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The objective of this paper is to predict the noise radiated from submarine propellers with different control surface types (the cross- and X-type). When the propellers are free from cavitation, such as those of submarines at a diving depth, the radiated noise dominate, due to unsteady propeller forces. A well-known submarine model (DARPA SUBOFF) is taken as the computing sample. Simulations for hydrodynamics, including stern wakes and unsteady propeller forces, are carried out by using CFD (Computational Fluid Dynamics) technology, and the results are compared with the experimental data. The accuracy of the predicted noise depends on the CFD results. Comparisons between the CFD results and the experimental data are in good agreement. The CFD results are treated as dipole strengths in the linear wave theory to predict the radiated noise caused by the unsteady forces of the propeller. It is found that, when the control surface is of the X-type, the propeller inflow is more uniform, and the radiated noise can be decreased by about 5 dB compared to the cruciform control surface. [ABSTRACT FROM AUTHOR]

Effects of isobutene (i-C 4 H 8) with the unique molecular structure on hydrogen explosions are investigated in a 14 L spherical chamber at 100 kPa and 298 K. The results reveal that for lean hydrogen-air mixtures, the maximum explosion overpressure, maximum pressure rise rate, and deflagration index show a trend from rise to decline. However, for stoichiometric and rich hydrogen-air mixtures, pressure parameters decrease monotonously with increasing i-C 4 H 8. The chemical suppression mechanism of i-C 4 H 8 on hydrogen explosions is revealed in detail by numerical simulation. The relevant analyses show that i-C 4 H 8 can not only change the chain reaction path and cut off the hydrogen-oxygen reaction, but also strengthen the consumption of oxygen and H radicals. This work will provide a novel theoretical foundation for hydrogen explosion prevention and control. [Display omitted] • Effects of i-C 4 H 8 on flame and pressure of hydrogen are observed. • Hydrogen explosions can be effectively suppressed by less than 6.0% i-C 4 H 8. • I-C 4 H 8 can change hydrogen-oxygen chain reaction pathways. • I-C 4 H 8 suppresses hydrogen explosions by enhancing oxygen consumption. [ABSTRACT FROM AUTHOR]

The effects of isobutene (i-C 4 H 8) and carbon dioxide (CO 2) on hydrogen explosions have been explored in a 14 L spherical chamber at 100 kPa and 298 K. The results show that compared with CO 2 , the cooperation of i-C 4 H 8 and CO 2 can more effectively suppress the explosion pressure, pressure rise rate, and deflagration index. The minimum suppression concentration of CO 2 with 1.5% i-C 4 H 8 is much lower than that of CO 2 alone. Numerical simulation reveals the mechanism of the suppression of i-C 4 H 8 and CO 2. I–C 4 H 8 changes the reaction paths, and the addition of CO 2 further lowers the adiabatic flame temperature and the active radical concentration. The excellent performance of the cooperation of i-C 4 H 8 and CO 2 in hydrogen explosions will provide a new idea for the prevention and control of hydrogen explosions. • The cooperation of i-C 4 H 8 and CO 2 is better than using CO 2 alone. • I–C 4 H 8 can effectively reduce the minimum suppression concentration of CO 2. • The suppression mechanism of i-C 4 H 8 and CO 2 in hydrogen explosions is revealed. [ABSTRACT FROM AUTHOR]

[Display omitted] In order to develop a green and efficient nano suppressant for aluminum (Al) dust explosion, MCN with layered structure was synthesized with low-cost urea as precursor via simple calcination technology. The suppression performance of MCN on the flame propagation of 30 μm and 5 μm Al dust with the concentration of 1000 g/m3 was experimentally studied. Results showed that with the addition of MCN increasing, the flame luminous intensity, flame propagation velocity and fluctuating trend of mixture-Al dust were greatly decreased. After adding 500 g/m3 and 700 g/m3 to 30 μm and 5 μm Al dust, the average flame propagation velocities declined by 73.24 % and 94.07 % separately. The minimum inerting concentration of 30 μm and 5 μm Al dust was 600 g/m3 and 900 g/m3. Explosion residuals were analyzed to further reveal the suppression mechanism of MCN in detail. The good performance of MCN provided a potential direction to develop efficient suppressants on the suppression of Al dust explosions to improve process safety. [ABSTRACT FROM AUTHOR]

Melamine-phytate (MEL-PA) nanoflakes are formed by supramolecular self-assembly technology using melamine (MEL) and bio-based phytic acid (PA) as the building blocks. This work explores the possibility of this two-dimensional nanomaterial as flame retardant. The layered MEL-PA with the loading of 1, 2 and 3 wt% are incorporated into polypropylene (PP) matrix. MEL-PA is dispersed well in the PP matrix. Thermal stability and flame retardant performance of PP/MEL-PA composites are investigated. Compared with neat PP, the addition of 2 wt% MEL-PA decreases the peak heat release rate from 756 to 608 kW/m2. Char yield of PP is improved by MEL-PA, and the chemical structure and graphitization degree of residual char are studied to reveal flame retardant mechanism. [ABSTRACT FROM AUTHOR]

The flame behavior and pressure characteristics of vented propane-air explosions at elevated static activation pressures (P stat) were investigated in a duct with a length-to-diameter (L/D) ratio of 7. The impact of the discharge traction and the coupling effect of the internal flame front and pressure waves on the flame propagation behavior were captured. The effect of increasing P stat on the vented flame length and width under a fixed vent was weak. The influences of P stat on the pressure profiles and maximum reduced pressure (P red) were investigated. The increase of P stat mitigated the blocking effect of external explosion on P red and further promoted the discharge pressure drop rate to be controlled within the limit of the discharge capacity of the vent. The formation mechanisms of the two main external pressure peaks were analyzed. For the larger D v conditions, the sensitivity of high P stat to the increase of maximum external pressure was higher than that of low P stat. A modified model of P red was developed considering the effects of elevated P stat and vent coefficient K V , which is proved to have a good performance in vented explosion ducts with a large L/D ratio. [ABSTRACT FROM AUTHOR]

