Typical Melt Research Articles

The Systematics of Olivine CaO + Cr-Spinel in High-Mg# Arc Volcanic Rocks: Evidence for in-Situ Mantle Wedge Depletion at the Arc Volcanic Front

Abstract We investigated the state of the arc background mantle (i.e. mantle wedge without slab component) by means of olivine CaO and its Cr-spinel inclusions in a series of high-Mg# volcanic rocks from the Quaternary Trans-Mexican Volcanic Belt. Olivine CaO was paired with the Cr# [molar Cr/(Cr + Al) *100] of Cr-spinel inclusions, and 337 olivine+Cr-spinel pairs were obtained from 33 calc-alkaline, high-K and OIB-type arc front volcanic rocks, and three monogenetic rear-arc basalts that lack subduction signatures. Olivine+Cr-spinels display coherent elemental and He–O isotopic systematics that contrast with the compositional diversity of the bulk rocks. All arc front olivines have low CaO (0.135 ± 0.029 wt %) relative to rear-arc olivines which have the higher CaO (0.248 ± 0.028 wt %) of olivines from mid-ocean ridge basalts. Olivine 3He/4He–δ18O isotope systematics confirm that the olivine+Cr-spinels are not, or negligibly, affected by crustal basement contamination, and thus preserve compositional characteristics of primary arc magmas. Variations in melt H2O contents in the arc front series and the decoupling of olivine CaO and Ni are inconsistent with controls on the olivine CaO by melt water and/or secondary mantle pyroxenites. Instead, we propose that low olivine CaO reflects the typical low melt CaO of high-Mg# arc magmas erupting through thick crust. We interpret the inverse correlation of olivine CaO and Cr-spinel Cr# over a broad range of Cr# (~10–70) as co-variations of CaO, Al and Cr of their (near) primary host melts, which derived from a mantle that has been variably depleted by slab-flux driven serial melt extraction. Our results obviate the need for advecting depleted residual mantle from rear- and back-arc region, but do not upset the larger underlying global variations of melt CaO high-Mg# arc magmas worldwide, despite leading to considerable regional variations of melt CaO at the arc front of the Trans-Mexican Volcanic Belt.

Sensitivity of the MAR regional climate model snowpack to the parameterization of the assimilation of satellite-derived wet-snow masks on the Antarctic Peninsula

Abstract. Both regional climate models (RCMs) and remote sensing (RS) data are essential tools in understanding the response of polar regions to climate change. RCMs can simulate how certain climate variables, such as surface melt, runoff and snowfall, are likely to change in response to different climate scenarios but are subject to biases and errors. RS data can assist in reducing and quantifying model uncertainties by providing indirect observations of the modeled variables on the present climate. In this work, we improve on an existing scheme to assimilate RS wet snow occurrence data with the “Modèle Atmosphérique Régional” (MAR) RCM and investigate the sensitivity of the RCM to the parameters of the scheme. The assimilation is performed by nudging the MAR snowpack temperature to match the presence of liquid water observed by satellites. The sensitivity of the assimilation method is tested by modifying parameters such as the depth to which the MAR snowpack is warmed or cooled, the quantity of water required to qualify a MAR pixel as “wet” (0.1 % or 0.2 % of the snowpack mass being water), and assimilating different RS datasets. Data assimilation is carried out on the Antarctic Peninsula for the 2019–2021 period. The results show an increase in meltwater production (+66.7 % on average, or +95 Gt), along with a small decrease in surface mass balance (SMB) (−4.5 % on average, or −20 Gt) for the 2019–2020 melt season after assimilation. The model is sensitive to the tested parameters, albeit with varying orders of magnitude. The prescribed warming depth has a larger impact on the resulting surface melt production than the liquid water content (LWC) threshold due to strong refreezing occurring within the top layers of the snowpack. The values tested for the LWC threshold are lower than the LWC for typical melt days (approximately 1.2 %) and impact results mainly at the beginning and end of the melting period. The assimilation method will allow for the estimation of uncertainty in MAR meltwater production and will enable the identification of potential issues in modeling near-surface snowpack processes, paving the way for more accurate simulations of snow processes in model projections.

