Melting Temperature Range Research Articles

Phosphate: a neglected argument in studies of ancient glass technology

The phosphate content of ancient alkali-glass has been tested as an indicator for biogenic ash, used in glass production. The living tissue of plants and vertebrates accumulates phosphate that remains in native ash as a main component (1 to over 10 wt%) forming together with biologically essential element oxides a complex chemical fingerprint that characterises any glass made with it. If, instead of native plant ash its alkali extract is used, soluble oxides are concentrated in the extract whilst insoluble oxides get depleted, leading to a different elemental fingerprint of the glass. Geogenic raw-materials for glass production like quartz-rich sand, evaporitic natron, or limestone are virtually phosphate free (below detection limit up to ≈0.15 wt%). Several collections of ancient glass stemming from different archaeological excavations, regions and times have been analysed by instrumental methods (WD-XFA, ED-XFA, thermal techniques), i.e. flat- and hollow K–Ca glass dated 1699/1714 N = 340, Na–Ca glass 13th/14th cy N = 94, Na–Ca glass 7th/9th cy N = 110, and alkali-Ca glass La Tene N = 395. Although the phosphate content of native alkali plant ash gets diluted with quartz sand by a factor of roughly two in glass production, it remains a main component of the product glass. Wood-ash glass contains 1–3 wt% phosphate, whilst glass manufactured from halophyte ash contains around 0.2–1 wt%. When processed wood-ash is used, the phosphate content in glass sinks below 1 wt%, the depletion factor amounting to roughly 8–15. Glass made from evaporitic soda displays phosphate contents below 0.2 wt% in the cases examined. The phosphate content of ancient alkali glass thus indicates whether virtually phosphate-free evaporitic soda has been used as a flux, or native ash of halophile plants. Ternary melting diagrams reveal at least three groups of alkali glass: Naturally coloured forest glass displays a broad distributional pattern with minimum melting temperatures ranging from 1200 to ≥1450 °C, colourless potash-extract glass from 900 to ≈1200 °C, and the typical, tight cluster of Roman sodium-calcium glass ranges from 800 to ≈900 °C. The wide-spread sodium-lime glass made with native halophytic ash, contains besides Na2O as the chemical main component always some K2O, and melting temperatures range from 800 to ≈1000 °C.

A time-resolved current method and TSC under vacuum conditions of SEM: Trapping and detrapping processes in thermal aged XLPE insulation cables

Thermal aging of cross-linked polyethylene (XLPE) can cause serious concerns in the safety operation in high voltage system. To get a more detailed picture on the effect of thermal aging on the trapping and detrapping process of XLPE in the melting temperature range, Thermal Stimulated Current (TSC) have been implemented in a Scanning Electron Microscope (SEM) with a specific arrangement. The XLPE specimens are molded and aged at two temperatures (120°C and 140°C) situated close to the melting temperature of the material. The use of SEM allows us to measure both leakage and displacement currents induced in samples under electron irradiation. The first represents the conduction process of XLPE and the second gives information on the trapping of charges in the bulk of the material. TSC associated to the SEM leads to show spectra of XLPE discharge under thermal stimulation using both currents measured after electron irradiation. It was found that leakage current in the charging process may be related to the physical defects resulting in crystallinity variation under thermal aging. However the trapped charge can be affected by the carbonyl groups resulting from the thermo-oxidation degradation and the disorder in the material. It is evidenced from the TSC spectra of unaged XLPE that there is no detrapping charge under heat stimulation. Whereas the presence of peaks in the TSC spectra of thermally aged samples indicates that there is some amount of trapped charge released by heating. The detrapping behavior of aged XLPE is supported by the supposition of the existence of two trap levels: shallow traps and deep traps. Overall, physico-chemical reactions under thermal aging at high temperatures leads to the enhancement of shallow traps density and changes in range of traps depth. These changes induce degradation of electrical properties of XLPE.

