Search results for: sodium carbonate surface

Authors: Pola Goldberg Oppenheimer, Stephan Hofmann, Sumeet Mahajan

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Owing to its fingerprint molecular specificity and high sensitivity, surface-enhanced Raman scattering (SERS) is an established analytical tool for chemical and biological sensing capable of single-molecule detection. A strong Raman signal can be generated from SERS-active platforms given the analyte is within the enhanced plasmon field generated near a noble-metal nanostructured substrate. The key requirement for generating strong plasmon resonances to provide this electromagnetic enhancement is an appropriate metal surface roughness. Controlling nanoscale features for generating these regions of high electromagnetic enhancement, the so-called SERS ‘hot-spots’, is still a challenge. Significant advances have been made in SERS research, with wide-ranging techniques to generate substrates with tunable size and shape of the nanoscale roughness features. Nevertheless, the development and application of SERS has been inhibited by the irreproducibility and complexity of fabrication routes. The ability to generate straightforward, cost-effective, multiplex-able and addressable SERS substrates with high enhancements is of profound interest for miniaturised sensing devices. Carbon nanotubes (CNTs) have been concurrently, a topic of extensive research however, their applications for plasmonics has been only recently beginning to gain interest. CNTs can provide low-cost, large-active-area patternable substrates which, coupled with appropriate functionalization capable to provide advanced SERS-platforms. Herein, advanced methods to generate CNT-based SERS active detection platforms will be discussed. First, a novel electrohydrodynamic (EHD) lithographic technique will be introduced for patterning CNT-polymer composites, providing a straightforward, single-step approach for generating high-fidelity sub-micron-sized nanocomposite structures within which anisotropic CNTs are vertically aligned. The created structures are readily fine-tuned, which is an important requirement for optimizing SERS to obtain the highest enhancements with each of the EHD-CNTs individual structural units functioning as an isolated sensor. Further, gold-functionalized VACNTFs are fabricated as SERS micro-platforms. The dependence on the VACNTs’ diameters and density play an important role in the Raman signal strength, thus highlighting the importance of structural parameters, previously overlooked in designing and fabricating optimized CNTs-based SERS nanoprobes. VACNTs forests patterned into predesigned pillar structures are further utilized for multiplex detection of bio-analytes. Since CNTs exhibit electrical conductivity and unique adsorption properties, these are further harnessed in the development of novel chemical and bio-sensing platforms.

Keywords: carbon nanotubes (CNTs), EHD patterning, SERS, vertically aligned carbon nanotube forests (VACNTF)

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Authors: Nassima Hamzaoui, Mostefa Ghamnia

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Nanoscale thin films of pure and Mn-doped Nickel oxide (NiO) were prepared by dissolving nickel chloride hexahydrate (NiCl2, 6H2O) and manganese chloride tetrahydrate (MnCl2,4H2O) under experimental conditions. The resulting solution was stirred at room temperature for 30 OC minutes in order to obtain homogeneity. The solution was sprayed onto heated glass substrates. The films obtained were characterized by X-ray diffraction to verify crystallinity. Atomic force microscopy (AFM) reveals surface topographical structure. UV-visible spectroscopy shows good transparency of the NiO layers.

Keywords: films, NiO, AFM, X-ray diffraction

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Authors: İsmail Kavdır, M. Burak Büyükcan, Ferhat Kurtulmuş

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Table olive is a valuable product especially in Mediterranean countries. It is usually consumed after some fermentation process. Defects happened naturally or as a result of an impact while olives are still fresh may become more distinct after processing period. Defected olives are not desired both in table olive and olive oil industries as it will affect the final product quality and reduce market prices considerably. Therefore it is critical to sort table olives before processing or even after processing according to their quality and surface defects. However, doing manual sorting has many drawbacks such as high expenses, subjectivity, tediousness and inconsistency. Quality criterions for green olives were accepted as color and free of mechanical defects, wrinkling, surface blemishes and rotting. In this study, it was aimed to classify fresh table olives using different classifiers and NIR spectroscopy readings and also to compare the classifiers. For this purpose, green (Ayvalik variety) olives were classified based on their surface feature properties such as defect-free, with bruised defect and with fly defect using FT-NIR spectroscopy and classification algorithms such as artificial neural networks, ident and cluster. Bruker multi-purpose analyzer (MPA) FT-NIR spectrometer (Bruker Optik, GmbH, Ettlingen Germany) was used for spectral measurements. The spectrometer was equipped with InGaAs detectors (TE-InGaAs internal for reflectance and RT-InGaAs external for transmittance) and a 20-watt high intensity tungsten–halogen NIR light source. Reflectance measurements were performed with a fiber optic probe (type IN 261) which covered the wavelengths between 780–2500 nm, while transmittance measurements were performed between 800 and 1725 nm. Thirty-two scans were acquired for each reflectance spectrum in about 15.32 s while 128 scans were obtained for transmittance in about 62 s. Resolution was 8 cm⁻¹ for both spectral measurement modes. Instrument control was done using OPUS software (Bruker Optik, GmbH, Ettlingen Germany). Classification applications were performed using three classifiers; Backpropagation Neural Networks, ident and cluster classification algorithms. For these classification applications, Neural Network tool box in Matlab, ident and cluster modules in OPUS software were used. Classifications were performed considering different scenarios; two quality conditions at once (good vs bruised, good vs fly defect) and three quality conditions at once (good, bruised and fly defect). Two spectrometer readings were used in classification applications; reflectance and transmittance. Classification results obtained using artificial neural networks algorithm in discriminating good olives from bruised olives, from olives with fly defect and from the olive group including both bruised and fly defected olives with success rates respectively changing between 97 and 99%, 61 and 94% and between 58.67 and 92%. On the other hand, classification results obtained for discriminating good olives from bruised ones and also for discriminating good olives from fly defected olives using the ident method ranged between 75-97.5% and 32.5-57.5%, respectfully; results obtained for the same classification applications using the cluster method ranged between 52.5-97.5% and between 22.5-57.5%.

Keywords: artificial neural networks, statistical classifiers, NIR spectroscopy, reflectance, transmittance

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Authors: Okba Belahssen, Said Benramache

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This paper presents wear behavior of the plasma-nitrided 20MnCr5 steel. Untreated and plasma nitrided samples were tested. The morphology was observed by scanning electron microscopy (SEM). The plasma nitriding behaviors of 20MnCr5 steel have been assessed by evaluating tribological properties and surface hardness by using a pin-on-disk wear machine and microhardness tester. Experimental results showed that the nitrides ε-Fe2−3N and γ′-Fe4N present in the white layer improve the wear resistance.

