Search results for: surface functionalization of magnetic nanoparticles

Authors: Ahmad Sabry Mohamad, Kai F. Hoettges, Michael Pycraft Hughes

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This study investigates nanowires using Dielectrophoresis (DEP) in non-aqueous suspension of Tin (IV) Oxide (SnO2) nanoparticles dispersed in N,N-dimenthylformamide (DMF). The self assembly of nanowires in DEP impedance spectroscopy can be determined. In this work, dielectrophoretic method was used to measure non-organic molecules for estimating the permittivity and conductivity characteristic of the nanowires. As in aqueous such as salt solution has been dominating the transport of SnO2, which are the wire growth threshold, depend on applied voltage. While DEP assembly of nanowires depend on applied frequency, the applications of dielectrophoretic collection are measured using impedance spectroscopy.

Keywords: dielectrophoresis, impedance spectroscopy, nanowires, N, N-dimenthylformamide, SnO2

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Authors: Nitu Chhikaraa, S. B. Tyagia, Kiran Jainb, Mamta Kharkwala

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The I–III–VI2 semiconductor Nanocrystals such as AgInS2 have great interest for various applications such as optical devices (solar cell and LED), cellular Imaging and bio tagging etc. we synthesized the phase and shape controlled chalcopyrite AgInS2 (AIS) colloidal nanoparticles by thermal decomposition of metal xanthate at low temperature in an organic solvent’s containing surfactant molecules. Here we are focusing on enhancements of photoluminescence of AgInS2 Nps by coating of ZnS at low temperature for application of optical devices. The size of core shell Nps was less than 50nm.by increasing the time and temperature the emission of the wavelength of the Zn coated AgInS2 Nps could be adjusted from visible region to IR the QY of the AgInS2 Nps could be increased by coating of ZnS from 20 to 80% which was reasonably good as compared to those of the previously reported. The synthesized NPs were characterized by PL, UV, XRD and TEM.

Keywords: PL, UV, XRD, TEM

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Authors: B. Sajeena Beevi, P. P. Jose, G. Madhu

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The aim of this study was to obtain the optimal conditions for biogas production from anaerobic digestion of organic fraction of municipal solid waste (OFMSW) using response surface methodology (RSM). The parameters studied were initial pH, substrate concentration and total organic carbon (TOC). The experimental results showed that the linear model terms of initial pH and substrate concentration and the quadratic model terms of the substrate concentration and TOC had significant individual effect (p < 0.05) on biogas yield. However, there was no interactive effect between these variables (p > 0.05). The highest level of biogas produced was 53.4 L/Kg VS at optimum pH, substrate concentration and total organic carbon of 6.5, 99gTS/L, and 20.32 g/L respectively.

Keywords: anaerobic digestion, biogas, optimization, response surface methodology

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Authors: Jessie Rapoza, Petr Moroshkin, Jimmy Xu

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Chirality is omnipresent, in nature, in life, and in the field of physics. One intriguing example is the homochirality that has remained a great secret of life. Another is the pairs of mirror-image molecules – enantiomers. They are identical in atomic composition and therefore indistinguishable in the scalar physical properties. Yet, they can be either therapeutic or toxic, depending on their chirality. Recent studies suggest a potential link between abnormal levels of certain D-amino acids and some serious health impairments, including schizophrenia, amyotrophic lateral sclerosis, and potentially cancer. Although indistinguishable in their scalar properties, the chirality of a molecule reveals itself in interaction with the surrounding of a certain chirality, or more generally, a broken mirror-symmetry. In this work, we report on a system for chiral molecule detection, in which the mirror-symmetry is doubly broken, first by asymmetric structuring a nanopatterned plasmonic surface than by the incidence of circularly polarized light (CPL). In this system, the incident circularly-polarized light induces a surface plasmon polariton (SPP) wave, propagating along the asymmetric plasmonic surface. This SPP field itself is chiral, evanescently bound to a near-field zone on the surface (~10nm thick), but with an amplitude greatly intensified (by up to 104) over that of the incident light. It hence probes just the molecules on the surface instead of those in the volume. In coupling to molecules along its path on the surface, the chiral SPP wave favors one chirality over the other, allowing for chirality detection via the change in an optical rectification current measured at the edges of the sample. The asymmetrically structured surface converts the high-frequency electron plasmonic-oscillations in the SPP wave into a net DC drift current that can be measured at the edge of the sample via the mechanism of optical rectification. The measured results validate these design concepts and principles. The observed optical rectification current exhibits a clear differentiation between a pair of enantiomers. Experiments were performed by focusing a 1064nm CW laser light at the sample - a gold grating microchip submerged in an approximately 1.82M solution of either L-arabinose or D-arabinose and water. A measurement of the current output was then recorded under both rights and left circularly polarized lights. Measurements were recorded at various angles of incidence to optimize the coupling between the spin-momentums of the incident light and that of the SPP, that is, spin-momentum locking. In order to suppress the background, the values of the photocurrent for the right CPL are subtracted from those for the left CPL. Comparison between the two arabinose enantiomers reveals a preferential signal response of one enantiomer to left CPL and the other enantiomer to right CPL. In sum, this work reports on the first experimental evidence of the feasibility of chiral molecule detection via optical rectification in a metal meta-grating. This nanoscale interfaced electrical detection technology is advantageous over other detection methods due to its size, cost, ease of use, and integration ability with read-out electronic circuits for data processing and interpretation.

