Search results for: surface treatments

Authors: H. B. Rekha, Usha N. Murthy, Prashanth, Ashoka

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Dyes are manufactured to have high chemical resistance because they are normally species, very difficult to degrade (reactive dyes). It damages flora and fauna. Furthermore, coloured components are highly hazardous. So removal of dyes becomes a challenge for both textile industry and water treatment facility. Dyeing wastewater is usually treated by conventional methods such as biological oxidation and adsorption but nowadays them becoming in-adequate because of large variability of composition of waste water. In the present investigation, mild steel electrodes of varying surface area were used for treatment of synthetic textile dye. It appears that electro-chemical coagulation could be very effective in removing coloured from wastewater; it could also be used to remove other parameters like chlorides, COD, and solids to some extent. In the present study, coloured removal up to 99% was obtained for surface area of mild steel electrode of 80 cm2 and 96% of surface area of mild steel electrode of 50 cm2. The findings from this study could be used to improve the design of electro-chemical treatment systems and modify existing systems to improve efficiency.

Keywords: electrochemical coagulation, mild steel, colour, environmental engineering

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Authors: Wilson Handoko, Farshid Pahlevani, Isha Singla, Himanish Kumar, Veena Sahajwalla

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Aluminium bronze alloys are well known for their superior abrasion, tensile strength and non-magnetic properties, due to the co-presence of iron (Fe) and aluminium (Al) as alloying elements and have been commonly used in many industrial applications. However, continuous exposure to the marine environment will accelerate the risk of a tendency to Al bronze alloys parts failures. Although a higher level of corrosion resistance properties can be achieved by modifying its elemental composition, it will come at a price through the complex manufacturing process and increases the risk of reducing the ductility of Al bronze alloy. In this research, the use of ironmaking slag and waste plastic as the input source for surface modification of Al bronze alloy was implemented. Microstructural analysis conducted using polarised light microscopy and scanning electron microscopy (SEM) that is equipped with energy dispersive spectroscopy (EDS). An electrochemical corrosion test was carried out through Tafel polarisation method and calculation of protection efficiency against the base-material was determined. Results have indicated that uniform modified surface which is as the result of selective diffusion process, has enhanced corrosion resistance properties up to 12.67%. This approach has opened a new opportunity to access various industrial utilisations in commercial scale through minimising the dependency on natural resources by transforming waste sources into the protective coating in environmentally friendly and cost-effective ways.

Keywords: aluminium bronze, waste-based surface modification, tafel polarisation, corrosion resistance

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Authors: I. F. Ejim, F. L. Kamen

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Aims: In this experiment, algae oil extraction with a combination of n-hexane and ethanol was investigated. The effects of extraction solvent concentration, extraction time and temperature on the yield and quality of oil were studied using Response Surface Methodology (RSM). Experimental Design: Optimization of algae oil extraction using Box-Behnken design was used to generate 17 experimental runs in a three-factor-three-level design where oil yield, specific gravity, acid value and saponification value were evaluated as the response. Result: In this result, a minimum oil yield of 17% and maximum of 44% was realized. The optimum values for yield, specific gravity, acid value and saponification value from the overlay plot were 40.79%, 0.8788, 0.5056 mg KOH/g and 180.78 mg KOH/g respectively with desirability of 0.801. The maximum point prediction was yield 40.79% at solvent concentration 66.68 n-hexane, temperature of 40.0°C and extraction time of 4 hrs. Analysis of Variance (ANOVA) results showed that the linear and quadratic coefficient were all significant at p<0.05. The experiment was validated and results obtained were with the predicted values. Conclusion: Algae oil extraction was successfully optimized using RSM and its quality indicated it is suitable for many industrial uses.

