Low Degree Of Order Research Articles

Effect of annealing time on solid solution microstructure and memory properties of additive Fe-Mn-Si-Cr-Ni alloy

Annealing plays a pivotal role in optimizing the morphology and quantity of cooling martensite within the solid solution matrix of additively manufactured Fe-based memory alloys. In this study, we utilized laser filament deposition to create Fe-17Mn-6Si-9Cr-5Ni alloy, and subsequently compared the microstructure and memory properties of the alloy following two treatments: a 900[Formula: see text]C× 60 min solution treatment and a solid solution + annealing treatment at various durations at 600[Formula: see text]C. Our aim was to investigate how annealing time impacts the memory properties of additively manufactured Fe-Mn-Si-Cr-Ni alloys in their solid solution state, focusing on microstructural changes during the metamorphic and revertive states. The findings reveal that after the solution treatment, the alloy contains a higher number of cooling martensite units, but their arrangement is disordered, indicating a lower degree of order. However, after a 10 min annealing treatment, the quantity of cooling martensite slightly diminishes, while their arrangement becomes more orderly. With prolonged annealing, both the quantity of cooling martensite and the grain size of the alloy decrease significantly. Consequently, after a 10-min annealing treatment, the alloy exhibits a 31% increase in shape recovery rate under a 6% pre-deformation compared to the alloy subjected solely to the solution treatment, and the recoverable strain reaches 4.59%. This demonstrates that an appropriately timed annealing process can transform the disordered cooling martensite within the solid solution structure of additive manufacturing Fe-based memory alloys into a more regular arrangement, thereby enhancing their memory performance.

Exact subdomain and embedded interface polynomial integration in finite elements with planar cuts

The implementation of discontinuous functions occurs in many of today’s state-of-the-art partial differential equation solvers. However, in finite element methods, this poses an inherent difficulty: efficient quadrature rules available when integrating functions whose discontinuity falls in the element’s interior are for low order degree polynomials, not easily extended to higher order degree polynomials, and cover a restricted set of geometries. Many approaches to this issue have been developed in recent years. Among them, one of the most elegant and versatile is the equivalent polynomial technique. This method replaces the discontinuous function with a polynomial, allowing integration to occur over the entire domain rather than integrating over complex subdomains. Although eliminating the issues involved with discontinuous function integration, the equivalent polynomial tactic introduces its problems. The exact subdomain integration requires a machinery that quickly grows in complexity when increasing the polynomial degree and the geometry dimension, restricting its applicability to lower order degree finite element families. The current work eliminates this issue. We provide algebraic expressions to exactly evaluate the subdomain integral of any degree polynomial on parent finite element shapes cut by a planar interface. These formulas also apply to the exact evaluation of the embedded interface integral. We provide recursive algorithms that avoid overflow in computer arithmetic for standard finite element geometries: triangle, square, cube, tetrahedron, and prism, along with a hypercube of arbitrary dimensions.

Effect of cooling rate on the order degree, residual stress, and room temperature mechanical properties of Fe-6.5wt.%Si alloy

The top side-pouring twin-roll casting (TSTRC) process was used to prepare a 100 × 1.7 mm non-oriented Fe-6.5 wt% Si alloy as-cast strip. The as-cast strip is directly rolled at 700 °C into 0.4 mm without the intermediate hot rolling step. This paper discusses the effects of different cooling rates in furnace cooling, air cooling, oil quenching, and water quenching on the order degree, residual stress, room temperature mechanical properties, and cold-rolled processing properties of Fe-6.5wt.%Si alloy after annealing of warm-rolled sheets are systematically investigated. Meanwhile, the effects of order degree, residual stress, and grain boundary element segregation on the mechanical properties were analyzed. The results show that as the cooling rate increases, the order degree of the Fe-6.5 wt% Si alloy decreases and the maximum residual tensile stress increases. The fracture modes of the furnace cooling, air cooling, and oil quenching samples are through-crystal disintegration fracture, and the fracture mode of the water quenching samples is an along-crystal fracture. The oil-quenched samples exhibit good room temperature plasticity due to the relatively low order degree and residual tensile stresses in the Fe-6.5wt.%Si alloy. Oil quenching improves the room temperature plasticity and cold rolling properties of Fe-6.5wt.%Si alloy warm rolled sheets, reduces edge cracks, and offers greater room temperature cold rolling processibility of the Fe-6.5wt.%Si alloy warm rolled sheets.

