bluuebunny/crossref_metadata_2025 huggingface dataset:
Exploring Crossmodal Associations Between Sound and the Chemical Senses: A Systematic Review Including Interactive Visualizations
Authors: Rodríguez Brayan , Reyes Luis H. , Reinoso-Carvalho Felipe
Published: September 2023

This is the first systematic review that focuses on the influence of product-intrinsic and extrinsic sounds on the chemical senses involving both food and aroma stimuli. This review has a particular focus on all methodological details (stimuli, experimental design, dependent variables, and data analysis techniques) of 95 experiments, published in 83 publications from 2012 to 2023. 329 distinct crossmodal auditory–chemosensory associations were uncovered across this analysis. What is more, instead of relying solely on static figures and tables, we created a first-of-its-kind comprehensive Power BI dashboard (interactive data visualization tool by Microsoft) on methodologies and significant findings, incorporating various filters and visualizations allowing readers to explore statistics for specific subsets of experiments. We believe that this review can be helpful for researchers and practitioners working in the food and beverage industry and beyond these scopes (e.g., cosmetics). Theoretical and practical implications discussed in this article point to computational approaches that facilitate decision-making regarding multisensory experimental methodology design.
DNA barcoding confirms the validity of Anthidium melanopygum Friese, 1917 stat. nov. (Hymenoptera: Megachilidae) as a distinct species of Western Asia
Authors: KASPAREK MAX , FATERYGA ALEXANDER V.
Published: September 2023

Heinrich Friese described Anthidium spiniventris [sic] from Palestine in 1899, and A. melanopygum as a “variety” of it from Turkey in 1917. While A. melanopygum was subsequently recognized as a subspecies of A. spiniventre, a morphological examination of new material of both taxa suggests that these taxa represent distinct species. This was also confirmed by genetic barcoding of the mitochondrial cytochrome c oxidase subunit 1 (COI) gene, which revealed the two taxa form distinct clades with an average genetic distance of 5.69%, while the genetic within-group distance of these two taxa was only 0.14% for A. melanopygum and 0% for A. spiniventre. Anthidium melanopygum has a wide distribution that extends from Greece and Bulgaria in the west across Turkey and Iran to Turkmenistan in the east. By contrast, A. spiniventre has a restricted, disjunct distribution with isolated populations in the southern Levant and Iran.
Asymmetric Arctic and Antarctic Warming and Its Intermodel Spread in CMIP6
Authors: Zhang Yihan , Kong Yunqi , Yang Song , Hu Xiaoming
Published: September 2023

Under the background of global warming, the Arctic region has warmed faster than the Antarctic, which is referred to as asymmetric Arctic and Antarctic warming. The new generation of model simulations from the CMIP6 offers an opportunity to identify the major factors contributing to the asymmetric warming and its intermodel spread. In this study, the preindustrial and abrupt-4 × CO2 experiments from 18 CMIP6 models are examined to extract the asymmetric warming and its intermodel spread. A climate feedback-response analysis method is applied to reveal the contributions of external and internal feedback processes to the asymmetric warming and its intermodel spread, by decomposing total warming into the partial temperature changes caused by individual factors. It is found that a seasonal energy transfer mechanism (SETM) dominates in both polar warmings. The direct consequence of the sea ice declining in response to the anthropogenic forcing is an increase in the effective heat capacity of the ocean surface layer. Such an increase in the effective heat capacity temporally withholds most of the extra solar energy absorbed during summer and then releases it during winter, contributing to stronger warming in winter. However, the background oceanic circulation in the Southern Ocean, namely, the Antarctic Circumpolar Current, continually transports energy equatorward, resulting in a suppressed SETM and surface warming in the Antarctic. The key factor that accounts for intermodel spread in the asymmetric warming is the difference in their strengths of SETM. The poleward atmospheric transport and water vapor feedback also contribute to the intermodel spread.

Significance Statement

The asymmetric Arctic and Antarctic warming, as a response to the increase in CO2, can regulate global atmospheric and oceanic circulations via meridional temperature gradient. Previous studies have all ascribed the key role of the ocean in the asymmetric warming over the two poles with a lack of comprehensive understanding of the roles of other feedback processes. This study emphasizes that oceanic circulation is the root of the asymmetric warming via suppressing sea ice retreat and the associated SETM in the Antarctic, instead of increasing ocean heat uptake and equatorward transport only. For the intermodel spread in the asymmetric warming over two poles, the differences in the strength of all processes involving the SETM among models are the prominent issue.
Evaluating the Multiscale Implementation of Valid Time Shifting within a Real-Time EnVar Data Assimilation and Forecast System for the 2022 HWT Spring Forecasting Experiment
Authors: Gasperoni Nicholas A. , Wang Xuguang , Wang Yongming , Li Tsung-Han
Published: September 2023

