Combined Effects Of Nanoparticles Research Articles

Experimental study on static and impact properties of concrete incorporating nano-SiO2, nano-Al2O3 and Fe2O3 in single and combined forms

This paper presents a comparative evaluation of the single and combined effect of nanoparticles on the static and impact properties of concrete. Nano-SiO2, nano-Al2O3 and nano-Fe2O3 were used separately and in combined forms as partial replacements of cement by 1% and 2% by weight. The impact of nanoparticles on the unit weight, compressive strength, split tensile strength, flexural strength, toughness, fracture energy, impact performance of concrete was experimentally examined. In addition, the effect of these nanoparticles on the microstructure of concrete was investigated using SEM analysis. Moreover, to evaluate the commercial production of such concretes, the cost effectiveness of use of nanoparticles in concrete was also discussed. Desirability function analysis was also conducted to compare the overall performance of the tested concretes. The results revealed that use of nano materials in concrete had a positive effect on improving their mechanical performance. Nanoparticles increased the compressive strength, split tensile strength, flexural strength, and energy absorption capacity of concrete. Use of nanoparticles didn't show any significant influence on the unit weight of concrete. Moreover, the results also showed that nano materials didn't have a good influence on the impact performance of concrete. SEM analysis showed that use of nanoparticles improved the microstructure of concrete.

Impact of Titanium Oxide Nanoparticles on Growth, Pigment Content, Membrane Stability, DNA Damage, and Stress-Related Gene Expression in Vicia faba under Saline Conditions

This study investigates the effects of titanium dioxide nanoparticles (nTiO2) on Vicia faba under salinity stress. Plants were treated with either 10 or 20 ppm nTiO2 and subjected to two different concentrations of salinity (100 and 200 mM NaCl) as well as the combined effect of nanoparticles and salinity. Salinity induced a reduction in dry weight, increased electron leakage and MDA content, increased chromosomal aberrations and DNA damage, and reduced transcript levels of some stress- and growth-related genes. nTiO2 treatment increased dry weight in unstressed plants and mitigated the salinity-damaging effect in stressed plants. nTiO2 application improved cell division, decreased chromosomal aberrations, and reduced DNA damage in plants under saline conditions. The upregulation of antioxidant genes further supports the protective role of nTiO2 against oxidative stress. Particularly significant was the ability of nTiO2 to enhance the upregulation of heat shock protein (HSP) genes. These findings underscore the potential of nTiO2 to reduce the osmotic and toxic effects of salinity-induced stress in plants.

Development of eco-friendly alkali-activated nanocomposites comprising micro-fibers at ambient curing conditions

Geopolymers (GOPL) can play a vital role in the sustainability of concrete construction. The addition of nanoparticles and micro-fibers to GOPL can improve the mechanical and microstructural performance by densifying the matrix and providing the bridging effect against the internal cracking mechanism. Therefore, an extensive investigation on the improvement of the various characteristics of the GOPL is required to make it feasible for practical applications. Moreover, the combined effect of nanoparticles and micro-fibers on various features of GOPL needs further insights. This study investigates the microstructural, mechanical, fracture, and toughness performance of micro-basalt fiber (MBF)-reinforced coal ash-made GOPL using different proportions of nano-sodium oxide at ambient curing conditions. The percentage of nano-sodium oxide examined in the present study varied from 0% to 4% by weight. The MBF amount is kept the same for all fabricated samples at 0.5% by weight. Scanning electron microscopy is used for assessing the microstructural cracking and failure behavior of GOPL pastes. The findings of the present study divulged that the usage of 3% nano-sodium oxide in MBF-reinforced GOPL mix presented the highest increase of 29%, 55%, 24%, and 60% for the compression strength, flexure strength, fracture toughness, and impact strength, respectively. Further increase in the content of nano-sodium oxide prompted the agglomeration of nanoparticles leading to a reduction in the performance of the GOPL. The outcomes of scanned electron microscopy delineated that the addition of nano-sodium oxide refined the interfacial regions and promoted the polymerization process of the GOPL which enriched the microstructure and fabricated a highly densified GOPL paste.