Keywords: algae oil, response surface methodology, optimization, Box-Bohnken, extraction

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Authors: Moustafa Osman Mohammed

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This paper introduces topological order in descried social systems starting with the original concept of autopoiesis by biologists and scientists, including the modification of general systems based on socialized medicine. Topological order is important in describing the physical systems for exploiting optical systems and improving photonic devices. The stats of topological order have some interesting properties of topological degeneracy and fractional statistics that reveal the entanglement origin of topological order, etc. Topological ideas in photonics form exciting developments in solid-state materials, that being; insulating in the bulk, conducting electricity on their surface without dissipation or back-scattering, even in the presence of large impurities. A specific type of autopoiesis system is interrelated to the main categories amongst existing groups of the ecological phenomena interaction social and medical sciences. The hypothesis, nevertheless, has a nonlinear interaction with its natural environment 'interactional cycle' for exchange photon energy with molecules without changes in topology. The engineering topology of a biosensor is based on the excitation boundary of surface electromagnetic waves in photonic band gap multilayer films. The device operation is similar to surface Plasmonic biosensors in which a photonic band gap film replaces metal film as the medium when surface electromagnetic waves are excited. The use of photonic band gap film offers sharper surface wave resonance leading to the potential of greatly enhanced sensitivity. So, the properties of the photonic band gap material are engineered to operate a sensor at any wavelength and conduct a surface wave resonance that ranges up to 470 nm. The wavelength is not generally accessible with surface Plasmon sensing. Lastly, the photonic band gap films have robust mechanical functions that offer new substrates for surface chemistry to understand the molecular design structure and create sensing chips surface with different concentrations of DNA sequences in the solution to observe and track the surface mode resonance under the influences of processes that take place in the spectroscopic environment. These processes led to the development of several advanced analytical technologies: which are; automated, real-time, reliable, reproducible, and cost-effective. This results in faster and more accurate monitoring and detection of biomolecules on refractive index sensing, antibody-antigen reactions with a DNA or protein binding. Ultimately, the controversial aspect of molecular frictional properties is adjusted to each other in order to form unique spatial structure and dynamics of biological molecules for providing the environment mutual contribution in investigation of changes due to the pathogenic archival architecture of cell clusters.

Keywords: autopoiesis, photonics systems, quantum topology, molecular structure, biosensing

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Authors: Alireza Nejadmohammad Namaghi

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Investigators have reported that mulches increase production potential in arid and semi arid lands. Mulches are covering materials that are used on soil surface for efficiency irrigation, erosion control, weed control, evaporation decrease and improvement of water perpetration. Our aim and local situation determine the kind of material that we can use. In this research we used different mulches including chemical mulch (M1), Aquasorb polymer, manure mulch (M2), Residue mulch (M3) and polyethylene mulch (M4), with control treatment (M0), without usage of mulch, on germination, biomass dry matter and cottonseed yield (Varamin variety) in Kashan area. Randomized complete block (RCB) design have measured the cotton yield with 3 replications for measuring the biomass dry matter and 4 replication in tow irrigation periods as 7 and 14 days. Germination percentage for M0, M1, M2, M3 and M4 treatment were receptivity 64, 65, 76, 57 and 72% Biomass dry matter average for M0, M1, M2, M3 and M4 treatment were receptivity 276, 306, 426, 403 and 476 gram per plot. M4 treatment (polyethylene Mulch) had the most effect, M2 and M3 had no significant as well as M0 and M1. Total yield average with respect to 7 days irrigation for M0, M1, M2, M3 and M4 treatment were receptivity 700, 725, 857, 1057 and 1273 gram per plot. Dunken ne multiple showed no significant different among M0, M1, M2, and M3, but M4 ahs the most effect on yield. Total yield average with respect to 14 days irrigation for M0, M1, M2, M3 and M4 treatment were receptivity 535, 507, 690, 957 and 1047 gram per plot. These were significant difference between all treatments and control treatment. Results showed that used different mulches with water decrease in dry situation can increase the yield significantly.

Keywords: mulch, cotton, arid land management, irrigation systems

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Authors: E. G. Zaki, M. A. Migahed, A. M. Al-Sabagh, E. A. Khamis

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Inhibition effect of four novel nonionic surfactants based on sulphonamide, of linear alkyl benzene sulphonic acid (LABS), was reacted with 1 mole triethylenetetramine, tetraethylenepentamine then Ethoxylation of amide X 65 type carbon steel in oil wells formation water under H2S environment was investigated by electrochemical measurements. Scanning electron microscopy (SEM) and energy dispersion X-ray (EDX) were used to characterize the steel surface. The results showed that these surfactants act as a corrosion inhibitor in and their inhibition efficiencies depend on the ethylene oxide content in the system. The obtained results showed that the percentage inhibition efficiency (η%) was increased by increasing the inhibitor concentration until the critical micelle concentration (CMC) reached The quantum chemistry calculations were carried out to study the molecular geometry and electronic structure of obtained derivatives. The energy gap between the highest occupied molecular orbital and lowest unoccupied molecular orbital has been calculated using the theoretical computations to reflect the chemical reactivity and kinetic stability of compounds.

