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Municipal solid waste incineration (MSWI) fly ash containing heavy metals is hazardous solid waste that requires safe disposal. Alkali-activated treatment can effectively improve the environmental safety of MSWI fly ash. Due to the low alumina content of MSWI fly ash, the addition of nanoalumina (NA) solves the defect to enhance the ability of solidification/stabilization (S/S) and maximize the utilization of MSWI fly ash. NA/MSWI fly ash solidified body was prepared by alkali-activated technology in this work. In this study, NA was added (0–3 wt.%) to explore its effects on mechanical properties and heavy metal immobilization efficiency of NA/MSWI fly ash solidified body. Research results revealed that when the addition of NA was 2 wt.%, the compressive strength of solidified bodies can significantly increase by 38.0% and 42.8% at 7 and 28 days, respectively. Meanwhile, the leaching concentration of heavy metals in NA/MSWI fly ash solidified body can noticeably reduce with the immobilization efficiency of above 99.5%. Adding NA promoted the ratio of stable state on Pb and Zn in solidified bodies. A series of microscopic characterization analyses indicated that NA stimulated gels and Friedel's salt formation, and N–A–S–H was also found in the NA/MSWI fly ash solidified body, enhancing S/S heavy metals by physical adsorption, physical encapsulation, and chemical bonding. Therefore, this study paves a potential new way for the application of nanomaterials in S/S MSWI fly ash through alkali-activated technology, and nanoalumina is a more promising candidate. [ABSTRACT FROM AUTHOR]

In this work, epoxy resin-based composites reinforced with nanoclays, nanoalumina, carbon nanotubes (CNTs) (0.15, 0.50, and 1.50% vol were submitted to morphological characterization by scanning (SEM) and transmission (TEM) electron microscopies, electrical tests through electrical impedance spectroscopy, and electromagnetic analyses (scattering parameters), in the frequency range of 8.2 to 12.4 GHz. SEM images of the CNT composite revealed nanotube clusters in the matrix. The proximity between the CNTs is corroborated by the increase in the electrical conductivity of the composite due to the formation of a long-range electron transport network, which favored the polarization effect, absorption losses (SEA = 1.33 dB), reflection (SER = 3.38 dB) and reflection loss (RL = -6.61 dB at 10.8 GHz). Composites with nanoclays and nanoalumina showed no significant electrical and electromagnetic results.

This research consists of the fabrication of synthetic gels of hydrated calcium silicate (C-S-H gel) and hydrated calcium aluminate silicates (C-A-S-H gel) in aqueous solution oversaturated in calcium hydroxide. These gels were fabricated using nanomaterials with different specific surface area; two nanosilicas (NS), OX50 and A200 (50 and 200 m2/g respectively) and two nanoaluminas (NA), A65 and A130 (65 and 130 m2/g). Mixtures were carried out maintaining a Ca/Si = 2 ratio and variable Al/Si ratios of 0.1, 0.5 and 1. The effect of aluminium incorporation in the C-S-H gel was studied using the nuclear magnetic resonance technique (29Si MAS-NMR), and the information obtained was further processed using the mathematical deconvolution method. Chemical shift bands were delimited to identify the structures. From the results obtained, modifications of the tetrahedral (Qn) in the dreierketten structure were observed in the different combinations, as well as the modification of the bridging tetrahedral (Q2b) due to the presence of aluminium replacing the silica bridging tetrahedron Q2b(1Al). High Q4 values were detected in the C-S-H gel with NS OX50 and this could be associated to a double chain formation very similar to a perfect tobermorite. The length of the mean chains (MCL) was very variable in each blend, but some trends were observed as the Al/Si = 1 ratio and the Al/Si = 0.1 ratio maintain or increases the MCL respectively. The results are interesting and concrete case mixtures with NS OX50 show original trends that have not yet been reported in the literature. Resumen: Esta investigación consiste en la fabricación de geles sintéticos de silicato de calcio hidratado (gel C-S-H) y de silicatos de aluminato de calcio hidratados (gel C-A-S-H) en solución acuosa sobresaturada en hidróxido de calcio. Estos geles se fabricaron utilizando nanomateriales con diferente superficie específica; dos nanosílicas (NS), OX50 y A200 (50 y 200 m2/g respectivamente) y dos nanoaluminas (NA), A65 y A130 (65 y 130 m2/g). Las mezclas se realizaron manteniendo una relación Ca/Si = 2 y proporciones variables de Al/Si de 0,1, 0,5 y 1. El efecto de la incorporación de aluminio en el gel C-S-H se estudió mediante la técnica de resonancia magnética nuclear (29Si MAS-NMR), y la información obtenida se procesó posteriormente mediante el método de deconvolución matemática. Se delimitaron las bandas de desplazamiento químico para identificar las estructuras. A partir de los resultados obtenidos, se observaron modificaciones del tetraedro (Qn) en la estructura dreierketten en las diferentes combinaciones, así como la modificación del tetraedro puente (Q2b) debido a la presencia de aluminio que sustituye al tetraedro puente de sílice Q2b(1Al). Se detectaron altos valores de Q4 en el gel C-S-H con NS OX50 y esto podría estar asociado a una formación de doble cadena muy similar a la de una tobermorita perfecta. La longitud de las cadenas medias (MCL) fue muy variable en cada mezcla, pero se observaron algunas tendencias como que la relación Al/Si = 1 y la relación Al/Si = 0,1 mantienen o aumentan la MCL, respectivamente. Los resultados son interesantes y las mezclas de casos concretos con NS OX50 muestran tendencias originales que aún no se han reportado en la literatura.