Combined effects of nanoparticles and ultrasonic field on thermal energy storage performance of phase change materials with metal foam

To further improve the performance of thermal energy storage (TES) system with phase change materials (PCMs), this paper proposed a novel method, i.e. combining the additions of TiO2 nanoparticles, metal foam and the provision of ultrasonic field, investigated its synergetic effects in enhancing conduction and convection heat transfer. The thermal characteristics, including the TES time distributions and the energy consumption of the TES system, were discussed to evaluate the combined effects of TiO2 nanoparticles and ultrasonic field on the TES rate and TES efficiency. The results showed that the latent TES time reduction index reached 46.50%, when the TiO2 nanoparticles concentration was 5.0 wt% and the ultrasonic power was 100 W, while the TES efficiency dropped to 10.66%. Increasing TiO2 nanoparticles concentration and ultrasonic power positively improved the TES rate due to conduction heat transfer enhanced by nanoparticles and convection heat transfer enhanced by the acoustic streaming effect and the cavitation effect of the ultrasonic field, but which negatively reduced the TES efficiency mainly due to the energy consumption of the ultrasonic field. Therefore, the effects of the ultrasonic field introduced at four action stages on the TES rate and TES efficiency were compared, and it confirmed that introducing ultrasonic field at the latent TES stage was better than that in the sensible TES stage. Additionally, the proposed novel combined method needed to consider the priority relationship between TES rate and TES efficiency for designing the TES system, favoring the potentials for further advances in TES applications.

Combined Effect of Zinc Oxide Nanoparticles and Bacteria on Osmolytes and Antioxidative Parameters of Rice (Oryza sativa L.) Plant Grown in Heavy Metal-Contaminated Water

With the advancement in nanotechnology, the use of nanoparticles has been enhanced dramatically in biomedical, agriculture, and industrial processes. However, the combined effect of nanoparticles and bacteria on plant growth in heavy metal (Cd, Cr, Cu, and Pb)-contaminated wastewater is greatly limited. Therefore, the recent work was designed to determine the synergistic impact of green synthesized zinc oxide nanoparticles (ZnO-NPs) (5-10 mg/L) and Bacillus spp. ( Bacillus cereus and Lysinibacillus macroides) on the physiological and biochemical activities of rice seedlings under heavy metal- (HM-) contaminated water. The results revealed that germination percentage (36%), root-shoot length (5.11 and 3.41 cm), fresh shoot-root weight (0.05 and 0.011 g), dry shoot-root weight (0.008 and 0.009 g), Chl a, Chl b, and carotenoid (5.4, 3.2 mg/g, and 4.3 μg/g), total soluble sugar (TSS) (26.44 mg/g), and total soluble protein (TSP) (21.99 mg/g) content considerably reduced in the plant tissues while combined impact of bacteria and ZnO NPs alleviates HM stress in contaminated water and improved seed germination (70%), root-shoot length (9.93 and 11.82 cm), fresh shoot-root weight (0.125 and 0.131 g), dry shoot-root weight (0.0532 and 0.042 g), Chl a, Chl b, and carotenoid (18.8, 13.9 mg/g, and 17.1 μg/g), TSS (57.651 mg/g), and TSP (47.990 mg/g) content. Lipid peroxidation induced by HM stress increased the amount of thiobarbituric acid reactive substances (TBRAS) (17.321 nM/mg) and hydrogen peroxide (H2O2) content (14.5 μM/g), stress markers such as glycine betaine (GB) (40.731 mg/g) and proline (Pro) (38.812 μmol/g) and antioxidant enzymes (SOD, POD, CAT, and APX) (180.87 U/mg, 450.677, 0.1066, and 0.631 μm/min/mg) under HM stress while the combined effect of ZnO NPs and bacteria reduced TBRAS (5.431 nM/mg), H2O2 content (2.25 μM/g), stress markers such as GB (24.731 mg/g) and Pro (18.811 μmol/g), and SOD, POD, CAT, and APX (187.53, 194.88, 0.061, and 0.271 μm/min/mg) contents. The present study suggested a potential role of combined impact of nanoparticles and bacteria in remediation of heavy metals from wastewater by improving plant growth.

Improving The Properties of a Polyester-Based Composite Using Nanoparticle Fillers

In this work, unsaturated polyester, resin, matrix reinforced, with fiberglass mat chopped were developed using TiO2 and SiO2 Nanoparticles as filler materials. The individual and combined effects of nanoparticles on the nanocomposite and material properties were examined. An improvement in Young’s modulus (39,3%) using combined weight of TiO2+ SiO2 was observed to be 3%. Examined nanoparticles have shown normal distribution in grain size indicated to be within standard limit, therefore boosting nanocomposite material to have excellent hardness, roughness, impact, and flexural resistance. DSC was characterized by transitions in this material. SEM and EDS techniques were used to confirm the formation of TiO2 and SiO2. The nanocomposites can be used in light-shielding, applications as well as in the industrial sectors.

