Lower Strength Loss Research Articles

Removal of Organic Aerosols from Furnace Flue Gas by Ceramic Filters

Organic aerosols have severe effects on human health and climate change. In this study, a pilot-scale ceramic filter was used to remove the organic aerosols from furnace flue gas produced from industrial processes. The performance of ceramic filter and long-term stability of ceramic material were investigated. It showed that gas permeation flux fluctuated at a high level, which was the result of the surface filtration and special self-regeneration of the vertical ceramic filter. Removal efficiencies of TSP, PM10, and PM 2.5 aerosols were higher than 98.5%, and the rejection mechanisms were concluded as sieving, surface adhesion, and pore channel capture. Chemical characteristics of aerosol were analyzed based on FTIR spectra. Main organic compounds in the collected aerosols were paraffin binder, carboxylic acids, and esters. Carboxylic acids and esters were the products of the chemical reactions of paraffin and oxygen at high temperatures. After a long-term operation, ceramic membranes exhibited low flexural strength loss and slight variation in pore size distribution and the microstructure remained unchanged. Therefore, porous alumina membranes have potential for applications in the of removal organic aerosol emissions from industrial processes before reaching the atmosphere.

Core–satellite Ag@BaTiO3 nanoassemblies for fabrication of polymer nanocomposites with high discharged energy density, high breakdown strength and low dielectric loss

Dielectric polymer nanocomposites with high dielectric constant have wide applications in high energy density electronic devices. The introduction of high dielectric constant ceramic nanoparticles into a polymer represents an important route to fabricate nanocomposites with high dielectric constant. However, the nanocomposites prepared by this method generally suffer from relatively low breakdown strength and high dielectric loss, which limit the further increase of energy density and energy efficiency of the nanocomposites. In this contribution, by using core-satellite structured ultra-small silver (Ag) decorated barium titanate (BT) nanoassemblies, we successfully fabricated high dielectric constant polymer nanocomposites with enhanced breakdown strength and lower dielectric loss in comparison with conventional polymer-ceramic particulate nanocomposites. The discharged energy density and energy efficiency are derived from the dielectric displacement-electric field loops of the polymer nanocomposites. It is found that, by using the core-satellite structured Ag@BT nanoassemblies as fillers, the polymer nanocomposites can not only have higher discharged energy density but also have high energy efficiency. The mechanism behind the improved electrical properties was attributed to the Coulomb blockade effect and the quantum confinement effect of the introduced ultra-small Ag nanoparticles. This study could serve as an inspiration to enhance the energy storage densities of dielectric polymer nanocomposites.

The effects of zinc aluminum phosphate (ZPA) and zinc aluminum polyphosphate (ZAPP) mixtures on corrosion inhibition performance of epoxy/polyamide coating

The epoxy/polyamide coating was loaded with different pigment mixtures of the zinc phosphate (ZP), zinc aluminum phosphate (ZPA) and zinc aluminum polyphosphate (ZAPP) pigments. The electrochemical impedance spectroscopy (EIS) and salt spray test were used to investigate corrosion inhibition performance of the coatings. The adhesion strengths of the coatings were measured by a pull-off test. Results revealed lower coating pull-off strength loss when the ZPA and ZAPP pigments were used. A significant decrease in number of blisters together with low pull-off strength loss and best corrosion inhibition properties were observed when the mixture of 80:20 of ZAPP:ZPA was used.

Texture and temperature dependence on the mechanical characteristics of copper electrodeposits

The relationships between grain morphology, preferred orientation, and mechanical performance of commercial grade electrodeposited Cu foils (VLP, MP and HTE) were clarified in this study. Electro-deposited Cu foils showing (220) and (111) growth textures had fine grains of which the distribution was fan-shaped or well-aligned along the through-thickness direction respectively. On the other hand, the (200)-oriented Cu foils consisted of randomly grown coarse grains. Electron backscatter diffraction (EBSD) analysis of the cross-sectioned foils revealed that all the samples exhibited diffuse in-plane texture (on the plane of the foils). The growth texture of the Cu grains dominated Young's modulus of the foils measured by nanoindentation along the through-thickness direction of the Cu foils, in decreasing order was (111), (220) and then (200) oriented foils. With respect to tensile properties, the effect of grain size was more pronounced for tensile strength. The (220)-oriented Cu foils possessed a superior combination of tensile strength and ductility. However, the (200)-oriented foils exhibited a poorer deformation resistance but a lower strength loss at elevated temperatures. Serration in the tensile stress–strain curves could be observed at 150°C and became intense at 250°C. In addition to dynamic strain aging, low temperature dynamic recrystallization also accounted for this instability in flow stress.