The goal of this paper is to analyze the aging behavior and the mechanism evolution of nano-Al2O3 (NA)-reinforced styrene-butadiene-styrene (SBS) asphalt under different thermal-oxidative aging conditions. First, NA/SBS-modified asphalt and SBS-modified asphalt with different aging levels were prepared. Second, the viscosity and high temperature rheological performance of the specimens were tested and the property-related aging indexes were calculated and compared. Third, a Fourier transform infrared (FTIR) test of the specimen was conducted and the chemical group-related aging indexes were calculated and analyzed. Fourth, gel permeation chromatography (GPC) was used to analyze the molecular weight of the specimens under different aging levels. Then, an atomic force microscope (AFM) was adopted to analyze the microsurface morphology of different specimens. Finally, correlation analysis between property-related indexes and chemical group indexes was conducted. The results show that NA can enhance the thermal-oxidative aging resistance of SBS asphalt. NA can inhibit the increase in sulfoxide groups and the degradation of the SBS polymer with the increase in aging. NA can slow down the formation of large molecule during the aging process. The degree of change in both the bee structures and micromorphological roughness of NA/SBS asphalt is lower than that of SBS asphalt under different aging levels. [ABSTRACT FROM AUTHOR]

Although Nanoalumina is widely used in many biomedical applications, its potential toxic effect on pregnant women and developing embryos/fetuses has not been reported. In this investigation, the maternal and developmental toxicity caused by Nanoalumina during gestation and the potential preventive role of the pumpkin seed oil (PSO) were evaluated. Four groups of pregnant rats were orally administered during days 5–19 of gestation as follows: control group, Nanoalumina group (70 mg/kg b.w), PSO- group (4 ml/kg b.w.), and Nanoalumina plus PSO- group. Nanoalumina induced detrimental impacts in pregnancy outcomes, fetal growth retardation, morphological anomalies, hepatic and neural DNA damage, and histopathological changes in hepatic and neural tissues of both mother and fetus, respectively. Furthermore, the level of MDA is significantly increased and activities of GSH and CAT are significantly reduced in both tissues of nanoalumina‐administered rats. PSO co administration improved pregnancy outcomes, fetal growth parameters, DNA damage, antioxidant defenses the histopathological changes of nanoalumina‐gavaged rats and significantly diminished MDA level. Finally, PSO has a preventive role against the detrimental impacts of nanoalumina in dams and fetuses probably via its potential to prevent reactive oxygen species. [ABSTRACT FROM AUTHOR]

Recently, silicone rubber (SiR) is preferably used in high-voltage cable accessories because it offers a wide range of voltage and temperature applications and excellent electrical and mechanical properties. Furthermore, the SiR exhibits flexibility and inhibits oxidation. In this paper, the electrical tree behavior of SiR nanocomposites containing nanoalumina and halloysite nanoclay was investigated; moreover, the nanofiller concentrations were predetermined at 0 vol%, 1 vol%, 2 vol%, and 3 vol%. The electrical tree growth was observed at room temperature at 8 kVrms after tree inception voltage (TIV). The TIV and electrical tree growth in SiR nanocomposites were monitored using an online digital monitoring system, which consisted of a stereomicroscope and a digital camera. The experimental results indicated that the addition of 1 vol%-2 vol% nanoalumina in SiR composite significantly improved the TIV and electrical tree growth rate. However, the addition of 3 vol% nanoalumina in the SiR composite reduced the TIV and accelerated the electric tree growth rate. In the presence of halloysite nanoclay of approximately 3 vol%, the SiR composite showed improved TIV and electrical tree growth rate.