Effect of nanoparticle surfactants on droplet formation in a flow-focusing microchannel

Nanoparticle surfactants, formed at liquid–liquid interfaces by the interactions between functional groups on nanoparticles and polymers having complementary end-functionality, have been recently proposed as an excellent interface stabilizer to cover liquid droplets for applications of substance encapsulation and delivery. However, the effects of nanoparticle surfactants on the production of liquid droplets in a microfluidic channel have not been comprehensively understood yet, which is a key prerequisite for achieving various functions in real applications. In this study, we have performed a systematic investigation on the effects of nanoparticle surfactants on droplet formation in a flow-focusing microchannel by using microfluidic experiments and theoretical analysis. We have found that simultaneously adding carboxylated nanoparticles into the dispersed phase and amino-terminated polymers into the continuous phases significantly decreases the droplet size but increases the production rate. More importantly, we have indicated that the combined effect of nanoparticles and polymers is much greater than the sum of their individual effects, which is mainly attributed to the significant reduction of the oil–water interfacial tension by the formation of nanoparticle surfactants. Besides, via analyzing the competition between hydrodynamic and interfacial forces acting on the droplet, we have established a theoretical criterion for the prediction of the droplet size with considering the effects of nanoparticle surfactants, which shows a good agreement with the experimental data.

Combined effects of different sizes of ZnO and ZIF-8 nanoparticles co-exposure with Cd2+ on HepG2 cells

Heavy metal and nanoparticles (NPs) emitted in the environment have attracted worldwide attention. But the combined effect of NPs and heavy metals is still unclear. In this study, the combined effect of zinc-based NPs and Cd2+ on HepG2 cells was investigated by combining biological indicator detection methods with time-resolved inductively coupled plasma mass spectrometry (TRA-ICP-MS) single cell analysis, and the combined effect of Zn2+ and Cd2+ was also investigated for a comparison. High-dose of ZnO or ZIF-8 NPs co-exposure with Cd2+ would reduce the cell viability while low-dose of ZnO or ZIF-8 NPs co-exposure with Cd2+showed antagonism and the particle size has no remarkable effect on the combined toxicity. In the antagonism, Zn2+ would increase cellular Zn amount through increasing the expression of ZIP8 and ZIP14 transporters to manage the ROS generation, but the zinc-based NPs would decrease expression of these transporters to decrease cellular Cd amount to help maintain the cell viability. Thus, we should hold a dialectical thinking about the pollution of NPs emissions in the environment.

Combined effects of nanoparticles and surfactants upon foam stability

We investigate effects of surfactants with different charges (anionic, cationic, and non-ionic) on foam stability in the presence of charge-stabilized silica (SiO2) nanoparticles. Toward this aim, a comprehensive series of experiments on a Hele-Shaw cell and a foam column is conducted at bubble and bulk-scale respectively, that is, investigating the phenomenologies of foam coarsening by gas diffusion and bubble coalescence, and separately by gravitational drainage. Our results show that nanoparticles, despite their ability to position themselves at liquid–gas interfaces and thus limit the resulting surface tension coefficient, do not necessarily have a positive effect on foam stability; the nature and magnitude of this effect depends strongly on the nature of the surfactant, its concentration and the concentration of nanoparticles. In less stable systems, significant coarsening occurs. Both results from bubble-scale and the bulk-scale experiments suggest that compatibility experiments are pre-requisite to foam stability analysis to test the compatibility between surfactants and nanoparticles.

Acute toxicity evaluation of nanoparticles mixtures using luminescent bacteria.

As the application of nanoparticles (NPs) and their release to the environment has increased, it is important to verify their toxicity, with a special emphasis on particle solubilization and the interaction of NP mixtures. In the current study, a model luminescent bacteria, Vibrio fischeri, was employed to test the acute toxicity of individual NPs and their binary mixtures, including metal NPs (ZnNPs, CuNPs) and metal oxide NPs (ZnONPs, CuONPs). The independent action model was used to reflect the synergistic, additive, or antagonistic interactions of binary mixtures of these NPs. The results showed that the median effective concentration (EC50) inhibited the luminescence of V. fischeri were 20.5, 4.1, 11.6, and 118.7mgL-1 for ZnNPs, CuNPs, ZnONPs, and CuONPs, respectively, suggesting that the toxicity of these NPs to V. fischeri were as the following order: CuNPs > ZnONPs > ZnNPs > CuONPs. The combined effect of NPs were found to be antagonistic for CuNPs-ZnONPs and CuNPs-CuONPs, synergistic for CuONPs-ZnNPs, CuNPs-ZnNPs, and ZnONPs-CuONPs, and additive for ZnNPs-ZnONPs, revealing a complex pattern of possible interactions. The differences of dissolved metal ions partly accounted for the different combined toxicity of binary mixtures of NPs. The findings have important implications for better understanding the true environmental risk of NP mixtures.