Effects of Fe-6.5wt.%Si alloys prepared by different cooling methods on ordered structure and mechanical properties

The non-oriented Fe-6.5wt.%Si alloy cast strip with a width of 100 mm and a thickness of 1.7 mm was prepared by the top side-pouring twin-roll-casting (TSTRC) process. The surface quality of the air-cooled and water-cooled cast strip was good. Compared with the Fe-6.5wt.%Si alloy ingot, the Fe-6.5wt.%Si alloy cast strip has a fine solidification structure and exhibits certain plasticity at room temperature. Microhardness, XRD, and TEM investigated the ordered structure and degree of Fe-6.5wt.%Si alloys prepared by three different cooling methods. The results show that the Fe-6.5wt.%Si alloy ingot prepared by the standard method has many B2-ordered phases and D03-ordered phases, and the order degree is high. The Fe-6.5wt.%Si alloy cast strip prepared by the TSTRC process has a low degree of order and only contains a small B2-ordered phase. The faster cooling rate effectively inhibits the formation of the D03-ordered phase and B2-ordered phase. The growth of the ordered phase also reduces the reverse domain boundary energy, reduces the motion resistance of superdislocations, and increases its mobility, thereby improving the room temperature plasticity of Fe-6.5wt.%Si alloy cast strips.

Relationship between nitrogen fertilizer and structural, pasting and rheological properties on common buckwheat starch

Nitrogen is an essential element for the yield and quality of grain. In this study, the structural and physicochemical properties of two common buckwheat varieties under four nitrogen levels (0, 90, 180, 270 kg N ha−1) at one location in two years were investigated. With increasing nitrogen level, the contents of moisture and amylose decreased but the contents of ash and crude protein increased. Excessive nitrogen application significantly increased the granule size, but reduced the light transmittance, water solubility, swelling power, absorption of water and oil. All the samples showed a typical A – type pattern, while high relative crystallinity and low order degree were observed under high nitrogen level. The samples under high nitrogen level had lower textural properties, pasting properties and rheological properties but higher pasting temperature and gelatinization enthalpy. These results indicated that nitrogen fertilizer significantly affected the structural and physicochemical properties of common buckwheat starch.

Functionalized Crystalline N-Trimethyltriindoles: Counterintuitive Influence of Peripheral Substituents on Their Semiconducting Properties.

Three crystalline N-trimethyltriindoles endowed with different functionalities at 3, 8 and 13 positions (either unsubstituted or with three methoxy or three acetyl groups attached) are investigated, and clear correlations between the electronic nature of the substituents and their solid-state organization, electronic properties and semiconductor behavior are established. The three compounds give rise to similar columnar hexagonal crystalline structures; however, the insertion of electron-donor methoxy groups results in slightly shorter stacking distances when compared with the unsubstituted derivative, whereas the insertion of electron-withdrawing acetyl groups lowers the crystallinity of the system. Functionalization significantly affects hole mobilities with the triacetyl derivative showing the lowest mobility within the series in agreement with the lower degree of order. However, attaching three methoxy groups also results in lower hole mobility values in the OFETs (0.022 vs. 0.0014 cm2 V−1 s−1) in spite of the shorter stacking distances. This counterintuitive behavior has been explained with the help of DFT calculations performed to rationalize the interplay between the intramolecular and intermolecular properties, which point to lower transfer integrals in the trimethoxy derivative due to the HOMO wave function extension over the peripheral methoxy groups. The results of this study provide useful insights into how peripheral substituents influence the fundamental charge transport parameters of chemically modified triindole platforms of fundamental importance to design new derivatives with improved semiconducting performance.