Keywords: plasma-nitriding, alloy 20mncr5, steel, friction, wear

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Authors: Usama Massoud, Abeer A. Kenawy, El-Said A. Ragab, Abbas M. Abbas, Heba M. El-Kosery

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Vertical Electrical Sounding (VES) and Transient Electro Magnetic (TEM) survey have been applied for characterizing the groundwater aquifers at El Sadat industrial area. El-Sadat city is one of the most important industrial cities in Egypt. It has been constructed more than three decades ago at about 80 km northwest of Cairo along the Cairo–Alexandria desert road. Groundwater is the main source of water supplies required for domestic, municipal, and industrial activities in this area due to the lack of surface water sources. So, it is important to maintain this vital resource in order to sustain the development plans of this city. In this study, VES and TEM data were identically measured at 24 stations along three profiles trending NE–SW with the elongation of the study area. The measuring points were arranged in a grid like pattern with both inter-station spacing and line–line distance of about 2 km. After performing the necessary processing steps, the VES and TEM data sets were inverted individually to multi-layer models, followed by a joint inversion of both data sets. Joint inversion process has succeeded to overcome the model-equivalence problem encountered in the inversion of individual data set. Then, the joint models were used for the construction of a number of cross sections and contour maps showing the lateral and vertical distribution of the geo-electrical parameters in the subsurface medium. Interpretation of the obtained results and correlation with the available geological and hydrogeological information revealed TWO aquifer systems in the area. The shallow Pleistocene aquifer consists of sand and gravel saturated with fresh water and exhibits large thickness exceeding 200 m. The deep Pliocene aquifer is composed of clay and sand and shows low resistivity values. The water bearing layer of the Pleistocene aquifer and the upper surface of Pliocene aquifer are continuous and no structural features have cut this continuity through the investigated area.

Keywords: El Sadat city, joint inversion, VES, TEM

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Authors: G. Venkatesha, Urs Samarth, H. K. Ramaraju, Arun Kumar Sharma

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The projection for Groundwater states that the total domestic water demand for greater Bangalore would increase from 1,170 MLD in 2010 to 1,336 MLD in 2016. Dependence on groundwater is ever increasing due to rapid Industrialization & Urbanization. It is estimated that almost 40% of the population of Bangalore is dependent on groundwater. Due to the unscientific disposal of domestic and industrial waste generated, groundwater is getting highly polluted in the city. The scale of this impact will depend mainly upon the water-service infrastructure, the superficial geology and the regional setting. The quality of ground water is equally important as that of quantity. Jointed and fractured granites and gneisses constitute the major aquifer system of BBMP area. Two new observatory Borewells were drilled and lithology report has been prepared. Petrographic Analysis (XRD/XRF) and Water quality Analysis were carried out as per the standard methods. Petrographic samples were analysed by collecting chip of rock from the borewell for every 20ft depth, most of the samples were similar and samples were identified as Biotite-Gneiss, Schistose Amphibolite. Water quality analysis was carried out for individual chemical parameters for two borewells drilled. 1st Borewell struck water at 150ft (Total depth-200ft) & 2nd struck at 740ft (Total depth-960ft). 5 water samples were collected till end of depth in each borewell. Chemical parameter values such as, Total Hardness (360-348, 280-320) mg/ltr, Nitrate (12.24-13.5, 45-48) mg/ltr, Chloride (104-90, 70-70)mg/ltr, Fe (0.75-0.09, 1.288-0.312)mg/ltr etc. are calculated respectively. Water samples were analysed from various parts of BBMP covering 750 sq kms, also thematic maps (IDW method) of water quality is generated for these samples for Post-Monsoon season. The study aims to explore the sub-surface Lithological layers and the thickness of weathered zone, which indirectly helps to know the Groundwater pollution source near surface water bodies, dug wells, etc. The above data are interpreted for future ground water resources planning and management.

Keywords: lithology, petrographic, pollution, urbanization

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Authors: Mohammad Syed Ali Molla, Mohammed Azim, Mohammad Esharuzzaman

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Centrifugal-casting machine is used in manufacturing special machine components like multi-layer journal bearing used in all internal combustion engine, steam, gas turbine and air craft turboengine where isotropic properties and high precisions are desired. Moreover, this machine can be used in manufacturing thin wall hightech machine components like cylinder liners and piston rings of IC engine and other machine parts like sleeves, and bushes. Heavy-duty machine component like railway wheel can also be prepared by centrifugal casting. A lot of technological developments are required in casting process for production of good casted machine body and machine parts. Usually defects like blowholes, surface roughness, chilled surface etc. are found in sand casted machine parts. But these can be removed by centrifugal casting machine using rotating metallic die. Moreover, die rotation, its temperature control, and good pouring practice can contribute to the quality of casting because of the fact that the soundness of a casting in large part depends upon how the metal enters into the mold or dies and solidifies. Poor pouring practice leads to variety of casting defects such as temperature loss, low quality casting, excessive turbulence, over pouring etc. Besides these, handling of molten metal is very unsecured and dangerous for the workers. In order to get rid of all these problems, the need of an automatic pouring device arises. In this research work, a robot assisted pouring device and a centrifugal casting machine are designed, developed constructed and tested experimentally which are found to work satisfactorily. The robot assisted pouring device is further modified and developed for using it in actual metal casting process. Lot of settings and tests are required to control the system and ultimately it can be used in automation of centrifugal casting machine to produce high-tech machine parts with desired precision.

Keywords: bearing, centrifugal casting, cylinder liners, robot

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Authors: Kayode Fatokun, Nozipho N. Motsa

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Field experiments were carried out during the summer/autumn (first trial) and winter/spring (second trial) seasons of 2019 and 2021 inDlangubo, Ngwelezane, and Mtubatubaareas of KwaZulu-Natal Province of South Africa to study the drought amelioration effects and impact of 2 locally available organic wastes [filter cake (FC) and macadamia husk compost (MHC)] on the productivity, and physiological responses of 4 orange-fleshed sweet potato cultivars (Buregard cv., Impilo, W-119 and 199062.1). The effects of FC and MHC were compared with that of inorganic fertilizer (IF) [2:3:2 (30)], FC+IF, MHC+IF, and control. The soil amendments were applied in the first trials only. Climatic data such as humidity, temperature, and rainfall were taken via remote sensing. The results of the first trial indicated that filter cake and IF significantly performed better than MHC. While the strength of filter cake may be attributable to its rich array of mineral nutrients such as calcium, magnesium, potassium, sodium, zinc, copper, manganese, iron, and phosphorus. The little performance from MHC may be attributable to its water holding capacity. Also, a positive correction occurred between the yield of the test OFSP cultivars and climatic factors such as rainfall, NDVI, and NDWI values. Whereas the inorganic fertilizer did not have any significant effect on the growth and productivity of any of the tested sweet potato cultivars in the second trial; FC, and MHC largely maintained their significant performances. In conclusion, the use of FC is highly recommended in the production of the test orange-fleshed sweet potato cultivars. Also, the study indicated that both FC and MHC may not only supply the needed plant nutrients but has the capacity to reduce the impact of drought on the growth of the test cultivars. These findings are of great value to farmers, especially the resource-poorones.