• LFLs of NH 3 , H 2 and NH 3 /H 2 are investigated under different conditions. • Prediction models of NH 3 , H 2 and NH 3 /H 2 mixtures LFL are established. • OH radicals in elementary reactions are crucial to the effect of LFL. In this paper, the lower flammability limits (LFLs) of NH 3 /H 2 mixtures under different initial pressures (50–250 kPa) and initial temperatures (20–100 °C) are experimentally and numerically investigated. The LFLs of ammonia and hydrogen are reduced by the increase of the initial temperature, and the reduction of ammonia LFL is greater than that of hydrogen. An increase in initial pressure decreases the LFL of ammonia but increases the LFL of hydrogen. The LFL of the NH 3 /H 2 mixture is reduced by the increase of H 2 , which is consistent with Le Chatelier's Law. When H 2 reaches 10%, the LFL trend of the mixture with the initial temperature and initial pressure is similar to that of hydrogen. The LFL prediction models of NH 3 , H 2 and NH 3 /H 2 mixtures under different initial temperatures and initial pressures are established. The changes of OH radicals in elementary reactions are crucial to the effect of LFL. Except for H + O 2 = O + OH and 2OH = O + H 2 O, the main OH ROP of NH 3 is NO 2 + H = NO + OH, NH 2 + OH = NH + H 2 O and NH 3 + OH = NH 2 + H 2 O, while the main OH of H 2 ROP is OH + H 2 = H + H 2 O, which may be the reason why the LFLs of NH 3 and H 2 are different. [ABSTRACT FROM AUTHOR]

• A heat pump simultaneously driven by a gas engine and an electrical motor proposed. • A prototype was developed and tested to approve the feasibility. • Compressor rotation speed and engine power ratio can both change the heating capacity. • Engine power ratio can be adjusted for better efficiency and economic performance. • The heat pump has higher efficiency and less operating costs than traditional systems. The gas engine-driven heat pump (GEHP) has a higher primary energy ratio (PER) than the electric heat pump (EHP) for heating, but has a lower PER than the EHP for cooling. To exploit the advantages of GEHP and EHP, a heat pump system where the compressor could be driven simultaneously by a gas engine and motor was proposed in the paper. An experimental platform was established to investigate the feasibility and performance of the HPHP system. In addition, numerical models were built for further performance analyses. The results indicate that: (1) Increases in the rotation speed of the compressor and engine power ratio lead to an increase in the total heating capacity. The rotation speed should be adjusted first to meet the required heating load, and then the engine power ratio can be adjusted to achieve better performance; (2) Engine power ratio changes the loads of the engine and motor, thus their efficiencies change, leading to different PERs of the HPHP system. Under different local gas and electricity prices, the engine power ratio can also be adjusted to reach a minimum operating cost; (3) For the case-studied commercial building in Beijing, the annual primary energy consumptions for HPHP, GEHP, and EHP are 94.2, 95.7, and 100.0 kWh/m2, respectively. In addition, HPHP saves operating costs by 17.5 % and 35.1 % compared to GEHP and EHP, respectively, with static payback periods of 2.45 and 1.47 years, even if it is only used for heating in winter. [ABSTRACT FROM AUTHOR]

• The Sm-Nd isotopic compositions of apatite in MRB were analyzed in situ. • A Sm-Nd isochron age of 1490±480 Ma was determined for apatite in MRB, different from bulk-rock age. • Pyroxene, not apatite, is the major REE carrier in MRB. • The hydrothermal fluids could have derived from an enriched reservoir in the Martian crust. The observations of Martian orbiters and rovers have suggested that there were fluids on the surface of early Mars. However, the geochemical properties of those fluids are unclear. The Martian regolith breccia meteorites (MRB), the source materials of which are thought to have formed at 4.4 Ga, may have recorded interactions with fluids on Mars. Here, we have analyzed the in situ Sm-Nd isotopic compositions and trace element contents of apatite in MRB and have obtained a Sm-Nd isochron age of 1490±480 Ma. This young age indicates that the MRB apatites were altered by fluids and have exchanged trace elements with fluids. The very negative initial ε 143 Nd, combined with the previously reported positive δ D and δ 37 Cl in the MRB apatites, indicate that Martian fluids originated from a geochemically enriched reservoir in the crust. The large ranges of rare earth element abundance (ΣREE) and of the chondrite normalized ratio of La and Yb [(La/Yb) N ] indicate the chemical complexity of the fluids that interacted with the apatites in the MRB. The apatite REE compositions were used to further determine the pH values of Martian fluids equilibrated with the MRB apatites, which varied from ∼3 to ∼8. The apatite X-site Cl contents indicate that the Cl contents in Martian fluids in equilibrium with the MRB apatites at 400 °C and 1 bar could be up to 1857 ppm, within the range of terrestrial hydrothermal fluids. Combined with previously reported geochemical data from Martian meteorites, our study suggests that fluids may have been present throughout the early geological history of Mars. [ABSTRACT FROM AUTHOR]

The effect of sodium chloride (NaCl) on cadmium (Cd) uptake, translocation, and oxidative stress was investigated using 2 tobacco cultivars differing in Cd tolerance. The growth inhibition of the tobacco plants exposed to Cd toxicity was in part alleviated by moderate addition of NaCl in the culture solution. Cadmium concentration of shoots and roots in the 2 cultivars increased with increasing Cd levels in the solution and decreased with the addition of NaCl. The addition of NaCl could alleviate the oxidative stress caused by Cd toxicity, as reflected by reduced production of malondialdehyde and recovered or enhanced activities of antioxidative enzymes catalase and glutathione peroxidase. The results also showed that the enhancement of antioxidative enzyme activity by NaCl for the tobacco plants exposed to Cd stress is related to induced Ca signaling. Environ Toxicol Chem 2013;32:1420-1425. © 2013 SETAC [ABSTRACT FROM AUTHOR]

