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Moisture crosslinking of polyolefins has attracted increasing attention because of its high efficiency, low cost, and easy processing. However, the crucial shortcoming of moisture crosslinking is that the side reaction of peroxide scorch (precrosslinking) simultaneously occurs in silane grafting. It has been recognized that making peroxide precrosslinking useful is an effective way to broaden the application of moisture crosslinking. A novel foaming process combined with moisture crosslinking is proposed. The matrix of ethylene–propylene–diene terpolymer grafted with silane vinyl triethoxysilane (EPDM-g-VTES) was prepared by melt grafting, with dicumyl peroxide as initiator. Foaming was then carried out with azodicarbonamide (AC) as the blowing agent by making use of precrosslinking. Subsequently, the EPDM-g-VTES foams were immersed in a water bath to achieve moisture crosslinking with dibutyl tin dilaurate as the catalyst. The results showed that VTES was grafted onto EPDM and the EPDM-g-VTES foams were successfully crosslinked by moisture. The EPDM-g-VTES compounds with AC obtained great cells by compression molding with the help of precrosslinking. The mechanical property of the EPDM-g-VTES foam was improved by moisture crosslinking. The moisture-cured foam with 4 wt% AC had an expansion ratio of about three times, which could bear large deformation and showed a high energy-absorption effect.

In this work, tetrakis(dimethyllamino)ethylene (TDAE) plasticized polynorbornene (PNB) was used as the matrix, sulfur (S) and dicumyl peroxide (DCP) were simultaneously used as crosslinking agents to construct dual covalent cross-linking networks in PNB. The effects of different amounts of cross-linkers on the crosslinking degree, mechanical property, glass transition temperature, and PNB shape memory performance were investigated. Two crosslinking mechanisms were examined by Fourier transform infrared spectrometer and Raman spectrometer. The results showed that sulfur-rich cross-linked PNB exhibited a higher crosslinking degree, tensile strength, and slightly higher glass transition temperature than the DCP-rich system. Cross-linked PNB presented better shape memory performance than the uncross-linked one. Sulfur-rich cross-linked PNB showed even better shape memory behavior than the DCP-rich system, both with a shape fixation ratio of over 99% and a shape recovery ratio of over 90%. The reaction mechanism of sulfur and DCP in cross-linking PNB was different. Sulfur reacted with the α-H in PNB to form monosulfide bonds, disulfide bonds, and polysulfide bonds in PNB and the number of polysulfide bonds increased with increased amounts of sulfur. DCP reacted with the double bonds in PNB to form C-C covalent bond crosslinking networks. The crosslinking mechanism revealed that the sulfur-containing cross-linked bonds, especially polysulfide bonds, were more flexible and bore large deformation, which gave the PNB excellent mechanical properties and ensured a higher shape entropy elastic recovery ratio.

Modified nanoparticles are increasingly being used in the manufacture of multi-purpose polymers of high-performance. Most modifications only focus on the improvement of strength or toughness of the composite materials. These adjustments are however limited by the traditional molding method. In this paper, low molecular weight poly ( d -lactic acid) (PDLA) was coated on the surface of silica dioxide (SiO2) using the green chemical method. This realized nano dispersion of SiO2 in the poly (L-lactic acid)/poly (butylene adipate terephthalate) biodegradable blend (PLLA/PBAT) and uniform distribution of Stereocomplex Crystallites (SC) in the matrix. The mechanical properties of composites were dependent on their crystallization behavior, which was influenced by the temperature of 3D printing nozzle to achieve the “strength-toughness” transition. The PDLA modified SiO2 (SiO2-PDLA) evenly nano dispersed in the composite, and it did not agglomerate even at 5 wt %. The heat resistance of the composites improved with an increase in SiO2-PDLA, attributed to the SC. At a temperature of the 3D printing nozzle of 180 °C, the tensile strength of composites was greatly enhanced by the distribution of SC and SiO2-PDLA in the composite material. At a nozzle temperature of 210 °C, the SC melted. The PDLA grafted on SiO2 can act as a low molecular weight plasticizer to improve the toughness of composites.

Millions of tons of iron-bearing manganese residue are produced as a by-product of the electrolytic manganese industry. And the environmental contamination caused by manganese residue has received increasing attention. This paper focuses on the recovery of iron and manganese from high iron-bearing manganese residues. Manganese ferrite in manganese residues is initially decomposed by oxidative roasting, and the intermediates are magnetized in a reductive roasting step. The roasted product is milled and subjected to multi-stage magnetic separation. The optimum conditions are as follows: roasting at 750 °C under air flow for 30 min, roasting in a CO atmosphere at 750 °C for 30 min, and separating under a magnetic intensity of 1000 G for weak magnetic separation and of 12,000 G for strong magnetic separation. The recovery and grade of iron in the iron concentrate were 72.29% and 62.21%, respectively, and those of manganese in the manganese concentrate were 90.75% and 35.21%, respectively. This study demonstrates that the combination of roasting and magnetic separation provides a promising process for the recovery of iron and manganese from high-iron-bearing manganese residues.