In the present work, the effects of adding nanoalumina and marble dust on the wear behavior of dental composites were investigated. The hardness of dental composite was determined using Vickers micro-hardness tester. A two-body abrasive wear test was performed on the dental wear simulator under the medium of artificial saliva. The experiments were performed as per the Taguchi orthogonal array and steady state condition by varying parameters such as filler content, normal load, sliding velocity, and number of cycles. The hardness results indicated that the incorporation of 5 wt. % of nanoalumina increased the hardness of the dental composite by 12%, whereas the incorporation of 5 wt. % of marble dust increased the hardness of the dental composite by 7%. Also, for the experiments as per the Taguchi orthogonal array, the mean volumetric wear in the case of nanoalumina-filled dental composite was 9.6% less than that of marble dust-filled dental composite. However, in both the cases, the volumetric wear increased with the increase in normal load, sliding speed, and number of cycles but decreased with the increase in filler content. Analysis of variance (ANOVA) of the results indicated that normal load was less significant compared to filler content, sliding speed, and number of cycles.

The aims of the present study were to develop a dental composite filled with silanized nanoalumina and then to investigate the effect of nanoalumina filler on the two-body and three-body wear behavior under distilled water and food slurry medium, respectively. The dental composites were fabricated by adding silane treated nanoalumina filler particle in the weight percentage of (0–3 wt.%) to the matrix of BisGMA, TEGDMA, CQ and EDMAB. Two-body and three-body wear tests were performed in dental wear simulator machine with varying parameters such as normal load, chewing speed and chamber temperature in such a way as to simulate mastication process. Taguchi’s orthogonal array (L16) design, steady state condition and ANOVA were applied to evaluate the optimum parameter for minimum wear and effect of each parameter on the wear performance of dental composites. The finding of the result indicated that mean volumetric wear rate of dental composite in distilled water (i.e. two-body abrasion) was 33.23% more than that of the same composite in food slurry condition (i.e. three-body abrasion).

Cellulose-based aerogel, due to its rich reserves, environmental friendliness and porous structure, is considered as a new type of adsorbents for treating oil and water pollution. However, the functionalization of cellulose aerogel is still required for the efficient increase of its adsorption performance in wide applications. The combination of nanomaterials could significantly improve the adsorption capability of nanocellulose aerogel. In this work, nanocomposite aerogels comprising of nanocellulose and nanoalumina (NC/Al 2 O 3) are produced via a solvent-free method and the effect of weight ratios between nanocellulose and nanoalumina on the adsorption properties of NC/Al 2 O 3 aerogels has been studied. The results reveal that the NC/Al 2 O 3 aerogel with a low density of 5.1 mg cm−3 could obtain the optimal pore microstructures and the highest oil and organic solvent adsorption capacities with the preparation condition under the nanocellulose/nanoalumina weight ratio of 1:0.25 and 0.4 wt% of nanocellulose in aqueous solution. The presence of nanoalumina facilitates the change of microstructure morphologies, the increase of BET specific surface area and the adsorption capacities of NC aerogel. Compared with pure NC aerogel (74.07 ± 1.67, 69.87 ± 1.01, 81.21 ± 3.20, 52.07 ± 1.70, 48.49 ± 1.01, 75.45 ± 3.58 and 87.03 ± 0.46 g g−1 for thiophene, anhydrous ethanol, ethyl acetate, cyclohexane, sesame oil, acetone and dichloromethane, respectively), the NC/Al 2 O 3 aerogel manifests an outstanding adsorption capacity (108.07 ± 0.37, 89.91 ± 4.83, 93.93 ± 3.81, 71.13 ± 2.48, 64.83 ± 2.25, 85.19 ± 3.87 and 117.65 ± 5.68 g g−1, accordingly). By considering the desirable performance features and the convenient fabrication approach, this nanocellulose nanocomposite aerogel might be a feasible alternative for oily waste water recovery and conservation of environment. [ABSTRACT FROM AUTHOR]