Abstract: Protein fibril assembly at acidic conditions has recently attracted increasing interests in the fields of biochemical and food science, however, the obtained knowledge about the assembly of the proteins with complex structure (e.g. plant 7S/11S globulins) is still limited. This study investigated the influence of NaCl addition (0–300mM) on the fibril assembly of soy 7S globulins (β-conglycinin), induced by heating at 80°C and pH 2.0, with the aim of confirming the improvement of their fibril assembly by electrostatic screening. The formed fibril formation was investigated by using Th T fluorescence and atomic force microscopy (AFM) techniques. Heat-induced structure changes were traced by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and circular dichroism spectroscopy (CD). The results indicated that the whole fibril assembly experienced protein dissociation/hydrolysis and subsequent fibrillization process, and increasing NaCl concentration progressively increased the amount of formed fibrils, and even fibril length. AFM analyses confirmed that the increase in NaCl concentration shortened the time at which the short fibrils were visually observed, and the morphology of formed fibrils, including height of fibrils, width at half-height, and coil periodicity, slightly varied with the added NaCl concentration. The CD analyses indicated that increasing NaCl concentration greatly favored formation of β-type secondary structure, as well as extensive disruption of tertiary and/or quaternary conformations. These results confirmed that the electrostatic screening greatly improved the heat-induced fibril assembly process of soy β-conglycinin at pH 2.0. The improvement of fibril formation was largely attributed to increased extent of conformational changes at higher ionic strength. These findings would provide important information about the fibril assembly of plant oligomeric globulins at acidic pH that have important implications for the development of protein protein-based fibrillar gels. [Copyright &y& Elsevier]

• A rotating foam stirrer reactor (RFSR) was used to intensify ozone mass transfer. • A correlation for the mass transfer coefficient of ozone in the RFSR was obtained. • A Fe-Co heterogeneous catalytic ozonation process in the RFSR was proposed. • The above process greatly improved ozonation efficiency of Acid Red B wastewater. A novel multiphase tank reactor with foam block stirrer, also called rotating foam stirrer reactor (RFSR), was used to intensify ozone mass transfer and oxidation of synthetic textile wastewater processes for the first time. Results show that the RSFR can improve the ozone mass transfer process by adjusting operation conditions and gas hydromechanics. In order to predict the volumetric mass transfer coefficient, a set of correlation was developed within ±15% deviation. Further, based on an Acid Red B (ARB) solution used as simulated synthetic textile wastewater, it was found that the removal efficiency was improved by intensifying ozone mass transfer process, and changing operation conditions can promote the transformation of the ozone oxidation path to an indirect reaction way. Finally, results show that the Fe-Co oxides coated on the foam block stirrer can further intensify the degradation processes in the ARB solution. This study gives a fundamental understanding of the intensification mechanism of the RFSR and shows the promising prospect of an RFSR used in in the wastewater treatment. [ABSTRACT FROM AUTHOR]

• Experiments on the effect of supply air humidification on the energy and emission performance of domestic condensing boiler is undertaken. • Supply air humidification is beneficial for improving boiler efficiency, which is higher when the humidity of supply air is larger. • More latent heat can be recovered in the condensing heat exchange process of condensing boiler by supply air humidification. The traditional coal-fired boiler used for heating has a low efficiency and emits large amounts of pollutants. Thus, the use of natural-gas-fired boilers has become a popular method for heating all over the world owing to their cleanliness and high efficiency. Condensing domestic gas boilers have higher thermal efficiency than traditional boilers. However, they waste a large amount of heat. Supply-air humidification provides a beneficial effect on the efficiency of heat recovery, but the effects of supply-air humidification on the thermal performance of combustion and the amount of heat recovered from the latent heat remain unclear. Moreover, the effect of air humidification on pollutant emission must be further investigated. In this study, an experiment was conducted to investigate the effects of supply-air humidification on the thermal efficiency and emissions of a domestic boiler. The results indicated that supply-air humidification is beneficial for the improvement of the overall boiler efficiency. The maximum improvements in the boiler efficiency were 3.7% and 3.8% when the excess-air ratios were 1.3 and 1.1, respectively. Supply-air humidification had a significant effect on the condensing heat-exchange process. The maximum increments of the condensed water were 20.2% and 23.47% when the excess-air ratios were 1.3 and 1.1, respectively. When the excess-air ratio was 1.3 and the temperature and relative humidity of the supply air were 41.22 °C and 12.06%, respectively, almost half of the latent heat from the flue gas was recovered. Supply-air humidification reduced the concentration of NO x to a value within the emission limit. However, the amount of humidification needs to be controlled within a reasonable range to avoid massive generation of CO. [ABSTRACT FROM AUTHOR]

High-quality type IIa large diamond crystals are synthesized with Ti/Cu as nitrogen getter doped in an FeNi–C system at temperature ranging from 1230 °C to 1380 °C and at pressure 5.3–5.9 GPa by temperature gradient method. Different ratios of Ti/Cu are added to the FeNi–C system to investigate the best ratio for high-quality type IIa diamond. Then, the different content of nitrogen getter Ti/Cu (Ti : Cu = 4 : 3) is added to this synthesis system to explore the effect on diamond growth. The macro and micro morphologies of synthesized diamonds with Ti/Cu added, whose nitrogen concentration is determined by Fourier transform infrared (FTIR), are analyzed by optical microscopy (OM) and scanning electron microscopy (SEM), respectively. It is found that the inclusions in the obtained crystals are minimal when the Ti/Cu ratio is 4:3. Furthermore, the temperature interval for diamond growth becomes narrower when using Ti as the nitrogen getter. Moreover, the lower edge of the synthesis temperature of type IIa diamond is 25 °C higher than that of type Ib diamond. With the increase of the content of Ti/Cu (Ti : Cu = 4 : 3), the color of the synthesized crystals changes from yellow and light yellow to colorless. When the Ti/Cu content is 1.7 wt%, the nitrogen concentration of the crystal is less than 1 ppm. The SEM results show that the synthesized crystals are mainly composed by (111) and (100) surfaces, including (311) surface, when the nitrogen getter is added into the synthesis system. At the same time, there are triangular pits and dendritic growth stripes on the crystal surface. This work will contribute to the further research and development of high-quality type IIa diamond. [ABSTRACT FROM AUTHOR]

