Search results for: nanoparticle aggregates

Authors: Rui Sang, Fei Deng, Alexander Engel, Ewa M. Goldys, Wei Deng

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In this study, we brought together X-ray induced photodynamic therapy (X-PDT) and chemo-drug (5-FU) for the treatment on colorectal cancer cells. This was achieved by developing a lipid-polymer hybrid nanoparticle delivery system (FA-LPNPs-VP-5-FU). It was prepared by incorporating a photosensitizer (verteporfin), chemotherapy drug (5-FU), and a targeting moiety (folic acid) into one platform. The average size of these nanoparticles was around 100 nm with low polydispersity. When exposed to clinical doses of 4 Gy X-ray radiation, FA-LPNPs-VP-5-FU generated sufficient amounts of reactive oxygen species, triggering the apoptosis and necrosis pathway of cancer cells. Our combined X-PDT and chemo-drug strategy was effective in inhibiting cancer cells’ growth and proliferation. Cell cycle analyses revealed that our treatment induced G2/M and S phase arrest in HCT116 cells. Our results indicate that this combined treatment provides better antitumour effect in colorectal cancer cells than each of these modalities alone. This may offer a novel approach for effective colorectal cancer treatment with reduced off-target effect and drug toxicity.

Keywords: pdt, targeted lipid-polymer nanoparticles, verteporfin, colorectal cancer

Procedia PDF Downloads 53

Authors: I. Miličević, M. Hadzima Nyarko, R. Bušić, J. Simonović Radosavljević, M. Prokopijević, K. Vojisavljević

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This paper investigates the effects of different treatment methods of rubber aggregates for self-compacting concrete (SCC) on compressive strength and modulus of elasticity. SCC mixtures with 10% replacement of fine aggregate with crumb rubber by total aggregate volume and with different aggregate treatment methods were investigated. The rubber aggregate was treated in three different methods: dry process, water-soaking, and NaOH treatment plus water soaking. Properties of SCC in a fresh and hardened state were tested and evaluated. Scanning electron microscope (SEM) analysis of three different SCC patches were made and discussed. It was observed that applying the proposed NaOH plus water soaking method resulted in the improvement of fresh and hardened concrete properties. It resulted in a more uniform distribution of rubber particles in the cement matrix, a better bond between rubber particles and the cement matrix, and higher compressive strength of SCC rubberized concrete.

Keywords: compressive strength, modulus of elasticity, NaOH treatment, rubber aggregate, self-compacting rubberized concrete, scanning electron microscope analysis

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Authors: Soraya Hoornam, Zeinab Sanaee

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Lithium-ion batteries are widely used for providing energy for mobile electronic devices. Graphite is a traditional anode material that was used in almost all commercialized lithium-ion batteries. It gives a specific capacity of 372 mAh/g for lithium storage. But there are multiple better choices for storing lithium that propose significantly higher specific capacities. As an example, silicon-based materials can be mentioned. In this regard, SiO₂ material can offer a huge specific capacity of 1965 mAh/g. Due to this high lithium storage ability, large volume change occurs in this electrode material during insertion and extraction of lithium, which may lead to cracking and destruction of the electrode. The use of nanomaterials instead of bulk material can significantly solve this problem. In addition, if we insert lithium in the active material of the battery before its cycling, which is called pre-lithiation, a further enhancement in the performance is expected. Here, we have fabricated an anode electrode of the battery using SiO₂ nanomaterial mixed with Graphite and assembled a lithium-ion battery half-cell with this electrode. Next, a pre-lithiation was performed on the SiO₂ nanoparticle-containing electrode, and the resulting anode material was investigated. This electrode has great potential for high-performance lithium-ion batteries.

Keywords: SiO₂ nanoparticles, lithium-ion battery, pre-lithiation, anode material

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Authors: Mary Joy B. Amoguis, Alonah Jane D. Labtic, Hyna Wary Namoca, Aira Jane V. Original

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Animal waste has been rapidly increasing due to the growing animal population and the lack of innovative waste management practices. In a country like the Philippines, animal waste is rampant. This study aims to minimize animal waste by producing garden bricks using cat stool as an additive. The research study analyzes different levels of concentration to determine the most efficient combination in terms of compressive strength and durability of cat stool as an additive to garden bricks. The researcher's first collects the cat stool and incinerates the different concentrations. The first concentration is 25% cat stool and 75% cement mixture. The second concentration is 50% cat stool and 50% cement mixture. And the third concentration is 75% cat stool and 25% cement mixture. The researchers analyze the statistical data using one-way ANOVA, and the statistical analysis revealed a significant difference compared to the controlled variable. The research findings show an inversely proportional relationship: the higher the concentration of cat stool additive, the lower the compressive strength of the bricks, and the lower the concentration of cat stool additive, the higher the compressive strength of the bricks.