Composition and compatibilization induced morphology alteration in PVDF/LLDPE blends: correlation between rheology and morphology

Correlation between the rheology and morphology of PVDF/LLDPE blends as well as the effect of LLDPE-g-MA compatibilizer on the microstructure and viscoelastic properties of these blends were studied in detail. Morphology development from matrix-dispersed to co-continuous and again to dispersed-matrix was well predicted using various linear viscoelastic analyses and confirmed via direct SEM experiments and continuity index analysis. Compatibilization induced alteration in the microstructure of the blends, particularly PVDF/PE 50/50 blend from co-continuous morphology to dispersed-matrix one, was also concluded from viscoelastic analysis and confirmed. It was shown that the feeding order had a distinct effect on morphology of the blends near the phase inversion composition. “Phase within a phase within a phase” morphology was observed near the phase inversion region, provided that the components are fed simultaneously. Different melting and crystallization temperature range of PVDF and PE phases was understood to be the main reason of this observation. It was also shown that compatibilization had higher impact on LLDPE-rich blends than PVDF-rich blends, while narrowed the co-continuity composition range.

Thermorheologically Complex Self-Seeded Melts of Propylene–Ethylene Copolymers

A novel approach to study self-nucleation in semicrystalline polymers is presented. Self-nucleation, i.e., the peculiar increase of recrystallization kinetics associated with a range of melting temperatures above or below the melting point, is investigated in parallel with differential scanning calorimetry (DSC) and rheological measurements, for a series of metallocene propene/ethylene random copolymers of varying comonomer content. DSC experiments revealed the exact temperature region where self-nucleation effects are detected in the various samples, while with dynamic viscoelastic results the obedience to the time–temperature superposition principle (TTS) is tested, for both self-nucleated and homogeneous melts. Self-nucleated melts do not obey to the TTS principle, contrary to fully isotropic copolymer melts. Such rheological thermocomplexity constitutes the first physical experimental evidence of the presence of melt heterogeneities, which act as self-nuclei when the melt is cooled and recrystallizes....

Reaction mechanisms of potassium oxysalts based energetic composites

Ignition temperature is a simple and important parameter that pertains to both the practical aspects of thermite usage as well as a key to exploring reaction mechanisms. In this study, nine aluminum-fueled oxysalt-containing thermites including K2S2O8, K2SO4, KIO4, KIO3, KClO4, KClO3, KBrO3, KNO3 and K3PO4, were investigated. Results from combustion cell tests show that these thermites can be divided into two groups, with the reactive thermites (e.g., Al–K2S2O8) generating ∼10× higher of pressure and ∼10× shorter of burn time than the less reactive thermites in the aforementioned list (e.g., Al–K2SO4). Thermal decomposition analysis of these oxysalts at both slow and fast heating rates (0.17K/s v.s. 105K/s) demonstrates that these oxysalts have a wide range of oxygen release and melting temperatures. On the other hand, the ignition temperatures of the reactive thermites (in Ar and air) are consistent with the temperature of polymorphic phase change of alumina (close to the melting point of Al), indicating that the limiting initiation step of these thermites is the acceleration of outward diffusion flux of Al. In addition, the ignition temperatures of these reactive thermites in vacuum are much higher than those in Ar, suggesting that ignition is based on the interaction between outwardly diffused Al, and generated gas phase O2. In contrast, the ignition temperatures of the two less reactive thermites are insensitive to pressure. They ignite at temperatures much higher than the melting point of Al, although lower than the decomposition temperature of the corresponding oxysalts, indicating a condensed phase reaction mechanism. Finally, by employing carbon as a non-melting, non-oxide coated fuel, we found an essentially direct correlation between the oxygen release temperature and the ignition temperature.

