Preparation and Flame Retardant Properties of Calcium–Aluminium Hydrotalcite with Root Cutting Silicate Layers as Bamboo Flame Retardants

Bamboo has been widely used in architecture, decoration and other fields because of its advantages of short growth period, high strength and degradability. However, bamboo, as a combustible material like wood, are easy to burn and cause building fires. However, the existing bamboo water-based flame retardants have some shortcomings, such as strong hygroscopicity and easy loss, which limits the application of bamboo products. In order to improve the flame retardant performance of bamboo, CaAl-SiO2 layered double hydroxide (LDH) as bamboo flame retardant was synthesised by coprecipitation method. The influence of preparation technology on CaAl–SiO3–LDH structures and properties as well as the flame retardant and smoke suppression characteristics of flame retardant-treated bamboo was discussed. The results revealed that the crystallisation temperature, crystallisation time and crystallisation concentration of CaAl–SiO3–LDHs considerably affected its structure and properties. The optimum technological parameters for preparing CaAl–SiO3–LDHs by using the coprecipitation method are as follows: crystallisation temperature of 100 °C, crystallisation time of 9 h and Ca2+ solution molar concentration of 0.33 mol/L. Compared with nonflame-retardant wood, CaAl–SiO3–LDH flame retardant treatment delayed the peak time of the heat release rate by 20 s and the ignition time by 77.78% and increased the carbon residue rate by 9.54%. This study can provide reference for the research of new flame retardant for bamboo products.

New temperature and oxygen fugacity data of Martian nakhlite from Northwest Africa (NWA) 5790 and implications for shallow sulphur degassing

Newly analysed titanomagnetite–ilmenite (Tim–Ilm) intergrowths from Martian nakhlite meteorite Northwest Africa (NWA) 5790 yielded crystallisation temperature up to 1032 °C and oxygen fugacity (fO2) up to ΔQFM + 1.6, notably higher than previous estimates for nakhlite magmas (temperature < 950 °C, fO2 = ΔQFM − 0.5 to ΔQFM + 1). To interpret how the magma was reduced from ΔQFM − 0.5 to ΔQFM + 1.6, we used D-Compress to model the sulphur degassing process within a single thick lava pile. For fO2 to significantly decrease in this extended range, a sulphur-rich (S content 4000–7000 ppm) Martian lava flow had to degas all the sulphur species at a certain final degassing pressure, which was 2–4 bar for NWA 988 and Lafayette and < 0.7 bar for Y-000593 and Nakhla. These final degassing pressure data are in good agreement with the Martian nakhlite burial depth estimated by other petrological and geochemical methods. These estimates are also comparable with the excavation depth of ~ 40 m based on the small (6.5 km in diameter) impact crater over the Elysium lava plain. The fO2-controlled sulphur degassing pressure may constitute a method for estimating the burial depth of sulphur-rich lava flows on Mars.

Composites of Cysteamine Functionalised Graphene Oxide and Polypropylene

Cysteamine functionalised reduced graphene oxide (rGO) was grafted to polypropylene-graft-maleic anhydride (PP-g-MA) and subsequently melt blended with PP. The covalent bridging of rGO to PP-g-MA via the cysteamine molecule and co-crystallization are routes to promoting interfacial interactions between rGO and the PP matrix. A rheological percolation threshold was achieved for a nanofiller loading between 3 wt% and 5 wt%, but none detected for the composites prepared with un-functionalized rGO. At low loadings (0.1 wt%), functionalized rGO is well dispersed in the PP matrix, an interconnecting filler-filler, polymer-filler and polymer-polymer network is formed, resulting in increased tensile toughness (1 500%) and elongation at break (40%) relative to neat PP. Irrespective of whether the rGO was functionalised or not, it had a significant effect on the crystallization behavior of PP, inducing heterogeneous nucleation, increasing the crystallisation temperature (Tm) of PP by up to 10°C and decreasing the crystalline content (Xc) by ∼30% for the highest (5 wt%) filler loading. The growth of the monoclinic a-phase of PP is preferred on addition of functionalised rGO and b crystal growth suppressed.

New temperature and oxygen fugacity data of Martian nakhlite from Northwest Africa (NWA) 5790 and implications for sulphur degassing depth

Newly analysed titanomagnetite–ilmenite (Tim–Ilm) intergrowths from Martian nakhlite meteorite Northwest Africa (NWA) 5790 yielded crystallisation temperature up to 1032°C and oxygen fugacity (fO2) up to ΔQFM + 1.6, notably higher than previous estimates for nakhlite magmas (temperature < 950°C, fO2 = ΔQFM-1 to ΔQFM + 1). To interpret how the magma was reduced from ΔQFM-1 to ΔQFM + 1.6, we used D-Compress to model the sulphur degassing process. For fO2 to significantly decrease in this extended range, the sulphur-rich Martian magma had to degas all the sulphur species at a certain final degassing pressure, which was 2–4 bar for NWA 988 and Lafayette and < 0.7 bar for Y-000593 and Nakhla. These final degassing pressure data are in good agreement with the Martian nakhlite burial depth estimated by other petrological and geochemical methods. These estimates are also comparable with the excavation depth of ~ 40 m based on the small (6.5 km in diameter) impact crater over the Elysium lava plain. The fO2-controlled sulphur degassing pressure may constitute a method for estimating the burial depth of sulphur-rich lava flows on Mars.