The Influence of Glacier Mass Balance on River Runoff in the Typical Alpine Basin

Quantifying the effects of alpine GMB (Glacier Mass Balance) on river runoff is an important content of climate change. Uncertainty exists in GMB monitoring when applying remote-sensing technology. There are several reasons for these uncertainties, such as terrain deviation co-registration among different topographic data, the mismatch between GSE (Glacier Surface Elevation) from satellite monitoring and the GMB that comprises the physical glacier properties, the driving factors of GMB, and the response patterns of the runoff within the basin. This paper proposed a method based on the ridge line co-registration of DEMs (Digital Elevation Models), and the Tailan River basin, which is a typical glacier melt runoff recharge basin located in the southern Tianshan Mountains, was selected. Abnormal values in GSE changes were removed using ice thickness data, and the GSE results were optimized based on the regularity of the GSE change with altitude to estimate the GMB. The driving factors of the GMB and the response characteristics of the runoff in the basin were also explored. The results showed that the accuracy of the optimized GSE results across different periods has improved by more than 25%. The mean annual thinning value of GSE in the basin from 2000 to 2022 was −0.25 ± 0.02 m·a−1, corresponding to a GMB value of −0.30 ± 0.02 m w.e.a−1, indicating a consistent GMB loss state. Combined with climate data, the glaciers in the basin were impacted by rising temperatures, and the smallest increase in annual precipitation in the basin was insufficient to compensate for the GMB loss. Moreover, in the past 22 years, glacier meltwater accounts for 46.15% of the total runoff in the Tailan River basin.

Zircon age spectra to quantify magma evolution

Abstract The past decades have seen tremendous advances in analytical capabilities regarding the sensitivity, spatial selectivity, and instrumental precision of U-Th-Pb zircon geochronology. Along with improved zircon pretreatment to mitigate the effects of Pb-loss, these advancements have resulted in the emergence of U-Th-Pb dating as the most widely used geochronometer. In parallel, it became increasingly obvious that modern analytical techniques can resolve zircon age dispersal beyond instrumental uncertainties and that this dispersion cannot be attributed to Pb-loss or inheritance. Hence, there is a pressing need to refine statistical procedures for displaying and interpreting dispersed age data from volcanic and plutonic rocks, where zircon ages were traditionally assigned to the quasi-instantaneous events of eruption and magma emplacement, respectively. The ability to resolve zircon age spectra, which often range over timescales of 103–106 years, also offers new opportunities to monitor magmatic processes, because zircon crystallization directly relates to the temperature and composition of its host melt. This relation is, at least for typical subalkaline melt compositions, well calibrated by multiple zircon saturation experiments, although absolute saturation temperatures derived from them can vary by tens of degrees. Moreover, zircon saturation thermometry is supported by the trace element and isotopic inventory of zircon, which records the thermochemical and compositional evolution of melts at high fidelity. Here, we first review the properties of true zircon age spectra that are defined by a statistically robust overdispersion relative to analytical uncertainties. Secondly, we evaluate existing models and present new models that aim to quantitatively translate the properties of zircon age spectra into parameters controlling the longevity and thermal evolution of crustal magma bodies such as magma recharge flux and duration. These developing approaches, which aspire to capture all processes that affect the formation and dispersal of zircon in dynamic crustal magma systems, have the potential to foster an improved understanding of magmatism with implications for volcanic hazard assessment, geothermal energy uses, and the origins of ore deposits.

Significant transitions of microstructure and mechanical properties in laser additive manufacturing AlCoCrFeNi2.1 eutectic high-entropy alloy under heat treatment

In this work, the AlCoCrFeNi2.1 eutectic high-entropy alloys (EHEAs) were fabricated by laser additive manufacturing and subsequently heat-treated at various temperatures between 800 and 1200 °C to achieve excellent strength-plasticity synergy. The high solidification rate of selective laser melting (SLM) leads to instability of the eutectic growth front, resulting in a typical melt pool morphology of equiaxed and columnar crystals for AlCoCrFeNi2.1. The body-centered cubic (BCC) content of ∼82% in the SLM specimens leads to a higher tensile strength of ∼1175 MPa and poorer plasticity of ∼6.42%. After heat treatment, the BCC transforms to face-centered cubic (FCC) and the microstructure changes to a dendrite containing eutectic lamellar structure. As the temperature increases, Ni–Al aggregates, B2 phase particles precipitate and grow in the BCC matrix. Meanwhile, the uniform heating mode eliminates the orientation of the SLM melt pool structure, reduces the internal stress and dislocation density of the SLM alloy. In addition, high-temperature heating promotes the stable growth of lamellar structure. These combined effects allow the strength-plasticity trade-off to be achieved in the heat-treated specimen. The HT-1200 sample has a strength of 1065 MPa and a ductility of 21.97%.