Keywords: corrosion, surfactants, steel surface, quantum

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Authors: Ouahiba Taamallah, Tarek Litim

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This work relates to the physico-geometrical aspect of the surface layers of 100C6 steel having undergone the burnishing treatment by hard steel ball. The application of tip diamond burnishing promotes better roughness compared to turning. In addition, it allows the surface layers to be consolidated by work hardening phenomena. The optimal effects are closely related to the parameters of the treatment and the active part of the device. With an 80% improvement in roughness resulting from the treatment, burnishing can be defined as a finishing operation within the machining range. With a 40% gain in consolidation rate, this treatment is an efficient process for material consolidation.

Keywords: 100C6 steel, burnishing, hardening, roughness

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Authors: Cristian Viespe, Dana Miu

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Surface acoustic wave (SAW) sensors with nanoparticles (NPs) of various dimensions and concentrations embedded in different types of polymer sensing films for detecting volatile organic compounds (VOCs) were studied. The sensors were ‘delay line’ type with a center frequency of 69.4 MHz on ST-X quartz substrates. NPs with different diameters of 7 nm or 13 nm were obtained by laser ablation with lasers having 5 ns or 10 ps pulse durations, respectively. The influence of NPs dimensions and concentrations on sensor properties such as frequency shift, sensitivity, noise and response time were investigated. To the best of our knowledge, the influence of NP dimensions on SAW sensor properties with has not been investigated. The frequency shift and sensitivity increased with increasing NP concentration in the polymer for a given NP dimension and with decreasing NP diameter for a given concentration. The best performances were obtained for the smallest NPs used. The SAW sensor with NPs of 7 nm had a limit of detection (LOD) of 65 ppm (almost five times better than the sensor with polymer alone), and a response time of about 9 s for ethanol.

Keywords: surface acoustic wave sensor, nanoparticles, volatile organic compounds, laser ablation

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Authors: Annika Schmidt, Ausama Hadi Ahmed, Carlo Menon

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End effectors for robotic systems are becoming more and more advanced, resulting in a growing variety of gripping tasks. However, most grippers are application specific. This paper presents a gripper that interacts with an object’s surface rather than being dependent on a defined shape or size. For this purpose, ingressive and astrictive features are combined to achieve the desired gripping capabilities. The developed prototype is tested on a variety of surfaces with different hardness and roughness properties. The results show that the gripping mechanism works on all of the tested surfaces. The influence of the material properties on the amount of the supported load is also studied and the efficiency is discussed.

Keywords: claw, dry adhesion, insects, material properties

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Authors: Ibrahim Mostafa El-Mongy, Abdelmegid Allam

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In this article analysis and investigation of the effect of loading a horn antenna with frequency selective surface (FSS) of crossed dipoles of finite size is presented. It is fabricated on Rogers RO4350 (lossy) of relative permittivity 3.33, thickness 1.524 mm and loss tangent 0.004. Basically it is applied for filtering and minimizing the interference and noise in the desired band. The filtration is carried out using a finite FSS of crossed dipoles of overall dimensions 98x58 mm2. The filtration is shown by limiting the transmission bandwidth from 4 GHz (8–12 GHz) to 0.25 GHz (10.75–11 GHz). It is simulated using CST MWS and measured using network analyzer. There is a good agreement between the simulated and measured results.

Keywords: antenna, filtenna, frequency selective surface (FSS), horn

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Authors: Maximiliano K. Pagliarini, Ana Carolina T. Malavolta, Isabela M. Morita, Regina Maria M. Castilho