A novel nano-clay flame retardant (HNTs@MEL-PA) is prepared by modifying halloysite nanotubes (HNTs) with supramolecular self-assembly technology using melamine (MEL) and bio-based phytic acid (PA) as the building blocks. Transmission electron microscopy images and Fourier transform infrared spectra show that the surface of HNTs is successfully decorated with MEL-PA supramolecular aggregates by hydrogen bonding. The feasibility of using HNTs@MEL-PA as a flame retardant for polypropylene (PP) is explored. Compared with PP/HNTs composites, the dispersion of HNTs@MEL-PA and its interfacial interactions with PP matrix are greatly improved. Heat release of PP is decreased in a certain degree and its smoke release is greatly reduced by HNTs@MEL-PA. With the addition of 15 wt% HNTs@MEL-PA, total smoke production of PP is decreased from 15.7 to 10.2 m2, indicating the greatly improved fire safety. Flame retardant and smoke suppression mechanisms of HNTs@MEL-PA are proposed based on thermal decomposition results and the analysis on char residue. Image 1 • HNTs were modified by supramolecular self-assembly technology. • Combustion behaviors of PP/HNTs@MEL-PA composites were investigated. • Flame retardant and smoke suppression mechanisms of HNTs@MEL-PA were concluded. [ABSTRACT FROM AUTHOR]

The possibility of layered melamine-phytate (MEL-PA) as an efficient synergist for intumescent flame retardant (IFR) is explored. The synergistic effects of MEL-PA on polypropylene (PP)/IFR composites are investigated in terms of flammability tests and combustion under forced-flaming condition. The addition of MEL-PA can effectively improve limited oxygen index (LOI) of PP composites. When 2 mass% MEL-PA is incorporated, the LOI value is enhanced from 33.0 to 35.1%. In addition, fire-retardant performance is increased with the addition of MEL-PA. The heat and smoke releases of PP/IFR are greatly reduced by MEL-PA. When IFR is partially replaced by 0.5, 1.0 and 2.0 mass% MEL-PA, total smoke production values are decreased by 27.2%, 34.8% and 57.6%, respectively. Raman spectra analysis indicates that the adding of MEL-PA results in higher graphitization degree of char layer. This work proves that MEL-PA and IFR have a good synergistic effect on flame-retardant PP. [ABSTRACT FROM AUTHOR]

Large diamond single crystals doped with NiS are synthesized under high pressure and high temperature. It is found that the effects on the surface and shape of the synthesized diamond crystals are gradually enhanced by increasing the NiS additive amount. It is noted that the synthesis temperature is necessarily raised to 1280°C to realize the diamond growth when the additive amount reaches 3.5% in the synthesis system. The results of Fourier transform infrared spectroscopy (FTIR) demonstrate that S is incorporated into the diamond lattice and exists in the form of C–S bond. Based on the FTIR results, it is found that N concentration in diamond is significantly increased, which are ascribed to the NiS additive. The analysis of x-ray photoelectron spectroscopy shows that S is present in states of C–S, S–O and C–S–O bonds. The relative concentration of S compared to C continuously increases in the synthesized diamonds as the amount of additive NiS increases. Additionally, the electrical properties can be used to characterize the obtained diamond crystals and the results show that diamonds doped with NiS crystals behave as n-type semiconductors. [ABSTRACT FROM AUTHOR]

The inclusions in large diamond single crystals have effects on its ultimate performance, which restricts its industrial applications to a great extent. Therefore, it is necessary to study the inclusions systematically. In this paper, large diamond single crystals with different content values of inclusions are synthesized along the (100) surface by the temperature gradient method (TGM) under 5.6 GPa at different temperatures. With the synthetic temperature changing from 1200 °C to 1270 °C, the shapes of diamonds change from plate to low tower, to high tower, even to steeple. From the microscopic photographs of the diamond samples, it can be observed that with the shapes of the samples changing at different temperatures, the content values of inclusions in diamonds become zero, a little, much and most, correspondingly. Consequently, with the temperature growing from low to high, the content values of inclusions in crystals increase. The origin of inclusions is explained by the difference in growth rate between diamond crystal and its surface. The content values of inclusions in diamond samples are quantitatively calculated by testing the densities of diamond samples. And the composition and inclusion content are analyzed by energy dispersive spectroscopy (EDS) and x-ray diffraction (XRD). From contrasting scanning electron microscopy (SEM) photographs, it can be found that the more the inclusions in diamond, the more imperfect the diamond surface is. [ABSTRACT FROM AUTHOR]

The large single-crystal diamond with FeS doping along the (111) face is synthesized from the FeNi–C system by the temperature gradient method (TGM) under high-pressure and high-temperature (HPHT). The effects of different FeS additive content on the shape, color, and quality of diamond are investigated. It is found that the (111) face of diamond is dominated and the (100) face of diamond disappears gradually with the increase of the FeS content. At the same time, the color of the diamond crystal changes from light yellow to gray-green and even gray-yellow. The stripes and pits corrosion on the diamond surface are observed to turn worse. The effects of FeS doping on the shape and surface morphology of diamond crystal are explained by the number of hang bonds in different surfaces of diamond. It can be shown from the test results of the Fourier transform infrared (FTIR) spectrum that there exists an S element in the obtained diamond. The N element content values in different additive amounts of diamond are calculated. The XPS spectrum results demonstrate that our obtained diamond contains S elements that exist in S–C and S–C–O forms in a diamond lattice. This work contributes to the further understanding and research of FeS-doped large single-crystal diamond characterization. [ABSTRACT FROM AUTHOR]

In order to synthesize high-quality type-IIa large diamond, the selection of catalyst is very important, in addition to the nitrogen getter. In this paper, type-IIa large diamonds are grown under high pressure and high temperature (HPHT) by using the temperature gradient method (TGM), with adopting Ti/Cu as the nitrogen getter in Ni70Mn25Co5 (abbreviated as NiMnCo) or Fe55Ni29Co16 (abbreviated FeNiCo) catalyst. The values of nitrogen concentration (Nc) in both synthesized high-quality diamonds are less than 1 ppm, when Ti/Cu (1.6 wt%) is added in the FeNiCo or Ti/Cu (1.8 wt%) is added in the NiMnCo. The difference in solubility of nitrogen between both catalysts at HPHT is the basic reason for the different effect of Ti/Cu on eliminating nitrogen. The nitrogen-removal efficiency of Ti/Cu in the NiMnCo catalyst is less than in the FeNiCo catalyst. Additionally, a high-quality type-IIa large diamond size of 5.0 mm is obtained by reducing the growth rate and keeping the nitrogen concentration of the diamond to be less than 1 ppm, when Ti/Cu (1.6 wt%) is added in the FeNiCo catalyst. [ABSTRACT FROM AUTHOR]