Keywords: cat stool, garden bricks, cement, concentrations, animal wastes, compressive strength, durability, one-way ANOVA, additive, incineration, aggregates, stray cats

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Authors: S. Rashidi, L. C. Abdullah, R. Walvekar, K. Mohammad, F-R. Ahmadun, M. Y. Faizah

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In this research, stability and rheology behavior of Multi-walled carbon nanotube (MWCNT) nanofluids by using Xanthan Gum as a dispersant were measured. This paper addresses the effects of Xanthan Gum (XG) concentration and nanoparticle loading on stability and viscosity of nanofluids. The stability of nanofluids is measured by Zeta Sizer Nano-ZS (Malvern Instruments, ZEN 3600). The zeta potential of the stable samples was analyzed. The rheological behavior of carbon nanotube CNT nanofluids was analyzed using rheometer (Model AR G2, TA Instrument). Both stability and viscosity of the nanofluids increased with increasing CNT and XG concentration. The experimental results indicated that the zeta potential of nanofluid samples is stable. The results demonstrated that the zeta potential was affected by the CNT concentration and is augmented in parallel with increasing CNT concentration. The rheology results showed that the viscosity of CNT/XG nanofluid was increased. The escalated viscosity of CNT/XG nanofluid is owing to the higher van der Waals interaction between the CNT nanoparticles. On the other hand, the viscosity of the CNT/XG nanofluid decreases with increasing temperature. In summary, this research provides useful insight into the behavior of CNT nanofluids.

Keywords: nanofluid, carbon nanotube, stability, rheology

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Authors: P. Parthiban, J. Karthikeyan

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This paper deals with the performance of semi-light weight concrete, prepared by using wood ash pellets as coarse aggregates which were improved by partial replacement of cement with alccofine. Alccofine is a mineral admixture which contains high glass content obtained through the process of controlled granulation. This is finer than cement which carries its own pozzolanic property. Therefore, cement could be replaced by alccofine as 0%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, and 70% to enhance the strength and durability properties of concrete. High range water reducing admixtures (HRWA) were used in these mixes which were dosed up to 1.5% weight of the total cementitious content (alccofine & cement). It also develops the weaker transition zone into more impermeable layer. Specimens were subjected in both the accelerated curing method as well as conventional curing method. Experimental results were compared and reported, in that the maximum compressive strength of 32.6 MPa was achieved on 28^th day with 30% replacement level in a density of 2200 kg/m³ to a conventional curing, while in the accelerated curing, maximum compressive strength was achieved at 40% replacement level. Rapid chloride penetration test (RCPT) output results for the conventional curing method at 0% and 70% give 3296.7 and 545.6 coulombs.

Keywords: Alccofine, compressive strength, RCPT, wood ash pellets

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Authors: Satya Eswari Jujjavarapu, Swasti Dhagat, Lata Upadhyay, Reecha Sahu

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Silver nanoparticles have a broad range of antimicrobial and antifungal properties ranging from soaps, pastes to sterilization and drug delivery systems. These can be synthesized by physical, chemical and biological methods; biological methods being the most popular owing to their non-toxic nature and reduced energy requirements. Microbial surfactants, produced on the microbial cell surface or excreted extracellularly are an alternative to synthetic surfactants for the production of silver nanoparticles. Hence, they are also called as green molecules. Microbial lipopeptide surfactants (biosurfactant) exhibit anti-tumor and anti-microbial properties and can be used as drug delivery agents. In this study, biosurfactant was synthesized by using a strain of acillus subtilis. The biosurfactant thus produced was analysed by emulsification assay, oil spilling test, and haemolytic test. Biosurfactant-mediated silver nanoparticles were synthesised by microwave irradiation of the culture supernatant and further characterized by UV–vis spectroscopy for a range of 400-600 nm. The UV–vis spectra showed a surface plasmon resonance vibration band at 410 nm corresponding to the peak of silver nanoparticles.

Keywords: biosurfactant, Bacillus subtilis, silver nano particle, lipopeptide

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Authors: B. Paygozar, S.A. Dizaji, A.C. Kandemir

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In this study, the effects of the modified adhesive including different concentrations of Nano-silica are surveyed on the bonding strength of the adhesive scarf joints. The nanoparticles are added in two different concentrations, to an epoxy-based two-component structural adhesive, Araldite 2011, to survey the influences of the nanoparticle weight percentage on the failure load of the joints compared to that of the joints manufactured by the neat adhesive. The effects of being exposure to a moist ambience on the joint strength are also investigated for the joints produced of both neat and modified adhesives. For this purpose, an ageing process was carried out on the joints of both neat and improved kinds with variable immersion periods (20, 40 and 60 days). All the specimens were tested under a quasi-static tensile loading of 2 mm/min speed so as to find the quantities of the failure loads. Outcomes indicate that the failure loads of the joints with modified adhesives are measurably higher than that of the joint with neat adhesive, even while being put for a while under a moist condition. Another result points out that humidity lessens the bonding strength of all the joints of both types as the exposure time increases, which can be attributed to the change in the failure mode.