Fabrication of durable and non-leaching triclosan-based antibacterial polypropylene

Despite achieving broadscale commercial applications, Polypropylene (PP) is prone to bacterial contamination, which poses huge threats to public health. Applying antibacterial agents in polymer matrix is recognized as a widespread method to endow PP biocidal properties. Herein, we report a preparation of triclosan (TCS) based antibacterial PP through free radical grafting. As the methyl acrylate group is introduced to the TCS in advance to synthesize a radical-active monomer (f), PP-f products are successfully prepared via two typical free radical grafting reactions, solution grafting (PP-f-sg) and melt grafting (PP-f-mg). Although showing high f content (up to 12.7 mol%), PP-f-sg samples are of low monomer utilization (less than 50%) and the grafting reaction must be assisted by comonomers. On the contrary, PP-f-mg samples with modest f content (from 0.08 to 0.34 mol%) reveal satisfying monomer efficiency (over 80%) without the help of any comonomers, which demonstrates significant advantages. When addition amount of f reaches 0.12 mol% (1.0 wt%), antibacterial rates (R) of PP-f exceed 99% against both E. coli and S. aureus. Since covalent bonds are formed between TCS and PP chains, the biocidal properties of PP-f are durable and non-leaching. The R of PP-f maintains over 90% after ethanol extraction, while those extracted samples made by physical blending of TCS and PP completely lose their antimicrobial properties.

Structural and luminescence investigations of Gd3+ - Er3+ doped in lithium aluminum borate glasses using XANES and EXAFS techniques

The typical melt quenching technique was utilized to produce a possibly unique series of Gd3+ and Er3+ dual doped borate glasses with a composition of 25Li2O–5Al2O3-XGd2O3-(69.0-X)B2O3-1.0Er2O3. The amorphous nature and information on chemical bindings of the materials were validated by using fundamental characterization techniques such as X-ray diffraction, Fourier transform infrared, X-ray absorption near-edge structure, and optical screening to identify their features (absorption, excitation, and emission). The refractive index of the glasses improves from 1.5487 to 1.628 as the concentration of Gd2O3 increases. The optical absorption spectra of Er3+ doped glasses were measured from the ultraviolet (UV) through the visible (Vis) and near infrared (NIR) ranges with varying Gd2O3 concentrations in order to determine their optical properties. This luminescence was found to be predominant in photoluminescence spectra, which were obtained at an optimum doping Gd2O3 concentration of 7.5 mol%. The impact of Er3+ doping was assessed through photoluminescence, which exhibited a broad, intense NIR band at 1537 nm ascribed to the 4I13/2 → 4I15/2 transition of Er3+ ions at λEx = 486, 526, 651, and 978 nm excitation, which exhibits outstanding increased intensity with the Er3+ concentration until it reaches 1.0 mol %. A look at visible and near-infrared optical, it is observed that LAGd7.5BEr1.0 glass is a more potential candidate for photonic devices.

Comparison of methods to characterize the penetration of hot melt adhesive into paper

Abstract In the use of hot melt adhesives in the production of paper-based packaging, the controlled penetration of the adhesive is important to obtain rapid setting rates, good bond strength, and the efficient use of adhesive. Measuring adhesive penetration depth has been limited to cross-sectional images, but quantifying the depth of penetration is difficult from these images. No quantitative method is well established in the literature. Four different techniques are compared to quantitatively measure adhesive penetration depth. Two methods involve separating the paperboard from the adhesive layer. Two other methods use of silicone oil penetration and mercury porosimetry to measure the decrease of pore volume after the adhesive is applied. These methods are compared with samples generated for various parameters. Experiments were conducted using a typical hot melt glue on uncoated and coated paperboard sample. Cross-sectional images from Scanning Electron Microscopy (SEM) confirm the penetration of some samples. The accuracy and repeatability of these methods were compared. Because of some issues with trying to repeatably remove the paper layer for the weight and thickness methods, and the time and cost of the mercury porosimeter method, the silicone oil method is a nice method to characterize the adhesive penetration depth.

