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This experimental study focuses on the corrosion behavior of aluminum alloys in hydrogen sulfide (H2S) gas and liquid phases. The corrosion behaviors of 3A21, 6061, and 6063 aluminum alloys are investigated via scanning electron microscopy, energy dispersive spectroscopy, and thermogravimetry-differential scanning calorimetry. The results show that the corrosion rates of the three types of aluminum alloys increase with temperature, and the slope of the corrosion rate curve decreases gradually after reaching a certain temperature. At 75 °C, the corrosion rate reached 0.0675 mm/a, 0.0881 mm/a and 0.0613 mm/a in the gas phase, respectively. The corrosion products show white-yellow-gray irregular pits and a honeycomb-like morphology, and the main components are aluminum hydroxide, alumina, and aluminum sulfide. In particular, the 6061 aluminum alloy presents the most severe corrosion in H2S gas. Compared with the H2S gas phase, the corrosion rate in the liquid phase is higher. Additionally, the irregular pitting and honeycomb-like morphologies are more evident. Corrosion becomes more significant as temperature increases. Although the corrosion products in the two phases are composed of the same components, the content in the liquid phase is higher. The heat absorption and mass loss of the corrosion products present the same regularity. This indicates that the corrosion of the H2S liquid phase on the aluminum alloy is more significant than that of the H2S gas phase. [ABSTRACT FROM AUTHOR]

Scanning electron microscope (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) were used to analyze the surface micromorphology and components of the iron oxide sulfide powders respectively. Differential scanning calorimetry (DSC) and thermogravimetry (TG) were used to investigate the self-heating properties. It was observed that temperature had a significant effect on the microscopic morphology and composition of the sulfide products. The product powders were homogeneously distributed in small particles and the composition of the products were converted from non-stationary FeS to FeS 2 with the sulfidation temperature increased. The apparent activation energy at a sulfidation temperature of 300 °C was 66.5 % of that at a sulfidation temperature of 150 °C. The apparent activation energies were 114.65 kJ/mol, 95.41 kJ/mol, 89.5 kJ/mol and 76.27 kJ/mol respectively at 150 °C, 200 °C, 250 °C and 300 °C during the self-heating reaction phase. There was only one main weight loss phase for the 100 °C, 150 °C and 200 °C products, while the 250 °C and 300 °C products had an additional weight loss phase before the main weight loss phase. The apparent activation energies of the main weight loss phase of the five temperature products were 318.1–333.7 kJ/mol, 266.2–293.2 kJ/mol, 212.7–234.0 kJ/mol, 174.7–193.1 kJ/mol and 168.7–188.7 kJ/mol, respectively. The apparent activation energies of the first weight loss phase of the 250 °C and 300 °C products were 217.4–243.2 kJ/mol and 198.2–214.6 kJ/mol respectively. The mechanism function for the thermal oxidation of elemental sulfur in the first weight loss phase was determined to follow the spherical contraction phase boundary reaction model, i.e. g(α)= [1-(1-α)1/3]m. In the main weight loss phase, the mechanism function for the thermal oxidation of iron sulfate followed the random nucleation followed by subsequent growth model, i.e. g(α)= [ln(1-α)]m. [ABSTRACT FROM AUTHOR]

• Burst pressure has a significant effect on the hazard of hydrogen explosion venting. • The damage area of the venting flame increases with the increase of burst pressure. • Mastering dynamic evolution is the effective means of achieving explosion protection. • Mastering explosion protection mechanisms is essential for the hydrogen development. A series of experiments are carried out to investigate the effect of burst pressure on hydrogen explosion venting in a 20 L square vessel. Pressure buildup and flame evolution are recorded using piezoelectric pressure transducers, high speed camera, high speed infrared camera and schlieren system. The results show that both the maximum explosion pressure (P max) inside and outside the vessel increase with the increasing burst pressure, and the P max in the external space decreases rapidly with the increase of the distance from the vent port. Compared to the burst pressure of 0 kPa, the P max inside the vessel and at 1200 mm increased by 79.1 % and 153.6 %, respectively, when the burst pressure was 325 kPa. The venting flame surface during the propagation is smoother with the increasing burst pressure, the width and area of the flame also increases. There is little effect of burst pressure on the maximum flame propagation distance (L max), but with the increase of burst pressure, the flame propagation time is shortened and the average propagation velocity is increased. The venting flame propagation time is shortened from 5.0 ms to 3.5 ms with the burst pressure increases from 0 kPa to 325 kPa. The high temperature zone of venting flame is mainly distributed in the flame front, while the maximum flame temperature (T max) gradually increases with the increase of burst pressure. The increase in burst pressure results in an increase in the turbulence intensity inside the vessel and an advance in the time to stabilization inside the vessel. Furthermore, the moment at which flow backflow occurs at the vent port is advanced from 16.5 ms to 8.5 ms with the increase in burst pressure. [ABSTRACT FROM AUTHOR]