Keywords: bonding strength, humidity, nano-silica, scarf joint

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Authors: Majede Modheji, Hamid Emadi, Hossein Vojoudi

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An efficient magnetic mesoporous structure was designed and prepared for the facile pre-concentration of As(III) ions. To prepare the sorbent, a core-shell magnetic silica nanoparticle was covered by MCM-41 like structure, and then the surface was modified by guanidine via an amine linker. The prepared adsorbent was investigated as an effective and sensitive material for the adsorption of arsenic ions from the aqueous solution applying a normal batch method. The imperative variables of the adsorption were studied to increase efficiency. The dynamic and static processes were tested that matched a pseudo-second order of kinetic model and the Langmuir isotherm model, respectively. The sorbent reusability was investigated, and it was confirmed that the designed product could be applied at best for six cycles successively without any significant efficiency loss. The synthesized product was tested to determine and pre-concentrate trace amounts of arsenic ions in rice and natural waters as a real sample. A desorption process applying 5 mL of hydrochloric acid (0.5 mol L⁻¹) as an eluent exhibited about 98% recovery of the As(III) ions adsorbed on the GA-MSMP sorbent.

Keywords: arsenic, adsorption, mesoporous, surface modification, MCM-41

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Authors: Roslinda Nazar, Amin Noor, Khamisah Jafar, Ioan Pop

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In this paper, the steady laminar three-dimensional boundary layer flow and heat transfer of a copper (Cu)-water nanofluid in the vicinity of a permeable shrinking flat surface in an otherwise quiescent fluid is studied. The nanofluid mathematical model in which the effect of the nanoparticle volume fraction is taken into account is considered. The governing nonlinear partial differential equations are transformed into a system of nonlinear ordinary differential equations using a similarity transformation which is then solved numerically using the function bvp4c from Matlab. Dual solutions (upper and lower branch solutions) are found for the similarity boundary layer equations for a certain range of the suction parameter. A stability analysis has been performed to show which branch solutions are stable and physically realizable. The numerical results for the skin friction coefficient and the local Nusselt number as well as the velocity and temperature profiles are obtained, presented and discussed in detail for a range of various governing parameters.

Keywords: heat transfer, nanofluid, shrinking surface, stability analysis, three-dimensional flow

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Authors: Purnima Rawat, Divya Vohora, Sarika Gupta, Farhan J. Ahmad, Sushama Talegaonkar

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Nanoparticles (NPs) that target bone tissue were developed using PLGA–mPEG (poly(lactic-co-glycolic-acid)–polyethylene glycol) diblock copolymers by using pamidronate as a bone-targeting moieties. These NPs are expected to enable the transport of hydrophilic drugs. The NP was prepared by in situ polymerization method, and their in- vitro characteristics were evaluated using dynamic light scattering, transmission electron microscopy (TEM) and in phosphate-buffered solution. The bone targeting potential of the NP was also evaluated on in-vitro pre-osteoblast MCT3E1 cell line using ALP activity, degree of mineralization and RT-PCR assay. The average particle size of the NP was 101.6 ± 3.7nm, zeta potential values were negative (-25±0.34mV) of the formulations and the entrapment efficiency was 93± 3.1 % obtained. The moiety of the PLGA–mPEG–pamidronate NPs exhibited the best apatite mineral binding ability in-vitro MCT3E1 pre-osteoblast cell line. Our results suggested that the developed nanoparticles may use as a delivery system for Pamidronate in bone repair and regeneration, warranting further evaluation of the treatment of bone disease.

Keywords: nanoparticle, pamidronate, in-situ polymerization, osteoblast

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Authors: Mihai Liviu Despa

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The paper tackles the topic of determining the cost of innovation in software development projects. Innovation can be achieved either in a planned or unplanned manner. The paper approaches the scenarios were innovation is planned for. As a starting point an innovative software development project is analyzed. The project is depicted step by step as it was implemented, from inception to delivery. Costs that are proprietary to innovation in software development are isolated based on the author’s personal experience in managing the above mentioned project. Innovation costs components identified by the author are then validated using open discussions with software development professionals and projects managers on LinkedIn groups. In order to receive relevant feedback only groups that focus on software development and innovation management are targeted. Additional innovation cost components suggested by software development professionals and projects managers are also considered. Based on the identified cost components an indicator is built. The indicator is meant to formalize the process of determining the cost of innovation in a software development project. The indicator aggregates all the innovation cost components that are identified in the research process. The process of calculating each cost component is also described. Conclusions are formulated and new related research topics are submitted for debate.