Preparation and characterization of lithium disilicate-fluorcanasite glass-ceramics for dental applications

The purpose of this research is to discuss the preparation, characterization, and characteristics of lithium disilicate-fluorcanasite (LF) glass-ceramics in order to develop new dental glass-ceramics. A typical melt quenching method was used to produce the lithium disilicate (LD) and fluorcanasite (FC) types of glass. Following that, the LD and FC glass frits were combined and remelted in the following LD:FC ratios of 100:0, 0:100, 75:25, and 50:50 wt%, represented by S1, S2, S3, and S4, respectively. Based on the thermal analysis data, the glass-ceramic samples were fabricated through the heat treatment method. XRD and SEM were used to characterize the phase formation and microstructures of the prepared glass-ceramics. Archimedes' principle, three-point bending, and chemical solubility tests were used to determine density, flexural strength, and chemical solubility, respectively. The elastic modulus and fracture toughness of the selected samples were also evaluated using a Vickers hardness test. It was found that the S3 glass-ceramic sample (S3-789) has a longer LD crystalline phase than that of the S4 glass-ceramic sample (S4-788), resulting in a higher density and hardness. Furthermore, the S3-789 sample had by far the greatest Vickers hardness, elastic modulus, fracture toughness, and flexural strength, so it was chosen for future study to assess its bioactivity in SBF due to its superior mechanical properties and good machinability. The SBF bioactivity test validated the S3-789 sample's high bioactive performance. As a result, the S3-789 sample may be a good option for use as a novel material in dental applications.

Functionalization of poly(butylene adipate‐co‐terephthalate) with itaconic anhydride through graft copolymerization

AbstractPoly(butylene adipate‐co‐terephthalate) (PBAT) was functionalised with itaconic anhydride (IA) via melt grafting in a batch mixer, initiated by dicumyl peroxide (DCP). It was found that the ratio of IA to DCP is critical to avoid undesired side reactions, such as crosslinking and chain scission. PBAT and other polyesters with low aliphatic hydrocarbon content are relatively unreactive toward radical graft modification, providing relatively low degree of grafting. Using 2 wt% IA and 1.2 wt% DCP gave the highest degree of grafting (1%), with little indication of crosslinking or chain scission. The complex reaction mechanism of grafting presents a clear competition between grafting, homopolymerization, crosslinking, and chain scission. Using non‐isothermal kinetic modeling, it was shown that the reaction is not first order, and that models making this assumption leads to incorrect results. Using the Vyazovkin model‐free method, the effective rate constant was predicted over a typical melt processing temperature range. Low reagent concentration resulted in the lowest effective rate constant, and it was shown that the activation energy changes with conversion and is also affected by reagent concentration.

Optimisation of single contour strategy in selective laser melting of Ti-6Al-4V lattices

PurposeSelective laser melting (SLM) is increasingly used to manufacture bone implants from titanium alloys with particular interest in porous lattice structures. These complex constructs have been shown to be capable of matching native bone mechanical behaviour leading to improved osseointegration while providing numerous clinical advantages, encouraging their broad use in medical devices. However, producing lattices with a strut diameter similar in scale to a typical SLM melt pool or using the same process parameters and scan strategies intended for bulk solid components may lead to geometric inaccuracies. The purpose of this study is to evaluate and optimise the single contour strategy for the production of Ti-6Al-4V lattices.Design/methodology/approachHerein, the potential of an unfilled single contour (SC) scanning strategy to improve the reproducibility of porous lattices when compared with a single contour and fill approach (SC + F) is explored. For this purpose, two parametric analysis were carried out on Ti-6Al-4V diamond unit cell lattices with different strut sizes and scan strategies. Porosity and accuracy measurements were correlated with processing parameters and printing strategy to provide the optimal processing window for lattice manufacturing.FindingsSC is shown to be a viable strategy for production of Ti-6Al-4V lattices with a strut diameter below 350 µm. Parametric analysis highlights the limits of this method in producing fully dense struts with energy density presented as a useful practical tool to guide some aspects of parameter selection (design strut diameter achieved at approximately 0.1 J/mm in this study). Finally, a process map combining data from both parametric studies is provided to guide, predict and control lattice strut geometry and porosity obtained using the SC strategy.Originality/valueThese results explore the use of non-standard SC scanning strategy as a viable method for producing strut-based lattice structures and compare against the traditional contour and fill approach (SC + F).