Keywords: Chirality, detection, molecule, spin

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Authors: Nyeng P. Gyang

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Even though past, current and future trends suggest that multicore and cloud computing systems are increasingly prevalent/ubiquitous, this class of parallel systems is nonetheless underutilized, in general, and barely used for research on employing parallel Delaunay triangulation for parallel surface modeling and generation, in particular. The performances, of actual/physical and virtual/cloud multicore systems/machines, at executing various algorithms, which implement various parallelization strategies of the incremental insertion technique of the Delaunay triangulation algorithm, were evaluated. T-tests were run on the data collected, in order to determine whether various performance metrics differences (including execution time, speedup and efficiency) were statistically significant. Results show that the actual machine is approximately twice faster than the virtual machine at executing the same programs for the various parallelization strategies. Results, which furnish the scalability behaviors of the various parallelization strategies, also show that some of the differences between the performances of these systems, during different runs of the algorithms on the systems, were statistically significant. A few pseudo superlinear speedup results, which were computed from the raw data collected, are not true superlinear speedup values. These pseudo superlinear speedup values, which arise as a result of one way of computing speedups, disappear and give way to asymmetric speedups, which are the accurate kind of speedups that occur in the experiments performed.

Keywords: cloud computing systems, multicore systems, parallel Delaunay triangulation, parallel surface modeling and generation

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Authors: Aliaa M. S. Salem, Soliman I. El-Hout, Amira Gaber, Hassan Nageh

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Nowadays, the development of poisonous gas detectors is considered to be an urgent matter to secure human health and the environment from poisonous gases, in view of the fact that even a minimal amount of poisonous gas can be fatal. Of these concerns, various inorganic or organic sensing materials have been used. Among these are conducting polymers, have been used as the active material in the gassensorsdue to their low-cost,easy-controllable molding, good electrochemical properties including facile fabrication process, inherent physical properties, biocompatibility, and optical properties. Moreover, conducting polymer-based chemical sensors have an amazing advantage compared to the conventional one as structural diversity, facile functionalization, room temperature operation, and easy fabrication. However, the low selectivity and conductivity of conducting polymers motivated the doping of it with varied materials, especially graphene, to enhance the gas-sensing performance under ambient conditions. There were a number of approaches proposed for producing polymer/ graphene nanocomposites, including template-free self-assembly, hard physical template-guided synthesis, chemical, electrochemical, and electrospinning...etc. In this work, we aim to prepare a novel gas sensordepending on Electrospun nanofibers of conducting polymer/RGO composite that is the effective and efficient expectation of poisonous gases like ammonia, in different application areas such as environmental gas analysis, chemical-,automotive- and medical industries. Moreover, our ultimate objective is to maximize the sensing performance of the prepared sensor and to check its recovery properties.

Keywords: electro spinning process, conducting polymer, polyaniline, polypyrrole, polythiophene, graphene oxide, reduced graphene oxide, functionalized reduced graphene oxide, spin coating technique, gas sensors

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Authors: Phakamani Xaba, Robert Huberts, Bilainu Oboirien

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It has been over 200 years since margarine was discovered and manufactured using liquid oil, liquified hardstock oils and other oil phase & aqueous phase ingredients. Henry W. Bradley first used vegetable oils in liquid state and around 1871, since then; spreads have been traditionally manufactured using liquified oils. The main objective of this study was to develop a process method to produce spreads using spray dried hardstock fat powders as a structing fats in place of current liquid structuring fats. A high shear mixing system was used to condition the fat phase and the aqueous phase was prepared separately. Using a single scraped surface heat exchanger and pin stirrer, margarine was produced. The process method was developed for to produce spreads with 40%, 50% and 60% fat . The developed method was divided into three steps. In the first step, fat powders were conditioned by melting and dissolving them into liquid oils. The liquified portion of the oils were at 65 °C, whilst the spray dried fat powder was at 25 °C. The two were mixed using a mixing vessel at 900 rpm for 4 minutes. The rest of the ingredients i.e., lecithin, colorant, vitamins & flavours were added at ambient conditions to complete the fat/ oil phase. The water phase was prepared separately by mixing salt, water, preservative, acidifier in the mixing tank. Milk was also separately prepared by pasteurizing it at 79°C prior to feeding it into the aqueous phase. All the water phase contents were chilled to 8 °C. The oil phase and water phase were mixed in a tank, then fed into a single scraped surface heat exchanger. After the scraped surface heat exchanger, the emulsion was fed in a pin stirrer to work the formed crystals and produce margarine. The margarine produced using the developed process had fat levels of 40%, 50% and 60%. The margarine passed all the qualitative, stability, and taste assessments. The scores were 6/10, 7/10 & 7.5/10 for the 40%, 50% & 60% fat spreads, respectively. The success of the trials brought about differentiated knowledge on how to manufacture spreads using non micronized spray dried fat powders as hardstock. Manufacturers do not need to store structuring fats at 80-90°C and even high in winter, instead, they can adapt their processes to use fat powders which need to be stored at 25 °C. The developed process method used one scrape surface heat exchanger instead of the four to five currently used in votator based plants. The use of a single scraped surface heat exchanger translated to about 61% energy savings i.e., 23 kW per ton of product. Furthermore, it was found that the energy saved by implementing separate pasteurization was calculated to be 6.5 kW per ton of product produced.