Keywords: innovation cost, IT project management, software development, innovation management

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Authors: I. Behroyan, P. Ganesan, S. He, S. Sivasankaran

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This study compares the predictions of five types of Computational Fluid Dynamics (CFD) models, including two single-phase models (i.e. Newtonian and non-Newtonian) and three two-phase models (Eulerian-Eulerian, mixture and Eulerian-Lagrangian), to investigate turbulent forced convection of Cu-water nanofluid in a tube with a constant heat flux on the tube wall. The Reynolds (Re) number of the flow is between 10,000 and 25,000, while the volume fraction of Cu particles used is in the range of 0 to 2%. The commercial CFD package of ANSYS-Fluent is used. The results from the CFD models are compared with results from experimental investigations from literature. According to the results of this study, non-Newtonian single-phase model, in general, does not show a good agreement with Xuan and Li correlation in prediction of Nu number. Eulerian-Eulerian model gives inaccurate results expect for φ=0.5%. Mixture model gives a maximum error of 15%. Newtonian single-phase model and Eulerian-Lagrangian model, in overall, are the recommended models. This work can be used as a reference for selecting an appreciate model for future investigation. The study also gives a proper insight about the important factors such as Brownian motion, fluid behavior parameters and effective nanoparticle conductivity which should be considered or changed by the each model.

Keywords: heat transfer, nanofluid, single-phase models, two-phase models

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Authors: Salima Bouadjela, Fatima Zohra Abdoune, Lahcene Mechernene

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PDLCs are currently considered as promising materials for specific applications such as creation of window blinds controlled by electric field, fog simulators, UV protective glasses, high data storage device etc. We know that the electrical field inside the liquid crystal is low compare with the external electric field [1,2]. An addition of high magnetic and electrical, properties containing compounds to the polymer dispersed liquid crystal (PDLC) will enhance the electrical, optical, and magnetic properties of the PDLC [3,4]. Low Concentration of inorganic nanoparticles TiO2 added to nematic liquid crystals (E7) and also combined with monomers (TPGDA) and cured monomer/LC mixture to elaborate polymer-LC-NP dispersion. The presence of liquid crystal and nanoparticles in TPGDA matrix were conformed and the modified properties of PDLC due to doped nanoparticle were studied and explained by the results of FTIR, POM, UV. Incorporation of nanoparticles modifies the structure of PDLC and thus it makes increase the amount of droplets and decrease in droplet size. we found that the presence of TiO2 nanoparticles leads to a shift the nematic-isotropic transition temperature TNI.

Keywords: nanocomposites, PDLC, phases diagram, TiO2

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Authors: Navid Zanganeh, Hafez Balavi, Farbod Sharif, Mahla Zabet, Marzieh Bakhtiary Noodeh

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Cerium oxide (CeO2) also known as cerium dioxide or ceria is a pale yellow-white powder with various applications in the industry from wood coating to cosmetics, filtration, fuel cell electrolytes, gas sensors, hybrid solar cells and catalysts. In this research, attempts were made to synthesize and characterization of CeO2 nano-particles via sol-gel method. In addition, the effect of aging time on the size of particles was investigated. For this purpose, the aging times adjusted 48, 56, 64, and 72 min. The obtained particles were characterized by x-ray diffraction spectroscopy (XRD), scanning electron microscopy (SEM), transmitted electron microscopy (TEM), and Brunauer–Emmett–Teller (BET). As a result, XRD patterns confirmed the formation of CeO2 nanoparticles. SEM and TEM images illustrated the nano-particles with cluster shape, spherical and a nano-size range which was in agreement with XRD results. The finest particles (7.3 nm) was obtained at the optimum condition which was aging time of 48 min, calcination temperature at 400 ⁰C, and cerium concentration of 0.004 mol. Average specific surface area of the particles at optimum condition was measured by BET analysis and recorded as 47.57 m2/g.

Keywords: aging time, CeO2 nanoparticles, size distribution, sol-gel

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Authors: Oktavia Eka Puspita

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The possibility of using Solid Lipid Nanoparticles (SLN) for topical use is an interesting feature concerning this system has occlusive properties on the skin surface therefore enhance the penetration of drugs through the stratum corneum by increased hydration. This advantage can be used to enhance the drug penetration of topical delivery such as Diclofenac sodium for the relief of signs and symptoms of osteoarthritis, rheumatoid arthritis and ankylosing spondylitis. The purpose of this study was focused on the preparation and physical characterization of Diclofenac sodium loaded SLN (D-SLN). D loaded SLN were prepared by hot homogenization followed by ultrasonication technique. Since the occlusion factor of SLN is related to its particle size the formulation of D-SLN in present study two formulations different in its surfactant contents were prepared to investigate the difference of the particle size resulted. Surfactants selected for preparation of formulation A (FA) were lecithin soya and Tween 80 whereas formulation B (FB) were lecithin soya, Tween 80, and Sodium Lauryl Sulphate. D-SLN were characterized for particle size and distribution, polydispersity index (PI), zeta potential using Beckman-Coulter Delsa™ Nano. Overall, the particle size obtained from FA was larger than FB. FA has 90% of the particles were above 1000 nm, while FB has 90% were below 100 nm.