External corrosion by soil’s components is a serious problem in many steel structures such as pipelines and tanks, thus many methods are applied to reduce this risk. Nanotechnology almost gives improving for conventional protection methods. Investigation on nano Al2O3 doped polypyrrole coating has been done on carbon steel structures to protect them in two simulated soil environments include (0.01M NaCl + 0.01M NaHCO3) and (0.01M NaCl + 0.01M Na2SO4). Electropolymerization of pyrrole monomer carried out in oxalic acid with suspended nano alumina using cyclic voltammogram method. Characterization of produced film was done by SEM/EDS and the results indicated the uniformly distribution of coating in the presence of nano alumina confirming the presence of Al2O3 NPs by EDS analysis. Also FTIR spectra showed the occurred incorporation between polypyrole and nanoalumina in deposited film on steel surface. The presence of nano alumina behaves as repaired to healing the defects in polymer film by chemical, mechanical and electrochemical factors and then gives long life time for service; this result was concluded through the improving in protection efficiency of Al2O3 NPs/PPy film compared with conventional red paint which is uses to protect carbon steel structures.

Abstract Al-6061 alloy based nanocomposites were synthesized using sol-gel prepared nanoparticles of α-alumina in their varying weight percentages (0, 0.5, 1.5, and 2.5 wt%) via powder metallurgy route. The synthesized nanocomposites were sintered and heat treated under solutionized and T6 conditions. Afterwards, electrochemical corrosion tests were performed in 3.5% NaCl solution to see the effect of nanoparticle addition on the corrosion behavior of the composites. Heat treatment results indicate that solutionized composites exhibit better corrosion resistance as compared to the composites treated under sintered condition. Heat treatment under T6 condition showed poorest corrosion resistance. Nanocomposite reinforced with 0.5 wt% of nanoparticles showed excellent corrosion resistance than that of 1.5 wt% of nanoalumina incorporated composite. After 2.5 wt% incorporation of nanoparticles, the corrosion rate of the composite becomes very high even more than that of the base alloy. Increase of nanoparticle concentration was found to increase their agglomeration at the grain boundary region that increases porosity in the composite. This ultimately increases the corrosion reaction because of the enhanced chemical reactivity. The microstructural examination of the synthesized nanocomposites were found in good agreement with the corrosion rate determined from electrochemical tests. Highlights • Nanoparticles of α-alumina were synthesized by sol-gel method. • Effect of heat treatment and nanoalumina content were studied on Al-6061 alloy. • Solutionized sample showed better corrosion resistance than sintered & T6 samples. • 0.5 wt% sample showed superior property than base alloy and rest of the composites. • Corrosion becomes worse than the alloy after reinforcing 2.5 wt% of nanoparticles. [ABSTRACT FROM AUTHOR]

Ultrahigh performance concrete (UHPC), which is characterized by dense microstructure and strain hardening behavior, provides exceptional durability and a new level of structural response to modern structures. However, the design of the UHPC matrix often requires the use of high quantities of supplementary cementitious materials, such as silica fume, which can significantly increase the cost and elevate the production expenses associated with silica fume handling. This paper demonstrates that a fiber-reinforced composite with properties similar to conventional UHPC can be realized with very low quantities of silica fume, such as 1% by mass of cementitious materials. The proposed UHPC is based on reference Type I cement or Type V Portland cement with very low C3A (2O3 nanofibers, and high-density polyethylene or polyvinyl alcohol macro fibers. Previous research has demonstrated that nanofibers act as a seeding agent to promote the formation of compact and nanoreinforced calcium silicate hydrate (C-S-H) clusters within the interparticle and nanofiber spaces, providing a nanoreinforcing effect. This approach produces a denser and stronger matrix. This research expands upon this principle by adding synthetic fibers to ultrahigh strength cement-based composites to form a material with properties approaching that of UHPC. It is indicated that the developed material provides improved strain hardening and compressive strength at the level of 160 MPa.