Keywords: amendments, drought, filter cake, macadamia husk compost, sweet potato

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Authors: Mohamed dammak

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Great attention has been paid to the design and synthesis of novel organic-inorganic compounds in recent decades because of their structural variety and the large diversity of atomic arrangements. In this work, the structure for the novel dimethyl aminopyridine tetrachlorocobaltate (C₇H₁₁N₂)₂CoCl₄ prepared by the slow evaporation method at room temperature has been successfully discussed. The X-ray diffraction results indicate that the hybrid material has a triclinic structure with a P space group and features a 0D structure containing isolated distorted [CoCl₄]2- tetrahedra interposed between [C7H11N²⁻]+ cations forming planes perpendicular to the c axis at z = 0 and z = ½. The effect of the synthesis conditions and the reactants used, the interactions between the cationic planes, and the isolated [CoCl4]2- tetrahedra are employing N-H...Cl and C-H…Cl hydrogen bonding contacts. The inspection of the Hirshfeld surface analysis helps to discuss the strength of hydrogen bonds and to quantify the inter-contacts. A phase transition was discovered by thermal analysis at 390 K, and comprehensive dielectric research was reported, showing a good agreement with thermal data. Impedance spectroscopy measurements were used to study the electrical and dielectric characteristics over a wide range of frequencies and temperatures, 40 Hz–10 MHz and 313–483 K, respectively. The Nyquist plot (Z" versus Z') from the complex impedance spectrum revealed semicircular arcs described by a Cole-Cole model. An electrical circuit consisting of a link of grain and grain boundary elements is employed. The real and imaginary parts of dielectric permittivity, as well as tg(δ) of (C₇H₁₁N₂)₂CoCl₄ at different frequencies, reveal a distribution of relaxation times. The presence of grain and grain boundaries is confirmed by the modulus investigations. Electric and dielectric analyses highlight the good protonic conduction of this material.

Keywords: organic-inorganic, phase transitions, complex impedance, protonic conduction, dielectric analysis

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Authors: Samuel Abebe Ebebo

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Scale precipitation causes a major issue for geothermal power plants because it reduces the production rate of geothermal energy. Each geothermal power plant's different chemical and physical conditions can cause the scale to precipitate under a particular set of fluid-rock interactions. Depending on the mineral, it is possible to have scale in the production well, steam separators, heat exchangers, reinjection wells, and everywhere in between. The scale consists mainly of smectite and trace amounts of chlorite, magnetite, quartz, hematite, dolomite, aragonite, and amorphous silica. The smectite scale is one of the difficult scales at injection wells in geothermal power plants. X-ray diffraction and chemical composition identify this smectite as Stevensite. The characteristics and the scale of each injection well line are different depending on the fluid chemistry. The smectite scale has been widely distributed in pipelines and surface plants. Mineral water equilibrium showed that the main factors controlling the saturation indices of smectite increased pH and dissolved Mg concentration due to the precipitate on the equipment surface. This study aims to characterize the scales and geothermal fluids collected from the Onuma geothermal power plant in Akita Prefecture, Japan. Field tests were conducted on October 30–November 3, 2021, at Onuma to determine the pH control methods for preventing magnesium silicate scaling, and as exemplified, the formation of magnesium silicate hydrates (M-S-H) with MgO to SiO2 ratios of 1.0 and pH values of 10 for one day has been studied at 25 °C. As a result, M-S-H scale formation could be suppressed, and stevensite formation could also be suppressed when we can decrease the pH of the fluid by less than 8.1, 7.4, and 8 (at 97 °C) in the fluid from O-3Rb and O-6Rb, O-10Rg, and O-12R, respectively. In this context, the scales and fluids collected from injection wells at a geothermal power plant in Japan were analyzed and characterized to understand the formation conditions of Mg-silicate scales with on-site synthesis experiments. From the results of the characterizations and on-site synthesis experiments, the inhibition method of their scale formation is discussed based on geochemical modeling in this study.

Keywords: magnesium silicate, scaling, inhibitor, geothermal power plant

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Authors: Hamideh Hamedi, Nima Rezaei, Sohrab Zendehboudi

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Separating emulsified oil contaminations from waste- or produced water is of interest to various industries. Magnetic particles (MPs) application for separating dispersed and emulsified oil from wastewater is becoming more popular. Stabilization of MPs is required through developing a coating layer on their surfaces to prevent their agglomeration and enhance their dispersibility. In this research, we study the effects of coating material, size, and concentration of iron oxide MPs on oil separation efficiency, using oil adsorption capacity measurements. We functionalize both micro-and nanoparticles of Fe3O4 using sodium dodecyl sulfate (SDS) as an anionic surfactant, cetyltrimethylammonium bromide (CTAB) as a cationic surfactant, and stearic acid (SA). The chemical structures and morphologies of these particles are characterized using Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), and Energy Dispersive X-ray (EDX). The oil-water separation results indicate that a low dosage of the coated magnetic nanoparticle with CTAB (0.5 g/L MNP-CTAB) results the highest oil adsorption capacity (nearly 100%) for 1000 ppm dodecane-in-water emulsion, containing ultra-small droplets (250–300 nm). While separation efficiency of the same dosage of bare MNPs is around 57.5%. Demulsification results of magnetic microparticles (MMPs) also reveal that the functionalizing particles with CTAB increase oil removal efficiency from 86.3% for bare MMP to 92% for MMP-CTAB. Comparing the results of different coating materials implies that the major interaction reaction is an electrostatic attraction between negatively charged oil droplets and positively charged MNP-CTAB and MMP-CTAB. Furthermore, the synthesized nanoparticles could be recycled and reused; after ten cycles the oil adsorption capacity slightly decreases to near 95%. In conclusion, functionalized magnetic particles with high oil separation efficiency could be used effectively in treatment of oily wastewater. Finally, optimization of the adsorption process is required by considering the effective system variables, and fluid properties.

Keywords: oily wastewater treatment, emulsions, oil-water separation, adsorption, magnetic nanoparticles

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Authors: Marinna Madrid, Nabiha Saklayen, Marinus Huber, Nicolas Vogel, Christos Boutopoulos, Michel Meunier, Eric Mazur

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Delivering material into cells is important for a diverse range of biological applications, including gene therapy, cellular engineering and imaging. We present a plasmonic substrate for delivering membrane-impermeable material into cells at high throughput and high efficiency while maintaining cell viability. The substrate fabrication is based on an affordable and fast colloidal self-assembly process. When illuminated with a femtosecond laser, the light interacts with the electrons at the surface of the metal substrate, creating localized surface plasmons that form bubbles via energy dissipation in the surrounding medium. These bubbles come into close contact with the cell membrane to form transient pores and enable entry of membrane-impermeable material via diffusion. We use fluorescence microscopy and flow cytometry to verify delivery of membrane-impermeable material into HeLa CCL-2 cells. We show delivery efficiency and cell viability data for a range of membrane-impermeable cargo, including dyes and biologically relevant material such as siRNA. We estimate the effective pore size by determining delivery efficiency for hard fluorescent spheres with diameters ranging from 20 nm to 2 um. To provide insight to the cell poration mechanism, we relate the poration data to pump-probe measurements of micro- and nano-bubble formation on the plasmonic substrate. Finally, we investigate substrate stability and reusability by using scanning electron microscopy (SEM) to inspect for damage on the substrate after laser treatment. SEM images show no visible damage. Our findings indicate that self-assembled plasmonic substrates are an affordable tool for high-throughput, high-efficiency delivery of material into mammalian cells.