Crystallization and melting characteristics of iPP nucleated by a sustainable eggshell powder-supported β-nucleating agent

The β-form crystals in isotactic polypropylene (iPP) are proved to be favorable and effective for developing general iPP plastics with high performance. Herein, sustainable eggshell power decorated with calcium pimelate (DES), an effective β-form nucleating agent for iPP, was fabricated via the interaction between pimelic acid and Ca2+ on the surface of eggshell powder at elevated temperature. DSC and FTIR analysis identified the reaction occurred and formation of calcium pimelate on surface of the eggshell powder. Then, the effects of the functionalized eggshell powder on the nonisothermal and isothermal crystallization behavior, melting characteristics and polymorph structures were investigated. From the nonisothermal crystallization experiments, the incorporation of supported β-form nucleator greatly enhanced the crystallization temperature of iPP. The content of β-form crystals (Kβ) could reach a value as high as 87% at 5 mass% DES load. Moreover, the crystallization and melting characteristics of iPP nucleated by DES were not changed under multiple scan conditions with melt temperature range from 190 to 250 °C. Interestingly, from the investigation of isothermal crystallization and subsequent melting behavior, it was found that DES is a temperature-dependent selective nucleator for inducing iPP crystallization. Main α-form crystals or β-form crystals could form when using high or low crystallization temperatures, respectively. Particularly, these results demonstrated a possibility to tailor the ratio of α-form crystals to β-form crystals by simply choosing isothermal crystallization conditions. Then the crystallization mechanism based on thermodynamics and kinetics factors was further discussed.

Microstructure and melting behavior of a solution‐cast polylactide stereocomplex: Effect of annealing

ABSTRACTThe effect of annealing on the microstructure and melting behavior of a solution‐cast polylactide (PLA) stereocomplex (sc) was systematically investigated by differential scanning calorimetry and small‐angle X‐ray scattering. A preorder state, an intermediate form between the amorphous and crystalline states, was found in the solution‐cast poly(l‐lactide)–poly(d‐lactide) blend. When the annealing temperature (Ta) was below 220 °C, a part of the preorder state directly formed thicker sc crystallites; these corresponded to the second melting peak, which appeared around 250 °C during the heating process. Although the rest melted and became the amorphous phase, it formed a thinner lamella under the restriction of the unmelted initial sc crystallites during annealing; the melting process of this lamella was parallel to that of the new melting peak, which appeared around 220 °C. The melting of the initial crystal formed as the solvent volatilized corresponded to the range of the first melting temperature around 230 °C. When Ta was above 220 °C, the preorder state melted completely, and the initial crystal experienced perfection process. Furthermore, the highest melting temperature of PLA sc (254.1 °C, with a fusion enthalpy of 125.5 J/g) was obtained when Ta was 235 °C. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44626.

Impact of glucansucrase treatment on structure and properties of maize starch

A glucansucrase isolated from Leuconostoc citreum SK 24.002 has the ability to catalyze transglycosylation and/or hydrolysis reactions on differently linked α‐glucose polymers. In this study, maize starch was modified using L. citreum glucansucrase, and its structure and properties were investigated. The total content of oligosaccharides was 2.72% for glucansucrase‐treated starch. The modified starch had a higher amylose level and molecular weight than did native starch. The chain‐length distribution showed a greater number of short (degree of polymerization, DP < 13) and long (DP > 30) branched chains in the modified starch. Compared with the native starch, the modified starch displayed a lower gelatinization enthalpy and a wider melting temperature range. The Englyst assay revealed that enzymatically modified starch had higher SDS and RS contents. Both the changes in molecular weight and the fine‐chain structure in the treated starches likely contribute to its low digestion capacity.