This work is to experimentally and theoretically explore the hydrogen cloud explosion subjected to external turbulence. In the experiments, the flame characteristics and explosion pressure are obtained using high-speed camera and pressure sensor. In the theoretical calculation, the peak explosion pressure is obtained using LM, LMIET and TM method. The results indicated that most flame characteristics in the experiments are located in the zone of wrinkled flamelets. The explosion-related parameters including flame propagation velocity, peak explosion pressure and peak rate of pressure rise continue to increase as the gear level increases from G0 to G3, increase firstly and then decrease as the equivalence ratio increases from Φ = 0.5 to Φ = 3.0. Due to ignoring flame acceleration propagation induced by flame instabilities, external turbulence and flame-induced turbulence, the peak explosion pressure obtained using experimental method is significantly larger than that obtained using LM method. Owing to considering the limit value of flame wrinkling level induced flame instabilities and flame-induced turbulence, the peak explosion pressure obtained using experimental method is significantly lower than that obtained using LMIET and TM method. • Effects of external turbulence on flame acceleration is analyzed. • Peak explosion pressure and peak rate of pressure rise are obtained. • Peak explosion pressure is calculated using LM, LMIET and TM method. [ABSTRACT FROM AUTHOR]

This paper reports the crystal growth of diamond from the FeNi–Carbon system with additive phosphorus at high pressures and high temperatures of 5.4–5.8 GPa and 1280–1360 °C. Attributed to the presence of additive phosphorus, the pressure and temperature condition, morphology, and color of diamond crystals change obviously. The pressure and temperature condition of diamond growth increases evidently with the increase of additive phosphorus content and results in the moving up of the V-shape region. The surfaces of the diamonds also become coarse as the additive phosphorus added in the growth system. Raman spectra indicate that diamonds grown from the FeNi-phosphorus-carbon system have more crystal defects and impurities. This work provides a new way to enrich the doping of diamond and improve the experimental exploration for future material applications. [ABSTRACT FROM AUTHOR]

The coefficient of performance (COP) and heating capacity of the absorption heat pump (AHP) decreased obviously as the evaporator inlet temperature dropped. Compression-assisted AHP (CAHP) could operate efficiently in colder conditions, and a prototype was constructed for experimental investigation. At a generator inlet of 130 °C, as the evaporator inlet decreases from −5 °C to −25 °C, the COP drops from 1.513 to 1.372, while the heating capacity deteriorates from 77.26 kW to 47.11 kW. Comparisons between CAHP and normal AHP indicated that CAHP can extend the lower limit of evaporator inlet temperature from −10 °C to −25 °C. Besides, CAHP can enhance the heating capacity by approximately 55.5–85.0% even when AHP can operate normally. Moreover, the improvement contributed by CAHP is greater under much colder conditions. The heating COP and capacity of CAHP are improved in all the conditions, while the primary energy efficiency is advantageous under lower evaporator inlet temperatures. [ABSTRACT FROM AUTHOR]

[Display omitted] • The Aluminum borate/Zinc borate (ATH/ZB) composite powder is synthesized successfully by the mechano-chemistry technology. • The minimum inhibition concentrations of ATH, ZB and ATH/ZB for aluminum dust explosion are determined. • ATH/ZB composite powder shows superior inhibition performance in comparison with ATH and ZB. • Inhibition mechanism of ATH/ZB for aluminum dust explosion is revealed in detail. This study proved that Aluminum hydroxide (ATH)/Zinc borate (ZB) composite powder could be adopted as excellent inhibitor for aluminum dust explosion, which was successfully synthesized by mechano-chemistry technology. Under the actions of collision, friction and combination forces, the surface energies of ATH and ZB particles were activated, leading to the close compounding of ATH/ZB. The inhibition effect of ATH/ZB on aluminum dust explosion was studied experimentally. Results showed that flame propagation behaviors and velocities were inhibited accordingly as the concentrations of inhibitors increased. Moreover, the minimum inhibition concentrations of ATH, ZB and ATH/ZB were determined, corresponding to 1000 g/m3, 1000 g/m3 and 600 g/m3, indicating that ATH/ZB had superior inhibition performance compared with ATH or ZB. Characterization tests were used to analyze the explosion residues. The inhibition mechanism of ATH/ZB for aluminum dust explosion primarily included three aspects: physical coating effect, heat absorbing effect and gas dilution effect. [ABSTRACT FROM AUTHOR]

In this research, the effect of ignition, initial pressure (50–250 kPa) and temperature (20–100 °C) on the lower flammability limit (LFL) of hydrogen/air mixture are investigated experimentally and numerically. The results show that with the ignition energy increases, the LFL of hydrogen decreases. When high voltage direct current power supply (HVDC) is used, the time for the flame to propagate to the edge of the window is much shorter than that of 15 kV high voltage transformer (15 kV HVT) ignition. As the initial pressure increases, the LFL of hydrogen increases. When HVDC is used, the time to reach the peak deflagration overpressure increases with the increase of initial pressure. However, when 15 kV HVT is used, the time to reach the peak deflagration overpressure is almost the same. As the initial temperature increases, the LFL of hydrogen decreases. The change of the LFL of hydrogen with 15 kV HVT ignition is greater than that of HVDC. Through the analysis of chemical kinetic factors, the effect of OH radical generation when the LFL of hydrogen increases with the increase of initial pressure is revealed. • Eleven ignition energies under two ignition modes are measured. • LFL are obtained under different ignition, initial pressure and temperature. • Chemical kinetic factors at LFL of hydrogen are analyzed. [ABSTRACT FROM AUTHOR]