Keywords: femtosecond laser, intracellular delivery, plasmonic, self-assembly

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Authors: Wasim Sajjad, Manzoor Ahmad, Sundas Qadir, Muhammad Rafiq, Fariha Hasan, Richard Tehan, Kerry L. McPhail, Aamer Ali Shah

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Aim: This study aims to investigate the possible radiation protective role of a compatible solute in the tolerance of radio-halophilic bacterium against stresses, like desiccation and exposure to ionizing radiation. Methods and Results: Nine different radio-resistant bacteria were isolated from desert soil, where strain WMA-LM19 was chosen for detailed studies on the basis of its high tolerance for ultraviolet radiation among all these isolates. 16S rRNA gene sequencing indicated that the bacterium was closely related to Stenotrophomonas sp. (KT008383). A bacterial milking strategy was applied for extraction of intracellular compatible solutes in 70% (v/v) ethanol, which were purified by high-performance liquid chromatography (HPLC). The compound was characterized as ectoine by 1H and 13C nuclear magnetic resonance (NMR), and mass spectrometry (MS). Ectoine demonstrated more efficient preventive activity (54.80%) to erythrocyte membranes and also inhibited oxidative damage to proteins and lipids in comparison to the standard ascorbic acid. Furthermore, a high level of ectoine-mediated protection of bovine serum albumin against ionizing radiation (1500-2000 Jm-2) was observed, as indicated by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis. Conclusion: The results indicated that ectoine can be used as a potential mitigator and radio-protective agent to overcome radiation- and salinity-mediated oxidative damage in extreme environments. Significance and Impact of the Study: This study shows that ectoine from radio-halophiles can be used as a potential source in topical creams as sunscreen. The investigation of ectoine as UV protectant also changes the prospective that radiation resistance is specific only to molecular adaptation.

Keywords: ectoine, anti-oxidant, stenotrophomonas sp., ultraviolet radiation

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Authors: Elsayed A. Elkhatib, Ahmed M. Mahdy, Mohamed L. Moharem, Mohamed O. Mesalem

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Mercury (Hg) is one of the most toxic and bio-accumulative heavy metal in the environment. However, cheap and effective in situ remediation technology is lacking. In this study, the effects of water treatment residuals nanoparticles (nWTR) on mobility, fractionation and speciation of mercury in an arid zone soil from Egypt were evaluated. Water treatment residual nanoparticles with high surface area (129 m 2 g-1) were prepared using Fritsch planetary mono mill. Scanning and transmission electron microscopy revealed that the nanoparticles of WTR nanoparticles are spherical in shape, and single particle sizes are in the range of 45 to 96 nm. The x-ray diffraction (XRD) results ascertained that amorphous iron, aluminum (hydr)oxides and silicon oxide dominating all nWTR, with no apparent crystalline iron–Al (hydr)oxides. Addition of nWTR, greatly increased the Hg sorption capacities of studied soils and greatly reduced the cumulative Hg released from the soils. Application of nWTR at 0.10 and 0.30 % rates reduced the released Hg from the soil by 50 and 85 % respectively. The power function and first order kinetics models well described the desorption process from soils and nWTR amended soils as evidenced by high coefficient of determination (R2) and low SE values. Application of nWTR greatly increased the association of Hg with the residual fraction. Meanwhile, application of nWTR at a rate of 0.3% greatly increased the association of Hg with the residual fraction (>93%) and significantly increased the most stable Hg species (Hg(OH)2 amor) which in turn enhanced Hg immobilization in the studied soils. Fourier transmission infrared spectroscopy analysis indicated the involvement of nWTR in the retention of Hg (II) through OH groups which suggest inner-sphere adsorption of Hg ions to surface functional groups on nWTR. These results demonstrated the feasibility of using a low-cost nWTR as best management practice to immobilize excess Hg in contaminated soils.

Keywords: release kinetics, Fourier transmission infrared spectroscopy, Hg fractionation, Hg species

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Authors: Gheorghiţa Mitran, Adriana Urdă, Mihaela Florea, Octavian Dumitru Pavel, Florentina Neaţu

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Oxidative dehydrogenation and hydrogenation reactions of L-malic acid are interesting ways for its transformation into valuable products, including oxaloacetic, pyruvic and malonic acids but also 1,4-butanediol and 1,2,4-butanetriol. Keto acids have a range of applicationsin many chemical syntheses as pharmaceuticals, food additives and cosmetics. 3-Hydroxybutyrolactone and 1,2,4-butanetriol are used for the synthesis of chiral pharmaceuticals and other fine chemicals, while 1,4-butanediol can be used for organic syntheses, such as polybutylene succinate (PBS), polybutylene terephthalate (PBT), and for production of tetrahydrofuran (THF). L-malic acid is a non-toxic and natural organic acid present in fruits, and it is the main component of wine alongside tartaric acid representing about 90% of the wine total acidity. Iron oxides dopped with cobalt (CoxFe3-xO4; x= 0; 0.05; 0.1; 0.15) were studied as catalysts in these reactions. There is no mention in the literature of non-noble transition metal catalysts for these reactions. The method used for catalysts preparation was coprecipitation, whileBET XRD, XPS, FTIR and UV-VIS spectroscopy were used for the physicochemical properties evaluation.TheXRD patterns revealed the presence of α-Fe2O3 rhombohedral hematite structure, with cobalt atoms well dispersed and embedded in this structure. The studied samples are highly crystalline, with a crystallite size ranged from 58 to 65 nm. The optical absorption properties were investigated using UV-Vis spectroscopy, emphasizing the presence of bands that correspond with the reported hematite nanoparticle. Likewise, the presence of bands corresponding to lattice vibration of hexagonal hematite structurehas been evidenced in DRIFT spectra. Oxidative dehydrogenation of malic acid was studied using as solvents for malic acid ethanol or water(2, 5 and 10% malic acid in 5 mL solvent)at room temperature, while the hydrogenation reaction was evaluated in water as solvent (5%), in the presence of 1% catalyst. The oxidation of malic acid into oxaloacetic acid is the first step, after that, oxaloacetic acid is rapidly decarboxylated to malonic acid or pyruvic acid, depending on the active site. The concentration of malic acid in solution, it, in turn, has an influence on conversionthis decreases when the concentration of malic acid in the solution is high. The spent catalysts after the oxidative dehydrogenation of malic acid in ethanol were characterized by DRIFT spectroscopy and the presence of oxaloacetic, pyruvic and malonicacids, along with unreacted malic acidwere observed on the surface. The increase of the ratio of Co/Fe on the surface has an influence on the malic acid conversion and on the pyruvic acid yield, while the yield of malonic acid is influenced by the percentage of iron on the surface (determined from XPS). Oxaloacetic acid yield reaches a maximumat one hour of reaction, being higher when ethanol is used as a solvent, after which it suddenly decreases. The hydrogenation of malic acid occurs by consecutive reactions with the production of 3-hydroxy-butyrolactone, 1,2,4-butanetriol and 1,4-butanediol. Malic acid conversion increases with cobalt loading increasing up to Co/Fe ratio of 0.1, after which it has a slight decrease, while the yield in 1,4-butanediol is directly proportional to the cobalt content.