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Among the ornamental plants, the Amaryllis (Hippeastrum X hybridum Hort.) is one of the most cultivated plants in Brazil because of their large and showy flowers. Thus, the consumer market wants better quality plants or to flourish more in less time. One of the devices that can make such improvements or accelerate the flowering process is the use of growth regulators. The objective of this research was to evaluate the use of different Stimulate® growth regulator doses and its constituents separately in the development and flowering of Hippeastrum X hybridum Hort. Cv Orange Souvereign. The experiment was conducted in a Pad & Fan greenhouse at UNESP, São Paulo State, Brazil from August to October 2014. The bulbs were placed in black vases of 1.2 L filled with commercial substrate and divided into 9 treatments: T1 – 10 mL L-1 of Stimulate®, T2 – 5 mL L-1 of Stimulate®, T3 – 0.5 mg L-1 of gibberellic acid (GA), T4 – 0.25 mg L-1 of GA, T5 – 0.45 mg L-1 of kinetin, T6 – 0.9 mg L-1 of kinetin, T7 – 0.5 mg L-1 of indolbutiric acid (IBA), T8 – 0.25 mg L-1 of IBA and T9 – distilled water (control). All treatments were diluted in water. The used design was completely randomized with six repetitions and two vessels, totalling 12 vessels per treatment. The evaluated characteristics were: number of leaves, length of leaf, number of rods, maximum height of rods, maximum diameter of rods, maximum number of flowers, beginning of flowering, flowering duration, and weight of bulbs. The results showed that the Stimulate® was not efficient in the conducted experiment conditions. However, the best treatment was 0.5 mg L-1 of IBA.

Keywords: bulbs, gibberellic acid, indolbutiric acid, kinetin, ornamental plants

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Authors: Mutavhatsindi Tshinakaho

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Invasive alien plants (IAP’s) are referred to as species that are non-native to the ecosystem under consideration. Whose introduction causes or is likely to cause economic, ecological, or environmental harm. The integrated management of the invasive plant, Tithonia diversifolia, will be assessed through two herbicide trials (one on the seedlings and the other on matured plants) and a competitive trial between Tithonia and invasive grass species. The initial herbicide trial will be undertaken at the University of Venda Agricultural greenhouse facilities, where Tithonia will be planted in pot plants and watered every after two days until they reach at least 30 cm and will then be subjected to four different herbicide treatments (Metsulfuron methyl, Fluroxypyr, Picloram, Triclopyr), water will be utilised as a control. The percentage damage to foliar will be recorded. The second herbicide trial will be undertaken at Levubu road site, where matured Tithonia will be cut at at least 10cm above the ground and the subjected to herbicide treatments (Picloram, Fluroxypyr, Imazapyr, and Water as a control). The site will be visited post treatment for assessment. For the competition trial, tall grass species will be chosen as competitors (Panicum maximum and Eragrostis murvula), they will be grown at six densities per pot in the greenhouse facilities at the University of Venda, were they will be kept watered for the duration of the experiment. At the end of the experiment, plants will be removed from pots, and the above and below ground biomass will be weighed. The expected results are to know the effective integrated management strategy for T. diversifolia, the effective rehabilitation of T. diversifolia invaded habitats, and the effective chemical control of T. diversifolia

Keywords: foliar, biomass, competition, invasion

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Authors: Si Abdallah Mayouf

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In this work, the effects of the wavy surface on free convection heat transfer boundary layer flow between two parallel wavy plates have been studied numerically. The two plates are considered at a constant temperature. The equations and the boundary conditions are discretized by the finite difference scheme and solved numerically using the Gauss-Seidel algorithm. The important parameters in this problem are the amplitude of the wavy surfaces and the distance between the two wavy plates. Results are presented as velocity profiles, temperature profiles and local Nusselt number according to the important parameters.

Keywords: free convection, wavy surface, parallel plates, fluid dynamics

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Authors: Ramez F. Saad, Ahmad Kobaissi, Bernard Amiaud, Julien Ruelle, Emile Benizri