Using pure Ti and hexagonal-BN powder as raw materials, TiB 2 –TiN ceramic composites were synthesized by high-pressure method at 5.0 GPa and 1400–1800 °C. The phase composition, microstructure, density and hardness of TiB 2 –TiN ceramic composites were analyzed. The results shown that when the pressure was constant, the synthesis temperature had an important effect on the phase composition of the samples. When TiB 2 –TiN ceramic composites synthesized at 1800 °C for 30 min, the relative density reached 96.2% and the maximum Vickers hardness reached 17.9 GPa with the load of 4.9 N. The grain size of the TiB 2 –TiN ceramic composites changed with the change of synthesis temperature, which resulted in the change of density and hardness. [ABSTRACT FROM AUTHOR]

Lysine sulfate (LS) powder is at high risk of fire and explosion during its production, processing and storage. Considering its edible and nutritive values, the selection for its explosion inhibitor requires both excellent inhibition performance and environmental friendliness. The inhibition performance of a natural food additive of sodium phytate (SP) on LS dust deflagration is investigated by comparing it with ammonium polyphosphate (APP), which is a widely used flame retardant. The deflagration characteristics of LS mixtures with various mass fractions of SP and APP are recorded by high-speed photography and fine thermocouples. The combustion heat is tested by micro-scale combustion calorimetry. Thermal stability of samples are studied by using a synchronous thermal analyzer. The results show that the deflagration of LS dust is completely suppressed when the mass fractions of APP and SP increase to 2% and 8%, respectively. The corresponding inhibition mechanisms are proposed based on the dust deflagration macroscopic results and microcosmic analysis on thermal decomposition products and residuals. These findings may provide a solution to reduce the probability and damage of dust explosions. [ABSTRACT FROM AUTHOR]

• Nacre-like GO-PTA paper is prepared by evaporation-induced self-assembly method. • Fire sensor-based GO-PTA exhibits ultrasensitive and durable warning response. • Enhancement in fire resistance of GO is attributed to in situ phosphorus doping. A novel nacre-like flame-retardant paper based on graphene oxide (GO), and phytic acid (PTA) is fabricated via evaporation-induced self-assembly. This facile method is time saving and low energy consuming. A facile approach is proposed to improve thermal oxidative stability of GO paper by in situ phosphorus doping during flame exposure. Then fire-alarm system is designed based on the high-temperature thermal reduction characteristic of GO. The GO paper functionalized with PTA (GO-PTA) can provide ultrasensitive, reliable and longtime fire early-warning signal. Fire alarm can be triggered at approximately 0.50 s when GO-PTA samples are attacked by fire. Phosphorus atoms are in situ doped into graphene layers during fire exposure, endowing GO-PTA paper with outstanding thermal oxidative stability, and thus alarm duration time of GO is greatly improved. The work develops advanced fire detection and early-warning sensors that provide reliable and continuous signals, which provide more available time for fire evacuation. [ABSTRACT FROM AUTHOR]

Organically modified ammonium polyphosphate (APP) flame retardant is prepared by supramolecular assembly method using melamine formaldehyde (MF) resin and phytic acid (PA) as building blocks. Surface characteristics of APP are modified, resulting in the enhancements in water resistance, dispersion in the polymer matrix and their compatibility. This supramolecular assembly modified APP (APP@MF-PA) matches well with charring-foaming agent (CFA) to achieve excellent fire safety for polypropylene (PP), and the superiority over conventional APP is observed. Heat, CO and CO 2 releases of PP are greatly decreased by the intumescent flame retardant (IFR) formulation containing APP@MF-PA and CFA. The modification of APP with MF-PA supramolecules are beneficial to improve the yield, insulation properties, graphitization degree and compactness of char. Flame-retardant mechanisms are demonstrated according to the investigations on gaseous and condensed phase products. This novel and facile modification method provides a new strategy for improving the flame-retardant efficiency of IFR. Image 1 • The surface characteristics of APP were modified by supramolecular assembly. • Fire hazards of PP were greatly reduced by this modified APP and CFA. • Flame retardant mechanisms were proposed. [ABSTRACT FROM AUTHOR]

The identification of hydrogen in a range of lunar samples and the similarity of its abundance and isotopic composition with terrestrial values suggest that water could have been present in the Moon since its formation. To quantify the effect of water on early lunar differentiation, we present new analyses of a high‐pressure, high‐temperature experimental study designed to model the mineralogical and geochemical evolution of the solidification material equivalent to 700 km deep lunar magma oceans first reported in Lin et al. (2017a). We also performed additional experiments to better quantify water contents in the run products. Water contents in the melt phases in hydrous run products spanning a range of crystallization steps were quantified directly using a secondary ion mass spectrometry (SIMS). Results suggest that a significant but constant proportion (68 ± 5%) of the hydrogen originally added to the experiments was lost from the starting material independent of run conditions and run duration. The volume of plagioclase formed during our crystallization experiments can be combined with the measured water contents and the observed crustal thickness on the Moon to provide an updated lunar interior hygrometer. Our data suggest that at least 45–354 ppm H2O equivalent was present in the Moon at the time of crust formation. These estimates confirm the inference of Lin et al. (2017a) that the Moon was wet during its magma ocean stage, with corrected absolute water contents now comparable to estimates derived from the water content in a range of lunar samples. [ABSTRACT FROM AUTHOR]

Hydrogen concentration profiles through olivine and pyroxene in peridotite xenoliths carried in rift basalts from northern Tanzania (Lashaine, Eledoi, and Kisite localities) show bell-shaped distributions, indicating that diffusive hydrogen loss has occurred in all minerals. Homogeneous major element concentrations and equilibration of hydrogen between the cores of olivine and coexisting pyroxene suggest that hydrogen loss resulted from diffusive degassing during host magma emplacement. For these samples, hydrogen diffusivities in olivine and coexisting pyroxene must be within the same order of magnitude, similar to experimentally determined diffusivities, but in contrast to previous observations made on xenolithic peridotites. We demonstrate here, for the first time using natural samples, that significant differences in activation energy is likely the primary parameter that causes the discrepancy between hydrogen diffusion in olivine and pyroxene observed in different suites of mantle xenoliths. Because hydrogen diffuses faster in olivine than in pyroxene as temperature increases, hydrogen loss in the Tanzanian mantle xenoliths must have occurred at relatively low temperatures (∼750 to ∼900 °C), whereas hydrogen loss observed in previous xenolith studies likely occurred at higher temperatures (∼950 to >1200 °C). Thus, the diffusive loss of hydrogen in the Tanzanian mantle xenoliths may have occurred at shallow depths or at the Earth's surface. [ABSTRACT FROM AUTHOR]