Multiscale valid time shifting (VTS) was explored for a real-time convection-allowing ensemble (CAE) data assimilation (DA) system featuring hourly assimilation of conventional in situ and radar reflectivity observations, developed by the Multiscale Data Assimilation and Predictability Laboratory. VTS triples the base ensemble size using two subensembles containing member forecast output before and after the analysis time. Three configurations were tested with 108-member VTS-expanded ensembles: VTS for individual mesoscale conventional DA (ConVTS) or storm-scale radar DA (RadVTS) and VTS integrated to both DA components (BothVTS). Systematic verification demonstrated that BothVTS matched the DA spread and accuracy of the best-performing individual component VTS. The 10-member forecasts showed BothVTS performs similarly to ConVTS, with RadVTS having better skill in 1-h precipitation at forecast hours 1–6, while Both/ConVTS had better skill at later hours 7–15. An objective splitting of cases by 2-m temperature cold bias revealed RadVTS was more skillful than Both/ConVTS out to hour 10 for cold-biased cases, while BothVTS performed best at most hours for less-biased cases. A sensitivity experiment demonstrated improved performance of BothVTS when reducing the underlying model cold bias. Diagnostics revealed enhanced spurious convection of BothVTS for cold-biased cases was tied to larger analysis increments in temperature than moisture, resulting in erroneously high convective instability. This study is the first to examine the benefits of a multiscale VTS implementation, showing that BothVTS can be utilized to improve the overall performance of a multiscale CAE system. Further, these results underscore the need to limit biases within a DA and forecast system to best take advantage of VTS analysis benefits.
Machine Learning Algorithms Predict Long-Term Postoperative Opioid Misuse: A Systematic Review
Authors: Emam Omar S. , Eldaly Abdullah S. , Avila Francisco R. , Torres-Guzman Ricardo A. , Maita Karla C. , Garcia John P. , Anne Brown Sally , Haider Clifton R. , Forte Antonio J.
Published: September 2023

Introduction

A steadily rising opioid pandemic has left the US suffering significant social, economic, and health crises. Machine learning (ML) domains have been utilized to predict prolonged postoperative opioid (PPO) use. This systematic review aims to compile all up-to-date studies addressing such algorithms’ use in clinical practice.

Methods

We searched PubMed/MEDLINE, EMBASE, CINAHL, and Web of Science using the keywords “machine learning,” “opioid,” and “prediction.” The results were limited to human studies with full-text availability in English. We included all peer-reviewed journal articles that addressed an ML model to predict PPO use by adult patients.

Results

Fifteen studies were included with a sample size ranging from 381 to 112898, primarily orthopedic-surgery-related. Most authors define a prolonged misuse of opioids if it extends beyond 90 days postoperatively. Input variables ranged from 9 to 23 and were primarily preoperative. Most studies developed and tested at least two algorithms and then enhanced the best-performing model for use retrospectively on electronic medical records. The best-performing models were decision-tree-based boosting algorithms in 5 studies with AUC ranging from .81 to .66 and Brier scores ranging from .073 to .13, followed second by logistic regression classifiers in 5 studies. The topmost contributing variable was preoperative opioid use, followed by depression and antidepressant use, age, and use of instrumentation.

Conclusions

ML algorithms have demonstrated promising potential as a decision-supportive tool in predicting prolonged opioid use in post-surgical patients. Further validation studies would allow for their confident incorporation into daily clinical practice.
Predicting the Finite Population Distribution Function under a Multilevel Model
Authors: Das Sumonkanti , Salvati Nicola , Chambers Ray
Published: September 2023

Chambers and Dunstan proposed a model-based predictor of the population distribution function that makes use of auxiliary population information under a general sampling design. Subsequently, Rao, Kovar, and Mantel proposed design-based ratio and difference predictors of the population distribution function that also use this auxiliary information. Both predictors (CD and RKM) assume a single level model for the target population. In this article we develop predictors of the finite population distribution function for a population that follows a multilevel model. These new predictors use the same smearing approach underpinning the CD predictor. We compare our new predictors with the CD and RKM predictors via design-based simulation, and show that they perform better than these single level predictors when there is significant intra-cluster correlation. The performances of these new two level predictors are also examined via an empirical study based on data from a large-scale UK business survey aimed at estimating the distribution of hourly pay rates.

AMS Subject Classification: Primary 62G30, Secondary 62G32
Determinants of Foreign Direct Investment: A Systematic Review of the Empirical Studies
Authors: Islam Mohammad Shaiful , Beloucif Ahmed
Published: September 2023

A growing body of literature is concerned with the factors that determine the inflows of foreign direct investment (FDI) into a host country. However, hardly any literature has been carried out to provide a systematic literature review (SLR) of the FDI determinants. An SLR methodology underlies this conceptual paper to evaluate and categorise a literature survey of 112 empirical studies published from 2000 to 2018. The result indicates that the size of the host market is the most robust determinant, followed by trade openness, infrastructure quality, labour cost, macroeconomic stability, human capital, and the growth prospect of the host country. Market size is highly significant in virtually all studies. This partly reflects the fact that most of the world’s FDI are market-seeking. This study provides a clear understanding of the scope of the research in the field of FDI determinants as the practical implication for future research.