Antistatic and Thermal Properties of Poly(Lactic Acid)/Polypropylene/Carbon Nanotube Nanocomposites

The aim of this study is to investigate the influence of carbon nanotubes (CNT) on the antistatic and thermal properties of poly(lactic acid)/polypropylene/carbon nanotubes (PLA/PP/CNT) nanocomposites. PLA/PP (blend ratio = 60:40) containing CNT (loading 1.0 to 2.5 phr) was melt-compounded followed by compression moulding. The antistatic properties of PLA/PP/CNT nanocomposites achieved at 2.5 phr CNT loading. Thermogravimetric analysis (TGA) results indicated that the thermal stability of PLA/PP/ CNT nanocomposite was higher than PLA/PP blend. Differential Scanning Calorimetry (DSC) results demonstrated that CNT reduced the cold crystallisation temperature of PLA, while increased the crystallisation temperature of PP, which evidenced the nucleatingability of CNT in the PLA/PP blends.

Do olivine crystallisation temperatures faithfully record mantle temperature variability?

&lt;p&gt;Crystallisation temperatures of primitive olivine crystals have been widely used as both a proxy for, or an intermediate step in calculating, mantle temperatures. The olivine-spinel aluminium-exchange thermometer has been applied to many samples from mid-ocean ridges, ocean islands and large igneous provinces, yielding considerable variability in primitive olivine crystallisation temperatures. We supplement the existing data with new crystallisation temperature estimates for Hawaii, in the range 1282&amp;#177;21 - 1375&amp;#177;19&amp;#176;C.&lt;/p&gt;&lt;p&gt;Magmatic temperatures may be linked to mantle temperatures if the thermal changes during melting can be quantified. Melting lowers the temperature of co-existing magma and solid mantle, owing to the latent heat of melting. The magnitude of this cooling depends on melt fraction, itself controlled by mantle temperature, mantle lithology and lithosphere thickness. All of these parameters are likely to vary both spatially and temporally. For robust quantification of mantle temperature variability, the controls of lithosphere thickness and mantle lithology on crystallisation temperatures must be isolated.&lt;/p&gt;&lt;p&gt;We develop a multi-lithology melting model that can predict crystallisation temperature. The model allows mantle temperature, lithospheric thickness, and fractions of mantle lherzolite, pyroxenite and harzburgite to be varied. Inverting the model using a Bayesian Monte Carlo routine enables assessment of the extent to which crystallisation temperatures require variations in mantle temperature. We find that the high crystallisation temperatures seen at mantle plume localities do require high mantle temperatures. However, in the absence of further constraints on mantle lithology or melt productivity, we cannot robustly infer variable plume temperatures in either the present-day or throughout the phanerozoic. This work demonstrates the limit of petrological thermometers when other geodynamic parameters are poorly known.&lt;/p&gt;

Pressure increase in a flat fracture filled with freezing liquid

The paper considers the problem of pressure variations in circular and rectangular flat fractures filled with liquid as the liquid crystallises, taking into account rigidity of the solid phase forming. We suppose that as a liquid crystallises, the volume it occupies inside the fracture changes due to the difference in density of the solid and liquid phases, and the fracture walls deform due to the pressure difference between the environment and the internal zone. Assuming that the solid and liquid phases are incompressible, we may equate the change in the internal fracture volume caused by the deformation of the surrounding walls to that in the volume of the liquid undergoing a state transition. We presume that crystallisation occurs at the top of the fracture, the temperature of the liquid is constant and equals its crystallisation temperature, and the phase boundary between the liquid and solid phases is flat. We consider the side walls and the bottom to be thermally insulated and perfectly rigid. We derived analytical expressions for determining the pressure

Магнитогидродинамический принцип 3D-печати для расплавов цветных металлов

The new principle of high-effective 3D-printing for liquid non-ferrous metals has been suggested. Electric current applies to the flow of liquid metal creates Ampere’s forces that increases pressure in the lowest part of this flow. Increased pressure causes raising of crystallisation temperature. The principal possibility of this process with regard to additional heating caused by this electric current has been investigated. It has been found that addition of ferromagnetic supplements could create parameters range wherein crystallization process is possible.

Oriented nucleation and crystal growth of Sr-fresnoite (Sr2TiSi2O8) in 2SrO·TiO2·2SiO2 glasses with additional SiO2

The oriented nucleation of Sr-fresnoite is barely affected by increasing the amount of SiO2 in glasses of the mol composition 2SrO·TiO2·2SiO2 + xSiO2 (x = 0 to 1.5) while keeping the crystallisation temperature constant. Bulk nucleation, growth selection and phase separation occur in the bulk.

On the crystallisation temperature of very high-density amorphous ice

VHDA prepared at high pressures and temperatures appears to be mainly free of (nano)crystallinity. It is the thermally most stable amorphous solid phase of water at elevated pressures reported so far. Water's no man's land's low temperature boundary is thus shifted to higher temperatures by up to 4 K.