Effects of microwave treatments and retrogradation on molecular crystalline structure and in vitro digestibility of debranched mung-bean starches

The objective of this study was to investigate morphology, molecular crystalline structure, and digestibility of debranched mung bean starches with or without microwave treatment and retrogradation at different temperature. The mung bean starch was firstly debranched with pullulanase, and then the debranched starch containing 20% moisture content was treated by microwave irradiation for 3 min with or without further retrograded at +25, +4, or −18 °C for 24 h. All treated starches exhibited the B + V-type crystalline polymorph as determined by the XRD and the 13CNMR. The FT-IR results showed that the debranched starches had lower degree of order but higher degree of double helix than those of the native starch. The microwave treatment or further recrystallization of the debranched starch for more 24 h significantly improved crystalline structure of starch granules with higher degree of relative crystallinity, degree of order, and degree of double helices. The resistant starch content of the treated starch was in a range of 39.7–52.8%, significantly higher than that of the native starch (15.6%). As a result, the microwave-assisted debranched starch with further crystallization for 24 h was found to have highly ordered structure of granules, which highly resisted to the enzyme digestion.

Poly(Alkylene 2,5-Thiophenedicarboxylate) Polyesters: A New Class of Bio-Based High-Performance Polymers for Sustainable Packaging.

In the present study, 100% bio-based polyesters of 2,5-thiophenedicarboxylic acid were synthesized via two-stage melt polycondensation using glycols containing 3 to 6 methylene groups. The so-prepared samples were characterised from the molecular point of view and processed into free-standing thin films. Afterward, both the purified powders and the films were subjected to structural and thermal characterisation. In the case of thin films, mechanical response and barrier properties to O2 and CO2 were also evaluated. From the results obtained, it emerged that the length of glycolic sub-units is an effective tool to modulate the chain mobility and, in turn, the kind and amount of ordered phases developed in the samples. In addition to the usual amorphous and 3D crystalline phases, in all the samples investigated it was possible to evidence a further phase characterised by a lower degree of order (mesophase) than the crystalline one, whose amount is strictly related to the glycol sub-unit length. The relative fraction of all these phases is responsible for the different mechanical and barrier performances. Last, but not least, a comparison between thiophene-based homopolymers and their furan-based homologues was carried out.

Effect of annealing on crystallization behavior in Cu15Zr85 amorphous film

The crystallization in Cu15Zr85 amorphous film was studied by using molecular dynamics simulation in a wide annealing temperature region. The effect of annealing temperature on crystallization behavior was evaluated. The degree of crystallization increases firstly and then decreases with the increasing of annealing temperature in Cu15Zr85 amorphous film. A comparison of interior and Surface-A components shows that Surface-A component has higher crystallization rate at low annealing temperature and lower degree of crystallization at high annealing temperature because of faster atomic diffusion. Structural evolution of surface monolayer is unique during annealing. No discernable crystal-like structure is found after annealed in the surface monolayer by directly observing the atomic structure. Surface monolayer with hexagon cluster has low degree of order at high annealing temperature because of the fast liquid-like diffusive motion and improved glass-forming ability.

Physicochemical and structural properties of sago starch

A comprehensive study was conducted to elucidate physicochemical and structural properties of sago starches. Two sago starch granules were oval in shape with an average diameter of 34.41 μm and had C-type polymorph with a crystallinity of about 28.13%. The amylose and resistant starch (RS) contents of two sago starches were higher than those of corn and potato starches. The two sago starches had a large amount of A and B1 chains (DP 6–24) which could form double helix structures. FTIR exhibited that the structure of two sago starches had a lower degree of order. The peak viscosity and breakdown of sago starch 2 were lower than corn starch, and the setback was higher than potato starch. Additionally, sago starches had lower gelatinization enthalpy and higher regeneration tendency. According to rheological results, sago starches showed lower shear thinning degree and thixotropy compared to corn and potato starches. Sago starch 1 gels represented the highest hardness, adhesiveness, springiness and cohesiveness, which could be used as potential food stabilizer. This study revealed the characteristics of two sago starches compared with other starches. The results indicated that the amylose content and amylopectin structures had significant influence on the physicochemical properties of sago starch.

Fully Biobased Superpolymers of 2,5-Furandicarboxylic Acid with Different Functional Properties: From Rigid to Flexible, High Performant Packaging Materials.