JEL Code: F14
Exploratory Development of Algorithms for Determining Driver Attention Status
Authors: Herbers Eileen , Miller Marty , Neurauter Luke , Walters Jacob , Glaser Daniel
Published: September 2023

Objective

Varying driver distraction algorithms were developed using vehicle kinematics and driver gaze data obtained from a camera-based driver monitoring system (DMS).

Background

Distracted driving characteristics can be difficult to accurately detect due to wide variation in driver behavior across driving environments. The growing availability of information about drivers and their involvement in the driving task increases the opportunity for accurately recognizing attention state.

Method

A baseline for driver distraction levels was developed using a video feed of 24 separate drivers in varying naturalistic driving conditions. This initial assessment was used to develop four buffer-based algorithms that aimed to determine a driver’s real-time attentiveness, via a variety of metrics and combinations thereof.

Results

Of those tested, the optimal algorithm included ungrouped glance locations and speed. Notably, as an algorithm’s performance of detecting very distracted drivers improved, its accuracy for correctly identifying attentive drivers decreased.

Conclusion

At a minimum, drivers’ gaze position and vehicle speed should be included when designing driver distraction algorithms to delineate between glance patterns observed at high and low speeds. Distraction algorithms should be designed with an understanding of their limitations, including instances in which they may fail to detect distracted drivers, or falsely notify attentive drivers.

Application

This research adds to the body of knowledge related to driver distraction and contributes to available methods to potentially address and reduce occurrences. Machine learning algorithms can build on the data elements discussed to increase distraction detection accuracy using robust artificial intelligence.
How Terminology Affects Users’ Responses to System Failures
Authors: Candrian Cindy , Scherer Anne
Published: September 2023

Objective

The objective of our research is to advance the understanding of behavioral responses to a system’s error. By examining trust as a dynamic variable and drawing from attribution theory, we explain the underlying mechanism and suggest how terminology can be used to mitigate the so-called algorithm aversion. In this way, we show that the use of different terms may shape consumers’ perceptions and provide guidance on how these differences can be mitigated.

Background

Previous research has interchangeably used various terms to refer to a system and results regarding trust in systems have been ambiguous.

Methods

Across three studies, we examine the effect of different system terminology on consumer behavior following a system failure.

Results

Our results show that terminology crucially affects user behavior. Describing a system as “AI” (i.e., self-learning and perceived as more complex) instead of as “algorithmic” (i.e., a less complex rule-based system) leads to more favorable behavioral responses by users when a system error occurs.

Conclusion

We suggest that in cases when a system’s characteristics do not allow for it to be called ”AI,” users should be provided with an explanation of why the system’s error occurred, and task complexity should be pointed out. We highlight the importance of terminology, as this can unintentionally impact the robustness and replicability of research findings.

Application

This research offers insights for industries utilizing AI and algorithmic systems, highlighting how strategic terminology use can shape user trust and response to errors, thereby enhancing system acceptance.
School segregation, student achievement, and educational attainment in Hungary
Authors: Hermann Zoltán , Kisfalusi Dorottya
Published: September 2023

Using large-scale administrative data from Hungary, we examine the effects of attending a high-poverty school in Grade 8 on academic achievement and later educational attainment, using a matching approach. We find that attending a high-poverty school is negatively associated with reading scores and secondary education attainment, while there is no significant association with math scores. Estimates are negative in the case of higher education enrollment, but their statistical significance depends on model specification. We find suggestive evidence that attending a high-poverty school has a large direct negative effect on educational attainment, over and above the indirect effect through lower test scores. This suggests that the negative effect of high-poverty schools on students’ noncognitive skills and later educational choices can be as important as the effect on achievement.
Biogeographical Impacts of Dental, Oral, and Craniofacial Microbial Reservoirs
Authors: Easter Q.T. , Matuck B. Fernandes , Warner B.M. , Byrd K.M.
Published: September 2023