Keywords: margarine emulsion, votator technology, margarine processing, scraped sur, fat powders

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Authors: T. J. Jemi Jeya, V. Sriram

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Pile Supported Caisson breakwater is an ecofriendly breakwater very useful in coastal zone protection. The model is developed by considering the advantages of both caisson breakwater and pile supported breakwater, where the top portion is a vertical or quarter circle caisson and the bottom portion consists of a pile supported breakwater defined as Vertical Pile Supported Breakwater (VPSCB) and Quarter-circle Pile Supported Breakwater (QPSCB). The study mainly focuses on comparison of run up over VPSCB and QPSCB under oblique waves. The experiments are carried out in a shallow wave basin under different water depths (d = 0.5 m & 0.55 m) and under different oblique regular waves (0⁰, 15⁰, 30⁰). The run up over the surface is measured by placing two run up probes over the surface at 0.3 m on both sides from the centre of the model. The results show that the non-dimensional shoreward run up shows slight decrease with respect to increase in angle of wave attack.

Keywords: Caisson breakwater, pile supported breakwater, quarter circle breakwater, vertical breakwater

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Authors: G. C. Santini, C. Potrich, L. Lunelli, L. Vanzetti, S. Marasso, M. Cocuzza, C. Pederzolli

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The relevance of circulating miRNAs as non-invasive biomarkers for several pathologies is nowadays undoubtedly clear, as they have been found to have both diagnostic and prognostic value able to add fundamental information to patients’ clinical picture. The availability of these data, however, relies on a time-consuming process spanning from the sample collection and processing to the data analysis. In light of this, strategies which are able to ease this procedure are in high demand and considerable effort have been made in developing Lab-on-a-chip (LOC) devices able to speed up and standardise the bench work. In this context, a very promising polydimethylsiloxane (PDMS)-based microdevice which integrates the processing of the biological sample, i.e. purification of extracellular miRNAs, and reverse transcription was previously developed in our lab. In this study, we aimed at the improvement of the miRNA extraction performances of this micro device by increasing the ability of its surface to absorb extracellular miRNAs from biological samples. For this purpose, we focused on the modulation of two properties of the material: roughness and charge. PDMS surface roughness was modulated by casting with several templates (terminated with silicon oxide coated by a thin anti-adhesion aluminum layer), followed by a panel of curing conditions. Atomic force microscopy (AFM) was employed to estimate changes at the nanometric scale. To introduce modifications in surface charge we functionalized PDMS with different mixes of positively charged 3-aminopropyltrimethoxysilanes (APTMS) and neutral poly(ethylene glycol) silane (PEG). The surface chemical composition was characterized by X-ray photoelectron spectroscopy (XPS) and the number of exposed primary amines was quantified with the reagent sulfosuccinimidyl-4-o-(4,4-dimethoxytrityl) butyrate (s-SDTB). As our final end point, the adsorption rate of all these different conditions was assessed by fluorescence microscopy by incubating a synthetic fluorescently-labeled miRNA. Our preliminary analysis identified casting on thermally grown silicon oxide, followed by a curing step at 85°C for 1 hour, as the most efficient technique to obtain a PDMS surface roughness in the nanometric scaleable to trap miRNA. In addition, functionalisation with 0.1% APTMS and 0.9% PEG was found to be a necessary step to significantly increase the amount of microRNA adsorbed on the surface, therefore, available for further steps as on-chip reverse transcription. These findings show a substantial improvement in the extraction efficiency of our PDMS microdevice, ultimately leading to an important step forward in the development of an innovative, easy-to-use and integrated system for the direct purification of less abundant circulating microRNAs.

Keywords: circulating miRNAs, diagnostics, Lab-on-a-chip, polydimethylsiloxane (PDMS)

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Authors: Elsayed G. Zaki, Nora A. Hamad, Hadeel G. El-Shorbagy

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The effect of watermelon rind extract as green inhibitors for the formation of calcium sulphate scale have been investigated using conductivity measurements concurrently with the scanning electron microscopy (SEM), and optical microscopic examinations. Mineral scales were deposited from the brine solution by cathodic polarization of the steel surface. The results show up that the anti-scaling property of the extracts could be attributed to the presence of citrulline. In solution, citrulline retards calcium sulphate precipitation via formation of a complex with the calcium cations. Thin, smooth and non adherent film formed over the steel surface, under cathodic polarization, by the deposition of the calcium- citrulline complex. The stability of the aqueous extracts with time was also investigated.

Keywords: anti-scaling, scale inhibitor, green extracts, water treatment

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Authors: Irene Carmagnola, Valeria Chiono, Sandra Pacharra, Jochen Salber, Sean McMahon, Chris Lovell, Pooja Basnett, Barbara Lukasiewicz, Ipsita Roy, Xiang Zhang, Gianluca Ciardelli