Mineral Thermometry and Fluid Inclusion Studies of the Pea Ridge Iron Oxide-Apatite–Rare Earth Element Deposit, Mesoproterozoic St. Francois Mountains Terrane, Southeast Missouri, USA

Mineral thermometry and fluid inclusion studies were conducted on variably altered and mineralized samples from the Mesoproterozoic Pea Ridge iron oxide-apatite (IOA)-rare earth element (REE) deposit in order to constrain P-T conditions, fluid chemistry, and the source of salt and volatiles during early magnetite and later REE mineralization. Scanning electron microscopy (SEM)-cathodoluminescence and SEM-backscatter electron images show that quartz and rutile precipitated before, during, and after magnetite and REE mineral growth. Ti-in-quartz and Zr-in-rutile equilibration temperatures range from ≤350° to 750°C in the amphibole, magnetite, hematite, and silicified zones where T increased during magnetite and quartz growth and dropped precipitously after fracturing and brecciation. Late drusy quartz cements within a REE-rich breccia pipe record the lowest T (≤315°–400°C). Liquid-, vapor-rich, and hypersaline (±hematite, calcite) fluid inclusions are common and liquid CO 2 is present locally. Salinities define three populations: saline (10–27 wt % NaCl equiv), hypersaline (34–>60 wt % NaCl equiv), and dilute (0–10 wt % NaCl equiv ). The wide range of eutectic melting temperatures (−67° to −19°C) suggests that saline inclusions trapped variable proportions of a CaCl-MgCl-FeCl-bearing fluid end member and an NaCl-KCl fluid end member. Homogenization temperatures and pressures of these saline inclusions suggest they were trapped when fluids unmixed into brine and vapor at T The Na/Cl, Na/K, and Cl/Br ratios of fluid inclusion extracts provide evidence for mixtures of magmatic hydrothermal fluids and evaporated seawater. Extracts from magnetite, hematite, and pyrite plot in the magmatic-hydrothermal field, indicating that Fe was derived from a magmatic source. Their enrichments in Mg and Ca are consistent with a mafic magmatic source. The positive correlation between Na/Mg and Na/Ca ratios may be due to halite saturation or albitization of igneous rocks. Extracts from barite in the REE-rich breccia pipes are enriched in Na and Br and plot near the seawater evaporation trend. He is highly enriched relative to Ne and Ar in fluid inclusion extracts, which precludes air as a source of He. Although the He is mostly of crustal origin, pyrite with a 3 He/ 4 He (R/R A ) of 0.1 contains up to 12% mantle He. Many extracts have low 20 Ne/ 22 Ne ratios due to nucleogenic production of 22 Ne in high F/O minerals such as fluorapatite or F biotite. The arrays of data for 3 He/ 4 He (R/R A ) and 22 Ne/ 20 Ne suggest that volatiles were derived from two sources, a moderate F mafic magma containing mantle He and a high F silicic magma with crustal He. Together with other evidence cited in this report, these data (1) support a magmatic hydrothermal origin for the Mesoproterozoic magnetite-apatite deposit with ore fluids derived from a concealed mafic to intermediate-composition intrusion, (2) suggest that the REE minerals in breccia pipes were either derived from apatite or precipitated in response to decompression and cooling during breccia pipe formation, (3) provide evidence for the influx of basinal brine, magmatic fluids from granitic intrusions, and meteoric water after breccia pipe formation, and (4) show that Pea Ridge was relatively unaffected by the late Paleozoic Mississippi Valley-type (MVT) Pb-Zn system in overlying Cambrian sedimentary rocks.

Characteristics of the numerous and widespread recurring slope lineae (RSL) in Valles Marineris, Mars