Although studies showed effects of nanoalumina (nano-Al 2 O 3 ) on Escherichia coli , no study completely provides understanding on how bacterial cells respond to damages, especially on how they initiate self-defense. In this study, we showed three types of responses of E. coli to damages caused by nano-Al 2 O 3 . Live, dead, and injured, bacteria showed improved survival rates reaching 104%, 116%, and 104% after exposure to 0.1, 1, and 10 mmol/L of nano-Al 2 O 3 respectively. Survival rates improved from 100% to 114%, corresponding to an exposure time of 0–9 h, and from 100% to 127%, corresponding to 0–1000 μg/L Al 3+ . Improvements were noted in survival rates of E. coli K12 MG1655, HB101, DH5α, and K12 MG1655 △lexA treated by nano-Al 2 O 3 in Luria–Bertani (LB) exposure system or K12 MG1655 in LB, normal saline(NS) and H 2 O exposure system. Bacterial cells transformed from long rods to ellipsoidal or nearly spherical as form of self-preservation mechanism; this phenomenon may be related to changes in membrane potential induced by free Al 3+ released from nano-Al 2 O 3 particles. Molecular mechanism of this response involved inhibited gene expression of sythesis and metabolism of carbohydrates, lipids and proteins. Findings presented in this study may improve understanding of potential danger of nanomaterials and control their spread to environmen. [ABSTRACT FROM AUTHOR]

The LZS glass-ceramic (19.58 Li 2 O·11.10ZrO 2 ·69.32SiO 2 ) have a high coefficient thermal expansion (CTE) which can be a limitation in some applications. The addition of alumina in a LZS glass-ceramic matrix is able to reduce the CTE significantly. This happens because of the alumina affinity with respect to lithium silicates to form β-spodumene (LiAlSi 2 O 6 ), a crystalline phase having a CTE nearly zero (0.9 × 10 −6 ° C −1 ). In this work, (1–5 vol%) Al 2 O 3 nanoparticles (13 nm) were added to a LZS (3.5 μm) glass-ceramic matrix to prepare composites with the main goal of evaluation the influence of Al 2 O 3 on their mechanical, thermal and electrical properties. Each composition was wet homogenized and then dried at 110 °C for 48 h for disaggregation. The composites, sintered at 900 °C for 30 min, with relative densities between 92% and 98%, showed zircon and β-spodumene as main crystalline phases. The incorporation of increasing additions of nanosized alumina progressively decreases the final density. This makes the properties to slightly decrease, also. The Young's modulus significantly decreases from 111 to 78 GPa of hardness due to the exponential variation with porosity, but the changes of toughness and hardness are much lower. The electrical conductivity was maintained within ±10-7 S·cm-1, and the dielectric constant ranged from 5 to 6 for all compositions. Thermal conductivity ranged around 4.2 to 3.5 W/mK. [ABSTRACT FROM AUTHOR]

The use of nanoalumina and iron-modified pumice (IMP) as adsorbents for removal of nitrate from aqueous solution was investigated. Adsorption experiments were carried out as a function of the pH, contact time, and concentration of nitrate. Both adsorbents were effective for the nitrate removal in a pH range of 4–6, and optimum removal of nitrate ions occurred in a pH 5.0. The adsorption of nitrate on both adsorbents reached equilibrium within 50 min. Nitrate sorption kinetics was well fitted by pseudo-second-order model. The maximum nitrate uptake capacities for nanoalumina and IMP were found to be 70.8 and 86.7 mg g−1, respectively. The kinetic results showed that the nitrate sorption to nanoalumina and IMP followed pseudo-second-order kinetics with a correlation coefficient greater than 0.99. The equilibrium data for both the adsorbents for nitrate removal were fitted to Langmuir and Freundlich isotherms, but the experimental data were found to be little better fitted by the Langmuir model. These results indicate that nanoalumina and IMP are interesting alternatives for nitrate removal from the aqueous solution. [ABSTRACT FROM PUBLISHER]

The present study shows the experimental results about the physical properties and microstructural changes of Portland cement with y and a alumina nanoparticles. All alumina samples were synthesized from an industrial byproduct. Cement matrix was additivated with nanoalumina at different quantities (from 0.5% up to 1% by weight of cement). Porosimetry and gas permeability tests on the hardened cementitious systems were performed. Results showed a 40% decrease in permeability for y-Al2O3 system. The surface analysis of the y-Al2O3-based cementitious specimens was carried out, resulting in a substantial decreasing of their surface area and pore volume in comparison with the reference material. Additionally, a-Al2O3-based cement systems showed less proportion of amorphous CSH gels and portlandite crystals were predominant. In contrast, y-Al2O3 -based composite materials exhibit well defined etringite crystals (needle-like structures), further remarkable changes in the CSH gel morphology, impacting on the macroscopic mechanical properties. [ABSTRACT FROM AUTHOR]