Hydrogen explosions happen occasionally, resulting in heavy casualties and huge property losses. Explosion venting as an effective method of explosion protection need to be further studied. In this work, the influence of hydrogen concentration (20%–60%) on the explosion venting was investigated. It was indicated that the maximum explosion pressure (P max) inside the vessel and in the vent pipe first increased and then decreased with the increase of hydrogen concentration. The P max in the vent pipe was always much larger than that inside the vessel. However, the P max outside the vessel increased gradually with increasing hydrogen concentration. The propagation characteristic and the temperature field distribution of the explosion venting flame were also analyzed. There was no obvious venting flame for 20% hydrogen concentration, because of the exhaustion of hydrogen inside the vessel. The change of the concentration affected the occurrence of secondary explosion, which affected the flame morphology, propagation velocity and flame temperature field distribution. The maximum temperatures were 1164 °C and 1207 °C for 50% and 60% hydrogen concentrations. Furthermore, changes of hydrogen concentration resulted in changes of the explosion intensity inside the vessel, thus affecting the flow field microstructure inside the vessel and near vent port. The stronger the explosion intensity, the more unstable the flow field microstructure and the shorter the time required to reach stability inside the vessel. • The influence of hydrogen concentration on the explosion venting was investigated. • P max externally increased with increasing concentration, unlike inside the vessel. • Flame propagation velocity and temperature distribution were analyzed intensively. • Second explosion affected the flame characteristics at high hydrogen concentration. [ABSTRACT FROM AUTHOR]

Proactive caching has emerged as a promising means to accommodate increased demands for wireless capacity. However, studies of proactive caching usually focus on minimizing the overall load of cache-aided networks. How to calculate each user’s caching gain is still an open problem. In this paper, a two-phase cache-aided network is investigated, in which users with heterogeneous preferences are served by a base station through a shared link. Effective throughput is considered as a performance metric, which describes the reduction in each user’s transmission cost. All possible values of effective throughputs achieved by legitimate caching policies form an achievable domain. It is proved that the achievable domain is a convex set and can be characterized by its boundary. A special type of caching policies, termed uncoded placement absolutely-fair (UPAF) caching, is studied. For the two-user case, games are formulated to allocate effective throughput gains for the two users. For the general multiuser case, a UPAF policy is proposed to organize user cooperation. It is shown that users with more concentrated preferences can obtain higher effective throughputs. [ABSTRACT FROM AUTHOR]

• Corrosion coupons bent different angles can simulate the column material under different stress conditions. • The corrosion degree of the coupon with 20° bend is higher than other coupons. • In the study time range, the corrosion rate first decreased, then increased and finally decreased. • In a certain temperature range, the temperature can promote the corrosion rate of 316 L stainless-steel. Stress corrosion is the main factor that results in corrosion and fractures of rectifying columns in the process industries. Stress corrosion of rectifying columns can result in significant economic losses to chemical industries, while also having a major impact on the quality of products produced, particularly polysilicon. This gives rise to the need for research involving stress corrosion of rectifying columns. Corrosion coupons, including those with welds and bends, were used to simulate various stress conditions of stainless steel. For the experiments, a 1.5 wt.% hydrochloric acid and 2.5 wt.% sodium chloride solution was prepared to simulate realistic working conditions for the steel. The experimental methods include static coupon experiment, electrochemical experiment, scanning electron microscope and X-ray diffraction. The corrosion products of the coupons consisted mostly of grey-green materials with loose surface layers and small amounts of black matter. The corrosion products were confirmed to be FeCl 2 and Fe 2 O 3 , and the corrosion degree of the bent 20° coupon was found to be greater than that of other types of coupons. Under low temperature conditions, the corrosion rate of the coupons initially decreased over time before increasing and then decreasing again. At high temperatures, the corrosion rate began to decrease earlier than at low temperatures. The bending tendency of the 20° hanging piece was the greatest and that of the 30° hanging piece was the smallest. Higher temperatures promoted stress corrosion, with increases in temperature resulting in more significant corrosion effects. The results reported herein provide a theoretical basis and technical guidance for important anticorrosion and safety designs for distillation columns to be used in the semiconductor polysilicon rectification process. [ABSTRACT FROM AUTHOR]

One-port magnetic surface acoustic wave (MSAW) resonators are fabricated by stacking multilayered (FeCoSiB/SiO2)n films directly on top of interdigital electrodes. It is shown that the magneto-acoustic response of the MSAW resonators critically depends the hysteresis of ΔE effect. For the magnetic multilayer without induced magnetic anisotropy, the resonance frequency (fR) exhibits a butterfly-like dependence on the external field, therefore, enabling bipolar detection of magnetic field smaller than its coercive field. However, for the magnetic multilayers with induced magnetic anisotropy, butterfly-like or loop-like fR–H curves are measured along the interdigtial electrode fingers or the SAW propagation direction, which can be attributed to the competition between the magnetic field-induced anisotropy and the stress-induced or shape anisotropy. [ABSTRACT FROM AUTHOR]

Data compression is an efficient technique for saving data storage and transmission costs in networks. Traditional data compression methods usually compress each content item according to its own statistical distribution of symbols and do not take into account user preferences on various content items. However, user preferences significantly impact the statistical distributions of symbols transmitted over communication links. This paper presents an edge source coding method to compress data at the network edge, in which codebooks are designed based on not only the statistical distributions of symbols in the content items but also the user preferences. In edge source coding, multiple content items might be compressed via the same codebook. For discrete user preferences, DCA (difference of convex functions programming algorithm) based and $k$ -means++ based algorithms are proposed to derive codebook designs. For continuous user preferences, a sampling method is applied to yield codebook designs. In addition, edge source coding is extended to the two-user case and codebooks are designed to utilize multicasting opportunities. Simulation results demonstrate that edge source coding significantly reduces transmission costs for short content items. [ABSTRACT FROM AUTHOR]