"Dry water" (DW) material is the powder with hydrophobic nano silica particles as the shell and water droplets as the core. The water content in DW is higher than 90%, thus, it is an effective fire extinguishing material. However, when DW is compressed under external pressures, it will crack with the core-shell structure being destroyed. In this work, the water phase in the core is modified as gel phase to enhance the internal pressure resistance of DW powder and its stability. More specifically, the feasibility and optimum preparation conditions of carrageenan gel based dry water (CGDW) material are explored and its fire extinguishing performance is revealed using fire extinguishing experiments. The results indicate that the CGDW powder performs better in fire extinguishing than ordinary ABC dry powder. The CGDW materials are green and environmental friendly, and show broad potentials in various applications. Unlabelled Image • The gel phase is formed in "dry water" powder to enhance its stability. • This preparation is inspired from temperature sensitive carrageenan gel. • Fire extinguishing performance of modified "dry water" powder was investigated. [ABSTRACT FROM AUTHOR]

Zirconium phenylphosphonate (ZrPP) nanoplatelets are decorated on the surface of reduced graphene oxide (RGO) based on π–π assembly interactions. The structure, composition, and morphology of ZrPP‐RGO assembly nanohybrid are well characterized. The dispersion of graphene in the nonpolar polypropylene (PP) matrix is improved by this modification. The enhancement mechanisms of dispersion in polymer matrix are clearly demonstrated. Significant improvements in flame retardancy and fire safety of PP are obtained by the incorporation of this assembly nanohybrid. Peak heat release rate and total heat release of PP composite containing 2 wt% ZrPP‐RGO assembly nanohybrid decrease by 35.8% and 23.6%, respectively, compared to those of neat PP. The assembly nanohybrid exhibits higher flame‐retardant effect than the counterparts of RGO and ZrPP. Furthermore, storage modulus of PP is greatly improved by this nanohybrid. This work proposes a novel method to prepare graphene‐based organic–inorganic nanohybrid and will expand the application of graphene. POLYM. COMPOS., 40:E1757–E1765, 2019. © 2018 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

In recent years, paper-based point-of-care testing (POCT) has been widely used in medical diagnostics, food safety and environmental monitoring. However, a high-cost, time-consuming and equipment-dependent sample pretreatment technique is generally required for raw sample processing, which are impractical for low-resource and disease-endemic areas. Therefore, there is an escalating demand for a cost-effective, simple and portable pretreatment technique, to be coupled with the commonly used paper-based assay (e.g. lateral flow assay) in POCT. In this review, we focus on the importance of using paper as a platform for sample pretreatment. We firstly discuss the beneficial use of paper for sample pretreatment, including sample collection and storage, separation, extraction, and concentration. We highlight the working principle and fabrication of each sample pretreatment device, the existing challenges and the future perspectives for developing paper-based sample pretreatment technique. [ABSTRACT FROM PUBLISHER]

In spite of major progress in the science and technology of diamond growth, large-scale commercial production of gem-quality, large, single-crystal diamonds has not been feasible. Recently, we easily synthesized various types of gem-quality, large, single-crystal diamonds (Ib, IIa, and IIb) using a cubic high-pressure apparatus (performance enhanced by new design of double bevel hybrid anvil). Our solution saves the cost associated with the presses need, increases the region of synthesis of gem-quality, large, single-crystal diamonds, and decreases the effects of fluctuations of the pressure or temperature in the cubic sample cell. In addition, the quality and electrical properties of synthetic diamonds have been studied in detail. The synthetic diamonds have been successfully applied as diamond anvils or jewelry. This represents a relatively simple, inexpensive, and effective solution for commercial production and scientific research on gem-quality, large, single-crystal diamonds using a cubic high-pressure apparatus. Large-scale commercial production of gem-quality diamonds has not been feasible. Recently, we easily synthesized various types of gem-quality diamonds using CHPA, whose performance is enhanced by new design of a double bevel hybrid-anvil. The quality and electrical properties of synthetic diamonds have been studied in detail. The synthetic diamonds have been successfully applied as diamond anvils or jewelry. [ABSTRACT FROM AUTHOR]

Three mononuclear Schiff base copper(II) complexes, [Cu(L1)2] (1), [Cu(L2)2] (2) and [Cu(L3)2] (3) (HL1= 2,4-dichloro-6-[(2-chloro-3-pyridyl)iminomethyl]phenol, HL2 = 2,4-dibromo-6-[(2-chloro-3-pyridyl)-iminomethyl]phenol, HL3 = 2-bromo-4-chloro-6-[(2-chloro-3-pyridyl)iminomethyl]phenol), have been synthesized and characterized by elemental analyses, IR, UV-Vis spectra, and X-ray single crystal diffraction. X-ray structures reveal each crystal unit contains two molecules and the coordination environment around the copper(II) atom is tetracoordinated by two Schiff base ligands, showing a tetrahedron geometry with some distortion. Pairs of intermolecular C-H···X (X = Cl or Br), C-H···N and C-H···O hydrogen bonds form many hydrogen bonding rings and play a crucial role in stabilizing the crystal structures. [ABSTRACT FROM AUTHOR]