High-pressure cryogelation (HPC) of individual (silica, alumina, their mechanical blends) and complex (silica/titania, alumina/silica/titania, AST) nanooxides were studied to reveal the influence of nanooxide composition and gelation conditions on changes in the textural characteristics of the materials. The temperature-pressure behavior of different phases (silica, alumina, and titania) under HPC can result in destroy of complex nanoparticles, especially large (100-200 nm in size) core-shell secondary nanoparticles composed of a number of small primary nanoparticles (~10 nm in size) covered by a shell destroyed under HPC. The main changes in the texture of HPC or gelled nanooxides are due to rearrangement (compaction) of secondary structures such as aggregates of primary nanoparticles and agglomerates of aggregates. This compaction enhances the pore volume but much weakly affect the specific surface area (with one exception of AST) because small primary nanoparticles (10-20 nm in size) are relatively stable during HPC. The HPC materials are characterized by enhanced mesoporosity shifted to macroporosity with decreasing specific surface area and increasing size of primary nanoparticles. Diminution of the freezing temperature from 208 to 77.4 K during HPC results in an increase in pressure (up to 1,050 atm in stainless steel freezing bombs) and enhanced compaction of aggregates and agglomerates but this does not practically affect the primary nanoparticles. The degree of decomposition of secondary core-shell nanoparticles of AST does not practically increase with this decreasing freezing temperature. Graphical Abstract: High-pressure cryogelation can destroy core-shell nanoparticles. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Thousands of abandoned wellbores may lie within the aerial extent of a CO 2 storage operation. These wellbores represent a potential leakage pathway and a leaky wellbore needs to be re-completed or otherwise repaired to restore seal integrity and ensure containment of the stored CO 2 . Due to the high cost of recompleting a well, a sufficient economic incentive exists if a viable seal repair technology is available. In this paper, we examine the use of epoxy nanocomposites as potential seal repair materials that have excellent bond characteristics with both steel and cement when cured in the subsurface environment. Test results show Novolac epoxy nanocomposites incorporating nanosilica, nanoclay or nanoalumina to have acceptable flowability that enable injection in wellbore cracks and significantly higher bond strength compared with standard microfine cement. [ABSTRACT FROM AUTHOR]

To study changes in the characteristics of gelled/dried nanooxides (fumed silicas PS300 and PS100, alumina, silica/titania ST, alumina/silica/titania AST), high-pressure cryogelation, HPCG (at 208K or 260K) or gelation (293K, 1atm) was carried out using 20wt.% aqueous suspensions pure or with addition of 0.1M NaCl. The nanooxide samples were studied after drying at room temperature. Maximal changes in the textural and crystalline characteristics are observed for cryogels with AST prepared at ~1000atm and 208K due to decomposition of complex nanoparticles. Its specific surface area SBET increases from 83 to 160m²/g, and the crystallinity degree grows by 11%. Mixing of PS300 and AST (1:1, w/w) in the suspension prevents the decomposition of AST particles in the cryogel since SBET decreases in comparison with that of the initial blend powders. Addition of NaCl (2.8wt.% in dried powders) reduces decomposition of AST particles due to changes in HPCG conditions. For binary ST, SBET increases but much smaller than for AST. HPCG of individual silica and alumina leads to a decrease in the SBET value; i.e. nanoparticles are not decomposed. A significant increase in the volume of large mesopores (pore radius 5-10nm