Resistance to acid and sulfate solutions of microwave-assisted high calcium fly ash geopolymer

In this paper, 90-W microwave radiation for 5 min plus a shortened heat curing period was applied to cure the fresh geopolymer paste. Results showed that microwave radiation contributed to the dissolution of fly ash in the alkaline solution. Numerous gel formations were observed in microscopic scale. This resulted in a dense composite and strong bonding between the fly ash and the geopolymer matrix leading to high strength gain compared to those of the control pastes cured at 65 °C for 24 h. In addition, resistances to the sulfuric acid and sulfate attacks of the microwave geopolymer were superior to that of the control as indicated by the relatively low strength loss. The microwave radiation also helped the geopolymer attaining thermal stability as the dense matrices were obtained.

A naphthyl-imide-based epoxy resin

A novel heat-resistant epoxy resin based on N, N’-bis(5-hydroxy-1-naphthyl) pyromellitic diimide was prepared and its cure kinetics with 4,4-diaminodiphenysulfone (DDS) was investigated by differential scanning calorimetry (DSC) under non-isothermal and isothermal conditions. Under non-isothermal condition, the effective activation energy calculated from the advanced isoconversional method (AICM) varies with curing conversion, which is different from that obtained by Kissinger’s model. This should be attributed to the formation of highly crosslinked network later in the curing stage. The isothermal curing process at different temperatures could be well fitted by Kamal’s model in the initial curing stage but deviates subsequently. The deviation is corrected by introducing a diffusion factor in Kamal’s model. In addition, the naphthyl-imide epoxy resin is used to prepare carbon fiber reinforced composites and their applications were explored. The composites exhibit a high glass transition temperature, low moisture absorption, sufficient flame retardance and especially very low tensile strength loss at high temperature.

Durability of concrete made with manganese slag as supplementary cementitious materials

This paper discusses mineral composition and pore microstructure characteristics of water-cooled manganese slag and its effects on durability of concrete. The Mn slag has an alveolate pore structure, and the ground Mn slag is characterized by multiangular shape which consists of α′-C2S, C3MS2, CaO·MnO·2SiO2 and C2AS. Experimental results show that the Mn slag has potential hydraulic reactivity. Concrete made with Mn slag as supplementary cementitious materials (SCMs) exhibits very low strength loss and weight loss in the synthetic seawater corrosion and freezing-thawing cycle tests. The research provides useful reference for knowing about Mn slag and for applying Mn slag to improve the durability of concrete.

The effect of SnO2 on the improvement of mechanical properties of MgO–MgAl2O4 composites

Incorporation of SnO2 into MgO–spinel (M–S) increased mechanical properties significantly. Relationships between the parameters improving mechanical properties and microstructural variables were examined. Basic parameters improving the mechanical properties of M–S–SnO2 composites were identified as follows: (a) when microcracks come across with either Mg2SnO4 particles or pores; crack branching and deviation of interlinked microcracks or crack arresting occurred more effectively than those of spinel particles, (b) fracture type was converted to intergranular fracture with incorporation of spinel into MgO, and transgranular fracture with addition of SnO2 to M–S; additionally with the incorporation of additives, (c) critical defect size, (d) work of fracture values increased, and (e) MgO grain size decreased. Rst thermal shock parameter values of M–S–SnO2 composites were markedly higher than those of M–S materials, associated with low strength loss, high thermal shock damage resistance and thus longer service life of M–S–SnO2 composites for high-temperature industrial applications.

