bluuebunny/crossref_metadata_2025_split huggingface dataset:
Deformulation of commercial linear low‐density polyethylene resins by advanced fractionation and analysis
Authors: Sigwinta Mawande , Ndiripo Anthony , Wewers Francois , Pasch Harald 
Published: November 2019

AbstractLinear low density polyethylene (LLDPE) exhibits a complex molecular structure that is characterized by molar mass and chemical composition distributions. Both molecular parameters complementarily influence the final application properties. Typically, the molecular structure of commercial polyolefins is characterized by a set of technical parameters including the melt flow index, the crystallization and melting temperatures and the comonomer content as obtained using Fourier transform infrared or NMR spectroscopy. LLDPEs with high comonomer contents are typically regarded as plastomers or elastomers. Due to their low crystallinities, characterization of these materials using crystallization‐based analytical techniques is of limited use since the majority of the material is rather amorphous. Such materials need specific alternative analytical methods that may be based on molar mass and/or chemical composition fractionation. Here it is shown that for a comprehensive analysis of LLDPEs with similar bulk properties, preparative molar mass fractionation (pMMF) and advanced analysis of the fractions are required. The pMMF fractions are comprehensively analyzed using size exclusion chromatography, differential scanning calorimetry and high‐temperature high‐performance liquid chromatography to provide detailed information on molar mass and copolymer composition. Correlated information of these molecular parameters is obtained by comprehensive two‐dimensional liquid chromatography. © 2019 Society of Chemical Industry
Relationship of Overuse Injuries and Extrascholastic Sport Participation in High School Athletes 2009‐2010 through 2015‐2016
Authors: Ryder Stephanie Cowherd , Gnirke Matthew , Laker Scott R. , Hoffmire Claire , Comstock R. Dawn 
Published: November 2019

IntroductionOveruse injuries (injuries due to repetitive loads with inadequate rest) can negatively affect high school athletes, but limited data exist on the effect of sports participation outside of the school‐sanctioned season on the development of overuse injuries.ObjectiveCompare overuse injury patterns among high school athletes who participate in extrascholastic athletics to those participating only in scholastic sports.DesignDescriptive cross‐sectional, secondary analysis of injury data collected on high school athletes across 22 sports over the 2009‐2010 through 2015‐2016 academic years.SettingDeidentified data collected as part of the High School Reporting Information Online study (HS RIO).ParticipantsHigh school athletes from a large convenience sample of U.S. high schools.Main Outcome MeasurementsInjury proportion ratios (IPRs) were computed overall and for individual sports to compare the proportion of overuse injuries in athletes competing in extrascholastic sports to athletes participating only in scholastic athletics.ResultsOverall, extrascholastic athletes experienced a higher proportion of overuse injuries compared to scholastic‐only athletes (IPR = 1.21, 95% confidence interval [CI] 1.13‐1.30), but this association varied by sport. Among extrascholastic athletes, a higher proportion of overuse injuries occurred in those simultaneously playing the same sport outside the school setting (IPR = 1.32, 95% CI 1.11‐1.57) as well as having experienced an injury within the past year (IPR = 1.63, 95% CI 1.36‐1.95) compared to those sustaining non‐overuse injuries.ConclusionsOveruse injuries were associated with extrascholastic athletics and occurred in higher proportion in extrascholastic athletes who were playing the same sport in more than one league.
Investigating the Dynamic Viscoelasticity of Single Polymer Chains using Atomic Force Microscopy
Authors: Liang Xiaobin , Nakajima Ken 
Published: November 2019

ABSTRACTIn single‐molecule force spectroscopy (SMFS), many studies have focused on the elasticity and conformation of polymer chains, but little attention has been devoted to the dynamic properties of single polymer chains. In this study, we measured the energy dissipation and elastic properties of single polystyrene (PS) chains in toluene, methanol, andN,N‐dimethylformamide using a homemade piezo‐control and data acquisition system externally coupled to a commercial atomic force microscope (AFM), which provided more accurate information regarding the dynamic properties of the PS chains. We quantitatively measured the chain length‐dependent changes in the stiffness and viscosity of a single chain using a phenomenological model consistent with the theory of viscoelasticity for polymer chains in dilute solution. The effective viscosity of a polymer chain can be determined using the Kirkwood model, which is independent of the intrinsic viscosity of the solvent and dependent on the interaction between the polymer and solvent. The results indicated that the viscosity of a single PS chain is dominated by the interaction between the polymer and solvent. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys.2019, 57, 1736–1743
Reliability analysis of gas turbine engine by means of bathtub‐shaped failure rate distribution
Authors: Ahsan Shazaib , Lemma Tamiru A. , Gebremariam Mebrahitom A. 
Published: November 2019