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Thrombosis and restenosis after stenting procedure can be prevented by promoting fast stent wall endothelialisation. It is well known that surface functionalisation with antifouling molecules combining with extracellular matrix proteins is a promising strategy to design biomimetic surfaces able to promote fast endothelialization. In particular, REDV has gained much attention for the ability to enhance rapid endothelialization due to its specific affinity with endothelial cells (ECs). In this work, a two-step plasma treatment was performed to polymerize a thin layer of acrylic acid, used to subsequently graft PEGylated-REDV and polyethylene glycol (PEG) at different molar ratio with the aim to selectively promote endothelial cell adhesion avoiding platelet activation. PEGylate-REDV was provided by Biomatik and it is formed by 6 PEG monomer repetitions (Chempep Inc.), with an NH2 terminal group. PEG polymers were purchased from Chempep Inc. with two different chain lengths: m-PEG6-NH2 (295.4 Da) with 6 monomer repetitions and m-PEG12-NH2 (559.7 Da) with 12 monomer repetitions. Plasma activation was obtained by operating at 50W power, 5 min of treatment and at an Ar flow rate of 20 sccm. Pure acrylic acid (99%, AAc) vapors were diluted in Ar (flow = 20 sccm) and polymerized by a pulsed plasma discharge applying a discharge RF power of 200 W, a duty cycle of 10% (on time = 10 ms, off time = 90 ms) for 10 min. After plasma treatment, samples were dipped into an 1-(3-dimethylaminopropyl)-3- ethylcarbodiimide (EDC)/N-hydroxysuccinimide (NHS) solution (ratio 4:1, pH 5.5) for 1 h at 4°C and subsequently dipped in PEGylate-REDV and PEGylate-REDV:PEG solutions at different molar ratio (100 μg/mL in PBS) for 20 h at room temperature. Surface modification was characterized through physico-chemical analyses and in vitro cell tests. PEGylated-REDV peptide and PEG were successfully bound to the carboxylic groups that are formed on the polymer surface after plasma reaction. FTIR-ATR spectroscopy, X -ray Photoelectron Spectroscopy (XPS) and contact angle measurement gave a clear indication of the presence of the grafted molecules. The use of PEG as a spacer allowed for an increase in wettability of the surface, and the effect was more evident by increasing the amount of PEG. Endothelial cells adhered and spread well on the surfaces functionalized with the REDV sequence. In conclusion, a selective coating able to promote a new endothelial cell layer on polymeric stent surface was developed. In particular, a thin AAc film was polymerised on the polymeric surface in order to expose –COOH groups, and PEGylate-REDV and PEG were successful grafted on the polymeric substrates. The REDV peptide demonstrated to encourage cell adhesion with a consequent, expected improvement of the hemocompatibility of these polymeric surfaces in vivo. Acknowledgements— This work was funded by the European Commission 7th Framework Programme under grant agreement number 604251- ReBioStent (Reinforced Bioresorbable Biomaterials for Therapeutic Drug Eluting Stents). The authors thank all the ReBioStent partners for their support in this work.

Keywords: endothelialisation, plasma treatment, stent, surface functionalisation

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Authors: C. Paglia, C. Mosca

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Synthetic resin floorsare often used in sport infrastructure. These organic materials are often in contact with a bituminous substrate, which in turn is placed on the ground. In this work, the damage of a basket resin field surface was characterized by means of visual inspection, optical microscopy, resin thickness measurements, adhesion strength, water vapor transmission capacity, capillary water adsorption, granulometry of the bituminous conglomerate, the surface properties, and the water ground infiltration speed. The infiltration speed indicates water pemeability. This was due to its composition: clean sand mixed with gravel. Relatively good adhesion was present between the synthetic resin and the bituminous layer. The adhesion resistance of the bituminous layer was relatively low. According to the required bitumoniousasphalt-concrete mixes AC 11 S, the placed material was more porous. Insufficient constipation was present. The spaces values were above the standard limits, while the apparent densities were lower compared to the conventional AC 11 mixtures. The microstructure outlines the high permeability and porosity of the bituminous layer. The synthetic resin wasvapourproof and did not exhibit capillary adsorption. It exhibited a lower thickness as required, and no multiple placing steps were observed. Multiple cavities were detected along with the interface between the bituminous layer and the resin coating with no intermediate layers. The layer for the pore filling in the bituminous surface was not properly applied. The swelling bubbles on the synthetic pavement were caused by the humidity in the bituminous layer. Water or humidity were present prior to the application of the resin, and the effect was worsened by the upward movement of the water from the ground.

Keywords: resin, floor, damage, durability

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Authors: Nouf Alharbi, James O'shea

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For decades, renewable energy sources have received considerable global interest due to the increase in fossil fuel consumption. The abundant energy produced by sunlight makes dye-sensitised solar cells (DSSCs) a promising alternative compared to conventional silicon and thin film solar cells due to their transparency and tunable colours, which make them suitable for applications such as windows and glass facades. The transfer of an excited electron onto the surface is an important procedure in the DSSC system, so different groups of dye molecules were studied on the rutile TiO2 (110) surface. Currently, the study of organic dyes has become an interest of researchers due to ruthenium being a rare and expensive metal, and metal-free organic dyes have many features, such as high molar extinction coefficients, low manufacturing costs, and ease of structural modification and synthesis. There are, of course, some groups that have developed organic dyes and exhibited lower light-harvesting efficiency ranging between 4% and 8%. Since most dye molecules are complicated or fragile to be deposited by thermal evaporation or sublimation in the ultra-high vacuum (UHV), all dyes (i.e, D5, SC4, and R6) in this study were deposited in situ using the electrospray deposition technique combined with X-ray photoelectron spectroscopy (XPS) as an alternative method to obtain high-quality monolayers of titanium dioxide. These organic molecules adsorbed onto rutile TiO2 (110) are explored by XPS, which can be used to obtain element-specific information on the chemical structure and study bonding and interaction sites on the surface.