Keywords: malic acid, oxidative dehydrogenation, hydrogenation, oxaloacetic acid

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Authors: Benjamin K. Ghansah, Richard K. Appoh, Iliya Nababa, Eric K. Forkuo

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The Nasia River is an important source of water for domestic and agricultural purposes to the inhabitants of its catchment. Major farming activities takes place within the floodplain of the river and its network of tributaries. The actual inundation extent of the river system is; however, unknown. Reasons for this lack of information include financial constraints and inadequate human resources as flood modelling is becoming increasingly complex by the day. Knowledge of the inundation extent will help in the assessment of risk posed by the annual flooding of the river, and help in the planning of flood recession agricultural activities. This study used a simple terrain based algorithm, Height Above Nearest Drainage (HAND), to delineate the floodplain of the Nasia River and its tributaries. The HAND model is a drainage normalized digital elevation model, which has its height reference based on the local drainage systems rather than the average mean sea level (AMSL). The underlying principle guiding the development of the HAND model is that hillslope flow paths behave differently when the reference gradient is to the local drainage network as compared to the seaward gradient. The new terrain model of the catchment was created using the NASA’s SRTM Digital Elevation Model (DEM) 30m as the only data input. Contours (HAND Contour) were then generated from the normalized DEM. Based on field flood inundation survey, historical information of flooding of the area as well as satellite images, a HAND Contour of 2m was found to best correlates with the flood inundation extent of the river and its tributaries. A percentage accuracy of 75% was obtained when the surface area created by the 2m contour was compared with surface area of the floodplain computed from a satellite image captured during the peak flooding season in September 2016. It was estimated that the flooding of the Nasia River and its tributaries created a floodplain area of 1011 km².

Keywords: digital elevation model, floodplain, HAND contour, inundation extent, Nasia River

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Authors: E. T. L. Cöuras Ford, V. A. C. Vale, J. U. L. Mendes

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Two of the objective principal in the study of the aerodynamics of vehicles are the safety and the acting. Those objectives can be reached through the development of devices modify the drainage of air about of the vehicle and also through alterations in the way of the external surfaces. The front lowest profile of the vehicle, for instance, has great influence on the coefficient of aerodynamic penetration (Cx) and later on great part of the pressure distribution along the surface of the vehicle. The objective of this work was of analyzing the aerodynamic behavior that it happens on some types the trucks of vehicles, based on experimentation in aerodynamic tunnel, seeking to determine the aerodynamic efficiency of each one of them.

Keywords: aerodynamic, vehicles, wind tunnel, safety, acting

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Authors: Monika Patel, Kazuaki Matsumura

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Synthetic hydrogels, with their unique properties such as porosity, strength, and swelling in aqueous environment, are being used in many fields from food additives to regenerative medicines, from diagnostic and pharmaceuticals to drug delivery systems (DDS). But, hydrogels also have some limitations in terms of homogeneity of drug distribution and quantity of loaded drugs. As an alternate, polymeric micelles are extensively used as DDS. With the ease of self-assembly, and distinct stability they remarkably improve the solubility of hydrophobic drugs. However, presently, combinational therapy is the need of time and so are systems which are capable of releasing more than one drug. And it is one of the major challenges towards DDS to control the release of each drug independently, which simple DDS cannot meet. In this work, we present an amphiphilic polypeptide based micelle hydrogel composite to study the dual drug release for wound healing purposes using Amphotericin B (AmpB) and Curcumin as model drugs. Firstly, two differently charged amphiphilic polypeptide chains were prepared namely, poly L-Lysine-b-poly phenyl alanine (PLL-PPA) and poly Glutamic acid-b-poly phenyl alanine (PGA-PPA) through ring opening polymerization of amino acid N-carboxyanhydride. These polymers readily self-assemble to form micelles with hydrophobic PPA block as core and hydrophilic PLL/PGA as shell with an average diameter of about 280nm. The thus formed micelles were loaded with the model drugs. The PLL-PPA micelle was loaded with curcumin and PGA-PPA was loaded with AmpB by dialysis method. Drug loaded micelles showed a slight increase in the mean diameter and were fairly stable in solution and lyophilized forms. For forming the micelles hydrogel composite, the drug loaded micelles were dissolved and were cross linked using genipin. Genipin uses the free –NH2 groups in the PLL-PPA micelles to form a hydrogel network with free PGA-PPA micelles trapped in between the 3D scaffold formed. Different composites were tested by changing the weight ratios of the both micelles and were seen to alter its resulting surface charge from positive to negative with increase in PGA-PPA ratio. The composites with high surface charge showed a burst release of drug in initial phase, were as the composites with relatively low net charge showed a sustained release. Thus the resultant surface charge of the composite can be tuned to tune its drug release profile. Also, while studying the degree of cross linking among the PLL-PPA particles for effect on dual drug release, it was seen that as the degree of crosslinking increases, an increase in the tendency to burst release the drug (AmpB) is seen in PGA-PPA particle, were as on the contrary the PLL-PPA particles showed a slower release of Curcumin with increasing the cross linking density. Thus, two different pharmacokinetic profile of drugs were seen by changing the cross linking degree. In conclusion, a unique charged amphiphilic polypeptide based micelle hydrogel composite for dual drug delivery. This composite can be finely tuned on the basis of need of drug release profiles by changing simple parameters such as composition, cross linking and pH.