AbstractDuring reliability analysis, analysts often encounter multiple repairable units operating in different environments for various applications such as marine, power generation, and propulsion. Thus, a reliability approach that accounts for varying operating conditions is invaluable to ensure system availability. Therefore, fault probability described by some characteristic parameters and their accurate estimation has been a vital task for understanding system's behavior. The time between failures is utilized to estimate Weibull parameters that define the system. The application of gas turbine is presented as a case study. Five different cases are discussed based on distinct operating conditions and faults. The results obtained demonstrate the effectiveness of the proposed method for assessing operational reliability. The three‐parameter Weibull distribution was found to best fit the failure data with the root mean square error between 0.0369 and 0.0688 for maximum likelihood estimation and 0.04184 and 0.0733 for the least square method. Based on these results, it is deduced that the system under consideration is at the end of its operational life. Furthermore, it is observed that an increase in maintenance interval leads to a decline in meantime to failure, which is indicative of the need to select maintenance interval wisely. Findings from this study helps to improve the understanding of gas turbine behavior based on reliability and survival analysis.
Stable isotope relationships between apatite phosphate (δ18O), structural carbonate (δ18O, δ13C), and collagen (δ2H, δ13C, δ15N, δ34S) in modern human dentine
Authors: Lehn Christine , Rossmann Andreas , Mayr Christoph 
Published: November 2019

RationaleThe use of multi‐isotopic analysis (δ2H, δ13C, δ15N, δ18O, and δ34S values) of modern human body tissues for provenancing of unknown individuals in forensics is increasing. Tooth dentine develops during childhood and adolescence, therefore providing geographical information from that period of life. Tooth apatite δ18O values are commonly used for the reconstruction of drinking water values, and H–C–N–S isotope ratios in collagen supply additional information about the composition of diet. We tested if dentine collagen δ2H values provide similar information to apatite δ18O values with a proof‐of‐concept study.MethodsTooth samples were taken from modern‐day individuals born in different regions of the world. Apatite and collagen were prepared from dentine. Stable isotope analyses were performed on apatite phosphate oxygen (δ18Ophos); oxygen and carbon of the structural carbonate (δ18Ocarb, δ13Ccarb); and hydrogen, carbon, nitrogen, and sulfur of the collagen (δ2Hcoll, δ13Ccoll, δ15N, δ34S).Resultsδ18Ophos, δ18Ocarb, and δ2Hcoll values are highly correlated in modern human dentine. There are significant relationships of δ18O values in the apatite fraction and δ2H values in the collagen fraction with local δ18O and δ2H precipitation values, respectively. Pearson correlation coefficients indicate no direct relationship between δ15N values and the isotope ratios of any other element. Weak relationships exist between collagen δ34S values and δ18Ocarb or δ18Ophos values.ConclusionsThe highly significant correlation of δ18Ophos, δ18Ocarb, and δ2Hcoll values in the modern human dentine implies that measurement of δ2H values in collagen or δ18O values in bioapatite will provide reliable information about the climate at the person's whereabouts.
Waste Xylose Mother Liquor Derived 3 D Graphene‐Like Porous Carbon with Ultrahigh Specific Capacitance and Energy Density for Supercapacitors
Authors: Zhang Yan‐Lei , Tang Zhi‐Shu 
Published: November 2019

AbstractIn this paper, we developed a simple strategy for preparing three‐dimensional porous carbon from xylose mother liquor for high‐performance supercapacitors. Through simple regulation of activation temperature, the porous carbon prepared under optimized conditions have a perfect honeycombed structure with fewer layers and co‐existing macropores, mesopores and micropores. The product also has high content of self doped hetero‐atoms of O (10.2 at%) and N (0.5 at%). The constructed supercapacitors based on this porous carbon exhibited excellent performance with fantastic specific capacitance of 544 F/g at 0.5 A/g, excellent rate performance of 260 F/g at 20 A/g, as well as long cycle stability of 90.2% capacitance retention after 10000 cycles at 10 A/g in 6 M KOH in three‐electrode systems. Notably, symmetric supercapacitors exhibited energy density of 22.3 Wh kg−1 at a power density of 448 W kg−1 in the aqueous electrolyte Na2SO4, and a even higher specific energy density of 42.8 Wh kg−1 was achieved at a high power density of 749.8 W kg−1 in the organic electrolyte Et4NBF4.
In Situ Intercalation of Bismuth into 3D Reduced Graphene Oxide Scaffolds for High Capacity and Long Cycle‐Life Energy Storage
Authors: Wang Mengying , Xie Songlin , Tang Chengqiang , Fang Xin , Liao Meng , Wang Lie , Zhao Yang , Wen Yunzhou , Ye Lei , Wang Bingjie , Peng Huisheng 
Published: November 2019