Development of Nanofluids for the Inhibition of Formation Damage Caused by Fines Migration: Effect of the interaction of Quaternary Amine (CTAB) and MgO Nanoparticles.

Fines migration is a common problem in the oil and gas industry that causes a decrease in productivity. In this sense, the main objective of this study is to develop nanocomposites based on the interaction of quaternary amine (hexadecyltrimethylammonium bromide—CTAB) and MgO to enhance the capacity of retention of fine particles in the porous medium. MgO nanoparticles were synthesized by the sol–gel method using Mg(NO3)2·6H2O as a precursor. Nanoparticles were characterized by dynamic light scattering (DLS), the point of zero charge (pHpzc), thermogravimetric analysis, and Fourier transform infrared spectroscopy (FT-IR). Different nanoparticle sizes of 11.4, 42.8, and 86.2 nm were obtained, which were used for preparing two system nanofluids. These systems were evaluated in the inhibition of fines migration: in the system I MgO nanoparticles were dispersed in a CTAB-containing aqueous solution, and system II consists of a nanocomposite of CTAB adsorbed onto MgO nanoparticles. The fines retention tests were performed using Ottawa sand 20/40 packed beds and fine particles suspensions at concentrations of 0.2% in a mass fraction in deionized water. Individual and combined effects of nanoparticles and CTAB were evaluated in different treatment dosages. The analysis of the interactions between the CTAB and the MgO nanoparticles was carried out through batch-mode adsorption and desorption tests. The best treatment in the system I was selected according to the fines retention capacity and optimized through a simplex-centroid mixture design for mass fractions from 0.0% to 2.0% of both CTAB and MgO nanoparticles. This statistical analysis shows that the optimal concentration of these components is reached for a mass fraction of 0.73% of MgO nanoparticles and 0.74% in mass fraction of CTAB, where the retention capacity of the porous medium increases from 0.02 to 0.39 mg·L−1. Based on the experimental results, the nanofluids combining both components showed higher retention of fines than the systems treated only with CTAB or with MgO nanoparticles, with efficiencies up to 400% higher in the system I and higher up to 600% in the system II. To evaluate the best performance treatment under reservoir conditions, there were developed core flooding tests at fixed overburden pressure of 34.5 MPa, pore pressure at 6.9 MPa and system temperature at 93 °C. Obtaining critical rate increases in 142.8%, and 144.4% for water and oil flow in the presence of the nanofluid. In this sense, this work offers a new alternative for the injection of nanocomposites as a treatment for the problem of fines migration to optimize the productivity of oil and gas wells.

Second Grade Bioconvective Nanofluid Flow with Buoyancy Effect and Chemical Reaction

This study mainly concerns with the examination of heat transfer rate, mass and motile micro-organisms for convective second grade nanofluid flow. The considered model comprises of both nanoparticles as well as gyrotactic micro-organisms. Microorganisms stabilize the suspension of nanoparticles by bio-convective flow which is generated by the combined effects of nanoparticles and buoyancy forces. The Brownian motion and thermophoretic mechanisms along with Newtonian heating are also considered. Appropriately modified transformations are invoked to get a non-linear system of differential equations. The resulting problems are solved using a numerical scheme. Velocity field, thermal and solute distributions and motile micro-organism density are discussed graphically. Wall-drag (skin-friction) coefficient, Nusselt, Sherwood and motile micro-organisms are numerically examined for various parameters. The outcomes indicate that for a larger Rayleigh number, the bio-convection restricts the upward movement of nanoparticles that are involved in nanofluid for the given buoyancy effect. Furthermore, larger buoyancy is instigated which certainly opposes the fluid flow and affects the concentration. For a larger values of fluid parameter, the fluid viscosity faces a decline and certainly less restriction is faced by the fluid. In both assisting and opposing cases, we notice a certain rise in fluid motion. Thermal layer receives enhancement for larger values of Brownian diffusion parameter. The random motion for stronger Brownian impact suddenly raises which improves the heat convection and consequently thermal distribution receives enhancement. Thermal distribution receives enhancement for a larger Lewis number whereas the decline is noticed in concentration distribution. The larger Rayleigh number results in a strong buoyancy force that effectively increases the fluid temperature. This also increases the concentration difference, thus more nanoparticles transport between surface and micro-organisms. Furthermore, for larger (Nb), the thermal state of fluid receives enhancement while a decline in motile density is observed. Numerical results show that mass flux is an enhancing function of both the (Le) and (Nb).