Influence of alkali and alkaline earths on structural and luminescence properties of Sm3+ doped lithium fluoro phosphate glass and different (Na, Mg, K, Ca and Sr) glass ceramics

Transparent glass ceramics comprising of BiPO4 nanocrystals in bismuth phosphate glass ceramics (59.5P2O5+15Bi2O3+10BaF2+10AF+05TeO2+0.5Sm2O3 where AF= alkali and alkaline earth fluorides) doped with Sm3+ ions were synthesized by typical melt quenching route. On the basis of data obtained from differential thermal analysis (DTA), prepared samples were analyzed for their thermal stability. Further powder X-Ray diffraction (PXRD) analysis has been done for all the samples to confirm the crystalline phase of BiPO4 and short-range order i.e., isotropic. Validations of various structural units were done with the help of FTIR. Spectral intensities were obtained using Judd-Ofelt (JO) theory for various absorption bands of Sm3+ ions using least square fit method for all the studied glass and glass ceramics. Various optical parameters of Sm3+ doped lithium phosphate glass and various glass ceramics were obtained from emission and absorption spectra studied in the present work. Theses optical parameters include JO intensity parameters (Ω2, Ω4 andΩ6), radiative transition probabilites (Aed), branching ratios (β), emission cross sections (σe), absorption cross sections (∑),gain bandwidths and optical gains (σe × Δλeff and σe × τR respectively). Influence of alkali and alkaline earths metals on radiation properties of various excited levels of Sm3+ has been investigated. In relation to the other glass networks and ceramics, SrF2 glass ceramics studied in the present work exhibited productive properties and could be useful in development of optical devices for visible laser applications.

The development of unlabeled probes-high resolution melting (UP-HRM) marker on SAD, IAA27 and ACC genes of oil palm

Abstract. Saputra TI, Roberdi, Nugroho YA, Artutiningsih W, Purba OS, Maryanto SD, Yono D, Utomo C, Liwang T. 2021. The development of unlabeled probes-high resolution melting (UP-HRM) marker on SAD, IAA27 and ACC genes of oil palm. Biodiversitas 22: 3356-3362. The unlabeled probes-high resolution melting (UP-HRM) marker is a useful tool for detecting of single nucleotide polymorphisms (SNPs). The objectives of this study were to develop UP-HRM markers to differentiate specific SNPs patterns on oil palm. The marker was developed and tested with Elaeis guineensis (Eg), Elaeis oleifera (Eo), Eo x Eg (hybrid), and was validated with 53 individuals of BC1F1 populations ((Eo x Eg) x Eg). Four UP-HRM markers were developed based on 2 SNPs in the stearoyl-acyl-carrier-protein 9-desaturase (EgSAD), 1 SNP in the auxin-responsive protein IAA27-like (EgIAA27), and 1 SNP in the 1-amino cyclopropane-1-carboxylate oxidase (EgACC) genes. The SNP discovery result showed that Eg was represented a reference homozygote genotype, while Eo was represented as an alternative homozygote genotype and the Eo x Eg hybrid was represented as a heterozygote genotype in all genes. The typical UP-HRM melt curve graph was successfully generated. This result was consistent with each genotype model for all four markers. The UP-HRM markers can distinguish each genotype according to the single-pass sequencing results. Furthermore, dendrogram analysis on validation divided 53 BC1F1 samples into three cluster groups.

Distribution and seasonal evolution of supraglacial lakes on Shackleton Ice Shelf, East Antarctica

Abstract. Supraglacial lakes (SGLs) enhance surface melting and can flex and fracture ice shelves when they grow and subsequently drain, potentially leading to ice shelf disintegration. However, the seasonal evolution of SGLs and their influence on ice shelf stability in East Antarctica remains poorly understood, despite some potentially vulnerable ice shelves having high densities of SGLs. Using optical satellite imagery, air temperature data from climate reanalysis products and surface melt predicted by a regional climate model, we present the first long-term record (2000–2020) of seasonal SGL evolution on Shackleton Ice Shelf, which is Antarctica's northernmost remaining ice shelf and buttresses Denman Glacier, a major outlet of the East Antarctic Ice Sheet. In a typical melt season, we find hundreds of SGLs with a mean area of 0.02 km2, a mean depth of 0.96 m and a mean total meltwater volume of 7.45×106 m3. At their most extensive, SGLs cover a cumulative area of 50.7 km2 and are clustered near to the grounding line, where densities approach 0.27 km2 km−2. Here, SGL development is linked to an albedo-lowering feedback associated with katabatic winds, together with the presence of blue ice and exposed rock. Although below-average seasonal (December–January–February, DJF) temperatures are associated with below-average peaks in total SGL area and volume, warmer seasonal temperatures do not necessarily result in higher SGL areas and volumes. Rather, peaks in total SGL area and volume show a much closer correspondence with short-lived high-magnitude snowmelt events. We therefore suggest seasonal lake evolution on this ice shelf is instead more sensitive to snowmelt intensity associated with katabatic-wind-driven melting. Our analysis provides important constraints on the boundary conditions of supraglacial hydrology models and numerical simulations of ice shelf stability.

