after surgery. Then the anastomotic site was reopened, and a segment of buccal branch and the anastomotic trunk were resected for detailed histologic study. Regenerated axons were counted, and the cross‐sectional area of axons and fasciculi was measured. Data obtained from both blink reflex measurement and histologic study demonstrate a good quality of regeneration of the facial nerve from the hypoglossal nerve completed 6 months after the operation. In addition a new nerve bundle was regenerated from the proximal stump of the facial nerve connecting to the anastomotic site in 80% of the animals. Postoperative change in innervation pattern of the facial nerve was also Illustrated.