Keywords: amphiphilic polypeptide, dual drug release, micelle hydrogel composite, tunable DDS

Procedia PDF Downloads 209

Authors: A.H. Martínez, T. López-Montero, R. Miró, R. Puig, R. Villar

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An alternative to mitigate the heat island effect is to pave streets and sidewalks with pavements that reflect incident solar energy, keeping their surface temperature lower than conventional pavements. The “Heat island mitigation to prevent global warming by designing sustainable pavements with reflective and photoluminescent properties (RELUM) Project” has been carried out with this intention in mind. Its objective has been to develop bituminous mixtures for urban pavements that help in the fight against global warming and climate change, while improving the quality of life of citizens. The technology employed has focused on the use of reflective pavements, using bituminous mixes made with synthetic bitumens and light pigments that provide high solar reflectance. In addition to this advantage, the light surface colour achieved with these mixes can improve visibility, especially at night. In parallel and following the latter approach, an appropriate type of treatment has also been developed on bituminous mixtures to make them capable of illuminating at night, giving rise to photoluminescent applications, which can reduce energy consumption and increase road safety due to improved night-time visibility. The work carried out consisted of designing different bituminous mixtures in which the nature of the aggregate was varied (porphyry, granite and limestone) and also the colour of the mixture, which was lightened by adding pigments (titanium dioxide and iron oxide). The reflectance of each of these mixtures was measured, as well as the temperatures recorded throughout the day, at different times of the year. The results obtained make it possible to propose bituminous mixtures whose characteristics can contribute to the reduction of urban heat islands. Among the most outstanding results is the mixture made with synthetic bitumen, white limestone aggregate and a small percentage of titanium dioxide, which would be the most suitable for urban surfaces without road traffic, given its high reflectance and the greater temperature reduction it offers. With this solution, a surface temperature reduction of 9.7°C is achieved at the beginning of the night in the summer season with the highest radiation. As for luminescent pavements, paints with different contents of strontium aluminate and glass microspheres have been applied to asphalt mixtures, and the luminance of all the applications designed has been measured by exciting them with electric bulbs that simulate the effect of sunlight. The results obtained at this stage confirm the ability of all the designed dosages to emit light for a certain time, varying according to the proportions used. Not only the effect of the strontium aluminate and microsphere content has been observed, but also the influence of the colour of the base on which the paint is applied; the lighter the base, the higher the luminance. Ongoing studies are focusing on the evaluation of the durability of the designed solutions in order to determine their lifetime.

Keywords: heat island, luminescent paints, reflective pavement, temperature reduction

Procedia PDF Downloads 35

Authors: Adriano Losso, Birgit Dämon, Stefan Mayr

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In vascular plants, water flows from roots to leaves in a metastable state, and even a small perturbation of the system can lead a sudden transition from the liquid to the vapor phase, resulting in xylem embolism (cavitation). Xylem embolism, induced by drought stress and/or freezing stress is caused by the aspiration of gaseous bubbles into xylem conduits from adjacent gas-filled compartments through pit membrane pores (‘air seeding’). At water potentials less negative than the threshold for air seeding, the surface tension (γ) stabilizes the air-water interface and thus prevents air from passing the pit pores. This hold is probably also true for conifers, where this effect occurs at the edge of the sealed torus. Accordingly, it was experimentally demonstrated that γ influences air seeding, but information on the relevance of this effect under field conditions is missing. In this study, we analyzed seasonal changes in γ of the xylem sap in two conifers growing at the alpine timberline (Picea abies and Pinus mugo). In addition, cut branches were perfused (40 min perfusion at 0.004 MPa) with different γ solutions (i.e. distilled and degassed water, 2, 5 and 15% (v/v) ethanol-water solution corresponding to a γ of 74, 65, 55 and 45 mN m-1, respectively) and their vulnerability to drought-induced embolism analyzed via the centrifuge technique (Cavitron). In both species, xylem sap γ changed considerably (ca. 53-67 and ca. 50-68 mN m-1 in P. abies and P. cembra, respectively) over the season. Branches perfused with low γ solutions showed reduced resistance against drought-induced embolism in both species. A significant linear relationship (P < 0.001) between P12, P50 and P88 (i.e. water potential at 12, 50 and 88% of the loss of conductivity) and xylem sap γ was found. Based on this correlation, a variation in P50 between -3.10 and -3.83 MPa (P. abies) and between -3.21 and -4.11 MPa (P. mugo) over the season could be estimated. Results demonstrate that changes in γ of the xylem sap can considerably influence a tree´s resistance to drought-induced embolism. They indicate that vulnerability analyses, normally conducted at a γ near that of pure water, might often underestimate vulnerabilities under field conditions. For studied timberline conifers, seasonal changes in γ might be especially relevant in winter, when frost drought and freezing stress can lead to an excessive embolism.

Keywords: conifers, Picea abies, Pinus mugo, timberline

Procedia PDF Downloads 296

Authors: Henri El Zakhem, Anthony Dahdah, Lara Frangieh, Jessica Koura

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Nowadays, the removal of whey produced in the dairy processes has been the most important problem in the dairy industry. Every year, about 47% of the 115 million tons of whey produced world-wide are disposed in the environment. Whey is a nutritious liquid, containing whey proteins (β-lactoglobulin, α-lactalbumin, immunoglobulin-G, proteose pepton), lactose, vitamins (B5, B2, C, and B6), minerals (Calcium, Magnesium, Phosphorous, Potassium, Chloride, and Sodium), and trace elements (Zinc, Iron, Iodine, and Copper). The first objective was to increase the economical and commercial value of whey which is considered as by-product. The second objective of this study was to formulate a new baby food with good nutritional, sensory and storage properties and acceptable to consumers using the cheese whey. The creation of the new product must pass through the following stages: idea stage, development stage which includes the business planning and the product development prototype, packaging stage, production stage, test marketing stage, quality control/sanitation. Three types of whey-based food were selected and prepared by mixing whey and apple, whey and banana as well as whey, apple, and banana.To compile with the recommended dietary allowances (RDA) and adequate intakes (AI) for vitamins and minerals, each sample is formed from 114g of sliced and smashed fruits mixed with 8 mL of whey. Mixtures are heated to 72oC for 15 seconds, and filled in pasteurized jars. Jars were conserved at 4oC. Following the experimental part, sensory evaluation made by an experienced panel took place. Hedonic tests results show that the mixture of whey, apple, and banana has the most delicious and sweetness taste followed by the mixture of whey and banana, and finally the mixture of whey and apple. This study was concluded with a managerial and engineering study that reveals that the project is economically profitable to be executed in Lebanon.