Recurring slope lineae (RSL) are narrow (0.5–5m) dark features on Mars that incrementally lengthen down steep slopes, fade in colder seasons, and recur annually. These traits suggest that liquid water is flowing in the shallow subsurface of Mars today. Here we describe High Resolution Imaging Science Experiment (HiRISE) observations of RSL within Valles Marineris (VM). We have identified 239 candidate and confirmed RSL sites within all the major canyons of VM, with the exception of Echus Chasma. About half of all the globally known RSL locations occur within VM and the areal density of RSL on Coprates Montes appears to be the greatest on the planet. VM RSL are heterogeneously distributed, as they are primarily clustered in certain areas while being conspicuously absent in other locations that appear otherwise favorable. RSL have been found on many of the interior layered deposits (ILDs) within VM. Such ILD RSL appear to traverse bedrock, instead of regolith like all other RSL. Forty-six of the VM RSL sites show incremental lengthening and exhibit similar behavior in most of the canyons of VM, but the RSL duration at one site in Juventae Chasma is significantly reduced. Furthermore, the lengthening seasonality depends solely on slope orientation, with typical VM RSL on a given slope lengthening for ∼42–74% of a Mars year. There are always RSL lengthening within VM, regardless of the season. If RSL are caused by water, such a long active season at hundreds of VM RSL sites suggests that an appreciable source of water must be recharging these RSL. Thermophysical modeling indicates that a melting temperature range of ∼246 − 264K is needed to reproduce the seasonal phenomenology of the VM RSL, suggesting the involvement of a brine consisting of tens of wt% salt. The mechanism(s) by which RSL are recharged annually remain uncertain. Overall, gaining a better understanding of how RSL form and recur can benefit the search for extant life on Mars and could provide details about an in situ water resource.

Study on Thermal Physical Properties of Al-Si8-Cu2-Mg Alloy

Parts of thermal physical properties of Al-Si8-Cu2-Mg alloy were studied. The curves were plotted showing the relationship between density, specific heat capacity, coefficient of thermal expansion and the variation of temperature for the first time with this alloy. The results show that the density was decreased when the temperature was raised, but the specific heat capacity and the coefficient of thermal expansion were first increased and then decreased. The solidus-liquidus temperatures, latent heat of fusion were studied, and the results show that the melting temperature range of this alloy was 507-596°C.

Minimizing Voiding in Bottom Terminated Components by Optimizing the Solder Paste Flux

Abstract Perhaps the single biggest challenge in PCB assembly today is voiding under bottom terminated components (BTCs) such as QFNs (quad-flat-pack, no-leads), D-Paks, and LGAs (land grid arrays). Many bottom terminated components, such as QFNs, have a large thermal pad on the bottom side which provides excellent thermal and electrical grounding properties. However, effectively soldering these components to minimize thermal pad voiding can be a challenge. Many automotive electronics assemblers are increasing this challenge by requiring less than 10% voids to improve reliability. The large deposit of printed solder paste required to solder the thermal pad typically induces flux entrapment and subsequent voiding during the reflow process. Large voids and/or a high number of voids cause decreased thermal conductivity and lower the mechanical strength of the resulting solder joints. The large solder paste deposit required may also cause the component to float and open up the electrical connections around the perimeter of the component. Another factor affecting voiding has been the transition to lead-free solder, which has been marked by the use of various SAC alloys. Most applications for surface mount assembly use SAC305 (96.5Sn/3.0Ag/0.5Cu) with a melting temperature range of 217–220°C. The higher temperatures required for lead-free soldering and the increased surface tension of the SAC alloy exacerbate the voiding issue. This paper will focus on the techniques for optimizing the assembly process for QFN components, with a focus on minimizing voiding. Best practices for lead-free reflow profiling, stencil aperture design, solder paste volume control, and the importance of flux chemistry to minimize void formation will be discussed.

Electron-beam additive manufacturing of high-temperature metals

Abstract

Thermal energy storage enhancement of a binary molten salt via in-situ produced nanoparticles

Thermal energy storage (TES) system is an essential component of any concentrating solar thermal power (CSP) plant to ensure a reliable plant operation even at night or cloudy weather. To enhance the TES capacity, a one-step method was proposed to synthesize nano-salts by in-situ production of CuO nanoparticles, via a high temperature decomposition of copper oxalate, in a binary salt used as a phase change material (PCM). The specific heat of the nano-salt both for solid and liquid phases were measured by differential scanning calorimetry (DSC) with the weight fraction of CuO nanoparticles varied from 0.1 to 3.0wt%. The maximum specific heat increment of 7.96% in solid phase and 11.48% in liquid phase, were achieved at a CuO nanoparticle concentration of 0.5wt%. A forming of intermediate layers composing of needle-like structures between nanoparticles and the salt was observed. The mixing model considering such an intermediate layer can be used to explain the observed specific heat enhancement at low particle concentrations. Both latent heat and onset temperature were decreased with increasing concentrations of CuO nanoparticles, while the melting temperature range was increased. When considering both latent heat and sensible heat contributions, the maximum increment of TES was achieved as 4.71% at 0.5wt% CuO concentration in the temperature range from 160°C to 300°C.