Multicasting can reduce network traffic in multiuser systems by serving multiple users simultaneously. The benefits of multicasting basically come from the overlapping and synchronism of user requests. Pushing and caching are techniques that prestore content items in buffers closer to users based on the prediction of user requests, thereby providing a promising approach to eliminating the asynchronism of user requests and creating multicasting opportunities. This paper studies a multiuser wireless communication system, in which the buffers for caching are deployed in the user terminals. Based on the request delay information (RDI) which describes when the users request content items in a deterministic or statistical way, a joint pushing and caching (JPC) method is presented to schedule the content items pushed by the base station and cached in the user buffers. In this paper, multicasting JPC systems work in two modes, without or with the feedback of RDI. Furthermore, RDI is classified into three forms, namely, noncausal, statistical, and causal. Static and dynamic JPC policies are, respectively, proposed for the two work modes. In addition, the effective throughput resulting from JPC under the three forms of RDI is demonstrated via theoretical analysis and simulation. [ABSTRACT FROM PUBLISHER]

TiO 2 -doped ZrO 2 (hereafter denoted as TDZ) nanofiltration (NF) membranes with stable tetragonal phases are efficiently fabricated via a modified colloidal sol-gel process using a mixture of Zr-inorganic salts and Ti-alkoxides. Nanometer-sized TiO 2 -ZrO 2 (hereafter denoted as TZ) colloidal sols with an average hydrodynamic diameter of ~2 nm are synthesized, showing good stability and reproducibility. The resulting TDZ materials are characterized by XRD, TEM, XPS, CA, mapping and nitrogen sorption. It is shown that the incorporation of Ti 4+ restrains the t→m phase transition, decreases the tetragonal crystallite size, enhances the hydrophilicity, increases the specific surface area and narrows the pore size distribution. Furthermore, these changes are promising for fabricating high performance NF membranes. The as-prepared TDZ NF membranes exhibit high performances with a low MWCO of ~500 Da and a high pure water permeability of 35~40 L m −2 h −1 bar −1 , as well as desired retention rates of 99.6% for Co 2+ , 99.2% for Sr 2+ and 75.5% for Cs + , in simulative radioactive waste water treatment. [ABSTRACT FROM AUTHOR]

A novel luminogen, CZ2TPAN, with typical D-A architecture was obtained. It shows intramolecular charge transfer and aggregation-induced emission characteristics with high solid-state efficiency of 65.3%. Moreover, it exhibits reversible mechanochromic behavior between crystalline and amorphous states with remarkable emission color change from green (504 nm) to yellow (545 nm). [ABSTRACT FROM AUTHOR]

• Interaction mechanism of wire mesh inhibition and ducted venting was analyzed. • Pressure showed an uptrend with increasing initial pressure and ignition energy. • The P max was increased gradually with the increases of the mesh number and layer. • The critical condition for the complete inhibition of venting flame was determined. • The negative pressure inside the vessel during explosion venting was explained. A set of experimental equipment for wire mesh inhibition and ducted venting on methane explosions was proposed. The effects of wire mesh parameters, venting parameters, and initial conditions on the explosion intensity were also investigated and the interaction mechanism between the wire mesh inhibition and ducted venting was analysed. The results indicated that the venting flame length decreased gradually and the explosion pressure inside the vessel increased with increasing wire mesh number and layer. Especially the venting flame did not appear outside the vessel under the five layers and 60 mesh number condition, which indicated that the explosion flame propagation was effectively inhibited by the metal wire mesh. With an increase in the venting diameter, the maximum explosion pressure (P max) inside the vessel decreased gradually. However, the P max and the maximum pressure rise rate ((dP/dt) max) were increased with an increase in the rupture pressure, and the appearance moment of the P max was decreased. The initial concentration, initial pressure, ignition energy and venting position as the important factors could evidently affect the combined effects of wire mesh inhibition and ducted venting for explosion protection. The P max inside the vessel first increased and then decreased with an increase in the methane concentration, and the explosion intensity was the highest under the equivalence ratio condition. With an increase in the initial pressure and energy, the P max also was increased. The pressures at the vessel and duct end under the vessel top venting were greater than that of duct end venting. [ABSTRACT FROM AUTHOR]

Synergy inhibition of wire mesh and spray mist on syngas explosion was researched. The correspondence between the explosion parameters under success and failure conditions were analyzed, and its influence regular and inhibition mechanism were revealed. An evident difference appeared in the correspondence at different synergy results. Compared with the failure, the pressure of lower end only experienced an acceleration rise under the success condition although the propagation velocity of flame was slightly increased as it approached wire mesh. Corresponding pressure was also reduced. After passing through wire mesh, flame propagation was evidently accelerated due to the turbulence disturbance caused by wire mesh despite the strong endothermic effect of mist. The corresponding explosion reaction rate was also increased. Pressures of two ends did not appear obvious change under the success condition, but the pressure of upper end was evidently reduced compared with the failure. Due to the combined effect of wire mesh disturbance and mist heat absorption, the velocity history showed a change of increasing firstly and then decreasing as the spray time increased after passing through wire mesh. The synergy inhibition was attributed to the combined physical and chemical effects, and was related to the syngas concentration and spray amount. [Display omitted] • Synergy effect of resistance/inhibition on protection of gas explosion was studied. • Correspondence between explosion parameter during success and failure was clarified. • Effects of mist amount and syngas concentration on explosion parameter were grasped. • Critical value of synergy effect for complete inhibition of explosion was proposed. • Effective engineering guidance was proposed and its synergy mechanism was revealed. [ABSTRACT FROM AUTHOR]