The human mouth, or oral cavity, is at the crossroads of our external and internal environments, and it is increasingly evident that local colonization of dental, oral, and craniofacial (DOC) tissues and cells by bacteria and viruses may also have systemic effects across myriad diseases and disorders. Better understanding of this phenomenon will require a holistic understanding of host-microbial interactions in both spatiotemporal and biogeographical contexts while also considering person-, organ-, tissue-, cell-, and molecular-level variation. After the acute phase interaction with microbes, the establishment of site-specific reservoirs constitutes an important relationship to understand within the human body; however, despite a preliminary understanding of how viral reservoirs originate and persist across the human body, the landscape of single-cell and spatial multiomic tools has challenged our current understanding of what cells and niches can support microbial reservoirs. The lack of complete understanding impacts research into these relevant topics and implementing precision care for microbial-induced or microbial-influenced diseases. Here, via the lens of acute and chronic microbial infections of the DOC tissues, the goal of this review is to highlight and link the emerging spatiotemporal biogeography of host-viral interactomics at 3 levels: (1) DOC cell types in distinct tissues, (2) DOC-associated microbes, and (3) niche-specific DOC pathologies. Further, we will focus on the impact of postacute infectious syndromes such as long COVID, neurodegenerative disorders, and other underappreciated postviral conditions. We will provide hypotheses about how DOC tissues may play roles systemically in these conditions. Throughout, we will underscore how COVID-19 has catalyzed a new understanding of these biological questions, discuss future directions to study these phenomena, and highlight the utility of noninvasive oral biofluids in screening, monitoring, and intervening to prevent and/or ameliorate human infectious diseases.
Understanding the nature of social embeddedness in police recruitment in England and Wales
Authors: Stubbs Gareth , Ben Ayed Elkaroui Elarbi , Harny Irianto
Published: September 2023

Recent research in England and Wales indicates that there may be a significant proportion of social embeddedness within policing recruitment. This suggests that there is a significant amount of support sought by potential recruits through their existing social networks. Existing studies have been qualitative and therefore do not assess scale. This study aims to address this research gap by gathering data from a single cohort n = 987 of police recruits in 2017. The recruit’s success was tracked throughout the process, resulting in comparative data that illustrates whether prior social contacts should be considered as a potentially causal variable in that success.
‘In Christ’: a participatory account
Authors: Ward Keith
Published: September 2023

Paul often uses the phrase ‘in Christ’ in his letters. Teresa Morgan has written an important book that rejects a participatory interpretation of this phrase, suggesting an encheiristic interpretation instead (that it means ‘in his hands’). I provide a participatory view, in terms of a sharing of divine and human minds, in experience, feeling and action. By considering Professor Morgan’s account of ‘en Christo’ in Galatians, I argue that a participatory view adds something important to, without detracting from, an encheiristic view.
Architecture as discernment: a reflection on the rebuilding of Coventry Cathedral, 1940–62
Authors: Schoenefeldt Henrik
Published: September 2023

Sixty years since its consecration, the architectural historian Henrik Schoenefeldt reflects on the theological questions underlying the plans for the post-war reconstruction of Coventry Cathedral. Covering the period from 1940 to 1962, this article explores the role of architecture in giving outward expression to the Cathedral Council’s discernment of a ministry reconciliation with a focus on Christian unity. At first this emerging identity articulated itself architecturally in symbolic acts and temporary interventions within the physical remains of the old cathedral. This was followed by proposals for the rebuilding, which culminated in Sir Basil Spence’s final design. However, his completed design reflects not only aspirations, but also the past ecclesiastical barriers towards ecumenicism. This suggests that its architecture did not represent a conclusion, but only an intermediate stage within a much longer, and still ongoing, process of discernment.
Religion and spirituality in contemporary health systems
Authors: Stripp Tobias Anker
Published: September 2023

Historically, religious institutions and healthcare systems have been inseparable, but they are often segregated in contemporary (post-)secular societies. A growing body of high-quality evidence from quantitative epidemiological studies during the last decade shows robust health benefits from religious and spiritual practices or conditions such as regularly attending religious services or having a sense of meaning and purpose. The potential public health implications of this evidence are a delicate matter. One might argue that, given the current evidence, it is unethical not to support citizens’ search for meaning and purpose on a structural level – irrespective of whether that search is related to the transcendent or not. While it is not feasible to ‘prescribe religion’ to improve health, current religious and spiritual institutions might be essential in providing a contemporary and relevant space for existential, spiritual and religious contemplation in secular cultures. But how can that be attained? Starting from international research on religion, spirituality and health, this article discusses potential implications for public health in relation to religious institutions in a secular culture. If faith is protective and healthy for us, is there a way in modern-day society to take advantage of the effect of religious and spiritual communities and practice to increase public health, despite the structural and ethical challenges provided in a (post-)secular country such as Denmark?
Can Critical Rationalism Become a Philosophy of Life?
Authors: Bar-Am Nimrod
Published: September 2023

In his last book, Agassi reiterates Critical Rationalism as a full-fledged philosophy of life. He criticizes Paternalism and Relativism as degenerative, and even pathological, attempts to grant life a meaning, and suggests, in their place, that fallibilism is the minimal condition for a meaningful life.
“A Matter of Long Centuries and Not Years”: Du Bois on the Temporality of Social Change
Authors: Ikuta Jennie C.
Published: September 2023