2D barcode becomes a famous technology in information security issue in this decade. We propose a security mechanism improvement method by applying the error correction with random segmentation (ECRS) technique. In this paper, we use private key array for segmentation of the original texts be-fore merging the segmented texts whose were encoded by using error correction coding approach. Our proposed method has two advantages when com-pare with the traditional Reed-Solomon error correction coding algorithm. On one hand, our ECRS performs random segmentation using multiple redundant code to protect data. On the other hand, the ECRS protects the code from being falsified by using encryption keys. Our experiments manifest that the proposed method improves the security degree of significance while just only few sacrificing coding times.

The isothermal kinetics of zinc ferrite in a COCO2-Ar atmosphere were investigated by using thermogravimetric analysis (TGA). X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) were applied in studying the mechanism of reduction roasting. Linear-fitting of the measured data indicates that the growth of nuclei model is the kinetic model, and the overall Ea was 72.75 kJ/mol; the kinetic equation was derived as follows: [ − ln ( 1 − α ) ] 3 2 = 3.1054 × 10 6 ⋅ P CO 0.766 ⋅ V CO 1.135 ⋅ e − 72.75 × 10 3 R T ⋅ t . The CO intensity impacts the reaction rate more significantly than the CO concentration. The XRD and XPS results of the roasted products reveal that due to the migration of zinc ions together with oxygen ions during reductive roasting, the generation of magnetite is much faster than zinc oxide, indicating that the nucleation of zinc oxide is the rate-determining step.

This study focuses on the combustion kinetics and particle fragmentation of raw and torrified pine shells and olive stones in a drop tube furnace (DTF). The two biomass fuels studied have been torrified in a nitrogen inert atmosphere at 280–300 °C. Both raw and torrified biomass fuels were then burned in the DTF. The data reported includes gas temperature and particle burnout measured along the DTF for five furnace temperatures (900, 950, 1000, 1050 and 1100 °C). In addition, measurements of particulate matter (PM) concentrations and size distributions were made for all the biomass fuels at 1100 °C in the middle and near the exit of the DTF. The results showed that: (1) The high heating value of the torrified biomass fuels are higher than those of the raw biomass fuels; specifically, for pine shells it increased by 25% and for olive stones by 18%; (2) in contrast with the torrefied olive stones, the torrified pine shells require similar residence times to attain overall burnout values comparable to those of the untreated material; (3) the kinetic data for both fuels, raw and torrified, indicates that the torrefaction reduces the activation energy of the present biomass chars; and (4) torrefaction does not promote particle fragmentation even for biomass fuels that present high tendency for it.

Dynamic texture describes the images sequence that continuously demonstrates movement of pixel's intensity change patterns in time. Two motion features, namely average radius and motion coherence index are extracted to find the different characteristics of fire and smoke. Since, the average radius of motion vectors describes the rapid of intensity change, whilst the motion coherence index has been developed to assess the coherent motion of intensity change. We propose a cutting-edge periodic series analysis to characterize fire and smoke dynamic textures. Our experimental results demonstrate the periodic motion pattern of fire and smoke. Besides, the periodicity index calculated by our proposed method is efficiently able to characterize fire and smoke dynamic textures, higher efficiency than calculated by traditional approach.

Dynamic texture has been described as images sequence that demonstrates continuous movement of pixels intensity change patterns in time. We consider the motion features of smoke and fire dynamic textures, which are important for fire calamity surveillance system to analyze the fire situation. We propose a method to understand the motion of intensity change. The objective is not only for classification purpose but also to characterize the motion pattern of fire and smoke dynamic texture. The radius of vector usually describes how fast the intensity change. The motion coherence index has been developed to assess the motion coherency between observed vector and its neighborhoods. We implement strategic motion coherence analysis to determine the motion coherence index of motion vector field in each video frame. In practical, both covariance stationarity of average radius and motion coherence index are efficiently used to investigate fire and smoke characteristics by applying periodicity index for analysis.

Combustion tests in a large-scale laboratory furnace were carried out to assess the feasibility of using biodiesel as a fuel in industrial furnaces. For comparison purposes, petroleum-based diesel was also used as a fuel. Initially, the performance of the commercial air-assisted atomizer used in the combustion tests was scrutinized under non-reacting conditions. Subsequently, flue gas data, including PM (particulate matter), were obtained for various flame conditions to quantify the effects of the atomization quality and excess air on combustion performance. The combustion data was complemented with in-flame temperature measurements for two representative furnace operating conditions. The results reveal that (i) CO emissions from biodiesel and diesel combustion are rather similar and not affected by the atomization quality; (ii) NOx emissions increase slightly as spray quality improves for both liquid fuels, but NOx emissions from biodiesel combustion are always lower than those from diesel combustion; (iii) CO emissions decrease rapidly for both liquid fuels as the excess air level increases up to an O2 concentration in the flue gas of 2%, beyond which they remain unchanged; (iv) NOx emissions increase with an increase in the excess air level for both liquid fuels; (v) the quality of the atomization has a significant impact on PM emissions, with the diesel combustion yielding significantly higher PM emissions than biodiesel combustion; and (vi) diesel combustion originates PM with elements such as Cr, Na, Ni and Pb, while biodiesel combustion produces PM with elements such as Ca, Mg and Fe.