Keywords: baby food, by-product, cheese whey, formulation

Procedia PDF Downloads 276

Authors: Swapnil A. Padvi, Dipak S. Dalal

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The chemistry of tetrazoles has been grown tremendously in the past few years because tetrazoles are important and useful class of heterocyclic compounds which have a widespread application such as anticancer, antimicrobial, analgesics, antibacterial, antifungal, antihypertensive, and anti-allergic drugs in medicinal chemistry. Furthermore, tetrazoles have application in material sciences as explosives, rocket propellants, and in information recording systems. In addition to this, they have a wide range of application in coordination chemistry as a ligand. Deep eutectic solvents (DES) have emerged over the current decade as a novel class of green reaction media and applied in various fields of sciences because of their unique physical and chemical properties similar to the ionic liquids such as low vapor pressure, non-volatility, high thermal stability and recyclability. In addition, the reactants of DES are cheaply available, low-toxic, and biodegradable, which makes them predominantly required for large-scale applications effectively in industrial production. Herein we report the [2+3] cycloaddition reaction of organic nitriles with sodium azide affords the corresponding 5-substituted 1H-tetrazoles in six different types of choline chloride based deep eutectic solvents under mild reaction condition. Choline chloride: ZnCl2 (1:2) showed the best results for the synthesis of 5-substituted 1 H-tetrazoles. This method reduces the disadvantages such as: the use of toxic metals and expensive reagents, drastic reaction conditions and the presence of dangerous hydrazoic acid. The approach provides environment-friendly, short reaction times, good to excellent yields; safe process and simple workup make this method an attractive and useful contribution to present green organic synthesis of 5-substituted-1H-tetrazoles. All synthesized compounds were characterized by IR, 1H NMR, 13C NMR and Mass spectroscopy. DES can be recovered and reused three times with very little loss in activity.

Keywords: click chemistry, choline chloride, green chemistry, deep eutectic solvent, tetrazoles

Procedia PDF Downloads 232

Authors: Wanida Wonsawat

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This research describes a voltammetric approach to determine amounts of vitamin C (Ascorbic acid) in orange juice sample, using three screen printed electrode. The anodic currents of vitamin C were proportional to vitamin C concentration in the range of 0 – 10.0 mM with the limit of detection of 1.36 mM. The method was successfully employed with 2 µL of the working solution dropped on the electrode surface. The proposed method was applied for the analysis of vitamin C in packed orange juice without sample purification or complexion of sample preparation step.

Keywords: ascorbic acid, vitamin C, juice, voltammetry

Procedia PDF Downloads 327

Authors: Visar Baxhuku, Halil Demolli, Alishukri Shkodra

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This paper presents the monitoring of vehicle movement, namely the developing of speed of vehicles during movement in a certain twist. The basic geometry data of twist are measured with the purpose of calculating the slide in border speed. During the research, measuring developed speed of passenger vehicles for the real conditions of the road surface, dry road with average damage, was realised. After setting values, the analysis was done in function security of movement in twist.

Keywords: critical sliding velocity, moving velocity, curve, passenger vehicles

Procedia PDF Downloads 424

Authors: Siyanbola Mojisola Funmilayo, Amao Emmanuel Ayodele

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The poultry industry in Nigeria has been played by a variety of problems, which include the search for feed ingredients that are not competed for by man. This has resulted in a reduced interest of farmers in the industry leading to a reduction in animal protein availability for human consumption as a consequence of a high cost of production. The incorporation of wild sunflower meal (Tithonia diversfolia, Hemsl A. Gray) (WSF Meal) and some others in poultry diets have been reported to result in compounded feed with nutrient profiles that compare favourable with feeds of conventional feedstuff and reduce feed cost as they reduce competition with humans. A 98-day feeding trial was used to evaluate the effect of Wild sunflower leaf (WSL) at varying levels on the hematology and biochemistry of cockerels. A total of one hundred and twenty(120) cockerel birds were randomly allotted into four experimental diets with three replicates per experimental diet (ten birds per replicate). Wild sunflower leaf was included in four graded levels ; 0, 5, 10, and 15%. Packed cell volume, Red blood cell count, White blood cell count, Hemoglobin count, Lymphocyte count, Neutrophil count, Platelets, Mean Corpuscular Hemoglobin Concentration (MCHC), Mean Corpuscular Hemoglobin (MCH), Aspartate aminotransferase (AST), Glucose, Urea, Chloride, Sodium, and Potassium ion values were significantly different (p<0.05) among the treatments. Mean values obtained for Creatinine, Total Protein, Alanine aminotransferase (ALT), Albumin, and Mean Corpuscular Volume (MCV) were not significantly different (p>0.05) in all the treatment. WSL could be included up to 15% in the diet of cockerel without any deleterious effect on the birds. Based on the results, up to 15% Wild sunflower meal (WSL) can be included in the diet of cockerel without any adverse effect on the hematology and biochemical indices of birds.

Keywords: biochemical changes, cockerels, hematology, wild sunflower leaf

Procedia PDF Downloads 447

Authors: A. Abdelnasser, M. Kumral, B. Zoheir, P. Weihed, M. Budakoglu, L. Gumus

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Atud gold deposits located at the central part of the Egyptian Eastern Desert of Egypt. It represents the vein-type gold mineralization at the Arabian-Nubian Shield in North Africa. Furthermore, this Au mineralization was closely associated with intense hydrothermal alteration haloes along the NW-SE brittle-ductile shear zone at the mined area. This study reports new data about the mineral chemistry of the hydrothermal and metamorphic minerals as well as the geothermobarometry of the metamorphism and determines the paragenetic interrelationship between Au-bearing sulfides and gangue minerals in Atud gold mine by using the electron microprobe analyses (EMPA). These analyses revealed that the ore minerals associated with gold mineralization are arsenopyrite, pyrite, chalcopyrite, sphalerite, pyrrhotite, tetrahedrite and gersdorffite-cobaltite. Also, the gold is highly associated with arsenopyrite and As-bearing pyrite as well as sphalerite with an average ~70 wt.% Au (+26 wt.% Ag) whereas it occurred either as disseminated grains or along microfractures of arsenopyrite and pyrite in altered wallrocks and mineralized quartz veins. Arsenopyrite occurs as individual rhombic or prismatic zoned grains disseminated in the quartz veins and wallrock and is intergrown with euhedral arsenian pyrite (with ~2 atom % As). Pyrite is As-bearing pyrite that occurs as disseminated subhedral or anhedral zoned grains replacing by chalcopyrite in some samples. Inclusions of sphalerite and pyrrhotite are common in the large pyrite grains. Secondary minerals such as sericite, calcite, chlorite and albite are disseminated either in altered wallrocks or in quartz veins. Sericite is the main secondary and alteration mineral associated with Au-bearing sulfides and calcite. Electron microprobe data of the sericite show that its muscovite component is high in all analyzed flakes (XMs= an average 0.89) and the phengite content (Mg+Fe a.p.f.u.) varies from 0.10 to 0.55 and from 0.13 to 0.29 in wallrocks and mineralized veins respectively. Carbonate occurs either as thin veinlets or disseminated grains in the mineralized quartz vein and/or the wallrocks. It has higher amount of calcite (CaCO3) and low amount of MgCO3 as well as FeCO3 in the wallrocks relative to the quartz veins. Chlorite flakes are associated with arsenopyrite and their electron probe data revealed that they are generally Fe-rich composition (FeOt 20.64–20.10 wt.%) and their composition is clinochlore either pycnochlorite or ripidolite with Al (iv) = 2.30-2.36 pfu and 2.41-2.51 pfu and with narrow range of estimated formation temperatures are (289–295°C) and (301-312°C) for pycnochlorite and ripidolite respectively. Albite is accompanied with chlorite with an Ab content is high in all analyzed samples (Ab= 95.08-99.20).