AbstractMetal anodes, such as zinc and bismuth have been regarded as ideal materials for aqueous batteries due to high gravimetrical capacity, high abundance, low toxicity, and intrinsic safety. However, their translation into practical applications are hindered by the low mass loading (≈1 mg cm−2) of active materials. Here, the multiscale integrated structural engineering of 3D scaffold and active material, i.e., bismuth is in situ intercalated in reduced graphene oxide (rGO) wall of network, are reported. Tailoring the rapid charge transport on rGO 3D network and facile access to nano‐ and microscale bismuth, the rGO/Bi hybrid anode shows high utilization efficiency of 91.4% at effective high load density of ≈40 mg cm−2, high areal capacity of 3.51 mAh cm−2 at the current density of 2 mA cm−2 and high reversibility of >10 000 cycles. The resulting Ni‐Bi full battery exhibits high areal capacity of 3.13 mAh cm−2 at the current density of 2 mA cm−2, far outperforming the other counterpart batteries. It represents a general and efficient strategy in enhancing the battery performance by designing hierarchically networked structure.
Base64 encoding and decoding at almost the speed of a memory copy
Authors: Muła Wojciech , Lemire Daniel 
Published: November 2019

SummaryMany common document formats on the Internet are text‐only such as email (MIME) and the Web (HTML, JavaScript, JSON, and XML). To include images or executable code in these documents, we first encode them as text using base64. Standard base64 encoding uses 64 ASCII characters, ie, both lower and upper case Latin letters, digits and two other symbols. We show how we can encode and decode base64 data at nearly the speed of a memory copy (memcpy) on recent Intel processors, as long as the data does not fit in the first‐level (L1) cache. We use the single‐instruction‐multiple‐data instruction set AVX‐512 available on commodity processors. Our implementation generates several times fewer instructions than previous single‐instruction‐multiple‐data‐accelerated base64 codecs. It is also more versatile, as it can be adapted, even at runtime, to any base64 variant by only changing constants.
Assessing task‐orientation potential in primary science textbooks: Toward a new approach
Authors: Andersen Katja N. 
Published: November 2019

AbstractTask orientation is currently a prominent concept under discussion in primary school didactics. It focuses on tasks along which pupils acquire competences on distinct levels of competence. The qualitative empirical study TAPSE (Textbook Analysis in Primary Science Education) pursues the question which conception of task orientation is present in current textbooks in primary science education. The study follows two foci: (a) The introduction of a new category system for the analysis of the task‐orientation potential of tasks, based on the further development of existing category systems for analyzing tasks; and (b) the analysis of 994 task statements in science textbooks with respect to the didactic quality of their task orientation. The sample included nine primary science textbooks, four from Germany, and five from Luxembourg. Textbooks were selected from the most frequently sold series in the respective country. All tasks of the textbooks were analyzed deductively and inductively by four coders in three steps: (a) Identifying tasks with task‐oriented potential; (b) itemizing different types of task‐orientation potential; and (c) comparing the textbooks with respect to country‐ and period‐specific manifestations of task orientation. Analysis indicated that (a) there are few tasks which meet the criteria of task orientation; (b) distinct types of task orientation can be generated, among which implicit forms dominate; and (c) differences occur in the characteristics of task orientation between older and newer textbooks as well as between German and Luxembourgish ones. Central points of discussion ensue from this: The need to develop models for social and cognitive activation for tasks, challenges for professional development for teachers, and support for pupils—in particular high achieving heterogenization.
Providing Integrated Total Catch Advice for the Management of Mixed Fisheries with an Eco-viability Approach
Authors: Briton Florence , Macher Claire , Merzeréaud Mathieu , Le Grand Christelle , Fifas Spyros , Thébaud Olivier 
Published: November 2019

AbstractWell-established single-species approaches are not adapted to the management of mixed fisheries where multiple species are simultaneously caught in unselective fishing operations. In particular, ignoring joint production when setting total allowable catches (TACs) for individual species is likely to lead to over-quota discards or, when discards are not allowed, to lost fishing opportunities. Furthermore, economic and social objectives have been poorly addressed in the design of fisheries harvest strategies, despite being an explicit objective of ecosystem-based fisheries management in many jurisdictions worldwide. We introduce the notion of operating space as the ensemble of reachable, single-species fishing mortality targets, given joint production in a mixed fishery. We then use the concept of eco-viability to identify TAC combinations which simultaneously account for multiple objectives. The approach is applied to the joint management of hake and sole fishing in the Bay of Biscay, also accounting for catches of Norway lobster, European seabass and anglerfish. Results show that fishing at the upper end of the MSY range for sole and slightly above Fmsy for hake can generate gains in terms of long-term economic viability of the fleets without impeding the biological viability of the stocks, nor the incentives for crews to remain in the fishery. We also identify reachable fishing mortality targets in the MSY ranges for these two species, given existing technical interactions.
Interest in Dialogic and Non-Dialogic Teacher Talk Situations in Middle School Science Classroom
Authors: Juuti Kalle , Loukomies Anni , Lavonen Jari 
Published: November 2019