Keywords: solid lipid nanoparticles, hot homogenization technique, particle size analysis, topical administration

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Authors: Rabah Laouar, Yahia Boudra, Adel Satouh, Adrian Boyce

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The ultramafic rocks of the Collo region crop out as « stratified » masses that cross-cut older metamorphic formation of the basement. These rocks are mainly peridotites and serpentinites. The peridotites are composed of olivine, orthopyroxene, clinopyroxene and spinel (chromite). The chemical composition of these lherzolites show a magnesian character with high MgO contents (34.4 to 37.5%), high Cr (0.14 to 0.27%), Ni (0.14 to 0.26%) and Co (34 to 133 ppm) and low CaO and Al₂O₃ (0.02 to 2.2 and 0.5 to 2.8 % respectively). They represent a residue (restite) of a mantle magmas partial melting. The chromite which represents about 2 to 3% of the rock is a ubiquitous mineral and shows two different generations: primary idiomorphic millimetric crystals and secondary very fine, xenomorphic and interstitial aggregates. The primary chromites are alumino-ferro-magnesian crystals. They show high Al₂O₃ (25.77% to 27.36%) and MgO (10.70% to 13.36%). Cr# (100*Cr/ (Al+Cr)) varies between 45 and 48, and Mg# (100*Mg/Mg+Fe₂+) varies between 49 and 59. On the other hand, the secondary interstitial grains are iron-rich chromites; they show low Al₂O₃ (4.67% to 9.54%) and MgO (4.60% to 4.65%). Cr# is relatively high (77 to 88) whereas Mg# show relatively low values, varying between 22 and 25. Oxygen isotopic composition of both types of chromites is consistent with their derivation from a mantle source (ð¹⁸O vary between +3.9 and +5.2‰), though a contribution of ¹⁶O-rich component to the secondary chromites is not ruled out.

Keywords: peridotites, serpentinites, chromite, partial melting, collo, Algeria

Procedia PDF Downloads 66

Authors: Faranak Beigmohammadi, Seyed Hadi Peighambardoust, Seyed Jamaledin Peighambardoust

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This study undertakes to investigate the ability of different kinds of nanocomposite films made of cloisite-30B with different percentages of silver and copper oxide nanoparticles incorporated into a low-density polyethylene (LDPE) polymeric matrix by a melt mixing method in order to inhibit the growth of microorganism in soy burger. The number of surviving cell of the total count was decreased by 3.61 log and mold and yeast diminished by 2.01 log after 8 weeks storage at 18 ± 0.5°C below zero, whilst pure LDPE did not has any antimicrobial effect. A composition of 1.3 % cloisite 30B-Ag and 2.7 % cloisite 30B-CuO for total count and 0 % cloisite 30B-Ag and 4 % cloisite 30B-CuO for yeast & mold gave optimum points in combined design test in Design Expert 7.1.5. Suitable microbial models were suggested for retarding above microorganisms growth in soy burger. To validation of optimum point, the difference between the optimum point of nanocomposite film and its repeat was not significant (p<0.05) by one-way ANOVA analysis using SPSS 17.0 software, while the difference was significant for pure film. Migration of metallic nanoparticles into a food stimulant was within the accepted safe level.

Keywords: modeling, nanocomposite film, packaging, soy burger

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Authors: Mont Kumpugdee-Vollrath, Khaled Abdallah

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Liposomes and pegylated liposomes were widely used as drug delivery system in pharmaceutical field since a long time. However, in the former time, polyethylene glycol (PEG) was connected into phospholipid after the liposomes were already prepared. In this paper, we intend to study the possibility of applying phospholipids which already connected with PEG and then they were used to prepare liposomes. The model drug resveratrol was used because it can be applied against different diseases. Cholesterol was applied to stabilize the membrane of liposomes. The thin film technique in a laboratory scale was a preparation method. The liposomes were then characterized by nanoparticle tracking analysis (NTA), photon correlation spectroscopy (PCS) and light microscopic techniques. The stable liposomes can be produced and the particle sizes after filtration were in nanometers. The 2- and 3-chains-PEG-phospholipid (PL) caused in smaller particle size than the 4-chains-PEG-PL. Liposomes from PL 90G and cholesterol were stable during storage at 8 °C of 56 days because the particle sizes measured by PCS were almost not changed. There was almost no leakage of resveratrol from liposomes PL 90G with cholesterol after diffusion test in dialysis tube for 28 days. All liposomes showed the sustained release during measuring time of 270 min. The maximum release amount of 16-20% was detected with liposomes from 2- and 3-chains-PEG-PL. The other liposomes gave max. release amount of resveratrol only of 10%. The release kinetic can be explained by Korsmeyer-Peppas equation. 