• Venting characteristics of gas/dust hybrid explosions was researched by experiment. • Relationship between the venting flame propagation and pressure rise was clarified. • Propagation characteristics of venting flame and its change mechanism were studied. • Distribution and variation of venting flame temperature field were analyzed deeply. • Physical model of gas/dust two-phase explosion venting process was established. This research focused on the venting characteristics and influence factor of methane and coal dust mixture explosions. The corresponding relationship between the venting parameters was analyzed and the effect of methane concentration was obtained. Results indicate that the venting flame propagation and pressure rise of vessel interior and exterior presented the clear corresponding relationship. The venting flame underwent the evolution process of "mushroom", "spherical" and "strip" structures. At 6% methane concentration, the venting flame was longest and its propagation velocity was fastest. During the extinguishing stage, the flame exhibited an obvious oscillation. The venting flame appeared a secondary venting phenomenon at 6% and 8% methane concentrations, and the phenomenon was more evidently at 8% methane concentration. The pressure at the venting pipe was the greatest and its change was also most significant, even appeared a larger negative value. Compared with the vessel interior, the pressure of vessel exterior was continuously decreased as the venting distance increased. The venting pressure was the greatest at 6% methane concentration, followed by 8% methane concentration. The pressures of four points at 4% methane concentration were respectively reduced by 25.0%, 34.9%, 43.8% and 81.8%. The corresponding flame temperature also presented the same change trend. Besides, the venting flame image showed a good correspondence with the temperature field distribution and the highest temperature appeared in the center of spherical flame. The secondary venting resulted in the recurrence of high temperature flame at the venting port (500℃-650℃) and was affected by the methane concentration inside the vessel. [ABSTRACT FROM AUTHOR]

• An accident on corrosion of a polycrystalline distillation column was investigated. • The main corrosion forms are pitting corrosion and stress corrosion caused by Cl−. • Corrosion rate of 316 L stainless steel is negatively correlated with the pH. • Corrosion rate of 316 L stainless steel is positively correlated with temperature. • Transformation from pitting corrosion to stress corrosion occurs at high temperature. Distillation column is a fundamental device for the production of the semiconductor polysilicon. Therefore, investigating corrosion leakage protection of the distillation column is of great significance because of the undetectable yet very significant consequences of corrosion leakage to the column. In this work, corrosion investigation of a polycrystalline silicon rectification tower is presented. The composition and crack morphology of the distillation column (316 L austenitic stainless steel) were detected and analysed using component and hardness analysers. The effects of pH and temperature on the corrosion rate were studied by conducting electrochemical experiments. According to the macroscopic test results, the surface of the tower was covered with a large number of pits and cracks of different depths. Furthermore, based on the metallographic analysis, SEM analysis, and energy spectrum analysis results, it was determined that the crack morphology was mostly intergranular and transgranular. Combined with the test data and process environment, it has been determined that the main forms of corrosion for rectification towers are pitting corrosion and stress corrosion caused by chloride ions. According to the results of electrochemical experiments, the corrosion rate of 316 L stainless steel is negatively correlated with pH value for a pH range of 4–6 at constant temperatures. However, the corrosion rate is positively correlated with temperature for the range of 60 °C–90 °C at constant pH values. From the analysis of the corrosion morphology, the corrosion failure mode of 316 L stainless steel is largely attributed to pitting corrosion when the column is operated at low temperatures (60 °C and 70 °C). However, at high temperatures (90 °C), a transformation from pitting corrosion to stress corrosion occurs along the crystalline form. To ensure the stable operation of the polysilicon rectification tower, this paper proposes corrosion protection measures based on the results of the analysis as described. [ABSTRACT FROM AUTHOR]

According to Brajanovski periodic layered model, a fractural medium can be equivalent to layered media with periodic distribution of fractural layers and background layers, but the analytical solution given by Brajanovski can only interpret the dispersion and attenuation effects of single characteristic unit model. In order to study the dispersion and attenuation features of multiple characteristic units, forward modeling methods are needed. Based on the theory of two-phase medium, Biot deduced the propagation equation of longitudinal waves in fluid-saturated porous media. However, there are two problems in the forward modeling using time-domain equation. One is the influences of boundary reflection, and the other is the introduction of cumulative error. For convenience, time-domain equation is rewritten in the frequency domain, thus constructing a one-dimensional rock physics model. Then, forward method is used to study the dispersion and attenuation features of fluid-saturated medium. Numerical simulation results are found to be in good agreement with the analytical solution. Furthermore, the frequency-domain forward method can analyze the velocity dispersion and energy attenuation of longitudinal waves in any multilayered fracture medium. By analyzing those numerical simulation results, it can be obtained that, as the length of characteristic unit increases or the number of characteristic unit decreases, both the starting frequency of dispersion and the peak frequency of attenuation shift to low, whatever the attenuation peaks are equal. In addition, the effects of porosity, permeability and fluid saturation on energy attenuation and velocity dispersion are also studied. Finally, the stress field and displacement field distributions of fluid-saturated fractural medium are given by the frequency-domain forward modeling method. [ABSTRACT FROM AUTHOR]