In light of the summer 2020 protests and their subsequent backlash, questions about the prospective timeline for achieving a racially just society have taken on renewed significance. This article investigates Du Bois’s writings between 1920 and 1940 as a lens through which to examine the temporality of social change. I argue that Du Bois’s turn to the role of white unreason explains the dual temporality of his political vision and the dual strategies that ensue. According to Du Bois, white supremacy is upheld not only by ignorance, but also by white unreason, reproduced through generations of institutional conditioning. Du Bois therefore turns to propaganda for transforming white unreason, thereby making a racially just society possible. But because the transformation of white unreason through propaganda is a slow process, Du Bois argues that Black Americans must ensure their survival through voluntary self-segregation. By presenting us with a framework of social change, Du Bois models how advocates of racial justice might navigate defeat without devolving into defeatism.
Rethinking Sustainability Reporting with Reference to the Inflation Reduction Act
Authors: Rao Sunita S.
Published: September 2023

This article explores the possible effects of the Inflation Reduction Act (IRA) on stand-alone corporate sustainability reporting and assurance on such reports. To this end, we use stakeholder theory to examine the potential impact of the IRA on sustainability reporting, which includes environmental, social, and governance indicators. It also explores the various ways of implementing measures to achieve high-quality sustainability reporting and guidelines for assurance of such reports. This article provides one of the first frameworks for organizations to initiate action on climate change.
Clinical impact of turn-up anastomosis in the treatment of type A acute aortic dissection
Authors: Shimamoto Takeshi , Komiya Tatsuhiko , Matsuo Takehiko
Published: September 2023

Background

The management of anastomosis and hemostasis of the dissected aorta remains challenging. This study aims to establish an optimal surgical strategy for type A acute aortic dissection by reviewing single-center data using the turn-up anastomosis technique.

Methods

Between 2003 and 2015, 264 consecutive patients with type A acute aortic dissection who underwent emergency surgery within 14 days of symptom onset were enrolled.

Results

The mean age of the patients was 67.7 ± 13.4 years, and 129 were males. The operative time and surgical bleeding were 390.9 ± 144.5 min and 2983.8 ± 3026.5 mL, respectively. In-hospital mortality was observed in 25 patients (9.4%), and 3 (1.1%) experienced uncontrolled bleeding (from the aortic root in two patients and coagulopathy due to dabigatran in one patient). Immediate reopening for bleeding was performed in 20 patients, and bleeding from the aortic anastomosis was observed at three proximal and two distal sites. Proximal re-dissection was observed in 18 patients; in all of which, glue was used, although two re-ruptures of the aortic root were observed among those without glue use. The rates of freedom from all-cause death, aortic death, and aortic events at postoperative 5 years were 78.5 ± 2.7%, 86.8 ± 2.1%, and 74.4 ± 2.9%, respectively. When these values were stratified according to the operative extent, no significant differences were observed.

Conclusions

Turn-up anastomosis facilitates short circulatory arrest, short operative time, and stable hemostasis, with few anastomotic complications during surgery for type A acute aortic dissection.
Epigraphic Practice and the Making of State Society in Eastern Madhya Pradesh (Circa Fifth–Sixth Centuries ce)
Authors: Jhanjh Dev Kumar
Published: September 2023

The essay explores the process of state formation under the Parivråjakas and the Uccakalpðyas in eastern Madhya Pradesh (MP) during circa fifth–sixth centuries ce. A total of 14 epigraphic records inform us about the development of the institutional structures under these two local powers. We delve into the process of transformation of the a»avika-råjya into full-fledged monarchical powers. Besides the internal factors, an attempt has been made to understand the external Gupta and Våkå»aka influence, in relation to the spread of Sanskrit culture, state society and pattern of patronage in eastern MP. Like the well-known Malwa corridor on the western side of MP, the present essay finds the making of another corridor that formed under these two local powers to the eastern side of MP. It, therefore, suggests the existence of another route that connected north India and the Deccan via central India, which catalysed the state formation in the region.
Design of a Fastener Based on Negative Poisson's Ratio Foam
Authors: Choi J.B. , Lakes R.S.
Published: September 2023

In this article we make use of the negative Poisson's ratio of recently developed cellular solids in the design of a press-fit fastener. Insertion of the fastener is facilitated by the lateral contraction which negative Poisson's ratio materials exhibit under compression. Removal of the fastener is resisted by the corre¬sponding elastic expansion under tension.
Heat Resistant Isocyanate Based Foams for Structural Applications
Authors: Sendijarevic V. , Sendijarevic A. , Lekovic H. , Torlic E. , Kresta J.E. , Klempner D. , Frisch K.C. , Hunter L. , Banuk R.
Published: September 2023