Nanoscience and nanotechnology provide numerous opportunities for enhancing the properties of wood composites. Formaldehyde emissions from wood composites are of great importance because of their negative impact on human health. Developing low formaldehyde-emitting particleboard and plywood panels as environmentally friendly composites by nanotechnology was the object of this study. The urea formaldehyde and melamine urea formaldehyde resins that were used to produce particleboard and plywood panels, respectively, were reinforced with various nanomaterials at different loading levels. Formaldehyde emission tests were carried out according to standard TS 4894 EN 120. The results acquired in this work indicated that nanomaterial reinforcement significantly affected the formaldehyde emission properties of the particleboard and plywood panels. Formaldehyde emissions of the composite panels decreased after reinforcement with nanoSiO2, nanoAl2O3, and nanoZnO materials at proper loading levels. Therefore, using nanotechnology, it is possible to produce environmentally friendly wood composite panels with low formaldehyde emissions. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, firstly mesoporous gamma and alpha-alumina with nanorod morphology, exhibiting high surface area (629.44m2 g−1), large pore volume (2.25cm3 g−1) and pore size (140.3Å) have been synthesised by a non-surfactant-templating sol–gel method. Then, new nanocatalysts, i.e. Au-NAl350, Au-NAl550, Au-NAl750, and Au-NAl1100 were prepared by deposition of gold nanoparticles on the various synthesised nanostructured alumina supports with different physicochemical properties; surface area (20.56–629.44m2 g−1), pore volume (0.63–2.25cm3 g−1) and pore size (73.88–143.76Å). Textural, morphological and structural characterisations of both nanoalumina supports and nanogold/nanoalumina catalysts were done by nitrogen physisorption, XRD, 27Al MAS NMR, TEM and FTIR study of low temperature CO-adsorption. The effect of physiochemical properties of the nanoalumina supports on the structure and catalytic activity of nanogold active phase were studied in the catalytic reduction of ferricyanide to ferrocyanide by thiosulphate under three reaction temperature; 20, 40 and 60°C. It was found that the Au-NAl550 nanocatalyst with large surface area (579m2 g−1), pore volume (2.13cm3 g−1) and pore size (141.05Å) has the highest catalytic activity. The characterisation results showed that Au nanoparticles highly and uniformly dispersed on the high surface area nanoalumina support. The metallic character of the gold nanoparticles, acidity and activity of catalyst were determined by structure, acidity and texture of the nanoalumina support. It was confirmed that the reduction reaction is totally controlled by the surface properties of catalyst. [Copyright &y& Elsevier]

Tsai et al. (Airborne nanoparticle exposures associated with the manual handling of nanoalumina and nanosilver in fume hoods. J Nanopart Res 2009; 11: 147–61) found that the handling of dry nanoalumina and nanosilver inside laboratory fume hoods can cause a significant release of airborne nanoparticles from the hood. Hood design affects the magnitude of release. With traditionally designed fume hoods, the airflow moves horizontally toward the hood cupboard; the turbulent airflow formed in the worker wake region interacts with the vortex in the constant-flow fume hood and this can cause nanoparticles to be carried out with the circulating airflow. Airborne particle concentrations were measured for three hood designs (constant-flow, constant-velocity, and air-curtain hoods) using manual handling of nanoalumina particles. The hood operator's airborne nanoparticle breathing zone exposure was measured over the size range from 5 nm to 20 μm. Experiments showed that the exposure magnitude for a constant-flow hood had high variability. The results for the constant-velocity hood varied by operating conditions, but were usually very low. The performance of the air-curtain hood, a new design with significantly different airflow pattern from traditional hoods, was consistent under all operating conditions and release was barely detected. Fog tests showed more intense turbulent airflow in traditional hoods and that the downward airflow from the double-layered sash to the suction slot of the air-curtain hood did not cause turbulence seen in other hoods. [ABSTRACT FROM PUBLISHER]

Objective: This study aimed at investigating the effect of nanoalumina on sex hormones, and fetuses in pregnant rats., Methods: In this study, sixty-four pregnant rats were divided into eight groups. The control and the injection-control group received normal food and water, and 0.5 ml of distilled water, respectively. Treatment groups were treated with 25, 50, 100, 250, 500, and 1000µg/ml concentrations of Nanoalumina from the 7th day until the 18th day of pregnancy. On the 18th day, the rats were investigated in terms of their hormone levels. We evaluated the number of healthy and aborted offspring, as well as fetus size., Results: Nanoalumina caused an increase in progesterone hormones at the concentrations of 250, and 500µg/ml, and a significant reduction in estrogen hormone and aborted fetuses at the concentrations of 250 and 500µg/ml (p<0.05). The largest and smallest size of fetuses were observed in 500µg/ml and 1000µg/ml, respectively. The highest number of aborted fetuses was observed in the group treated with the 500µg/ml concentration. There was no aborted fetuses with 25, 50,100, control, and injection-control groups., Conclusions: Due to nanoalumina toxicity, it must be used with caution.