Keywords: dyes, deposition, electrospray, molecules, organic, rutile, sensitised, XPS

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Authors: S. Al-Sowayan

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Rogowski coils are increasingly used for measurement of AC and transient electric currents. Mostly used Rogowski coils now are with circular or rectangular cores. In order to increase the sensitivity of the measurement of Rogowski coil and perform smooth wire winding, this paper studies the effect of increasing the mutual inductance in order to increase the coil sensitivity by presenting the calculation and simulation of a Rogowski coil with equilateral hexagonal shaped core and comparing the resulted mutual inductance with commonly used core shapes.

Keywords: Rogowski coil, mutual inductance, magnetic flux density, communication engineering

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Authors: Amir Gerayeli, Babak Moradi

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The continuously declining oil reservoirs and reservoirs aging have created a huge demand for utilization of Enhanced Oil Recovery (EOR) methods recently. Primary and secondary oil recovery methods have various limitations and are not practical for all reservoirs. Therefore, it is necessary to use chemical methods to improve oil recovery efficiency by reducing oil and water surface tension, increasing sweeping efficiency, and reducing displacer phase viscosity. One of the well-known methods of oil recovery is Alkaline-Surfactant-Polymer (ASP) flooding that shown to have significant impact on enhancing oil recovery. As some of the biggest oil reservoirs including those of Iran’s are fractional reservoirs with substantial amount of trapped oil in their fractures, the use of Alkaline-Surfactant-Polymer (ASP) flooding method is increasingly growing, the method in which the impact of several parameters including type and concentration of the Alkaline, Surfactant, and polymer are particularly important. This study investigated the use of Nano particles to improve Enhanced Oil Recovery (EOR). The study methodology included performing several laboratory tests on drill cores extracted from Karanj Oil field Asmary Formation in Khuzestan, Iran. In the experiments performed, Sodium dodecyl benzenesulfonate (SDBS) and 1-dodecyl-3-methylimidazolium chloride ([C12mim] [Cl])) were used as surfactant, hydrolyzed polyacrylamide (HPAM) and guar gum were used as polymer, Sodium hydroxide (NaOH) as alkaline, and Silicon dioxide (SiO2) and Magnesium oxide (MgO) were used as Nano particles. The experiment findings suggest that water viscosity increased from 1 centipoise to 5 centipoise when hydrolyzed polyacrylamide (HPAM) and guar gum were used as polymer. The surface tension between oil and water was initially measured as 25.808 (mN/m). The optimum surfactant concentration was found to be 500 p, at which the oil and water tension surface was measured to be 2.90 (mN/m) when [C12mim] [Cl] was used, and 3.28 (mN/m) when SDBS was used. The Nano particles concentration ranged from 100 ppm to 1500 ppm in this study. The optimum Nano particle concentration was found to be 1000 ppm for MgO and 500 ppm for SiO2.

Keywords: alkaline-surfactant-polymer, ionic liquids, relative permeability, reduced surface tension, tertiary enhanced oil recovery, wettability change

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Authors: Nesrine Benarous, Hassiba Bougueria, Nabila Moussa Slimane, Aouatef Cherouana

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Crystal polymorphism is important for the synthesis of more potent and bioactive pharmaceutical compounds, including their different properties, such as packing arrangement and conformation. In fact, polymorphism plays a vital role in drug development. Different parameters affect the crystallization and give their degree of freedom. Severalproperties affected polymorphism, like kinetics, thermodynamics, spectroscopy, and mechanical property. Various techniques are used for characterizing polymorphs, are crystallography, morphology, phase transitions, molecular motion, and chemical environment. In this work, crystal structures of two polymorphs (I and II) of the Schiff base (SB) title compound were prepared by condensation reaction. The crystal structures of both polymorphs were determined by single X-ray analysis. The two polymorphs crystallize in two different space groups: P21/c for I and Pbca for II. The dihedral angles between the two phenyl rings are 4.81º for I and 82.27º for II. Both crystal structures are built on the basis of moderate and weak hydrogen bonds, 𝜋-stacking, and halogen⋯halogeninteractions. On the other hand, Hirshfeld surface (HS) analysis indicates that the most important contributions to the crystal packing for the two polymorphs are from Cl⋯H/H⋯Cl, H⋯H, and N⋯H/H⋯N contacts. These are followed by C⋯H/H⋯C for compound I and C⋯C and by C⋯H/H⋯C contacts for compound II. Afterwards, the in vitro antibacterial activity revealed that the SB have been found effective against G- bacteria Klebsiella pneumonia andG+ bacteria Staphylococcus aureuswith MIC value of14.37μg/mL. Moreover, the SBexhibited moderate toxicity against Brine Shrimp with LC50 value of 44.19μg/mL.

Keywords: polymorph, crystal structure, hirshfeld surface analysis, in vitro antibacterial activity, toxicity

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Authors: Abdul Mutalib Md Jani, Abdul Hadi Mahmud, Mohd Tajuddin Mohd Ali