AbstractPrevious research has shown that dialogic teacher talk not only supports students’ understanding but also raises their interest. However, there is little, if any, research on the connection between dialogic talk and student interest in classroom situations. To investigate this connection, we collected video observations and experience sampling data. In total, 87 middle school students aged 14 to 16 participated in the study. Data were collected from the classes of six science teachers, and three lessons were video recorded in each teacher’s classroom. During the lessons, students were asked several times to express their interest in the situation through the experience sampling method (ESM). The measurements took place in situations where the teacher either talked with the students or talked to the whole group of students. The talk situations were categorised as dialogic or non-dialogic, based on the video recording. On a five-point scale of interest, the median value was 3.3 in non-dialogic talk situations and 3.5 in dialogic talk situations. We hypothesised that students’ interest would be higher in dialogic talk situations than in non-dialogic talk situations. The hypothesis was tested with a related samples Wilcoxon signed rank test, and the results supported the hypothesis (Z  =  −  2.62; p  <  0.05). The results suggest that dialogic talk may trigger students’ interest in science learning.
Measuring Neighborhood Order and Disorder: a Rapid Literature Review
Authors: Ndjila Steeve , Lovasi Gina S. , Fry Dustin , Friche Amélia A. 
Published: November 2019

Abstract
Purpose of Review
Neighborhood disorder has received attention as a determinant of health in urban contexts, through pathways that include psychosocial stress, perceived safety, and physical activity. This review provides a summary of data collection methods, descriptive terms, and specific items employed to assess neighborhood disorder/order.

Recent Findings
The proliferation of methods and terminology employed in measuring neighborhood disorder (or neighborhood order) noted over the past two decades has made related studies increasingly difficult to compare. Following a search of peer-reviewed articles published from January 1998 to May 2018, this rapid literature review identified 18 studies that described neighborhood environments, yielding 23 broad terms related to neighborhood disorder/order, and a total of 74 distinct measurable items.

Summary
A majority of neighborhood disorder/order measurements were assessed using primary data collection, often relying on resident self-report or investigatory observations conducted in person or using stored images for virtual audits. Items were balanced across signs of order or disorder, and further classification was proposed based on whether items were physically observable and relatively stable over time.
RemoveDEBRIS: An in-orbit demonstration of technologies for the removal of space debris
Authors: Aglietti G.S. , Taylor B. , Fellowes S. , Ainley S. , Tye D. , Cox C. , Zarkesh A. , Mafficini A. , Vinkoff N. , Bashford K. , Salmon T. , Retat I. , Burgess C. , Hall A. , Chabot T. , Kanani K. , Pisseloup A. , Bernal C. , Chaumette F. , Pollini A. , Steyn W.H. 
Published: November 2019

ABSTRACTThe RemoveDEBRIS mission has been the first mission to successfully demonstrate, in-orbit, a series of technologies that can be used for the active removal of space debris. The mission started late in 2014 and was sponsored by a grant from the EC that saw a consortium led by the Surrey Space Centre to develop the mission, from concept to in-orbit demonstrations, that terminated in March 2019. Technologies for the capture of large space debris, like a net and a harpoon, have been successfully tested together with hardware and software to retrieve data on non-cooperative target debris kinematics from observations carried out with on board cameras. The final demonstration consisted of the deployment of a drag-sail to increase the drag of the satellite to accelerate its demise.
Glacial erosion: status and outlook
Authors: Alley R. B. , Cuffey K. M. , Zoet L. K. 
Published: November 2019

AbstractGlacier-erosion rates range across orders of magnitude, and much of this variation cannot be attributed to basal sliding rates. Subglacial till acts as lubricating ‘fault gouge’ or ‘sawdust’, and must be removed for rapid subglacial bedrock erosion. Such erosion occurs especially where and when moulin-fed streams access the bed and are unconstrained by supercooling or other processes. Streams also may directly erode bedrock, likely with strong time-evolution. Erosion is primarily by quarrying, aided by strong fluctuations in the water system driven by variable surface melt and by subglacial earthquakes. Debris-bed friction significantly affects abrasion, quarrying and general glacier flow. Frost heave drives cirque headwall erosion as winter cold air enters bergschrunds, creating temperature gradients to drive water flow along premelted films to growing ice lenses that fracture rock, and the glacier removes the resulting blocks. Recent subglacial bedrock erosion and sediment flux are in many cases much higher than long-term averages. Over glacial cycles, evolution of glacial-valley form feeds back strongly on erosion and deposition. Most of this is poorly quantified, with parts open to argument. Glacial erosion and interactions are important to tectonic and volcanic processes as well as climate and biogeochemical fluxes, motivating vigorous research.