Ultrahigh performance concrete (UHPC), which is characterized by dense microstructure and strain hardening behavior, provides exceptional durability and a new level of structural response to modern structures. However, the design of the UHPC matrix often requires the use of high quantities of supplementary cementitious materials, such as silica fume, which can significantly increase the cost and elevate the production expenses associated with silica fume handling. This paper demonstrates that a fiber-reinforced composite with properties similar to conventional UHPC can be realized with very low quantities of silica fume, such as 1% by mass of cementitious materials. The proposed UHPC is based on reference Type I cement or Type V Portland cement with very low C3A (<1%) that also complies with Class H oil well cement specification, silica fume, small quantities of Al2O3 nanofibers, and high-density polyethylene or polyvinyl alcohol macro fibers. Previous research has demonstrated that nanofibers act as a seeding agent to promote the formation of compact and nanoreinforced calcium silicate hydrate (C-S-H) clusters within the interparticle and nanofiber spaces, providing a nanoreinforcing effect. This approach produces a denser and stronger matrix. This research expands upon this principle by adding synthetic fibers to ultrahigh strength cement-based composites to form a material with properties approaching that of UHPC. It is indicated that the developed material provides improved strain hardening and compressive strength at the level of 160 MPa. [ABSTRACT FROM AUTHOR]

In the present study, we reported the first adsorption characteristic of Ciprofloxacin (CFX) antibiotic onto synthesized alumina nanoparticles with surface modification by a polyanion. Strong polyanion poly(styrenesulfonate) (PSS), was used for surface modification of synthesized alumina nanoparticles. The alumina which was structural alpha phase, was confirmed by X-ray diffraction (XRD). The functional vibration groups of Al O and OH was characterized by Fourier transform infrared spectroscopy (FT-IR). The sphere morphology and particle size of about 40 nm was evaluated by Transmission electron microscopy (TEM), while the specific surface area of 6.08 m2/g was determined by Brunauer–Emmett–Teller (BET) method. Surface modification of nanoalumina with PSS enhanced a significant increase in CFX removal from aqueous solution. Some important parameters which influenced to the CFX removal including pH, contact time and adsorbent dosage, were systematically optimized. Under experimentally selected parameters, the removal efficiency and adsorption capacity of CFX using PSS-modified nanoalumina (PMNA) reached maximum of 97.8% and 34.5 mg/g, respectively. Adsorption isotherms of CFX onto PMNA were fitted well by the two-step adsorption model while adsorption kinetics of CFX followed the pseudo-second order. Based on the change in surface charge monitored by zeta potential, surface modification by FT-IR and adsorption isotherms, we suggest that CFX adsorption onto PMNA was induced by both electrostatic and non-electrostatic interactions but electrostatic attraction was dominant. The PMNA were reusable with high removal efficiency for CFX >96%. Removal efficiency for CFX in an actual hospital wastewater sample using PMNA achieved over 75%. Our results indicate that PMNA is a new and excellent adsorbent for antibiotic removal in wastewater treatment. • The α-Al 2 O 3 nanoparticles were successfully synthesized and modified by polyanion PSS to form PMNA. • High removal efficiency of ciprofloxacin (CFX) was 97.8 % and adsorption capacity was 34.5 mg/g. • The PMNA can be reusable with removal efficiency for CFX greater than 96 %. • Removal efficiency of CFX from an actual hospital wastewater sample using PMNA reached to 75%. • Adsorption isotherm and kinetic of CFX were in accordance with two-step and pseudo-second order models, respectively. [ABSTRACT FROM AUTHOR]

The fatigue life enhancement of fiber metal laminates (FMLs) through embedment of nanofiller into the epoxy has not reported hitherto, and it is the subject of this investigation. Due to its outstanding mechanical properties, nanoalumina is chosen as filler to enhance the fatigue life of FMLs. Tension-tension low cycle fatigue tests were conducted at various stress levels with different percentage of nanofillers, at constant frequency and stress ratio. The results showed that the fatigue characteristics of nano-modified FMLs outclassed the neat epoxy FMLs, and the 0.1-wt percentage of nanoalumina is found to be optimum. Improvement in fatigue life of FML is around 46%, 45% and 94% at a stress level of 50%, 60% and 70% of ultimate tensile strength (UTS) respectively at optimum nanoalumina. The great enhancement in fatigue life is attributed to the combined effect of interfacial strengthening, crack bridging, and pullout of nanoalumina, as evident from macro-to nano-scale fractography. • Fatigue strengthening of FMLs through epoxy modification by nano-Al 2 O 3 addition at various stress levels is investigated. • Nano-modified FMLs through LCF tests shown excellent fatigue performance with improved stiffness and strain bearing ability • Improvement in life is around 46, 45 and 94% at σ max of 50, 60 and 70% of UTS respectively at optimum nanoalumina addition. • Nanofiller has improved fatigue performance by combined effect of interfacial strengthening and crack bridging. [ABSTRACT FROM AUTHOR]