This paper describes unique types of isotropic urethane-isocyanurate and urethane-urea isocyanurate foams based on a combination of an aromatic polyester polyol and an amine-containing tetrol as the only polyols with a low functionality polymeric isocyanate. The effects of isocyanate index, foam density, and curing temperature, as well as the mode of foaming (free-rise versus moulded) on the foam properties, were studied. The foam isotropy index, defined as the ratio of compressive strength parallel and perpendicular to the foam rise, was 1.0 (ideal). The normalized compressive strength (parallel and perpendicular) was 13 kPa/kgm-3. The moulded PIR foams exhibited excellent durability in the drop weight impact test and a high degree of property retention at 121°C.
Heat Transfer and Ageing of Cellular Foam Insulation
Authors: Glicksman Leon R.
Published: September 2023

The mechanism of heat transfer through closed cell foam isulation can include conduction through gas in the cell interiors, conduction through the solid polymers, and thermal radiation. Each of these mechanisms is described. The rate of aging of foam insulation is related to the diffusion of air and blowing agents into the foam. Results for new HCFC's are given. Methods to enhance the thermal properties are presented.
Polyurethane Rigid Foam Systems for Metal-Faced Sandwich Panels for the 1990s
Authors: Jeffs G.M.F. , Rosbotham J.D. , Mathys B. , Frigo R.
Published: September 2023

Sandwich panels with polyurethane rigid foam cores are important building elements for a wide variety of applications. They are used for the cost effective construction of industrial and commercial buildingsand in many stages of the food chain, including cold storage, cold rooms and refrigerated transport containers and trucks.

The blowing agent used in the foam systems has traditionally been CFC-ll. This has contributed to the excellent thermal resistance of the panels but its use will be phased out by the year 2000.

Foam systems have been developed based on a wide variety of alternatives. These are designed to suit various national and international CFC phase-out schedules. These include systems based on 100% CO2, HCFC-22, HCFC-123 and HCFC-141b. In all cases the formulations have been based around the particular blowingagent to obtain the best combination of processing, physical and thermal resistance properties.

Because the HCFCs are now accepted to be transitional substances with a finite production lifetime, the foam systems based on HCFC-123 and -141b are designed to be “drop-In” replacements for those based on CFC-ll. This means that all changes are incorporated into the foam system rather than into the production process and that thermal resistance with those blowing agents equals that for systems based on CFC-11.

These panels have an important structural role to play and, in addition to the retention of foam strength, the adhesion between the foam and facing plays an important role in the overall performance of the panel. The parameters affecting adhesion have been investigated with the alternative systems and optimised processing conditions determined.

A family of foam systems has been developed to serve the metal-faced sandwich panel industry through the 1990s.
Amine-Free Catalyst Systems for Automotive Instrument Panels
Authors: Christfreund A. , Huygens E. , Eling B.
Published: September 2023

The requirements, composition and performance of modern automotive instrument panels have been thoroughly examined. In particular the antagonistic behaviour of conventional semi-rigid PU foam with the decorative skin cover made from either an ABS/PVC vacuum formed sheet or slush moulded PVC powder was investigated. Extended exposure to high temperatures of such composites has been shown to result in staining and embrittlement of the skin material.

ICI Polyurethanes, in conjunction with ICI EVC, has carried out an extensive programme of work to identify the mechanisms of discoloration and embrittlement. This paper summarises the results and shows the importance of PVC stabilizers, pigments and plasticizers and the use of amine catalysts in the polyurethane foam as the critical factors. Although amine-free catalysts were known the resulting polyurethane foams did not have the right balance of foam structure, physical properties and processing characteristics. Thus a novel amine-free catalyst system was developed which gave excellent staining resistance whilst maintaining the other foam properties and giving the required processing characteristics.
Assessment of the Fire Hazard Presented by a Burning Pool of Toluene Diisocyanate (TDI)
Authors: Marlair G. , Sand H.
Published: September 2023

Fire tests have been conducted with TDI under conditions simulating a pool fire originating, e.g. from a leakage of stored TDI. The facilities of Cerchar * provide conditions of a free-burning, well-ventilated fire. Burning rate, heat and smoke development and toxic gas emission were determined as a function of the pool diameter up to 1 m2. Results are compared with small scale test results.

Burning rate increases with increasing pool diameter reaching 2 kg/m2-min at 1 m2 area. Yields of permanent gases do not differ significantly with increasing pool area, with HCN amounting to 5 mg/g. Free TDI is found in fire gas up to 15 ppm corresponding to a yield of 7 mg/g.
Combustion Behaviour of Fabric and Polyurethane Flexible foam Mock-up Combinations under Cone Calorimetry Test Conditions
Authors: Vanspeybroeck R. , Van Hees P. , Vandevelde P.
Published: September 2023

The relative contributions of fabric and foam on important fire hazard parameters as measured in the cone calorimeter were determined for various mock-up combinations. Three commercial types of high resilience PU flexible slabstock foams, representing a wide range of combustion performance, were combined with three different fabrics; viz. polyester, polypropylene and combustion modified cotton.

Total heat release of the combinations correspond well with the value calculated from the individual components and is determined by the density and effective heat of combustion of the components, and the foam/fabric weight ratio. The foams show a smaller variation in effective heat of combustion than the fabrics.