Improvements on the mechanical properties and thermal shock behaviours of MgO–spinel composite refractories by ZrO 2 incorporation

Microstructural features and improvements on the mechanical properties and thermal shock behaviours of MgO–spinel composite refractories with ZrO 2 addition were examined. ZrO 2 incorporation into MgO–spinel led to improvements around ∼1.5-fold ratios on mechanical properties, R st values and thermal shock results. The basic parameters improving mechanical properties and thermal shock resistance of MgO–spinel–ZrO 2 composite refractories were determined as follows: (i) propagation of microcracks for a short distance by interlinking each other, (ii) stopping or deviation of microcracks when reaching pores or ZrO 2 particles, (iii) concurrent occurrence of mostly intergranular and some transgranular cracks on fracture surfaces, and with the addition of ZrO 2 (iv) the increase in bulk density, and (v) a significant decrease in MgO grain size. The improvements observed in thermo-mechanical properties confirmed that MgO–spinel–ZrO 2 refractories showed a low strength loss and high thermal shock damage resistance at high temperatures, leading to longer service lives for using industrial applications.

Study on Flue Gas Desulphurization Gypsum Plaster

Flue gas desulphurization (FGD) gypsum and fly ash are two kinds of solid waste in coal-fired power plant. The possible displacement content of fly ash in gypsum plaster was investigated in this paper. The effect of various chemicals retarders, such as Citric acid, sodium citrate and SC gypsum retarder, and water retention agent on the setting time, flexural strength and compressive strength of gypsum plaster was also studied. The results demonstrate that gypsum plaster has maximum mechanical properties and enough setting time at the rate of 20% fly ash replacing calcined gypsum; SC gypsum retarder effectively delays the setting time and has lower strength loss; The optimum level of water-retention agent for effective utilization of gypsum plaster is 0.2%.

Preparation of novel non-halogen flame-retardant papers.

Halogen-containing flame-retardant paper products have both good efficacies and cost competitiveness. However, facing increasingly stringent environmental protection and safety requirements, these products could become a liability in service. Developing effective and cost-competitive non-halogen flame retardant paper products has thus become a goal of product development by the paper industry. In this study, we investigated the application of certain papermaking functional additives, particularly minerals, to develop fire-resistant agents or flame-retardant papers that are not liable to become soggy when exposed to moisture in the atmosphere. Five inorganic pigments (calcium carbonate, kaolin clay, magnesium hydroxide, aluminum hydroxide, and sericite mica) and a swelling-type flame-retardant (a phosphor-nitrogen (P-N) organic compound) were examined. We applied the minerals either by internal addition to a pulp furnish and formation into base sheets, or by surface coating applied to commercial copy paper substrates, and finally by adding the minerals at different proportions internally to the pulp furnish and then surface coating with the P-N compound. The prepared sheets were tested for their flame-retardation performance. Service environment-simulated treatments were also conducted on the papers to observe changes in their mechanical properties, so as to find the optimal flame-retarding filler ratios and coating amount formulations. The economic efficiencies of the various formulations were also analyzed to serve as a database for research and industrial reference. In total, 5 blended formulas allowed the papers to attain a class Ⅰ flame-retardation rating. After the degradation test and economic analysis, we deemed that aluminum hydroxide and magnesium hydroxide were too expensive, and were liable to lose their fire-resistance after degradation. Sericite mica-treated paper showed lower strength losses after degradation treatment; however, the fire rating decreased to class Ⅲ. Calcium carbonate- and kaolin clay-based papers had reduced fire ratings to class Ⅱ after degradation.

The physical and chemical effects of long-term sulphuric acid exposure on hybrid modified cement mortar

Abstract The properties of a hybrid modified cement mortar (HM) after 5 years storage in a sulphuric acid solution were studied. HM was made by mixing ordinary portland cement (OPC), sand and water and subsequently adding Na 2 SiO 3 (water glass), Na 2 SiF 6 , polyvinyl acetate, lignosulphonate, and tributylphosphate. A control mortar (CM) was prepared by mixing OPC, sand, and water. The compressive strength losses after sulphuric acid attack were measured. The microstructures of HM and CM after sulphuric acid attack were observed and analyzed by using scanning electron microscopy (SEM), and the porosity and the pore size distribution were measured by using mercury intrusion porosimetry (MIP). Fourier-transform infrared (FT-IR) spectroscopy was utilized to determine the phases present in HM and CM after sulphuric acid attack. Test results show that many cracks appeared in the near-surface region and many needle-like crystals in the centre region of CM after 5 years sulphuric acid exposure, leading to a higher porosity of 28.6% and a higher strength loss of 50.6%. By contrast, a basically monolithic structure was kept in HM after 5 years sulphuric acid exposure, resulting in a lower porosity of 13.3% and a lower strength loss of 27.4%.