• A novel bio-based flame retardant was synthesized via a simple ionic reaction. • The synergistic effects of IFR on combustion behaviors of PLA were explored. • APP/ATMP-NA-Fe endowed PLA with excellent flame-retardant performance. The high flammability and severe melt-dripping during the combustion are the most marked fire hazards for polyesters, such as polylactic acid (PLA). In this work, a bio-based flame retardant (ATMP-NA-Fe) was successfully synthesized by a simple aqueous ionic reaction by using amino trimethylene phosphonic acid (ATMP), nicotinamide (NA) and FeCl 3 •6H 2 O as raw materials. The ATMP-NA-Fe and ammonium polyphosphate (APP) have good synergistic effects on improving the flame-retardant performance and retarding the combustion melt-dripping of PLA. With a 10 wt% total loading of ATMP-NA-Fe and APP (1:1), the limiting oxygen index value of corresponding PLA composite (PLA3) increases from 20.1% to 32.8%, and it passes UL-94 V-0 rating without melt dripping. The cone calorimetry results show that compared with pure PLA, the peak heat release rate, total heat release and average mass loss rate of PLA3 are reduced by 66.4%, 14.9% and 76.7%, respectively. Via the analysis on the condensed and gas phase products, the flame-retardant mechanism of PLA/APP/ATMP-NA-Fe composites is proposed. This work provides a new approach for improving flame-retardant performance of PLA and promoting the utilization of renewable resource. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel high-efficiency composite named PA@NH 2 -MCM41 was synthesized via self-assembly. • Nano-Al dust explosion was completely suppressed by only 33.3 wt% PA@NH 2 -MCM41. • A complex film based on Al x (HiPh y) was formed during the explosion suppression process. • The excellent capacity of PA@NH 2 -MCM41 was due to the synergy between gas and condensed phase effects. A novel chemical suppressant (PA@NH 2 -MCM41) was synthesized via self-assembly. NH 2 -MCM-41 was prepared using diatomaceous earth (DE) as the silica source. FTIR spectra showed that phytic acid (PA) was successfully grafted onto synthesized NH 2 -MCM-41 via hydrogen bonding. The highly ordered mesoporous structure of PA@NH 2 -MCM41 was observed from TEM and small angle X-ray diffraction (SAXRD). The effectiveness of PA@NH 2 -MCM41 in the suppression of nano-Al dust explosions was investigated. Experimental results suggested that the addition of PA@NH 2 -MCM41 could effectively reduce the average flame propagation velocity (V avg) and maximum explosion pressure (P max). After the addition of 16.7 wt% PA@NH 2 -MCM41, the V avg of the gas-phase flame was reduced by 75%. With addition of 28.6 wt% PA@NH 2 -MCM41, the P max of nano-Al dust decreased by 65.7%. As the mass fraction of PA@NH 2 -MCM41was increased to 33.3%, nano-Al dust explosion was completely suppressed. The SEM, FTIR and EDS results showed that a complex sealing film was formed on the surface of the explosion products, which occupied the open sites on the Al surface and thereby interrupted the Al evaporation and surface reaction. Subsequently, the suppression mechanism by which phosphorus containing suppressants consume free radicals and the interaction of PA molecules with the aluminum particle surface were revealed in depth. [ABSTRACT FROM AUTHOR]

• GO-PA paper is prepared by an evaporation-induced self-assembly method. • Fire sensor based GO-PA exhibits ultrasensitive and durable warning response. • Enhancement in fire resistance of GO is attributed to in situ phosphorus doping. Although traditional fire detectors are widely used in many occasions, they still show some limitations, such as slow fire response and poor resistance to severe conditions. Thus, it is urgent to design and exploit early fire-warning device with ultrafast response and flame-retardant ability to provide timely and fast alarm. Herein, graphene oxide paper functionalized with phosphoric acid (GO-PA) is fabricated by a facile and environmentally friendly water evaporation-induced self-assembly approach. Based on the flame-induced electrical resistance transformation characteristic of GO-PA, a fire-warning detector is designed to reliably monitor early fire. Fire alarm can be triggered within 0.5 s when GO-PA samples are attacked by fire. The GO-PA composite paper is more sensitive than GO-based fire sensors reported in the literature. Phosphorus atoms are in situ doped into graphene structure during flame exposure. Combustion reaction of GO is significantly retarded by the incorporated PA, thus fire duration time of GO is greatly improved. This work paves a new way to improve fire detection performance of GO-based sensors. This work provides a guide for the development of advanced fire detection and early-warning sensors to provide reliable and continuous alarm signals. [ABSTRACT FROM AUTHOR]

• Influence of wood dust concentration on deflagration parameters was investigated. • Suppression performance of Zr(OH) 4 on dust deflagration was better than that of SiO 2. • Zr(OH) 4 catalyzes the formation of more residuals with smaller crystallite size. • Suppression mechanisms of wood dust deflagration by ultrafine powder were studied. Flame propagation characteristics of wood dust deflagration and suppression mechanism of ultrafine powders are investigated systematically. The deflagration reaction intensity of wood dust increases firstly and then decreases with the increase in dust cloud concentration. This is due to factors such as oxygen supply, positive feedback among flame characteristic parameters. Thus, there is an equivalent dust concentration for greatest deflagration intensity. Nano-sized ultrafine zirconium hydroxide (Zr(OH) 4) and silicon dioxide (SiO 2) powder are introduced to suppress wood dust deflagration at the equivalent concentration. It is found that Zr(OH) 4 has a suppression effect of endothermic decomposition to generate zirconia (ZrO 2), dilution of oxygen and absorption of free radicals; while SiO 2 exerts suppression effect due to its high melting point and heat absorption. The suppression performance of Zr(OH) 4 is better than that of SiO 2. This is because that Zr(OH) 4 and ZrO 2 have a catalytic carbonization effect. It can not only improve thermal stability of wood particles by catalyzing production of high-temperature resistant residuals, but also promote the formation of catalytic sites to reduce crystallite size of carbon layer on wood particles surface, weakening heat and mass transfer between particles. [ABSTRACT FROM AUTHOR]

The synthesis of diamond single crystal in the Fe64Ni36-C system with h-BN additive is investigated at pressure 6.5 GPa and temperature range of 1300–1400°C. The color of the obtained diamond crystals translates from yellow to dark green with increasing the h-BN addition. Fourier-transform infrared (FTIR) results indicate that sp2 hybridization B-N-B and B-N structures generate when the additive content reaches a certain value in the system. The two peaks are located at 745 and 1425 cm−1, respectively. Furthermore, the FTIR characteristic peak resulting from nitrogen pairs is noticed and it tends to vanish when the h-BN addition reaches 1.1 wt%. Furthermore, Raman peak of the synthesized diamond shifts down to a lower wavenumber with increasing the h-BN addition content in the synthesis system. [ABSTRACT FROM AUTHOR]