Covering of PU flexible foams with a fabric results in general in a delay of ignition and peak rate of heat release. Performance of the mock-ups is mainly determined by the fabric but also influenced by the quality of the foam.
HCFC Blown Rigid Polyurcthane Foams and Refrigerator Liner Materials: The Search for Compatible Systems
Authors: Potter K.G. , Tweedale C.R.
Published: September 2023

With the traditional use of CFC-11 blown polyurethane foam for refrigerator insulation there has been limited need for interaction between the PU producers on the one hand and the producers of plastics used for liner materials on the other hand.

Taking into consideration their ozone depletion potential (ODP) and global warming potential (GWP) there is wide acceptance that HCFC-123 and -141b are the nearest “drop in” substitutes known today for CFC-11 replacement.

However, this has major implications as these new blowing agents are significantly more aggressive requiring novel approaches in terms of material choice for monolithic and/or co-extruded sheet to retain the optimum sheet thickness, productivity and economics of current materials.

This paper first of all summarises the current status of developments towards the reduction and eventual elimination of CFC-11 from rigid polyurethane foam systems used for the insulation of domestic refrigerators and freezers. It then addresses the problems of liner/alternative blowing agent interactions using tests which attempt to bridge the classical laboratory tests whilst acknowledging the ultimate need to run full scale processing, assembly and functional performance trials at refrigerator manufacturers.

Key parameters covered include thermal conductivity, its ageing, carbon dioxide permeability and adhesion between the polyurethane foam and the plastic liner.

Physical attack of the liners is studied employing two qualitative testa One involves an unconstrained situation with profiled vacuum formed liner in contact with HCFC blown foams; the other uses a prototype tool which incorporates shelf support and mullion in a restrained mode with an aluminium tool. New liner materials and combinations which are compatible with HCFC blown foams are identified as a result of this work.
Recent Developments in the Chemical Recycling of Flexible Polyurethanes*
Authors: Hooper Julian F.G. , Parrinello Giovanni , Parfondry Alain , Kroesen Dipl.Ing. Karl-Wilhelm
Published: September 2023

After general consideration of the factors currently influencing recycling practice, the main physical and Chemical routes for recycling polyurethanes are briefly presented.

A new process now under development to improve the glycolysis of flexible foams and elastomers is described. It is particularly suitable for recycling classified post-user materials, mainly from the automotive industry, back into simiiar applications. Glycolysis technology is thus brought closer to the point where a partially closed loop cycle can be realised.
Expanded Rubber Using ENR and Blends with PVC
Authors: Metherell C.
Published: September 2023

The physical properties of expanded rubbers made from natural rubber, ENR-25, ENR-50 and blends of the latter with PVC are compared. The effects of plasticisers are also investigated. Materials with densities between 0.15-0.5 Mg/m3 were obtained, all with very fine closed cell structures. The resilience of these materials could readily be varied. Foams made from ENR-50 and blends with PVC possessed very low compression set. All materials possessed low water adsorption.
The Behaviour of Commercially Important Di-isocyanates in Fire Conditions Part 1: Toluene Di-isocyanate (TDI)
Authors: Marlair G. , Prager F.H. , Sand H.
Published: September 2023

Several di-isocyanates have become commercially important materials, used as intermediates in the manufacture of a wide variety of polyurethane products, yet little is recorded on their behaviour if involved in fire. This paper describes a series of programmes carried out under the auspices of the International Isocyanate Institute Inc. First, a small scale laboratory investigation of the ignition, heat release, smoke and toxic gas production characteristics of di-isocyanates was carried out. Second, their behaviour in drumstock and pool fires, respectively, was examined, using full-sized samples and selected real-fire scenarios. Part 1 records the results for toluene di- isocyanate (TDI) showing the need for a modest energy input to ignite it from a pilot flame. It then burns in a steady rather than vigorous manner, leaving no residues. Toxic gases evolved are mainly carbon monoxide, while free isocyanate is likely in the early stages of the fire, and hydrogen cyanide may be important in well-developed fires. Drumstock material behaviour in a fire is dictated mainly by the rupture characteristics of the containers, which can be violent. A series of simple guidelines is suggested, which includes the need for firefighters to wear full protective clothing and fresh-air breathing equipment. It is also recommended that drumstock TDI should be stored away from easily ignitable materials.
Inherently Flame Retardant Rigid Polyurethane Foams Based on New Triazinic Polyether Polyols
Authors: Ionescu M. , Mihalache I. , Zugravu V. , Mihai S.
Published: September 2023

The synthesis of new triazinic polyols by oxyalkylation with the propyleneoxide of some well known condensation products derived from melamine (2,4,6-triamino-1,3,5-triazine), a heteroaromatic chain initiator, has been studied. By using the synthesized aromatic triazinic polyols in conventional foaming processes, rigid polyurethane foams with excellent physico-mechanical properties and inherent flame retardancy are obtained, better than those of rigid polyurethane foams derived from conventional aliphatic polyols based on sucrose.