Silicon dioxide nanoparticles have contrasting effects on the temporal dynamics of sulfonamide and β-lactam resistance genes in soils amended with antibiotics

Nanoparticles (NPs) and antibiotic resistant genes (ARGs), as emerging environmental contaminants, have been reported to be accumulated in the soil environment. The use of NPs have raised increasing concerns about their environmental impacts, but the combined effect of NPs and antibiotics on ARGs remains less understood. Here, we established laboratory microcosms to explore the impacts of different concentrations of SiO2 NPs on β-lactam and sulfonamide resistance genes in soils amended with β-lactam or sulfonamide. Illumina sequencing and quantitative PCR revealed that the addition of NPs increased the bacterial community diversity but had no significant effects on the bacterial abundance. Moreover, NPs and sulfonamide jointly increased the abundances of sulfonamide resistance genes, while the exposure of NPs and β-lactam decreased β-lactam resistance genes. The detected ARGs were associated closely with two mobile genetic elements (MGEs, the tnpA and intI1 genes), indicating that MGEs may contribute to the dissemination of ARGs. Correlation analysis indicated the shifts in potential bacterial hosts and the frequency of horizontal gene transfer were important factors explaining the patterns of ARGs. Furthermore, structural equation models indicated that NPs exposure decreased the abundances of β-lactam resistance genes by driving changes in bacterial community and MGEs, whereas the increased abundances of sulfonamide resistance genes were mainly associated with the bacterial community, diversity and MGEs mediated by NPs and antibiotics. These results suggested that the combined effects of NPs and antibiotics on soil bacterial resistance were different due to the types of antibiotics.

Ocean acidification increases the toxic effects of TiO2 nanoparticles on the marine microalga Chlorella vulgaris

Concerns about the environmental effects of engineered nanoparticles (NPs) on marine ecosystems are increasing. Meanwhile, ocean acidification (OA) has become a global environmental problem. However, the combined effects of NPs and OA on marine organisms are still not well understood. In this study, we investigated the effects of OA (pH values of 7.77 and 7.47) on the bioavailability and toxicity of TiO2 NPs to the marine microalga Chlorella vulgaris. The results showed that OA enhanced the growth inhibition of algal cells caused by TiO2 NPs. We observed synergistic interactive effects of pH and TiO2 NPs on oxidative stress, indicating that OA significantly increased the oxidative damage of TiO2 NPs on the algal cells. Importantly, the elevated toxicity of TiO2 NPs associated with OA could be explained by the enhanced internalization of NPs in algal cells, which was attributed to the slighter aggregation and more suspended particles in acidified seawater. Overall, these findings provide useful information on marine environmental risk assessments of NPs under near future OA conditions.

Three‐dimensional boundary layer flow over a rotating disk with power‐law stretching in a nanofluid containing gyrotactic microorganisms

AbstractThe nanofluid model containing microorganisms over a rotating disk with power‐law stretching is constructed in this paper. The combined effects of nanoparticles and microorganisms in nanofluid are investigated by solving the governing equations numerically. The numerical solutions of the skin friction coefficient and local Nusselt number are in agreement with the corresponding previously published results. The quantities of physical interest are graphically presented and discussed in detail. It is found that the power‐law stretching index has produced profound influence on the flow as well as the heat and mass transfer.

Ion capturing/ion releasing films and nanoparticles in liquid crystal devices

Nanoparticles dispersed in liquid crystals can change the concentration of mobile ions through the adsorption/desorption process. In the majority of the reported cases, the effects of nanoparticles on the electrical properties of liquid crystals are analysed, neglecting the interactions of ions with substrates. In this paper, the combined effect of nanoparticles and substrates on the concentration of ions in liquid crystals is discussed. Depending on the ionic purity of substrates and nanoparticles, the ion capturing/ion releasing regimes can be achieved. In addition, the concentration of mobile ions in liquid crystal nanocolloids also depends on the cell thickness.

Silica dioxide nanoparticles combined with cold exposure induce stronger systemic inflammatory response.