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The rapid growth of interest in surface modification of nanostructures materials that exhibit improved structural and functional properties is attracting more researchers. The unique properties of highly ordered nanoporous anodic aluminium oxide (NAAO) membrane have been proposed as a platform for biosensing applications. They exhibit excellent physical and chemical properties with high porosity, high surface area, tunable pore sizes and excellent chemical resistance. In this study, NAAO was functionalized with 3-aminopropyltriethoxysilane (APTES) to prepared silane-modified NAAO. Amine functional groups are formed on the surface of NAAO during silanization and were characterized using Fourier Transform Infrared spectroscopy (FTIR). The synthesis of multi segment of peptide on NAAO surfaces can be realized by changing the surface chemistry of the NAAO membrane via click chemistry. By click reactions, utilizing alkyne terminated with amino group, various peptides tagged on NAAO can be envisioned from chiral natural or unnatural amino acids using standard coupling methods (HOBt, EDCI and HBTU). This strategy seemly versatile since coupling strategy of dipeptide with another amino acids, leading to tripeptide, tetrapeptide or pentapeptide, can be synthesized without purification. When an appropriate terminus is selected, multiple segments of amino acids can be successfully synthesized on the surfaces. The immobilized NAAO should be easily separated from the reaction medium by conventional filtration, thus avoiding complicated purification methods. Herein, we proposed to synthesize multi fragment peptide as a model for capturing and attaching various small biomolecules on NAAO surfaces and can be also applied as biosensing device, drug delivery systems and biocatalyst.

Keywords: nanoporous anodic aluminium oxide, silanization, peptide synthesise, click chemistry

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Authors: A. Errasti, F. Doffagne, O. Foucrier, S. Kao, A. Meigne, H. Pellae, T. Rouland

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Renewable energy recovery is an important domain of research in past few years in view of protection of our ecosystem. Several industrial companies are setting up widespread recovery systems to exploit wave energy. Most of them have a large size, are implanted near the shores and exploit current flows. However, as oceans represent 70% of Earth surface, a huge space is still unexploited to produce energy. Present analysis focuses on surface small scale wave energy recovery. The principle is exactly the opposite of wheel damper for a car on a road. Instead of maintaining the car body as non-oscillatory as possible by adapted control, a system is designed so that its oscillation amplitude under wave action will be maximized with respect to a boat carrying it in view of differential potential energy recuperation. From parametric analysis of system equations, interesting domains have been selected and expected energy output has been evaluated.

Keywords: small scale wave, potential energy, optimized energy recovery, auto-adaptive system

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Authors: István Patkó, Hosam Bayoumi Hamuda, András Szeder

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In order to efficiently solve the problems created by the deepening energy crisis affecting Europe and the world, governments cannot neglect the opportunities of using the energy produced by sun collectors. In many of the EU countries there are sun collectors producing heat energy, e.g. in 2011 in the area of EU27 (countries which belong to European Union) + Switzerland altogether 37519126 m2 were operated, which are capable of producing 26.3 GWh heat energy. The energy produced by these sun collectors is utilized at the place of production. In the near future governments will have to focus more on spreading and using sun collectors. Among the complex problems of operating sun collectors, this article deals with determining the optimal tilt angle, directions of sun collectors. We evaluate the contamination of glass surface of sun collector to the produced energy. Our theoretically results are confirmed by laboratory measurements. The purpose of our work is to help users and engineers in determination of optimal operation parameters of sun collectors.

Keywords: heat energy, tilt angle, direction of sun collector, contamination of surface

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Authors: Mirabbos Mirkamalov, Zavkiddin Mirtoshev

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The M 1.6 class flare occurred on 6^th of September 2012. Our observations correspond to the active region NOAA 11560 with the heliographic coordinates N04W71. The event took place between 04:00 UT and 04:45 UT, and was close to the solar limb at the western region. The flare temperature correlates with flux peak, increases for a short period (between 04:08 UT and 04:12 UT), rises impulsively, attains a maximum value of about 17 MK at 04:12 UT and gradually decreases after peak value. Around the peak we observe significant emissions of X-ray sources. Flux profiles of the X-ray emission exhibit a progressively faster raise and decline as the higher energy channels are considered.

Keywords: magnetic reconnection, solar atmosphere, solar flare, X-ray emission

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Authors: Noboru Wakamoto, Kiyotaka Obunai, Kazuya Okubo, Toru Fujii

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The aim of this study is to moderate the dependence of counter frictional coefficient on temperature between counter surfaces and to reduce the wear of C/C composites at low temperature. To modify the C/C composites, Silica (SiO₂) powders were added into phenolic resin for carbon precursor. The preform plate of the precursor of C/C composites was prepared by conventional filament winding method. The C/C composites plates were obtained by carbonizing preform plate at 2200 °C under an argon atmosphere. At that time, the silicon carbides (SiC) were synthesized around the surfaces and the internal vacancies of the C/C composites. The frictional coefficient on the counter surfaces and specific wear volumes of the C/C composites were measured by our developed frictional test machine like pin-on disk type. The XRD indicated that SiC was synthesized in the body of C/C composite fabricated by current method. The results of friction test showed that coefficient of friction of unmodified C/C composites have temperature dependence when the test condition was changed. In contrast, frictional coefficient of the C/C composite modified with SiO₂ powders was almost constant at about 0.27 when the temperature condition was changed from Room Temperature (RT) to 300 °C. The specific wear rate decreased from 25×10^-6 mm²/N to 0.1×10^-6 mm²/N. The observations of the surfaces after friction tests showed that the frictional surface of the modified C/C composites was covered with a film produced by the friction. This study found that synthesizing SiC around surface and internal vacancies of C/C composites was effective to moderate the dependence on the frictional coefficient and reduce to the abrasion of C/C composites.