Keywords: liposome, NTA, resveratrol, pegylation, cholesterol

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Authors: H. Moalla, A. Frikha

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Multi-criteria decision aid methods consider decision problems where numerous alternatives are evaluated on several criteria. These methods are used to deal with perfect information. However, in practice, it is obvious that this information requirement is too much strict. In fact, the imperfect data provided by more or less reliable decision makers usually affect decision results since any decision is closely linked to the quality and availability of information. In this paper, a PROMETHEE-BELIEF approach is proposed to help multi-criteria decisions based on incomplete information. This approach solves problems with incomplete decision matrix and unknown weights within PROMETHEE method. On the base of belief function theory, our approach first determines the distributions of belief masses based on PROMETHEE’s net flows and then calculates weights. Subsequently, it aggregates the distribution masses associated to each criterion using Murphy’s modified combination rule in order to infer a global belief structure. The final action ranking is obtained via pignistic probability transformation. A case study of real-world application concerning the location of a waste treatment center from healthcare activities with infectious risk in the center of Tunisia is studied to illustrate the detailed process of the BELIEF-PROMETHEE approach.

Keywords: belief function theory, incomplete information, multiple criteria analysis, PROMETHEE method

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Authors: M.F. Elkady, Sahar Zaki, Desouky Abd-El-Haleem

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Silver nanoparticles (AgNPs) are already widely prepared using different technologies. However, there are limited data on the effects of hydrogen ion concentration on nano-silver production. In this investigation, the impact of the pH reaction medium toward the particle size, agglomeration and the yield of the produced bio-synthesized silver were established. Quasi-spherical silver nanoparticles were synthesized through the biosynthesis green production process using the Egyptian E. coli bacterial strain 23N at different pH values. The formation of AgNPs has been confirmed with ultraviolet–visible spectra through identification of their characteristic peak at 410 nm. The quantitative production yield and the orientation planes of the produced nano-silver were examined using X-ray spectroscopy (EDS) and X-ray diffraction (XRD). Quantitative analyses indicated that the silver production yield was promoted at elevated pH regarded to increase the reduction rate of silver precursor through both chemical and biological processes. As a result, number of the nucleus and thus the size of the silver nanoparticles were tunable through changing pH of the reaction system. Accordingly, the morphological structure and size of the produced silver and its aggregates were determined using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images. It was considered that the increment in pH value of the reaction media progress the aggregation of silver clusters. However, the presence of stain 23N biomass decreases the possibility of silver aggregation at the pH 7.

Keywords: silver nanoparticles, biosynthesis, reaction media pH, nano-silver characterization

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Authors: Ishaq Ahmad, Zhaomin Li, Liu Chengwen, Song Yan Li, Zihan Gu, Li Shaopeng

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In order to manage gas mobility in the reservoir, only a small amount of surfactant or polymer is needed because nanoparticles have the potential to improve foam stability. The aim is to enhance foam formation and stability, so it was decided to investigate the foam stability and foam ability of black rice husk ash. Several characterization techniques were used to investigate the properties of black rice husk ash. The best-performing anionic foaming surfactants were combined with black rice husk ash at different concentrations (ppm). Sodium dodecyl benzene sulphonate was used as the anionic surfactant. This study demonstrates the value of black rice husk ash (BRHA), which has a high silica concentration, for foam stability and ability. For the test, black rice husk ash and raw ash were used with SDS (Sodium Dodecyl Sulfate) and SDBS (Sodium dodecyl benzenesulfonate) surfactants under different parameters. Different concentration percentages were utilized to create the foam, and the hydrophobic test and shaking method were applied. The foam scanner was used to observe the behavior of the black rice husk ash foam. The high silica content of black rice husk ash has the potential to improve foam stability, which is favorable and could possibly improve oil recovery.

Keywords: black rice husk ash nanoparticle, surfactant, foam life, foam scanning

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Authors: Sanjib Kr Pal, S. Bhattacharyya

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Mixed convection of Cu-water nanofluid in an enclosure with thick wavy bottom wall has been investigated numerically. A co-ordinate transformation method is used to transform the computational domain into an orthogonal co-ordinate system. The governing equations in the computational domain are solved through a pressure correction based iterative algorithm. The fluid flow and heat transfer characteristics are analyzed for a wide range of Richardson number (0.1 ≤ Ri ≤ 5), nanoparticle volume concentration (0.0 ≤ ϕ ≤ 0.2), amplitude (0.0 ≤ α ≤ 0.1) of the wavy thick- bottom wall and the wave number (ω) at a fixed Reynolds number. Obtained results showed that heat transfer rate increases remarkably by adding the nanoparticles. Heat transfer rate is dependent on the wavy wall amplitude and wave number and decreases with increasing Richardson number for fixed amplitude and wave number. The Bejan number and the entropy generation are determined to analyze the thermodynamic optimization of the mixed convection.