Structural insights from a novel invertebrate triosephosphate isomerase from Litopenaeus vannamei

Triosephosphate isomerase (TIM; EC 5.3.1.1) is a key enzyme involved in glycolysis and gluconeogenesis. Glycolysis is one of the most regulated metabolic pathways, however little is known about the structural mechanisms for its regulation in non-model organisms, like crustaceans. To understand the structure and function of this enzyme in invertebrates, we obtained the crystal structure of triosephosphate isomerase from the marine Pacific whiteleg shrimp (Litopenaeus vannamei, LvTIM) in complex with its inhibitor 2-phosphogyceric acid (2-PG) at 1.7Å resolution. LvTIM assembles as a homodimer with residues 166–176 covering the active site and residue Glu166 interacting with the inhibitor. We found that LvTIM is the least stable TIM characterized to date, with the lowest range of melting temperatures, and with the lowest activation enthalpy associated with the thermal unfolding process reported. In TIMs dimer stabilization is maintained by an interaction of loop 3 by a set of hydrophobic contacts between subunits. Within these contacts, the side chain of a hydrophobic residue of one subunit fits into a cavity created by a set of hydrophobic residues in the neighboring subunit, via a “ball and socket” interaction. LvTIM presents a Cys47 at the “ball” inter-subunit contact indicating that the character of this residue is responsible for the decrease in dimer stability. Mutational studies show that this residue plays a role in dimer stability but is not a solely determinant for dimer formation.

Modeling of Building Envelope's Thermal Properties by Applying Phase Change Materials

All new buildings must be nearly zero-energy buildings (NZEB) by 2020, and all new buildings occupied and owned by public authorities must be NZEB after 2018. These targets are set in the European Member States according to the EU directive on the Energy Performance of Buildings [1]. It is a huge challenge is to achieve these goals in northern countries where traditional energy saving measures – insulation, window performance, heat recovery from ventilation systems - balance on the border of cost optimality. New solutions have to be implemented in the field of energy saving and storing.The biomimicry approach imitates processes found in nature to solve human problems that can provide conceptually new solutions. The example of northern mammals can serve as inspiration – fatty tissue functions as thermal insulator of the body, but phase change properties of the lipids are also used to store and release heat.Phase change materials (PCM) have received much attention as an alternative for energy saving and storing. The energy demand for heating the building and thus CO2 emissions can be reduced by the amount of latent heat stored in PCMs. Lately different concepts on PCM integration in the building envelope are emerging – built-in walls, ceilings, floors, as a thin layer or large storage tanks. In order to create new PCM integrated building components – a solar thermal façade system appropriate PCM has to be chosen. This paper reviews the selection of PCM in melting temperature range 21–22̊C.

Experimental investigation of thermal characteristics of lithium ion battery using phase change materials combined with metallic foams and fins

Phase change materials are of great interest in energy storage and energy management applications due to their high latent heat and excellent cycling stability. In this paper, the thermal characteristics of phase change materials (PCM) for thermal management of cylindrical 18650 lithium-ion battery (LIB) were experimentally investigated. A commercial paraffin wax with a melting temperaturerange between 47 - 53.8oC was used in this study. A metal cylinder with a heater was used to emulate the heat generation from a battery, which was surrounded with the paraffin PCM and containted in a metal housing. The experiment was conducted in an environmental test chamber with controlled ambient temperatures and power inputs. Both the battery temperature and the housing wall temperature were measured during steady-state heating and cyclic heating conditions. Since PCM has low thermal conductivity, thermal enhancement techniques were investigated by adding metal foams (MFs) or combining metallic foam and fins into the PCM to enhance the thermal conductivity. The battery temperatures were measured for all the cases and the results were analyzed and discussed.