A new additive flame retardant with a similar heteroaromatic triazinic structure (1, 3, 5-trichlormethylisocyanurate) was also successfully evaluated.

The non expensive and accessible raw materials, the facility of the reactions involved in this kind of synthesis, make the studied method very attractive from technological points of view.
Cell Size Measurement of Polymeric Foams
Authors: Sims G.L.A. , Khunniteekool C.
Published: September 2023

Micrographs of cell structure were analysed by three different techniques to determine apparent mean cell size and the apparent cell size distribution.

Excellent agreement for mean cell size was established between image analysis and a more simple counting technique based on a modified version of standard ASTM and British Standard methods. It was concluded that rapid accurate determination of apparent cell size was more readily obtained by the modified counting method.

Characterisation of cell size distribution was most accurately performed using an image analysis technique. However, a modified method [TGA 10(11)] provided a more efficient and cost effective method where general trends are required and absolute results are not essential.
Factors Affecting the Long Term Dimensional Stability of Rigid Foam for the Construction Industry
Authors: Daems D. , Rosbotham I.D.
Published: September 2023

For several years, the polyurethane industry has critically examined its products in order to meet present and possible future European environmental regulations. Particularly in the construction industry, research has moved in two directions, namely CFC replacement and halogen-free, fire retardant foam.

It is clear that the formulations have had to be adapted to the new types of blowing agents and the halogen-free additives in order to be able to compare favourably with the thermal and fire performance previously achieved. These changes have resulted in a need to understand the fundamental factors which determine the long term dimensional stability of foams, if one is to underwrite their long term performance.

From the theoretical understanding, it is then possible to assess the validity of current test methods and to design improved tests for the prediction of the long term dimensional stability of the new systems.

In this paper, the relevant fundamental factors have been examined individually. Factors which predominantly effect the polymer strength, processing, diffusion of gases and plasticisation have been grouped together and the combined effect under different conditions and in different applications within the construction area are discussed. Finally the prediction of long term behaviour via modelling is highlighted.

It was shown that the effect of the combined action of all parameters influencing the long term dimensional stability of foams has changed in new systems based on benign blowing agents, compared to conventional CFC 11 blown foams.
Advances in Polyurethanes for use in Acoustic Applications for the Automotive Sector
Authors: Cunningham A. , Duggan N.
Published: September 2023

This presentation reviews the performance of ICI's latest range of acoustic foams with respect to airborne noise attenuation. These foams have been specially designed to provide not only low densities with excellent flow and demould times, but also the design flexibility to select the most appropriate intrinsic foam acoustic performance for the specific application under consideration.
Effect of Phospho-Halogenated Polyethcr Polyol on Fire Behaviour of Rigid Polyurethane Foams Blown with Various Agents
Authors: Modesti M. , Simioni F.
Published: September 2023

The substitution of CFC-11 with blowing agents with low environmental impact, for the production of PU thermal insulating materials, implies the variation of several properties of the material. The worsening of fire behaviour of material, based on Ixol B 251, with flammable blowing agents (HCFC-141b, 2-chloro propane and n-pentane) can be reduced by modifying the formulation, i.e. by increasing the amount of flame retardants.

The results of the Oxygen Index test were compared with the data obtained from the ISO 3582, DIN 4102 - B2 and UNI 9177 test and gave a good correlation.

The initial thermal conductivity of the various foams is strictly linked with the thermal conductivity of the gas phase and increases with the new blowing agents and particularly in the case of n-pentane reaches values which are about 20% higher than that of foams blown with CFC-11.

Hydrocarbon type blowing agents do not change significantly the mechanical properties of the materials; small variations in mechanical properties with HCFC-141b should be attributed to the solvent action of the compound on the polymer matrix.
Development of Crosslinked Flexible PVC Foam Formulations
Authors: Yanez-Flores Isaura G. , Gilbert Marianne
Published: September 2023

Experiments were carried out to develop a peroxide based plasticised PVC formulation from which a crosslinked foam could be produced. Thermal analysis was used to investigate the reactions which occurred during crosslinking and blowing, and to select a suitable peroxide and crosslinking temperature. Solvent extraction was used to assess the amount of crosslinked material (gel content), and thermomechanical analysis was used to measure softening temperature of the foams produced. For selected samples, the reaction was scaled up so that tensile properties could be measured. Providing that a suitable peroxide was well dispersed in the plastisol, and in the presence of a crosslinking monomer, uniform crosslinked foams could be produced when a suitable spreading temperature was used. Gel content and softening temperature increased with peroxide and monomer concentration. The crosslinking reaction appeared to be similar to that occurring in the irradiation crosslinking of plasticised PVC studied previously.