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Agromining is a new technology that establishes agricultural systems on ultramafic soils in order to produce valuable metal compounds such as nickel (Ni), with the final aim of restoring a soil's agricultural functions. But ultramafic soils are characterized by low fertility levels and this can limit yields of hyperaccumulators and metal phytoextraction. The objectives of the present work were to test if the association of a hyperaccumulating plant (Alyssum murale) and a Fabaceae (Vicia sativa var. Prontivesa) could induce changes in physicochemical characteristics of a serpentine soil and in root architecture of a hyperaccumulating plant then lead to efficient agromining practices through soil quality improvement. Based on standard agricultural systems, consisting in the association of legumes and another crop such as wheat or rape, a three-month rhizobox experiment was carried out to study the effect of the co-cropping (Co) or rotation (Ro) of a hyperaccumulating plant (Alyssum murale) with a legume (Vicia sativa) and incorporating legume biomass to soil, in comparison with mineral fertilization (FMo), on the structure and physicochemical properties of an ultramafic soil and on root architecture. All parameters measured (biomass, C and N contents, and taken-up Ni) on Alyssum murale conducted in co-cropping system showed the highest values followed by the mineral fertilization and rotation (Co > FMo > Ro), except for root nickel yield for which rotation was better than the mineral fertilization (Ro > FMo). The rhizosphere soil of Alyssum murale in co-cropping had larger soil particles size and better aggregates stability than other treatments. Using geostatistics, co-cropped Alyssum murale showed a greater root surface area spatial distribution. Moreover, co-cropping and rotation-induced lower soil DTPA-extractable nickel concentrations than other treatments, but higher pH values. Alyssum murale co-cropped with a legume showed a higher biomass production, improved soil physical characteristics and enhanced nickel phytoextraction. This study showed that the introduction of a legume into Ni agromining systems could improve yields of dry biomass of the hyperaccumulating plant used and consequently, the yields of Ni. Our strategy can decrease the need to apply fertilizers and thus minimizes the risk of nitrogen leaching and underground water pollution. Co-cropping of Alyssum murale with the legume showed a clear tendency to increase nickel phytoextraction and plant biomass in comparison to rotation treatment and fertilized mono-culture. In addition, co-cropping improved soil physical characteristics and soil structure through larger and more stabilized aggregates. It is, therefore, reasonable to conclude that the use of legumes in Ni-agromining systems could be a good strategy to reduce chemical inputs and to restore soil agricultural functions. Improving the agromining system by the replacement of inorganic fertilizers could simultaneously be a safe way of rehabilitating degraded soils and a method to restore soil quality and functions leading to the recovery of ecosystem services.

Keywords: plant association, legumes, hyperaccumulating plants, ultramafic soil physicochemical properties

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Authors: Ariungerel Jargal

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: Cave mining is a bulk underground mining method, which allows large low-grade deposits to be mined underground. This method involves undermining the orebody to make it collapse under its own weight into a series of chambers from which the ore extracted. It is a useful technique to extend the life of large deposits previously mined by open pits, and it is a method increasingly proposed for new mines around the world. We plan to conduct a feasibility study using Electrical impedance tomography (EIT) technology to show how much subsidence there is at the intersection with the cave mining surface. EIT is an imaging technique which uses electrical measurements at electrodes attached on the body surface to yield a cross-sectional image of conductivity changes within the object. EIT has been developed in several different applications areas as a simpler, cheaper alternative to many other imaging methods. A low frequency current is injected between pairs of electrodes while voltage measurements are collected at all other electrode pairs. In the difference EIT, images are reconstructed of the change in conductivity distribution (σ) between the acquisition of the two sets of measurements. Image reconstruction in EIT requires the solution of an ill-conditioned nonlinear inverse problem on noisy data, typically requiring make simpler assumptions or regularization. It is noted that the ratio of current to voltage represents a complex value according to Ohm’s law, and that it is theoretically possible to re-express EIT. The results of the experiment were presented on the simulation, and it was concluded that it is possible to conduct further real experiments. Drill a certain number of holes in the top wall of the cave to attach the electrodes, flow a current through them, and measure and acquire the potential through these electrodes. Appropriate values should be selected depending on the distance between the holes, the frequency and duration of the measurements, the surface characteristics and the size of the study area using an EIT device.

Keywords: impedance tomography, cave mining, soil, EIT device

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Authors: Ying-Chang Yu, Yuan-Lung Lo