The flame resistance characteristics of wire mesh and its influence factor on syngas explosion were researched by experiment. Relationships between flame propagation and pressure rise at the flame resistance system two ends were clarified under different flame resistance results. And the effect of syngas concentration on explosion parameters was obtained and flame resistance mechanism was also revealed. Results indicate that the existence of wire mesh could indirectly affect pressure rise by affecting the flame propagation, and flame propagation and pressure rise presented a clear corresponding relationship. The wire mesh could play a better inhibiting role and reduce the explosion intensity, affecting by syngas concentration. As the flame resistance failed (c =30%), △ P max was effectively decreased from 0.81 MPa to 0.52 MPa above wire mesh and from 0.58 MPa to 0.39 MPa below wire mesh. And the reduction extent was more significant under flame resistance success (80.25% and 68.97%). With reduction of syngas concentration and increase of mesh layer, explosion parameters were evidently decreased. Especially the temperature above wire mesh did not present an increase trend and reach the ignition point of syngas under flame resistance success. The inhibition mechanism was mainly attributed to the combination of endothermic and wall effects. [ABSTRACT FROM AUTHOR]

• The temperature of H 2 jet flame with suppressants addition are analyzed. • Water mist containing DMMP exhibit good suppression effect on H 2 jet flame. • The influence of DMMP on lean CH 4 and lean H 2 flames is compared. • There is no combustion enhancement effect of DMMP on lean H 2 flame. This work investigates the suppression effect of water mist containing dimethyl methylphosphonate (DMMP) on H 2 jet flame. The flame appearances are analyzed and the flame temperature is recorded by a high-speed infrared camera. Results show that the suppression effect of water mist containing DMMP is better than that of pure water mist. To better understand the suppression effect of water mist containing DMMP, the burning velocity, heat production and free radicals are analyzed. Results indicate that suppressant could scavenge lots of free radicals to reduce the burning velocity in a wide range of equivalence ratios. Moreover, the influence of DMMP on lean CH 4 and H 2 flames is compared. Different with that of lean CH 4 flame, the combustion parameters of lean H 2 flame decline with DMMP addition. There is no combustion enhancement effect of DMMP on lean H 2 flame. Because of the higher combustion intensity of lean H 2 flame, the hydrocarbon in DMMP has little impact on the combustion. Furthermore, the reaction path of DMMP decomposition is analyzed. Results demonstrate that the rates of most phosphorus reactions in H 2 flame are larger than that in CH 4 flame. This work could provide foundation for improving the safety of hydrogen energy application. [ABSTRACT FROM AUTHOR]

• The combustion characteristic of LIB vent gases containing DMC was studied. • The fire risk of LIB vent gases was reduced with the addition of DMC. • The influence of H 2 O, Novec-1230 and DMMP on LIB vent gases flame was analyzed. • DMMP showed great suppression efficiency on both the lean and stoichiometric flame. The combustion of Lithium-ion battery (LIB) vent gases plays key roles in determining LIB fire hazard. Previous studies analyze the combustion of LIB vent gases without consideration of electrolyte. This work studies the combustion characteristic of LIB vent gases with dimethyl carbonate (DMC) addition. The flammability limit, laminar burning velocity (LBV), flame temperature and heat production are explored. For different components of LIB vent gases, most of combustion parameters decrease or remain unchanged with addition of DMC. It demonstrates that the fire risk of LIB vent gases reduces with DMC addition. Moreover, the influences of H 2 O, C 6 F 12 O (Novec-1230) and POCH 3 (OCH 3) 2 (DMMP) on LIB vent gases flame are investigated. At Φ = 1.0, all three suppressants suppress the flame. The lowest and highest suppression efficiency are H 2 O and DMMP. At Φ = 0.45, Novec-1230 enhances combustion, but DMMP reduces LBV which is quite different from the enhancement effect on CH 4 /air flame. This is mainly because of the reducing of O free radical and heat production. The sensitivity and path reaction of DMMP indicate that phosphorus species play important roles in suppressing lean flame. This work could deepen understanding of LIB vent gases combustion dynamics and provide guidance for choosing appropriate suppressants of LIB fire. [ABSTRACT FROM AUTHOR]

Ceramic nanofiltration (NF) membranes are becoming increasingly important for the recovery and purification of dyes and salts (e.g., NaCl) in high salinity waste streams. This work reports an aqueous sol–gel process for the preparation of high-flux yttria-stabilized-zirconia (YSZ) NF membranes derived from zirconium oxychloride, and the procedure is completely free of organic solvents. The use of zirconium oxychloride as a precursor dissolved in deionized water was expected to contribute to environmental protection and reduce cost. A crack-free thin YSZ layer was fabricated on α-Al 2 O 3 supported ZrO 2 ultrafiltration membranes. The YSZ NF membrane exhibited a great water permeability of 28 L m −2 h −1 bar −1 and a low molecular weight cut-off of 800 Da. Furthermore, the desalination and recovery were examined with fluorescent brightener wastewater in different operation parameters by YSZ NF membranes. The filtration results revealed that the fluorescent brightener retention increased slightly with increasing transmembrane pressure and cross-flow velocity. When the filtration was operated at 60 °C, the fluorescent brightener recovery value of 99% was obtained while the NaCl removal was greater than 98%, meanwhile the flux was up to 89 L m −2 h −1 under suitable conditions, indicating that ceramic NF membranes were the technology of choice in treatment of high temperature dye wastewater. [ABSTRACT FROM AUTHOR]