The Development of CaO-SiO2-B2O3-based Fluorine-Free Mold Flux for a Continuous Casting Process

Designing and developing high-performance fluorine-free (F-free) mold flux has become a hot topic in steel continuous casting processes, with concerns of environment protection and energy saving. In conventional commercial mold flux, fluorine plays important roles on the properties as it works as a fluxing agent; however, it tends to cause serious environmental and health problems. In this paper, a new F-free mold flux based on the CaO-SiO2-B2O3 slag system has been introduced through summarizing previous works. The melting temperature range of F-free mold flux decreases with the addition of Na2O/Li2O and B2O3; the viscosity and heat flux decrease with the increase of basicity and Na2O/Li2O, as well as the decrease of B2O3 contents. Also, the crystallization temperatures of F-free mold fluxes increase with the increase of basicity and Na2O/Li2O content. The analyses of EDS and XRD show that Ca11Si4B2O22 and Ca14Mg2(SiO4)8 are the two main precipitated crystalline phases in F-free mold fluxes, and that the Ca11Si4B2O22 is a common and stable crystalline phase in the designed F-free mold fluxes system that shows the potential to replace Ca4Si2O7F2 in conventional flourine-containing mold fluxes.

Effects of preparation methods on potato microstructure and digestibility: An in vitro study

The effects of preparation method (boiled, cooled, and reheated) on the structural characteristics and in vitro digestibility of potato were investigated. The highest equilibrium starch hydrolysis was obtained after boiling (82.21%), followed by reheating (66.98%) and cooling (54.31%). The potato after cooling treatment exhibited a narrower melting temperature range and a higher melting enthalpy compared with the potatoes after boiling and the microwave reheating. X-ray diffraction patterns revealed that the relative crystallinity of the cooled potato was higher than those of the reheated and boiled potatoes, consistent with the results in melting enthalpy. Moreover, compared with the boiled potato, a large number of wrinkles were observed on the surface of the cooled potato, whereas after microwave reheating, larger clearances of starch granule regions were found. This study demonstrated that cooling and microwave reheating significantly affected the potato’s microstructure and digestibility and were suggested as alternative choices to prepare potato dishes.

Diketonylpyridinium Cations as a Support of New Ionic Liquid Crystals and Ion-Conductive Materials: Analysis of Counter-Ion Effects.

Ionic liquid crystals (ILCs) allow the combination of the high ionic conductivity of ionic liquids (ILs) with the supramolecular organization of liquid crystals (LCs). ILCs salts were obtained by the assembly of long-chained diketonylpyridinium cations of the type [HOOR(n)pyH]+ and BF4−, ReO4−, NO3−, CF3SO3−, CuCl42− counter-ions. We have studied the thermal behavior of five series of compounds by differential scanning calorimetry (DSC) and hot stage polarized light optical microscopy (POM). All materials show thermotropic mesomorphism as well as crystalline polymorphism. X-ray diffraction of the [HOOR(12)pyH][ReO4] crystal reveals a layered structure with alternating polar and apolar sublayers. The mesophases also exhibit a lamellar arrangement detected by variable temperature powder X-ray diffraction. The CuCl42− salts exhibit the best LC properties followed by the ReO4− ones due to low melting temperature and wide range of existence. The conductivity was probed for the mesophases in one species each from the ReO4−, and CuCl42− families, and for the solid phase in one of the non-mesomorphic Cl− salts. The highest ionic conductivity was found for the smectic mesophase of the ReO4− containing salt, whereas the solid phases of all salts were dominated by electronic contributions. The ionic conductivity may be favored by the mesophase lamellar structure.