Comparison of different reactive organophosphorus flame retardant agents for cotton. Part II: Fabric flame resistant performance and physical properties

N-Methylol dimethylphosphonopropionamide (MDPA) is one of the most commonly used durable flame retardant agents for cotton. In our previous research, we developed a new flame retardant finishing system based on a hydroxy-functional organophosphorus oligomer (HFPO) and bonding agents, such as dimethyloldihydroxyethyleneurea (DMDHEU) and trimethylolmelamine (TMM). In this research, we compared the flame resistant performance as well as physical properties of the cotton fabric treated with these two flame retardant finishing systems. The cotton fabric treated with MDPA/TMM has a higher initial limiting oxygen index (LOI) than that of the fabric treated with HFPO/TMM due to higher nitrogen content in the system. The LOI of the cotton fabric treated with the HFPO and MDPA systems becomes identical when the treated fabric contains equal amount of phosphorus and nitrogen. The MDPA/TMM shows higher laundering durability on cotton than HFPO/TMM system. The fabric treated with HFPO/TMM and MDPA/TMM has low wrinkle resistance and low strength loss whereas the fabric stiffness significantly increases when the TMM concentration is increased.

Preparation of high performance non-dispersible concrete

A new-type underwater non-dispersible concrete admixture NDA was prepared, its function mechanism was analyzed, and C40 high performance non-dispersible underwater concrete was manufactured by applying NDA. The results indicate that NDA has a suitable workability, low strength loss, and excellent anti-dispersion; the fresh non-dispersible underwater concrete with NDA has high anti-dispersion, excellent workability such as self-compacting and not bleeding; hardened non-dispersible underwater concrete with NDA has a high strength, high durability such as high anti — abrasion, impermeability and anticorrosion.

Synergistic Effects of Trichoderma reesei Cellulases on the Properties of Knitted Cotton Fabric

Cotton knitted interlock fabric is treated with purified Trichoderma reesei cellulases. The action of cellobiohydrolases I and II (CBH I and CBH II) and endoglucanases I and II (EG I and II), alone and in different combinations, i.e., endo-endo, endo-exo, and exo-exo, is evaluated for reducing sugars, solubilized oligosaccharides, weight loss, bursting strength, and pilling tendency. According to the results, there are clear differences between individual enzymes and their defined mixtures. There is no correlation between high weight loss and good pilling results, and similarly, there is no correlation between weight and strength loss. Thus, the reduced pilling tendency can be obtained with significantly lower strength losses by tailoring the amount and type of different cellulases in the enzyme mixtures.

Damage to Continuous-filament Yarns during Weaving

A study of continuous-filament yarns and the damage caused to them during weaving is reported. In spite of experiencing greater stress and strain during weaving filaments used as warp show lower strength losses then similar filaments used as weft. This unexpected behaviour of continuous-filament yarn is explained on the basis of the different kinds of stress imposed separately on the warp and weft during weaving and of the structural sensitivity of the continuous-filament yarn to these forces. Several techniques were employed to examine and suitably explain the weakening brought about by mechanical stresses during weaving.

Response of Cottons to Chemical Treatments

Single fibers from six cottons were subjected to a resin finishing treatment during which the tension on each fiber was carefully controlled and systematically varied. It was observed that the changes in mechanical properties resulting from the treatment were highly dependent upon the tension exerted on each fiber during the treatment. Treatments at high tensions resulted in greater resilience increases and lower strength losses than corresponding treatments at low tensions. The six cottons responded differently to the variations in tension during the treat ment, and this differential response was related to fibrillar orientation as estimated by x-ray angle.