In the present paper, four fully biobased homopolyesters of 2,5-furandicarboxylic acid (2,5-FDCA) with a high molecular weight have been successfully synthesized by two-stage melt polycondensation, starting from the dimethyl ester of 2,5-FDCA and glycols of different lengths (the number of methylene groups ranged from 3 to 6). The synthesized polyesters have been first subjected to an accurate molecular characterization by NMR and gel-permeation chromatography. Afterward, the samples have been successfully processed into free-standing thin films (thickness comprised between 150 to 180 μm) by compression molding. Such films have been characterized from the structural (by wide-angle X-ray scattering and small-angle X-ray scattering), thermal (by differential scanning calorimetry and thermogravimetric analysis), mechanical (by tensile test), and gas barrier (by permeability measurements) point of view. The glycol subunit length was revealed to be the key parameter in determining the kind and fraction of ordered phases developed by the sample during compression molding and subsequent cooling. After storage at room temperature for one month, only the homopolymers containing the glycol subunit with an even number of −CH2– groups (poly(butylene 2,5-furanoate) (PBF) and poly(hexamethylene 2,5-furanoate) (PHF)) were able to develop a three-dimensional ordered crystalline phase in addition to the amorphous one, the other two appearing completely amorphous (poly(propylene 2,5-furanoate (PPF) and poly(pentamethylene 2,5-furanoate) (PPeF)). From X-ray scattering experiments using synchrotron radiation, it was possible to evidence a third phase characterized by a lower degree of order (one- or two-dimensional), called a mesophase, in all the samples under study, its fraction being strictly related to the glycol subunit length: PPeF was found to be the sample with the highest fraction of mesophase followed by PHF. Such a mesophase, together with the amorphous and the eventually present crystalline phase, significantly impacted the mechanical and barrier properties, these last being particularly outstanding for PPeF, the polyester with the highest fraction of mesophase among those synthesized in the present work.

Physicochemical and structural properties of starches isolated from quinoa varieties

Starches isolated from four quinoa varieties were analyzed for physicochemical, morphological, and structural properties. All varieties of quinoa starches (QS) have lower amylose content, ranging from 9.43% to 10.90%, than maize starch (22.58%) and potato starch (17.75%) and thus has lower water solubility index and higher swelling power. QS has lower pasting temperature and setback and breakdown than maize starch. QS has lower enthalpy change (△H) and exhibits good resistance to retrogradation. In terms of rheological properties, QS has lower degree of shear-thinning and thixotropy than maize and potato starch. Additionally, QS has irregular polygon granules with small granule diameters ranging from 1.21 μm to 1.95 μm and display the A-type X-ray diffraction pattern. The crystallinity of QS ranges from 21.00% to 29.67%, which is significantly lower than that of maize starch. Fourier-transform infrared spectroscopy showed that the QS structure is a double helix and has a lower degree of order than the structures of maize and potato starch. This study revealed the particular properties of QS with four varieties as compared with other starch varieties.

Warm deformation behavior and work-softening mechanism of Fe–6.5wt.%Si alloy

Warm deformation behavior of the Fe–6.5wt.%Si alloy was studied by isothermal compression in the temperature range of 300–700 °C. The results show that the influence of the ordered phases on the flow stress gradually weakens with increasing deformation temperature. The flow stress of the furnace-cooled sample with the high degree of order at 300 °C is higher than that of the quenched sample with the low degree of order, and the flow stresses of both samples are nearly the same at 500–700 °C. The hardness difference between two samples deformed at 500 °C gradually decreases with increasing strain, accompanying with a reduction in hardness of the furnace-cooled sample, which indicates a work-softening behavior. The analyses of dislocation configurations and ordered structure suggest that the dynamic recovery and deformation-induced disorder result in the work-softening behavior. An appropriate deformation temperature window for improving the formability of the Fe–6.5wt.%Si alloy is about 500–600 °C.

Deformation twinning characteristics in hot-rolled Fe-6.5wt%Si alloy with different degree of order

Tensile deformation behavior of the Fe-6.5 wt%Si alloy with different degree of order at intermediate temperatures (200-500 °C) was investigated. Deformation twinning was observed in this body centered cubic A2 phase together with ordered structures. It is found that the ductility of the quenched samples with low degree of order is higher than that of the furnace cooled samples with high degree of order. Deformation twinning occurred in the quenched samples after dislocation slip during deformation at 200-300 °C, while no deformation twins were observed in the furnace cooled samples. The results indicate that the low degree of order is an essential precondition for the deformation twinning, which can also enhance dislocation slip. The <001> orientation along the rolling direction and large grain size can reduce the critical twinning stress. High strain rate and low deformation temperature can further promote the formation of the twinning by dislocations pile-up and high work hardening rate. Our work provides new insights into the deformation mechanism in the Fe-6.5 wt%Si alloy.