Green ion-exchange bisfuranic polyamides by polycondensation with bio-based diamines

A monomer fully based on renewable materials was prepared from methyl 2-furoate and levulinic acid by condensation reaction under acidic conditions. The monomer is used for the synthesis of ion-exchange polyamides based on a new family of bisfuranic diesters. Polyamides prepared using typical melt polycondensation have provided a relatively simple and reliable way of preparing linear furanic polycondensates bearing regular structures with high yield. The ion-exchange polyamides were characterized by Fourier transform infrared spectroscopy and elemental analysis. The thermal behavior of the polymers was studied by differential scanning calorimetry and thermogravimetric analysis. The ion-exchange capacity was determined by direct titration of the dry polymer.

Rapid Solidification and Non-equilibrium Phase Constitution in Laser Powder Bed Fusion (LPBF) of AlSi10Mg Alloy: Analysis of Nano-precipitates, Eutectic Phases, and Hardness Evolution

The non-equilibrium phase evolution during laser powder bed fusion (LPBF) of AlSi10Mg alloy is thoroughly characterized and analyzed by means of advanced electron microscopy and analytical simulation of rapid solidification phenomenon. The evolution of microstructural strengthening agents such as inter-cellular eutectic phase and intra-cellular precipitates is presented in correspondence with the local variation of cellular/dendritic solidification patterns within a typical melt pool. The eutectic phase exhibits two different morphologies: lamellar and fibrous. As with the cell size variation, the overall volume fraction of eutectic phase and the lamella spacing is shown to gradually decrease by moving away from the melt-pool boundary (MPB), i.e., through crossing over from a coarse to a fine cellular zone. The eutectic-free regions within the α-Al cells contain a large number density of nano-sized precipitates that are predominantly Si-rich and are either fully or semi-coherent with the Al matrix. The formation of nano-precipitates is linked to the increased (non-equilibrium) solubility limits of α-Al cells due to the rapid solidification effect. For the first time, we identify such nano-precipitates with non-equilibrium crystal structures and morphologies: “Spheres” and “Ellipsoids” with Face Centered Cubic (FCC), and “Plates” and “Needles” with a Diamond Cubic (DC) superlattice structure that emerges from within the Al matrix. The microstructure in the heat-affected zone (HAZ) right underneath the MPB exhibits an absence of cell boundaries and eutectic phases while consisting primarily of large Si-rich and Mg-rich precipitates. Finally, the local variation of nano-hardness across a solidified melt pool is shown to correlate well with the corresponding profile of microstructural refinement, i.e., exhibiting a minimum at the HAZ and a peak at around the melt-pool centerline. The findings here can significantly advance the state of knowledge for the strengthening behavior in an as-built LPBF-processed AlSi10Mg alloy.

Analysis of Wetting Behavior and Solidification Process of Molten Urea on a Superhydrophobic Surface and Its Application in Large Granular Urea Production

The wetting behavior of polar high-temperature melt on superhydrophobic surfaces is rarely studied, although water wetting process under normal temperature has been widely investigated. In this work, molten urea was considered as the typical polar melt substance, and its wetting behavior and solidifying process on a polytetrafluoroethylene (PTFE)-coated superhydrophobic stainless steel surface (PSSSS) were investigated. The results confirm the super-repellency of PSSSS on molten urea droplets with a static angle of over 155° and a rolling angle of 3.5 ± 1°, which is consistent with the Cassie–Baxter state. Such a superurea-melt-phobic state is ascribed to the high roughness of the PTFE-coated surface and high cohesive energy density difference between the urea and PTFE. The solidification process of the urea melt on PSSSS occurred from the outside to inside in 44 s at 18 °C to form a compact urea granule of large size and high mechanical strength. This occurrence provides a feasible and promising granulat...