Keywords: micro-analytical data, mineral chemistry, EMPA, Atud gold deposit, Egypt

Procedia PDF Downloads 328

Authors: Maria Altamirano, Alfonso Duran

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Biostimulation has recently become important in order to improve the stability and performance of the anaerobic digestion (AD) process. This strategy involves the addition of nutrients or supplements to improve the rate of degradation of a native microbial consortium. With the aim of biostimulate sytrophism between secondary fermenting bacteria and methanogenic archaea, improving metabolite degradation and efficient conversion to methane, the addition of conductive materials, mainly carbon based have been studied. This research seeks to highlight the effect that coconut biochar (CBC) has on the metanogenic conversion of the organic fraction of municipal solid waste (OFMSW), analyzing the surface chemistry properties that give biochar its capacity to serve as a redox mediator in the anaerobic digestion process. The biochar characterization techniques were electrical conductivity (EC) scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), Fourier Transform Infrared Transmission Spectroscopy (FTIR) and Cyclic Voltammetry (CV). Effect of coconut biochar addition was studied using Authomatic Methane Potential Test System (AMPTS II) applying a one-way variance analysis to determine the dose that leads to higher methane performance. The surface chemistry of the CBC could confer properties that enhance the AD process, such as the presence of alkaline and alkaline earth metals and their hydrophobicity that may be related to their buffering capacity and the adsorption of polar and non-polar compounds, such as NH4+ and CO2. It also has aromatic functional groups, just as quinones, whose potential as a redox mediator has been demonstrated and its morphology allows it to form an immobilizing matrix that favors a closer activity among the syntrophic microorganisms, which directly contributed in the oxidation of secondary metabolites and the final reduction to methane, whose yield is increased by 39% compared to controls, with a CBC dose of 1 g/L.

Keywords: anaerobic digestion, biochar, biostimulation, syntrophic metabolism

Procedia PDF Downloads 192

Authors: Cosmas Pandit Pagwiwoko, Ammar Khaled Abdelaziz Abdelsamia

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Flutter as a phenomenon of flow-induced and self-excited vibration has to be recognized considering its harmful effect on the structure especially in a stage of aircraft design. This phenomenon is also important for a wind energy harvester based on the fluttering surface due to its effective operational velocity range. This multi-physics occurrence can be presented by two governing equations in both fluid and structure simultaneously in respecting certain boundary conditions on the surface of the body. In this work, the equations are resolved separately by two distinct solvers, one-time step of each domain. The modelling and simulation of this flow-structure interaction in ANSYS show the effectiveness of this loosely coupled method in representing flutter phenomenon however the process is time-consuming for design purposes. Therefore, another technique using the same weak coupled aero-structure is proposed by using system dynamics approach. In this technique, the aerodynamic forces were calculated using singularity function for a range of frequencies and certain natural mode shapes are transformed into time domain by employing an approximation model of fraction rational function in Laplace variable. The representation of structure in a multi-degree-of-freedom coupled with a transfer function of aerodynamic forces can then be simulated in time domain on a block-diagram platform such as Simulink MATLAB. The dynamic response of flutter at certain velocity can be evaluated with another established flutter calculation in frequency domain k-method. In this method, a parameter of artificial structural damping is inserted in the equation of motion to assure the energy balance of flow and vibrating structure. The simulation in time domain is particularly interested as it enables to apply the structural non-linear factors accurately. Experimental tests on a fluttering airfoil in the wind tunnel are also conducted to validate the method.

Keywords: flutter, flow-induced vibration, flow-structure interaction, non-linear structure

Procedia PDF Downloads 316

Authors: Malek Ali

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Composites materials of Poly (vinyl alcohol) (PVA)/Chitosan (CS) have been synthesized and characterized successfully. HNTs have been added to composites to enhance the mechanical and degradation properties by hydrogen bonding interactions, compatibility, and chemical crosslink between HNTs and PVA. PVA/CS/HNTs composites prepared with different concentration ratio. SEM micrographs of composites surface showed that more agglomeration with more chitosan ratio. Mechanical and degradation properties were characterized and the result indicates that Mechanical and degradation of 80%PVA/5%Chitosan/15%HNTs higher than the others PVA/CS/HNTs composites.

Keywords: PVA/chitosan, composites, PVA/CS/HNTs, HNTs

Procedia PDF Downloads 292

Authors: Natesan Balasubramanian, Palpandi Pounpandi, Venkatraman Thamil Priya, Vellasamy Shanmugaiah, Karubbiah Balakrishnan, Mandayam Anandam Thirunarayan

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Streptococcus agalactiae is commonly known as Group B Streptococcus (GBS) and it is the most common cause of life-threatening bacterial infection. GBS first considered as a veterinary pathogen causing mastitis in cattle later becomes a human pathogen for severe neonatal infections. In this present study, a total of 20 new clinical isolates of S. agalactiae were collected from male (6) and female patient (14) with different age group. The isolates were from Urinary tract infection (UTI), blood, pus and eye ulcer. All the 20 S. agalactiae isolates has clear hemolysis properties on blood agar medium and were identified by serogrouping and MALTI-TOF-MS analysis. Antibiotic susceptibility/resistance test was performed for 20 S. agalactiae isolates, further phenotypic resistance pattern was observed for tetracycline, vancomycin, ampicillin and penicillin. Genotypically we found two antibiotic resistance genes such as Betalactem antibiotic resistance gene (Tem) (70%) and tetracycline resistance gene Tet(O) 15% in our isolates. Six virulence factors encoding genes were performed by PCR in twenty GBS isolates, cfb gene (100%), followed by, cylE(90.47%), lmp(85.7%), bca(71.42%), rib (38%) and low frequency in bac gene (4.76%) were determined. Most of the S. agalactiae isolates produced strong biofilm in the polystyrene surface (hydrophobic), and low-level biofilm formation was found in glass tube (hydrophilic) surface. lytR is secreted protein and localized in bacterial cell wall, extra cellular membrane, and cytoplasm. In silico docking studies were performed for lytR protein with four antibiofilm compounds, including a peptide (PR39) with the docking study showed peptide has strong interaction followed by ellagic acid and interaction length is 2.95, 2.97 and 2.95 A°. In ligand EGCGO10 and O11 two atoms intract with lytR (Leu271), with binding bond affinity length is 3.24 and 3.14. The aminoacid Leu 271 is act as an impartant aminoacid, since ellagic acid and EGCG interact with same aminoacid.

Keywords: antibiotics, biofilms, clinical isolates, S. agalactiae, virulence

Procedia PDF Downloads 110