Keywords: conjugate heat transfer, mixed convection, nano fluid, wall waviness

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Authors: Chahinez Aissaoui, Cecile Diliberto, Jean-Michel Mechling

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The manufacture of metal foundry products requires the use of sand moulds, which are destroyed, and new ones made each time metal is poured. However, recycled sand requires a regeneration process that produces a polluted fine mineral phase. Particularly rich in heavy metals and organic residues, this foundry co-product is disposed of in hazardous waste landfills and requires an expensive stabilisation process. This paper presents the results of research that valorises this fine fraction of foundry sand by inerting it in a cement phase. The fines are taken from the bag filter suction systems of a foundry. The sample is in the form of filler, with a fraction of less than 140µm, the D50 is 43µm. The Blaine fineness is 3120 cm²/g, and the fines are composed mainly of SiO₂, Al₂O₃ and Fe₂O₃. The loss on ignition at 1000°C of this material is 20%. The chosen inerting technique is to manufacture cement pastes which, once hardened, will be crushed for use as artificial aggregates in new concrete formulations. Different percentages of volume substitutions of Portland cement were tested: 30, 50 and 65%. The substitution rates were chosen to obtain the highest possible recycling rate while satisfying the European discharge limits (these values are assessed by leaching). They were also optimised by adding water-reducing admixtures to increase the compressive strengths of the mixes.

Keywords: leaching, upcycling, waste, residuals

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Authors: Rasha S. Kamal, Reham I. El-Shazly, Reem K. Farag

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Green nano-branched structural compounds were synthesized by adding 1% by weight of clay nanoparticle to different moles ratios of either dodecyl acrylate or triethylenetetramine using a simple one-pot method. The synthesized nano polymers were provided with different terminations. In order to confirm the chemical structure of the produced nanocomposites, FTIR and 1HNMR spectroscopy were performed. Additionally, Dynamic Light Scattering (DLS) analysis was used to assess the size and dispersion of the produced branching nano polymers. Using a Gel-permeation chromatograph, the molecular weights of the produced modified green nano hyperbranched polymer with various terminations were determined. the prepared nano samples with different molar feed ratios dodecyl acrylate: triethylenetetramine (DDA: TETA) was designed as An, Bn, Cn, Dn and En. Moreover, the synthesized compounds are expressed as viscosity index improvers (VII); The VI rises when prepared additive concentrations in the solution improve, as does the VI as prepared hyperbranched polymers' triethylenetetramine content rises, and the most effective VI is (E). All of the synthesized green hyperbranched nanocomposites have Newtonian rheological behavior as their rheological behavior.

Keywords: green hyperbranched polymer, DLS, viscosity index improver, Michael addition, nano clay

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Authors: Samira Mahmoudkelayeh, Katayoun Taghizade, Mitra Pourvaziri, Elnaz Asadian

Abstract:

Over the recent decades, depletion of resources and environmental concerns made researchers and practitioners present sustainable approaches. Since construction process consumes a great deal of both renewable and non-renewable resources, it is of great significance regarding environmental impacts. Choosing sustainable construction materials is a remarkable strategy presented in many researches and has a significant effect on building’s environmental footprint. This paper represents an assessment framework for selecting best sustainable materials for exterior enclosure in the city of Tehran based on sustainability principles (eco-friendly, cost effective and socio-cultural viable solutions). To perform a comprehensive analysis of environmental impacts, life cycle assessment, a cradle to grave approach is used. A questionnaire survey of construction experts has been conducted to determine the relative importance of criteria. Analytic Network Process (ANP) is applied as a multi-criteria decision-making method to choose sustainable material which consider interdependencies of criteria and sub-criteria. Finally, it prioritizes and aggregates relevant criteria into ultimate assessed score.

Keywords: sustainable materials, building, analytic network process, life cycle assessment

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Authors: Joel Santhosh, N. Bhavani Shankar Rao

Abstract:

Problems associated with construction site have been known for many years. Construction industry has to support a world of continuing population growth and economic development. The rising costs of construction materials and the need to adhere to sustainability, alternative construction techniques and materials are being sought. To increase the applications of concrete paving blocks, greater understanding of products produced with locally available materials and indigenously produced mineral admixtures is essential. In the present investigation, concrete paving blocks may be produced with locally available aggregates, cement, fly ash and waste glass powder as the mineral admixture. The ultimate aim of this work is to ascertain the performance of concrete paving blocks containing fly ash and glass powder and compare it with the performance of conventional concrete paving blocks. Mix design is carried out to form M40 grade of concrete by using IS: 10262: 2009 and specification given by IRC: SP: 63: 2004. The paving blocks are tested in accordance to IS: 15658: 2006. It showed that the partial replacement of cement by fly ash and waste glass powder satisfies the minimum requirement as specified by the Indian standard IS: 15658: 2006 for concrete paving blocks to be used in non traffic, light traffic and medium-heavy traffic areas. The study indicated that fly ash and waste glass powder can effectively be used as cement replacement without substantial change in strength.