Rheological characterization of filled polyamide 11 and polyamide 12 solutions in polyols

ABSTRACTA thorough understanding of the rheological properties of real‐world, formulated polymer melts and solutions is important to fabricate articles via typical melt processing techniques. Polyamides have been studied extensively in the area of water purification applications. In this work, the viscosity of these homogeneous polyamide 11 and polyamide 12 solutions in specific polyols was measured in the single phase region as a function of shear rate and temperature via capillary rheometry. In addition, the viscosity of the same polyamide solutions containing various levels of dispersed, nanoscale calcium carbonate particles was characterized in order to understand the rheology of the filled systems. Viscosity‐reduced shear rate master curves were constructed by applying the principle of time–temperature superposition, and the activation energies were measured for the polyamide‐polyol solutions. The observed increase in viscosity caused by the addition of nanofiller could not be explained by simply applying a vertical shift to the master curve, and a density exponent was required to account for the stiffening mechanism. Also, the dependence of the relative viscosity on the filler loading was shown to be consistent with the hypothesis that the filler particles were organized in the form of small fractal aggregates. The filled polyamide 11 systems exhibited higher relative viscosities than the filled polyamide 12 systems, indicating a higher level of particle aggregation and larger mean cluster size for the filled polyamide 11 systems. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 48244.

Geochronology and Petrogenesis of Mafic-Intermediate Intrusions on the Northern Margin of the Central Tianshan (NW China): Implications for Tectonic Evolution

Late Paleozoic mafic-intermediate intrusions are widespread in the central Tianshan belt, but their tectonic settings remain controversial. Petrogenesis of these intrusions can provide insights into the tectonic evolution of the belt and its adjacent areas. This study presents new whole-rock geochemical and zircon U-Pb geochronology and Hf isotopic data for the Yaxi diorite and Qianzishan gabbro on the northern margin of the central Tianshan (NW China). Zircon U-Pb dating yielded the magma crystallization ages of 313±4 and 295±4 Ma for the Yaxi diorite and Qianzishan gabbro, respectively. They have lower Mg# values, Ni and Cr contents than typical mantle-derived primary melt, with negative correlations between MgO, TFeO and SiO2 contents, indicating clinopyroxene and olivine fractionation during magma evolution. They are characterized by enrichment of large ion lithophile elements (e.g., Rb, Ba and Sr) and depletion of high field strength elements (e.g., Nb, Ta and Ti) with high Ba/Th and Rb/Y, suggesting that their mantle sources had been metasomatized by slab-derived fluids. In addition, the Qianzishan gabbro has high Al2O3 contents (19.54 wt.%-20.88 wt.%) and positive Eu anomalies (Eu/Eu*=1.09-1.42), which can be attributed to accumulation of plagioclase. Geochemical and zircon Hf isotopic compositions reveal that both the Yaxi diorite and Qianzishan gabbro were derived from depleted lithospheric mantle in the spinel stability field with insignificant crustal contamination. In association with previous investigations, we suggest that the Yaxi and Qianzishan intrusions were emplaced in a subduction-related environment, which means that the subduction of the Junggar Ocean lasted at least to the earliest Permian.

Isothermal Crystallization Kinetics Study of Fully Aliphatic PA6 Copolyamides: Effect of Novel Long-Chain Polyamide Salt as a Comonomer.

N1, N6-bis (4-aminobutyl) adipamide (BABA) diamine and sebacic acid (SA), also called BABA/SA polyamide salt, were used in a typical melt polymerization processes of polyamide 6 (PA6) to form a series of PA6-BABA/SA copolyamides. The effects of BABA/SA on the isothermal crystallization kinetics of PA6-BABA/SA were studied for the first time. An isothermal crystallization analysis demonstrates that the PA6-BABA/SA matrix provided a higher crystallization rate and shorter half-crystallization time than virgin PA6 did. The degree of crystallization of the PA6-BABA/SA30 matrix was also the lowest among all of the samples considered herein. This result is attributed to the high nucleation efficacy of a small amount of BABA/SA in the crystallization of PA6. Values of the Avrami exponent (n) from 1.84 to 3.91 were observed for all of the polyamide samples, suggesting that the crystallization was involved via a two- to three-dimensional growth mechanism. These findings deepen our understanding of the structure–property relationship of PA6-BABA/SA copolyamides, favoring their practical application.