A fluorescent immunochromatographic test (FM-ICT) was developed for rapid detection of anti- Orientia tsutsugamushi antibodies in serum samples. The FM-ICT was constructed based on the dual-antigen sandwich method. Truncated 56 kDa outer membrane protein of O. tsutsugamushi strain SJ, was expressed in E. coli and mixed with those of Ptan and Gillam strains. A thin line of the protein mixture was precisely sprayed across a nitrocellulose membrane making this the "Test" line. Polyclonal antibodies (pAbs) to O.tsutsugamushi were sprayed in another line across the membrane making this the "Control" line. Fluorescent microspheres conjugated 56 kDa proteins reacting with sample serum will be captured on the "Test" line if the sample contains antibodies to O.tsutsugamushi. Several experimental parameters were optimized. After optimizing the reaction procedure, the results are visible, within 6 min, with the naked eye under ultraviolet light. The limit of detection (LOD) was determined to be 7.63 ng/mL with prepared polyclonal antibodies. No cross-reaction was observed with sera samples from other febrile diseases. In clinical evaluations, the strips showed 94.92% sensitivity (106/112) and 93.75% specificity (56/60). The FM-ICT we developed will provide a new tool for on-site diagnosis of scrub typhus. • Recombinant proteins of three epidemic strains were mixed as diagnostic antigen. • Fuorescent microsphere were used in immunochromatographic strip for lower LOD. • Results can be read by naked eyes with the help of a portable UV lamp. • Suitable for on-site diagnosis in lab, families, even in the wild or remote areas. [ABSTRACT FROM AUTHOR]

This study experimentally and numerically determined the effect of FM-200 on H 2 /air explosion. Firstly, the explosion pressure was investigated to evaluate the suppression efficiency. The results indicated that the effect of FM-200 on H 2 /air explosion was quite different for various equivalence ratios. FM-200 could enhance the explosion at lean mixture, but suppress the explosion at rich mixture. Then, the burning velocity, heat production and temperature free radicals were investigated. The results also demonstrated that FM-200 exhibited stronger suppression effect in rich explosion. In addition, the increase of free radicals indicated the enhancement effect of FM-200 at lean explosion. Last, the analysis of sensitivity and reaction path was performed to understand the suppression kinetics. It was shown that R1466 and R1468 could suppress explosion at Φ = 1.3 and 1.6, however, they changed into promoting explosion at Φ = 0.8 and 1.0. Moreover, the reaction path analysis indicated that CHF:CF 2 →CHF:O→CO could enhance explosion at Φ = 0.8. For CHF:CF 2 →CH 2 F→HF, it played an important role in scavenging H to suppress explosion at Φ = 1.6. Furthermore, it was indicated that there was a competition between the enhancement and suppression effect at Φ = 1.3. • Several characteristic parameters of hydrogen explosion with FM-200 addition were analyzed. • The explosion was enhanced with small volume fraction FM-200 addition at lean explosion. • Reaction R1466 and R1468 could suppress explosion at rich mixtures; but promote explosion at lean mixtures. • The analysis of reaction path was performed to understand the suppression kinetics. [ABSTRACT FROM AUTHOR]

• Inhibition characteristics of mist on gas/dust explosions was studied by experiment. • Pressure, flame temperature, propagation characteristics and products were analyzed. • Relationship between mixture explosion parameter under mist condition was clarified. • Effects of mist and methane concentrations on explosion inhibition were obtained. • Effective engineering suggestion was proposed and inhibition mechanism was reveale. Inhibition of water mist on the gas/dust two-phase explosions and its influence factor were studied inside the vessel. The effects of mist and methane concentrations on the pressure and its rise rate, flame propagation characteristics and its temperature were explored. Especially the explosion products were analyzed by the infrared spectroscopy. The weakening effect was revealed based on the corresponding relationship and changing rule of explosion parameters. As the flame developed and changed, the pressure rise showed the same correspondence. However, the corresponding moment was evidently prolonged compared with the case no mist. The mist could effectively inhibit the intensity of mixture explosions, causing a dark-irregular structure in the early stage and accelerating its extinction in the later stage. After the mist concentration increased, the explosion parameter was evidently reduced. As the methane concentration increased (4% ≤ c ≤ 10%), the explosion parameters appeared a trend of firstly rising and then reducing. As c = 6%, the explosion intensity was the greatest. After adding mist, the explosion parameter exhibited the same change regular. And the weakening effect of mist on the weaker flame was more outstanding and was constantly enhanced as the rise of mist concentration. Besides, the mist could effectively inhibit the pyrolysis and combustion reactions of macromolecular functional groups, further leading to evident increase in the functional group content inside the coal dust as the mist concentration increased. [ABSTRACT FROM AUTHOR]

• An accident of pipeline rupture in alkylation unit was investigate. • The failed pipeline structure provides conditions for hydrofluoric acid corrosion. • The decrease of pipeline strength is the direct cause of the accident. • The key factors to prevent pipeline leakage in alkylation unit were investigated. Owing to the corrosive, flammable, and explosive properties of pipeline materials in alkylation units, corrosion failure may result in leakage, fire, and explosion accidents. A bursting accident occurred in the 90° elbow of an alkylation unit pipeline. Failure analysis was performed by macroscopic analysis, metallographic analysis, chemical composition, corrosion form analysis, and corrosion product analysis. Finite element software was used to analyse the flow velocity, turbulence intensity, pressure, and wall stress distribution. The fault tree was combined with the analytic hierarchy process to realise the transformation of the structural importance-judgement factor-judgement matrix and to weight the events that may cause device corrosion failure. The results showed that uniform corrosion and stress corrosion of hydrofluoric acid occur in the pipeline and uniform corrosion is the dominant effect. Hydrofluoric acid corrosion leads to severe thinning of the pipe wall, making its strength drop below the bearing strength and rupture occurs. Quality of internal anticorrosion coating, water content of the medium and working temperature are the key factors to prevent pipeline leakage in alkylation unit. [ABSTRACT FROM AUTHOR]