Keywords: C/C composites, friction coefficient, wear, SiC

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Authors: Albina V. Moskvicheva, Gevorg G. Kazarian, Anna R. Valeeva, Marina A. Efimova, Malik N. Mukminov, Eduard A. Shuralev, Rustam Kh. Ravilov, Kamil S. Khaertynov

Abstract:

Improving the early diagnosis of tuberculosis and solving a number of problems associated with the differential diagnosis of Mycobacterium bovis infection, nonspecific tuberculin reactions caused by sensitization of the body by non-tuberculosis mycobacteria, is urgent. The filtrates and extracts of M. bovis cell surface components are promising antigens with diagnostic potential. The purpose of this study was to isolate and characterize antigenic proteins and determine the dominant M. bovis antigens recognized by the humoral immune system. The mycobacterial cells were homogenized on FastPrep-24. Gel-filtration chromatography was used to fractionate the lysates of cell surface component extracts and proteins isolated from M. bovis culture supernatant. The separated fractions were analyzed using two-dimensional gel electrophoresis followed by determination of antigen serological activity using immunoblot with specific hyperimmune rabbit blood serum. As a result of electrophoretic separation of components by molecular weight, 23 antigen fractions were obtained. Analysis of densitograms showed that the fractions contained two zones of antigens with pronounced serological activity, corresponding to molecular weights of 28 and 21 kDa. The high serological activity of the 28 kDa antigen was established by immunoblot using hyperimmune blood sera. Separated and characterized by M. bovis specific antigen with a molecular weight of 28 kDa was added to the collection of specific marker antigens for M. bovis.

Keywords: antigen, gel-filtration chromatography, immunoblot, Mycobacterium bovis

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Authors: Fadwa Haraka, Ahmad Elouatouati, Mourad Taha Janan

Abstract:

In this study, we propose a neural network based method in order to calculate the heat source temperature of isotropic plate with lower surface forced cooling. To validate the proposed model, the heat source temperatures values will be compared to the analytical method -variables separation- and finite element model. The mathematical simulation is done through 3D numerical simulation by COMSOL software considering three different materials: Aluminum, Copper, and Graphite. The proposed method will lead to a formulation of the heat source temperature based on the thermal and geometric properties of the base plate.

Keywords: thermal model, thermal resistance, finite element simulation, neural network

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Authors: Majid Haghshenas, James Wilson, Ranganathan Kumar

Abstract:

In this study, an Algebraic Coupled Level Set-Volume of Fluid (A-CLSVOF) method with capillary pressure treatment is proposed for the modeling of two-phase capillary flows. The Volume of Fluid (VOF) method is utilized to incorporate one-way coupling with the Level Set (LS) function in order to further improve the accuracy of the interface curvature calculation and resulting surface tension force. The capillary pressure is determined and treated independently of the hydrodynamic pressure in the momentum balance in order to maintain consistency between cell centered and interpolated values, resulting in a reduction in parasitic currents. In this method, both VOF and LS functions are transported where the new volume fraction determines the interface seed position used to reinitialize the LS field. The Hamilton-Godunov function is used with a second order (in space and time) discretization scheme to produce a signed distance function. The performance of the current methodology has been tested against some common test cases in order to assess the reduction in non-physical velocities and improvements in the interfacial pressure jump. The cases of a static drop, non-linear Rayleigh-Taylor instability and finally a droplets impact on a liquid pool were simulated to compare the performance of the present method to other well-known methods in the area of parasitic current reduction, interface location evolution and overall agreement with experimental results.

Keywords: two-phase flow, capillary flow, surface tension force, coupled LS with VOF

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Authors: M. S. M. Prahastomi, Riki Sunaryo, Lorasa Ximanes

Abstract:

The research takes place in EP Area, in the Northern part of Buton, Southeast Sulawesi Province, Indonesia. It is one example of karst areas that have good water resources potential. The landscape is in the form of valleys and hills which is good enough for recharge zone and discharge zones of groundwater. However, the geological characteristics of karst dissolution and a complex geological structure are quite influential to the groundwater flow system in the region. The Discharge of groundwater to the surface can be caused by a fracture in the rock, Underground River due to dissolution, and the contact between permeable rocks with impermeable rocks. In the concept of hydrogeology, groundwater is one of the components of the hydrological cycle which is closely linked to the availability of water under the surface, precipitation, infiltration, percolation, evapotranspiration, and surface runoff. Conceptually, the condition of recharge and discharge areas can be identified through a research distribution springs in a region. The understanding of the condition and the nature of the potential catchment area of groundwater flow, mainly from the catchment area to the discharge area, is urgently needed. This research aimed to assess the general geological conditions of the study area, which is expected to provide an overview of groundwater flow events that used by the public as well as industry. Behavioral characteristics of groundwater become an integral part in the search for potential groundwater in the study area. As for the research methods used hydrogeology mapping and laboratory works.

Keywords: Buton Island, groundwater conservation, hydrogeochemistry preliminary, karst

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Authors: S. Divya, M. Jose

Abstract:

Over the past years, industrial dyes have emerged as a significant threat to aquatic life, extensively detected in drinking water and groundwater, thus contributing to water pollution due to their improper and excessive use. To address this issue, the utilization of core-shell structures has been prioritized as it demonstrates remarkable efficiency in utilizing light energy for catalytic reactions and exhibiting excellent photocatalytic activity despite the availability of various photocatalysts. This work focuses on the photocatalytic degradation of Nd₂O₃@SiO₂ CSNs under UV light irradiation against MB and RhB dyes. Different characterization techniques, including XRD, FTIR, and TEM analyses, were employed to reveal the material's structure, functional groups, and morphological features. VSM and XPS analyses confirmed the soft, paramagnetic nature and chemical states with respective atomic percentages, respectively. Optical band gaps, determined using the Tauc plot model, indicated 4.24 eV and 4.13 eV for Nd₂O₃ NPs and Nd₂O₃@SiO₂ CSNs, respectively. The reduced bandgap energy of Nd₂O₃@SiO₂ CSNs enhances light absorption in the UV range, potentially leading to improved photocatalytic efficiency. The Nd₂O₃@SiO₂ CSNs exhibited greater degradation efficiency, reaching 95% and 96% against MB and RhB dyes, while Nd₂O₃ NPs showed 90% and 92%, respectively. The enhanced efficiency of Nd₂O₃@SiO₂ CSNs can be attributed to the larger specific surface area provided by the SiO₂ shell, as confirmed by surface area analysis using the BET surface area analyzer through N₂ adsorption-desorption.