Growing concern has been raised over the potential hazard of nanoparticles (NPs) on human health from ambient particulate air pollution. Silicon dioxide (SiO2) NPs are one of the most widely used nanoparticles in many sectors of industry. Research on NPs has focused mainly on their toxicity in organs. Meanwhile, NPs are present in the air year-round, but are more serious in winter. Thus, the aim of this study was to evaluate the inflammatory response to SiO2 NPs using in vivo test systems. The composition of particulate matter is complicated; however, elemental silicon accounts for a significant proportion. Cold exposure can induce many kinds of systemic reactions. Thus, the second aim of this study was also to evaluate the combined effect of NPs and cold exposure on human health. There is little research on the combined effects of nanoparticles and cold on inflammation. Sprague-Dawley rats were randomly divided into four groups: those exposed to SiO2 NPs by intratracheal instillation, those exposed to at 4°C 4h/day for 4weeks, a combined SiO2 NPs and cold exposure group, and a control group. Inflammatory cell infiltration in the lungs was mainly observed after exposure to SiO2 NPs or cold. Hematoxylin and eosin staining revealed that inflammation of the lungs was more serious in the combined group. In the white adipose tissue and brown adipose tissue of the combined groups, the mRNA expressions of pro-inflammatory cytokines were upregulated. In conclusion, SiO2 NPs combined with cold exposure induced a stronger systemic inflammatory response, accompanied by more serious health hazards.

Improvement of CO2 absorption using AL2O3 nanofluids in a stirred thermostatic reactor

The improvement of CO2 absorption by Al2O3 nanofluids with deionized water as the base fluid was studied experimentally. The reactor used was a stirred thermostatic reactor, operated batchwise. Pure CO2 was employed in all the experiments. The content of Al2O3 in nanofluids ranged from 0 to 0.2 % (wt). Sodium dodecyl benzene sulfonate (SDBS) was employed to improve the stability of the nanofluids, and the combined effect of nanoparticles and surfactants on the absorption enhancement was studied. The parameters such as the concentration of Al2O3 nanoparticles and surfactants, the stirring speed, and the ultrasonic time were varied. The results show that the nanoparticle mass fraction and the ultrasonic time have an optimum value for the CO2 absorption enhancement. The combination of surfactants and nanoparticles improves the enhancement performance of Al2O3 nanofluids more effectively than that without surfactants. With the increase of the stirring speed, the effective absorption ratio in stable nanofluids declines, while in poorly dispersed Al2O3 suspensions, it is increased first and then reduced. The mechanism of the Al2O3 nanofluid enhancing CO2 absorption is discussed accordingly. The absorption enhancement by the Al2O3 nanofluid is mainly attributable to convective motion induced by the Brownian motion.

A Numerical Model for Ammonia/Water Absorption From a Bubble Expanding at a Submerged Nozzle Into a Binary Nanofluid

An absorber is a major component in the absorption refrigeration systems, and its performance remarkably affects the overall system performance. A mathematical model for ammonia absorption from a bubble expanding at a submerged nozzle into a binary nanofluid was developed to analyze the effects of binary nanofluid on ammonia absorption in the forming process of a bubble. The combined effects of nanoparticles on heat transfer, mass transfer, and bubble size all were considered in the model. The concentration of nanoparticles, the radius of the nozzle, and the flow rate of ammonia vapor were considered as the key parameters. The numerical results showed that the enhancement of binary nanofluid for bubble absorption has the analogous tendency with the mass transfer enhancement of binary nanofluid. The diameter of the nozzle and the flow rate of ammonia vapor hardly affect the enhancement of the binary nanofluid for the absorption of bubble growing stage. The current investigation can result in a better understanding of the absorption process occurring in thermally driven absorption refrigeration systems.

Influence of Nanoparticle Loading on Craze Formation and Crack Propagation of Polycarbonate in Different Environments

In the present work, the craze formation and crack propagation of nanosilica-filled polycarbonate (PC) in different environments were investigated by using a bent strip test with constant strain and a creep test with static constant stress. The result of bent strip test indicates that crazes or microcracks are formed more easily in isopropanol (IPA) than in air, and the number of crazes increases with increasing particle loading in the matrix. The following three-point bending test shows a clear decrease of flexural properties of samples prebent in IPA compared to samples prebent in air. By creep test under constant loading, the samples tested in toluene fail much earlier than those tested in IPA due to accelerated diffusion of toluene into PC matrix and subsequent formation of macrovoids. The incorporation of nanoparticles in PC significantly improves the lifetime of PC composites in chemical agents due to combined effects of nanoparticles.