• Numerical model of methane explosion inhibition by the water mist was established. • Calculation result was validated by experiment through pressure and flame changes. • Heat transfer between water mist and explosion flame was analyzed quantitatively. • Vapor pressure as a component of explosion pressure in a closed vessel was studied. • Effects of mist parameter on heat transfer process and vapor pressure were studied. This numerical study focused on the heat transfer process between the ultrafine water mist and explosion flame, and the suppression mechanism of ultrafine water mist and the effect of mist parameter on methane explosion. Hence, a three-dimensional numerical model for methane explosion suppression by ultrafine water mist was established. Large eddy simulation and partially premixed combustion models were used to determine the explosion flow field characteristics and methane explosion process, respectively. The Euler-Lagrange equation was used to solve the continuous and discrete phases, and the coupling calculation was realized by alternately solving these two phase models. In addition, the validity of the numerical model and calculation method was verified by the experimental results. Mist vaporization, heat transfer between the gas and liquid phases, and influencing factors (including the mist diameter (d), mist velocity (v), and mist concentration (Q Mist)) were analyzed quantitatively. The results indicate that heat exchange mainly occurs in the reaction zone, and the heat exchange rate can be affected by the mist parameters, which further affects the temperature inside the vessel. Moreover, the vapor pressure generated from mist vaporization is an important component of the explosion pressure in the closed vessel, and it is comprehensively affected by the mist vaporization rate and temperature. Simultaneously, the mist parameters are also the key influencing factors for the above process. [ABSTRACT FROM AUTHOR]

• Relationship between flame propagation and pressure rising was analyzed deeply. • Effect and mechanism of obstacle parameters on explosion intensity were clarified. • Regular of flame "reverse oscillation" was determined and mechanism was discussed. • Effective suggestion was proposed based on the research for practical application. This experimental study focused on effect of obstacle on the syngas (H 2 /CO) explosion characteristics under lean-fuel conditions. The relationship between the flame propagation characteristics and explosion intensity, and effects of syngas concentration, obstacle number and blocking rate on explosion parameters were obtained. Results indicate that the flame propagation and pressure rise were corresponding inside the closed vessel. Obstacle could affect the flame propagation process by changing flame structure, which further indirectly affected the flame velocity and explosion intensity. The "reverse oscillation" flame appeared in the later stage due to the interaction between the flame front and reflected pressure wave, and affected by the obstacle condition and syngas concentration. Meanwhile, the peaks of velocity history were obviously increased, and their appearance moment and the interval time between adjacent peaks were decreased with increasing syngas concentration, obstacle number and blocking rate. Especially the maximum flame propagation velocity (v max) was increased by 88.90%, 60.59% and 61.65%, respectively. The maximum explosion pressure (△ P max) and two peaks of pressure rising rate history also presented an increasing trend. However, the first peak appearance moment had a slight delay due to the blocking effect with the increases of obstacle number and blocking rate in the initial stage of flame propagation. [ABSTRACT FROM AUTHOR]

Emissive electron donor–acceptor (D–A)conjugateshave a wide variety of applications in biophotonics, two-photon absorptionmaterials, organic lasers, long wavelength emitters, and so forth.However, it is still a challenge to synthesize high solid-state efficiencyD–A structured emitters due to the notorious aggregation-causedquenching (ACQ) effect. Though some D–A systems are reportedto show aggregation-induced emission (AIE) behaviors, most are onlyselectively AIE-active in highly polar solvents, showing decreasedsolid-sate emission efficiencies compared to those in nonpolar solvents.Here we report the triphenylamine (TPA) and 2,3,3-triphenylacrylonitrile(TPAN) based D–A architectures, namely, TPA3TPAN and DTPA4TPAN.Decoration of arylamines with TPAN changes their emission behaviorsfrom ACQ to AIE, making resulting TPA3TPAN and DTPA4TPAN nonluminescentin common solvents but highly emissive when aggregated as nanoparticles,solid powders, and thin films owing to their highly twisted configurations.Both compounds also display a bathochromic effect due to their intramolecularcharge transfer (ICT) attribute. Combined ICT and AIE features renderTPA3TPAN and DTPA4TPAN intense solid yellow emitters with quantumefficiencies of 33.2% and 38.2%, respectively. They are also thermallyand morphologically stable, with decomposition and glass transitiontemperatures (Td/Tg) being 365/127 and 377/141 °C, respectively. Multilayerelectroluminescence (EL) devices are constructed, which emit yellowEL with maximum luminance, current, power, and external quantum efficienciesup to 3101 cd/m2, 6.16 cd/A, 2.64 lm/W, and 2.18%, respectively.These results indicate that it is promising to fabricate high efficiencyAIE-ICT luminogens with tunable emissions through rational combinationand modulation of propeller-like donors and/or acceptors, thus pavingthe way for their biophotonic and optoelectronic applications. [ABSTRACT FROM AUTHOR]