Keywords: core shell nanocomposites, rare earth oxides, photocatalysis, advanced oxidation process

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Authors: Moshe Mello, Hilary Rutto, Tumisang Seodigeng

Abstract:

The adsorptive ability of different carbon materials, tire char (TC), demineralized tire char (DTC), activated tire char (ATC) and Aldrich supplied commercial activated carbon (CAC) was studied for desulfurization of tire pyrolytic oil (TPO). TPO with an initial sulfur content of 7767.7 ppmw was used in this present study. Preparation of ATC was achieved by chemical treatment of raw TC using a potassium hydroxide (KOH) solution and subsequent activation at 800°C in the presence of nitrogen. The thermal behavior of TC, surface microstructure, and the surface functional groups of the carbon materials was investigated using TGA, SEM, and FTIR, respectively. Adsorptive desulfurization of TPO using the carbon materials was performed and they performed in the order of CAC>ATC>DTC>TC. Adsorption kinetics were studied, and pseudo-first order kinetic model displayed a better fit compared to pseudo-second order model. For isotherm studies, the Freundlich isotherm model fitted to the equilibrium data better than the Langmuir isotherm model.

Keywords: ATC, desulfurization, pyrolysis, tire, TPO

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Authors: Rekab Djabri Hamza, Daoud Salah

Abstract:

We report first-principles calculations of structural and magnetic properties of TmAs compound in zinc blende(B3) and CsCl(B2), structures employing the density functional theory (DFT) within the local density approximation (LDA). We use the full potential linear muffin-tin orbitals (FP-LMTO) as implemented in the LMTART-MINDLAB code (Calculation). Results are given for lattice parameters (a), bulk modulus (B), and its first derivatives(B’) in the different structures NaCl (B1) and CsCl (B2). The most important result in this work is the prediction of the possibility of transition; from cubic rocksalt (NaCl)→ CsCl (B2) (32.96GPa) for TmAs. These results use the LDA approximation.

Keywords: LDA, phase transition, properties, DFT

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Authors: Jasim Uddin, Rod Smith, Malcolm Gillies

Abstract:

Surface irrigation is the most popular irrigation method all over the world. However, two issues: low efficiency and huge labour involvement concern irrigators due to scarcity in recent years. To address these issues, a smart automated furrow is conceptualised that can be operated using digital devices like smartphone, iPad or computer and a preliminary evaluation was conducted in this study. The smart automated system is the integration of commercially available software and hardware. It includes real-time surface irrigation optimisation software (SISCO) and Rubicon Water’s surface irrigation automation hardware and software. The automated system consists of automatic water delivery system with 300 mm flexible pipes attached to both sides of a remotely controlled valve to operate the irrigation. A water level sensor to obtain the real-time inflow rate from the measured head in the channel, advance sensors to measure the advance time to particular points of an irrigated field, a solar-powered telemetry system including a base station to communicate all the field sensors with the main server. On the basis of field data, the software (SISCO) is optimised the ongoing irrigation and determine the optimum cut-off for particular irrigation and send this information to the control valve to stop the irrigation in a particular (cut-off) time. The preliminary evaluation shows that the automated surface irrigation worked reasonably well without manual intervention. The evaluation of farmers managed irrigation events show the potentials to save a significant amount of water and labour. A substantial amount of economic and social benefits are expected in rural industries by adopting this system. The future outcome of this work would be a fully tested commercial adaptive real-time furrow irrigation system able to compete with the pressurised alternative of centre pivot or lateral move machines on capital cost, water and labour savings but without the massive energy costs.

Keywords: furrow irrigation, smart automation, infiltration, SISCO, real-time irrigation, adoptive control

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Authors: Anna Strąkowska, Marian Zaborski

Abstract:

The studies were focused on POSS application with methylvinylsilicone rubber (MVQ). The obtained results indicate that they can be successfully incorporated into silica-filled rubbers as modifying agents since they enhance cross-link density and improve most properties of the resulting network. It is also worth noting that the incorporation of POSS molecules resulted in stabilizing effect against adverse changes induced by the climatic, ozone or UV ageing of the rubbers. Furthermore, we obtained interesting results of rubbers surface modification using POSS functionalised with halogen groups (Cl, F, and Br). As the results, surface energy of the elastomeric composites and their hydrophobicity increased, barrier properties improved and thermal stability increased as well. Additionally, the studies with silicone rubber and POSS containing acidic and alkaline groups revealed composites with self-healing properties. The observed effects strictly depend on a kind and quantity of functional groups present in angles of POSS cages.

Keywords: elastomeric composites, POSS, properties modyfication, silicone rubber

Procedia PDF Downloads 355