Triptycene Tripods for the Formation of Highly Uniform and Densely Packed Self-Assembled Monolayers with Controlled Molecular Orientation.

When employing self-assembled monolayers (SAMs) for tuning surface and interface properties, organic molecules that enable strong binding to the substrate, large-area structural uniformity, precise alignment of functional groups, and control of their density are highly desirable. To achieve these goals, tripod systems bearing multiple bonding sites have been developed as an alternative to conventional monodentate systems. Bonding of all three sites has, however, hardly been achieved, with the consequence that structural uniformity and orientational order in tripodal SAMs are usually quite poor. To overcome that problem, we designed 1,8,13-trimercaptomethyltriptycene (T1) and 1,8,13-trimercaptotriptycene (T2) as potential tripodal SAM precursors and investigated their adsorption behavior on Au(111) combining several advanced experimental techniques and state-of-the-art theoretical simulations. Both SAMs adopt dense, nested hexagonal structures but differ in their adsorption configurations and structural uniformity. While the T2-based SAM exhibits a low degree of order and noticeable deviation from the desired tripodal anchoring, all three anchoring groups of T1 are equally bonded to the surface as thiolates, resulting in an almost upright orientation of the benzene rings and large-area structural uniformity. These superior properties are attributed to the effect of conformationally flexible methylene linkers at the anchoring groups, absent in the case of T2. Both SAMs display interesting electronic properties, and, bearing in mind that the triptycene framework can be functionalized by tail groups in various positions and with high degree of alignment, especially T1 appears as an ideal docking platform for complex and highly functional molecular films.

Insights into the isomeric effect on the self-assembly of donor-acceptor type aggregation-induced emission luminogens: Colour-tuning and shape-controlling

In this study, we reported the synthesis and aggregation-induced emission (AIE) properties of a new molecular system, comprised of six positional isomers. The presence of electron donor (D) and acceptor (A) units endows them with intramolecular charge transfer (ICT) effects. We studied how changing the positions of the D/A units affects the AIE properties, ICT strength as well as the energy levels of the molecular orbitals. In addition, the self-assembly behaviors of them show distinct isomeric effect: With the D/A units repositioning, various self-assembly architectures with sizes ranging from microscale to nanoscale appear sequentially, including filaments, sheets, rods, irregular particles, needles, fibrous interlocking textures. It was verified that the D/A units on para-position that pose linear dipole-dipole interaction would favor the formation of well-defined structures, otherwise the resulting assembly would be underdeveloped or ill-shaped due to low degree of order in the molecular packing. This study probed the relationships between molecular structure and self-assembly behaviour, and further makes the self-assembly customizable.

The Formation and Dynamic Evolution of Antiphase Domain Boundary in FeAl Alloy: Computational Simulation in Atomic Scale

The main objective of the present work is to build a model and analyze the dynamic evolution process of antiphase domain boundary (APDB) in FeAl alloy. The formation, evolution of APDB, long range order (LRO), the crystal structure transition, impact of temperature on LRO, are investigated. Comparisons with experiments proves that the model is competent for the dynamic investigation of APDB in microscopic scale and able to predict different boundary-types and their corresponding atoms distribution. The dynamic process shows that the initial distribution of premier micro domains determine the morphology of APDB. The morphological evolution of APDB significantly affects the quantity of APDB. The in situ observation shows that the crystal structure of a micro domain is altered by the APDB movement. The calculated LRO revealed that the atoms in Al-sublattice mainly contribute to the low order degree of FeAl at different temperatures.