In a Wistar rat model, prolonged supplementation of mustard seed (MS) to the diet significantly ameliorates the induction of colorectal carcinomas by 1,2-dimethylhydrazine (DMH). The expression of the splenocyte major histocompatibility complex class I (MHCI) was found significantly enhanced, whereas that of the major histocompatibility complex class II (MHCII) was significantly decreased. Compared to that of control animals, the proportion of spleenic B- and dendritic cells (DC) was amplified in the MS group. The expressions of MHCI, as well as that of MHCII, were increased in DC cells; whereas in B cells, MHCI expression was augmented but that of MHCII moderately decreased. The percentages of CD8+CD28+ and CD4+CD28+ cells were increased in the MS group, while the CD4+CD25+Foxp3+ subset was depressed. Plasma analysis showed that DMH-exposure induced amplified amounts of interleukin (IL)-4, IL-5, IL-10, and transforming growth factor-beta, whereas MS feeding counteracted this effect but enhanced IL-2, IL12p70, IL21, TNF-alpha, and interferon-gamma. In the SW480 colon adenocarcinoma cell-line, the cytotoxicity of spleenic T-cells from MS-fed animals was significantly increased. In the DMH-exposed rats, the expression of perforin in the spleenic T-cells was dramatically decreased, whereas MS abolished this depression. In summary, dietary MS suppresses DMH-induced immuno-imbalance as well as colon carcinogenesis in rats. [ABSTRACT FROM AUTHOR]

Abstract: Perfluorinated sulfonic acid ionomer/poly(N-vinylpyrrolidone) (PFSA/PVP) fibrous membranes with varying compositions were prepared by electrospinning. The morphology, physicochemical structure and water stability of these membranes were investigated by SEM, XRD, and FTIR. The crosslinking agent 4,4′-diazostilbene-2,2′-disulfonic acid disodium salt (DAS) was added to the spinning solutions, and its effect on electrospinning behavior and PFSA/PVP membrane morphology was investigated. Thermal annealing of the DAS-containing PFSA/PVP fibrous membranes resulted in improved water stability due to PVP crosslinking. The adsorption properties of the nanofiber membranes were measured by the ability to remove Cu2+ and Ca2+ ions from water. Nanofiber membranes with higher surface area provide more exposed functional groups and thus better ion removal capability. These functional PFSA/PVP nanofiber membranes show applicability in water treatment and may find potential applications in sensors and drug delivery or as components of the catalytic layer of proton-exchange membrane fuel cells. [Copyright &y& Elsevier]

• The flame evolution behavior of vapor cloud explosion ignited at different positions were analyzed. • Experiments of chained explosions for vertically distributed vapor clouds were conducted. • The effect of vapor cloud diameter and separation distance on the secondary explosion was discussed. • The regime of the enhanced secondary explosion was revealed. Chained explosions happened occasionally, leading to heavy casualties and huge property losses. However, the development regime of the chained explosions is unclear. Experiments of both single and two vertically distributed vapor clouds with different sizes, volume concentrations and ignition conditions were conducted. The experimental results show that the maximum overpressure generated by the primary methane/air mixture explosion increases with vapor diameter, but hardly changes with the ignition energy. The effect of ignition position on chained explosions is significant since the development trajectory of the primary explosion varies with the ignition position. The secondary explosion is more likely to be triggered in the case of ignition at the center of the primary vapor cloud. Because of the enhanced ignition and turbulence induced by the primary explosion, the maximum overpressure and rate of pressure rise of the secondary explosion are larger than that of the primary explosion and increase with a decrease in the separation distance between the two vapor clouds. In addition, the development of the explosion flame for the secondary explosion induced by a primary explosion is asymmetric due to the uncertain ignition point. [ABSTRACT FROM AUTHOR]

Triphenylacrylonitrile and diarylamine based D–π–A luminogens exhibit typical AIE characteristics with high solid state efficiency up to unity and switchable mechanochromism with high contrast, which render them multifunctional materials for versatile applications in optical storage, volatile organic compound (VOC) detection, OLEDs, etc. [ABSTRACT FROM AUTHOR]

• Combustibles, combustion aids, ignition sources, and tank corrosion are analyzed. • The aluminum float was subjected to SEM and EDS to investigate the corrosion. • Sulfur and iron contents of corrosion products were analyzed by elemental analysis. • Main causes of the accident are discussed, and the counter measures are proposed. With the rapid development of the petrochemical industry, sulfur-related devices are increasing. In this paper, a fire accident occurred in a petrochemical storage tank of a petrochemical enterprise. Through analysis, we found that the direct cause of the accident was the spontaneous combustion of ferrous sulfide (FeS), which caused the explosion of the oil and gas mixture between the floating disk and the tank top. In addition, we analyzed the corrosion of aluminum floating plates in oil tanks by Scanning Electron Microscope (SEM) and Energy Dispersive Spectrometer (EDS). The analyses showed that although AlMn1Cu aluminum alloy has high corrosion resistance, the material composition contains impurity elements such as silicon and iron, which weakens the corrosion resistance of aluminum alloy, and the intergranular corrosion and corrosion effects such as pitting corrosion cause cracks to form in the floating disk. The oil and gas that volatilize in the oil tank diffuse through the pores between the floating plate and the top of the tank to form an explosive mixture of oil gas and air. Next, the corrosion products of the manhole cover and the edge of the floating plate were sampled and were analyzed the sulfur and iron contents by elemental analysis. The results showed that the sulfur content in the sample of the manhole of the No. 1 tank was 25.04 wt%, and the sulfur content in the sample at the edge of the floating plate was 7.49 wt%. This was owing to the manhole at the bottom of tank No. 1 is not in contact with air. The edge of the floating plate of tank No. 1 has a low sulfur content due to the long-term contact with air and the burning process during an accident. Using Fault Tree Analysis (FTA), we conclude that the necessary conditions for the accident are appropriate heat storage conditions. The key factors are bad desulfurization effect on the refining process, sulfur in the crude oil, nonresistance of the tank material to corrosion and presence of S2- in the tank. Finally, corresponding countermeasures are proposed. [ABSTRACT FROM AUTHOR]