Experiments were conducted in a drop tube furnace (DTF) for a bituminous coal, two coal particle size distributions (unsieved coal with a mass mean diameter of 76 μm and sieved coal with a mass mean diameter of 29 μm) and three oxy-fuel atmospheres (21% O2/79% CO2, 26% O2/74% CO2 and 31% O2/69% CO2) at a furnace temperature of 1100 °C. For comparison purposes, tests were also performed under air firing conditions. The data reported includes gas temperatures, major gas species concentration and particle burnout measured along the DTF. In addition, a number of selected final char samples were also morphologically and chemically characterized. Under oxy-fuel conditions: (i) the near burner region (NBR) temperature increases and the HC and CO concentrations decrease as the O2 concentration in the oxidizer increases, regardless of the coal particle size; (ii) the NOx concentration levels along the DTF increase as the O2 concentration in the oxidizer increases, regardless of the coal particle size, but, compared with air combustion, the results show that oxy-coal combustion lowers the conversion of fuel-N to NO; and (iii) the NBR burnout levels increase as the O2 concentration in the oxidizer increases, regardless of the coal particle size. The combustion of the sieved coal yields higher NBR temperatures, lower NOx concentration and higher burnout levels along the DTF than the unsieved coal, regardless of the oxidizer composition. Carbon and nitrogen are released at about the same rate as total coal mass release, while hydrogen is released more rapidly regardless of the oxidizer composition and coal particle size. In the combustion of both unsieved and sieved coals, under oxy-fuel conditions, the final char structure becomes more porous as the O2 concentration in the oxidizer increases. The final char elemental composition is essentially independent of the oxidizer composition, but the combustion of the unsieved coal leads to chars with higher percentages of S and lower percentages of Cl than those from the sieved coal combustion.

Currently there is an increasing interest on a new generation of low cost biomass fuels derived from human activities like wood and forestry residues, crop residues and refuse derived fuels (RDF) produced from municipal or industrial solid waste. The main objective of this study is to evaluate the combustion behaviour and ash characteristics of a number of these renewable fuels, namely rice husk, straw, coffee husk and RDF derived from municipal waste. For comparisons purposes, the study also includes a bituminous coal and pine branches. The study was carried out in a drop tube furnace (DTF), where data was obtained for gas temperatures, particle burnout, and carbon, hydrogen and nitrogen release along the reactor for the six solid fuels. The analysis of the experimental data included the use of both a one dimensional (1D) model and the Fluent. The results reveal that biomass fuels yield particle burnout values comparable to those of coal due to a number of factors that have opposite effects, mainly their higher volatile matter, which increases the burnout, and their higher moisture content and larger particle size, which decreases it. According to the 1D model, the residence time of the particles in the DTF is strongly affected by the particle size, but the number of size fractions considered has little influence on the calculated burnout. Moreover, the use of the Sauter mean or mass median diameters is not appropriated to represent the biomass particle sizes in model calculations. Predicted burnout with the 1D model is similar to those predicted by the Fluent. The ash composition of the fuels revealed that RDF might have some corrosion and slagging potential, while the use of rice husk and straw could induce slagging through the formation of low melting temperature ashes.

This article describes an experimental investigation on ash deposit formation during the co-firing of coal with agricultural residues (wheat straw, olive stones and peach stones), whose main objective was to relate the deposition rate, morphology and composition of the deposits with the type of biomass used in the co-combustion process. The study was conducted in a large-scale laboratory furnace for relatively high co-firing ratios (0.4, energy basis). For comparison purposes, tests have also been performed for pure coal firing and co-firing of coal with pine branches. During the tests, the deposits were collected with the aid of an air-cooled stainless steel deposition probe, whose surface temperature was maintained at around 500 °C, and of an uncooled ceramic probe with a surface temperature of about 850 °C. Both probes were placed in a region inside the furnace in which the mean gas temperature was about 1000 °C, being the deposits collected after 2 h of exposure. A number of deposit samples were subsequently analyzed on a scanning electron microscope equipped with an energy dispersive X-ray detector. The results reveal that, in contrast with the co-firing of coal with pine branches, co-firing of coal with wheat straw and olive stones increase the ash deposition rate, as compared to pure coal firing. In addition, deposits resulting from the use of wheat straw and olive stones as secondary fuels present higher degree of adherence to surfaces. This is due to the high concentration of alkali metals present in the deposits composition, leading to compounds of low melting points. In particular, these two biomass fuels originated deposits with relatively high levels of K and S, which facilitate their sintering degree. The use of peach stones in the co-firing process led to a deposition rate similar to that of pure coal firing. However, the deposits present a relatively higher degree of adherence to the surfaces, which is probably due to the presence of higher levels of Na in its composition.