Origins and Geochemistry of Oolitic Dolomite of the Feixianguan Formation from the Yudongzi Outcrop, Northwest Sichuan Basin, China

The topic of dolomite formation has long presented a challenge to researchers. In this study, the origin of widely occurring oolitic dolomites from the Yudongzi outcrop in the lower Triassic Feixianguan formation in northwest Sichuan, China, was investigated through petrographic observations, and mineralogical and geochemical analysis. Analytical methods used include cathodoluminescence, X-ray diffraction, stable isotopes, and electronic microprobe characterization. The dolomites were categorized into three major genetic types according to their textural and structural characteristics, which reflect their various origins. The first genetic type of these dolomites, seepage reflux dolomitization, occurs in marly to microcrystalline dolomite during the penecontemporaneous stage, and displays negatively skewed δ18Ο (−2.83‰ Pee Dee Belemnite (PDB)), positively skewed δ13C (2.71‰ PDB), a low degree of order (0.48), and 87Sr/86Sr ratios of 0.707509–0.707634, indicating involvement of a Mg-rich brine fluid in an open evaporative environment. The second type, shallow burial dolomitization, is the most significant genetic type of dolomite reservoir in this area. This process produced dominantly silty to fine crystalline dolomite in a platform-margin oolitic beach facies with negatively skewed δ18Ο (−3.26‰ PDB), positively skewed δ13C (1.88‰ PDB), a high degree of order (0.70), and 87Sr/86Sr ratios of 0.707318–0.707661, which are related to seawater-derived fluids in a shallow burial environment. The third type is moderate to deep burial dolomitization, and is the main process responsible for zoned dolomite and dolomite with cloudy cores and clear rims (CCCR dolomite), which have the most strongly negatively skewed δ18Ο (−7.32‰ PDB), positively skewed δ13C (3.02‰ PDB), and 87Sr/86Sr ratios of 0.707217–0.707855, representing diagenetic alteration and fluid flow in a closed environment. These findings indicate that dolomite was likely affected by various degrees of burial and related marine-derived fluids, which will aid exploration efforts in high-quality hydrocarbon reservoirs in the Sichuan Basin.

Experimental and kinetic studies on co-gasification of petroleum coke and biomass char blends

The non-isothermal thermogravimetric method was applied to petroleum coke (PC), corncob char (CC) and their blends with the different mass ratios under CO2 atmosphere. The results show that CC with highly developed pore structure, high content of alkali metals and low degree of order had more reactivity than that of PC. The gasification reactivity of PC could be effectively improved by blending with CC. Meanwhile, there was obviously synergetic effect for the co-gasification of PC and CC. With the increase of mass ratio of CC, the synergetic effect first increased and then decreased. The synergetic effect was most obvious when CC mass ratio was 20%. Three nth-order representative gas-solid models: volume reaction model (VM), random pore model (RPM) and unreaction core model (URCM) were used to interpret the carbon conversion data. The overall fitting result of the RPM was slightly better than that of the VM and URCM. Furthermore, the synergetic effect between PC and CC was observed from the kinetics data calculated by RPM. The activation energy determined for PC and CC gasification was 203.2 kJ/mol and 243.3 kJ/mol, respectively, whereas, the lowest activation energy for their blends was 197.8 kJ/mol when CC ratio was 20%.

Dynamics of the sorption of phosphatidylcholine by mesoporous composites based on MCM-41

The possibility of predicting the breakthrough curves of a phospholipid (PL) during its sorption by mesoporous composites based on MCM-41 using models of the dynamics of sorption that consider the kinetics of adsorption (the Thomas model) and mixed diffusion (the asymptotic model) is demonstrated using phosphatidylcholine (PC) as an example. The effect the kinetic parameters have on the tailing of the sorption front with respect to the mixed diffusion limitation of the sorption of nonpolar biologically active substances (BASes) is shown. It is found that the ordered structure of composite materials based on MCM-41 ensures a high rate of mass transfer and thus little tailing of the sorption front, when compared to sorbents with a lower degree of order (silica gel and polymer materials) during the sorption of a phospholipid under dynamic conditions. Based on calculations of the parameter of pattern Λ under the conditions of the dynamic mode of sorption in mixed diffusion kinetics, it is shown that the sorption of phosphatidylcholine from hexane solutions by mesoporous composites based on MCM-41 allows the sorption chromatographic process to proceed in the most advantageous (quasi-equilibrium) mode.