Keywords: paving block, fly ash, glass powder, strength, abrasion resistance, durability

Procedia PDF Downloads 275

Authors: R. Santos Jiménez, A. San-Antonio-González, M. del Río Merino, M. González Cortina, C. Viñas Arrebola

Abstract:

On average, Europe generates around 890 million tons of construction and demolition waste (CDW) per year and only 50% of these CDW are recycled. This is far from the objectives determined in the European Directive for 2020 and aware of this situation, the European Countries are implementing national policies to prevent the waste that can be avoidable and to promote measures to increase recycling and recovering. In Spain, one of these measures has been the development of a CDW recycling guide for the manufacture of mortar, concrete, bricks and lightweight aggregates. However, there is still not enough information on the possibility of incorporating CDW materials in the manufacture of gypsum products. In view of the foregoing, the Universidad Politécnica de Madrid is creating a database with information on the possibility of incorporating CDW materials in the manufacture of gypsum products. The objective of this study is to improve this database by analysing the feasibility of incorporating two different CDW in a gypsum matrix: ceramic waste bricks (perforated brick and double hollow brick), and extruded polystyrene (XPS) waste. Results show that it is possible to incorporate up to 25% of ceramic waste and 4% of XPS waste over the weight of gypsum in a gypsum matrix. Furhtermore, with the addition of ceramic waste an 8% of surface hardness increase and a 25% of capillary water absorption reduction can be obtained. On the other hand, with the addition of XPS, a 26% reduction of density and a 37% improvement of thermal conductivity can be obtained.

Keywords: CDW, waste materials, ceramic waste, XPS, construction materials, gypsum

Procedia PDF Downloads 483

Authors: Fedda Y. Alzoubi, Ihsan A. Aljarrah

Abstract:

Silver nanoparticles (AgNPs) are one of the most vital and fascinating nanomaterials among several metallic nanoparticles that are involved in different applications, especially in biomedical applications. Samples of different alkaline water were prepared in order to study the effect of alkalinity of water on the optical properties, size, and morphology of colloidal AgNPs prepared according to the chemical reduction method using the prepared water samples. Ultraviolet-Visible spectrophotometer, Zeta-sizer, and Scanning electron microscope (SEM) have been utilized to carry out this study. Absorption spectra AgNPs in different alkaline water show a surface Plasmon resonance (SPR) peak at the wavelength of 420 nm. The position of this peak is sensitive to the shape of the particles, and in our case, it indicates that the particles are spherical. As the alkalinity increases, the intensity of the SPR peak decreases, indicating the aggregation of particles. Zeta-sizer measurements show that the average diameter for AgNPs in pure water is found to be 53.51 nm, and this value increases as the alkalinity increases. Zeta potential values of samples show that the negatively coated particles are stable in the solution. SEM images insure the spherical shape of the prepared nanoparticles and show that as the alkalinity increases the particles aggregate into larger particles.

Keywords: aggregation, alkalinity, colloid, nanoparticle

Procedia PDF Downloads 106

Authors: Md. Jahidul Islam, A. K. M. Rakinul Islam, M. Salamah Meherier

Abstract:

This study investigates the suitability of using plastic, such as polyethylene terephthalate (PET), as a partial replacement of natural coarse and fine aggregates (for example, brick chips and natural sand) to produce lightweight concrete for load bearing structural members. The plastic coarse aggregate (PCA) and plastic fine aggregate (PFA) were produced from melted polyethylene terephthalate (PET) bottles. Tests were conducted using three different water–cement (w/c) ratios, such as 0.42, 0.48, and 0.57, where PCA and PFA were used as 50% replacement of coarse and fine aggregate respectively. Fresh and hardened properties of concrete have been compared for natural aggregate concrete (NAC), PCA concrete (PCC) and PFA concrete (PFC). The compressive strength of concrete at 28 days varied with the water–cement ratio for both the PCC and PFC. Between PCC and PFC, PFA concrete showed the highest compressive strength (23.7 MPa) at 0.42 w/c ratio and also the lowest compressive strength (13.7 MPa) at 0.57 w/c ratio. Significant reduction in concrete density was mostly observed for PCC samples, ranging between 1977–1924 kg/m³. With the increase in water–cement ratio PCC achieved higher workability compare to both NAC and PFC. It was found that both the PCA and PFA contained concrete achieved the required compressive strength to be used for structural purpose as partial replacement of the natural aggregate; but to obtain the desired lower density as lightweight concrete the PCA is most suited.

Keywords: polyethylene terephthalate, plastic aggregate, concrete, fresh and hardened properties

Procedia PDF Downloads 415