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Building envelope design is one of the most popular design fields of architectural profession in nowadays. The main design trend of such system is to highlight the designer's aesthetic intention from the outlook of building project. Due to the trend of current façade design, the building envelope contains more and more layers of components, such as double skin façade, photovoltaic panels, solar control system, or even ornamental components. These exterior components are designed for various functional purposes. Most researchers focus on how these exterior elements should be structurally sound secured. However, not many researchers consider these elements would help to improve the performance of façade system. When the exterior elements are deployed in large scale, it creates an additional layer outside of original façade system and acts like a porous interface which would interfere with the aerodynamic of façade surface in micro-scale. A standard façade performance consists with 'water penetration, air infiltration rate, operation force, and component deflection ratio', and these key performances are majorly driven by the 'Design Wind Load' coded in local regulation. A design wind load is usually determined by the maximum wind pressure which occurs on the surface due to the geometry or location of building in extreme conditions. This research was designed to identify the air damping phenomenon of micro turbulence caused by porous exterior layer leading to surface wind load reduction for improvement of façade system performance. A series of wind tunnel test on dynamic pressure sensor array covered by various scale of porous exterior skin was conducted to verify the effect of wind pressure reduction. The testing specimens were designed to simulate the typical building with two-meter extension offsetting from building surface. Multiple porous exterior skins were prepared to replicate various opening ratio of surface which may cause different level of damping effect. This research adopted 'Pitot static tube', 'Thermal anemometers', and 'Hot film probe' to collect the data of surface dynamic pressure behind porous skin. Turbulence and distributed resistance are the two main factors of aerodynamic which would reduce the actual wind pressure. From initiative observation, the reading of surface wind pressure was effectively reduced behind porous media. In such case, an actual building envelope system may be benefited by porous skin from the reduction of surface wind pressure, which may improve the performance of envelope system consequently.

Keywords: multi-layer facade, porous media, facade performance, turbulence and distributed resistance, wind tunnel test

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Authors: Hari Singh, Abhishek Kamboj, Sudhir Kumar

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This investigation proposes a grey-based Taguchi method to solve the multi-response problems. The grey-based Taguchi method is based on the Taguchi’s design of experimental method, and adopts Grey Relational Analysis (GRA) to transfer multi-response problems into single-response problems. In this investigation, an attempt has been made to optimize the drilling process parameters considering weighted output response characteristics using grey relational analysis. The output response characteristics considered are surface roughness, burr height and hole diameter error under the experimental conditions of cutting speed, feed rate, step angle, and cutting environment. The drilling experiments were conducted using L27 orthogonal array. A combination of orthogonal array, design of experiments and grey relational analysis was used to ascertain best possible drilling process parameters that give minimum surface roughness, burr height and hole diameter error. The results reveal that combination of Taguchi design of experiment and grey relational analysis improves surface quality of drilled hole.

Keywords: metal matrix composite, drilling, optimization, step drill, surface roughness, burr height, hole diameter error

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Authors: Suryapeta Harini

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Road surface roughness is one of the essential aspects of the road's functional condition, indicating riding comfort in both the transverse and longitudinal directions. The government of India has made maintaining good surface evenness a prerequisite for all highway projects. Pavement distress data was collected with a Network Survey Vehicle (NSV) on a National Highway. It determines the smoothness and frictional qualities of the pavement surface, which are related to driving safety and ease. Based on the data obtained in the field, a regression equation was created with the IRI value and the visual distresses. The suggested system can use wireless acceleration sensors and GPS to gather vehicle status and location data, as well as calculate the international roughness index (IRI). Potholes, raveling, rut depth, cracked area, and repair work are all affected by pavement roughness, according to the current study. The study was carried out in one location. Data collected through using Bump integrator was used for the validation. The bump integrator (BI) obtained using deflection from the network survey vehicle was correlated with the distress parameter to establish an equation.

Keywords: roughness index, network survey vehicle, regression, correlation

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Authors: Asim Abbasi, Muhammad Sufyan

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The present experiment was carried out to examine the effects of silicon dioxide on tritrophic interaction of cotton, whitefly, and the predator Chrysoperla carnea. Population of whitefly was maintained on silicon treated and non-treated cotton for two generations in greenhouse net cages exposed to outside temperature and luminosity. The cotton was treated with silicon dioxide twice after 15 days intervals with 200 ppm concentration. A stock rearing of the natural predator was developed in the laboratory conditions. In the bioassay eggs of the predator all at the same age were individualized in glass petri plates that will be pierced with a pin to allow aeration and maintained in an incubator at 28 ± 2°C, 70 ± 10% relative humidity and 12h photo phase. Population of whitefly stayed on silicon treated, and non-treated cotton were offered to newly hatched chrysopid larvae until the end of the larval stage, assuring a permanent supply. Feeding preference of C. carnea along with longevity, survival of each instar larvae, pupation, adult emergence, and fecundity was checked. The results revealed that there was no significant difference in the feeding preference of C. carnea among both treatments. Durations of 1st and 2nd larval instar were also at par in both treatments. However overall longevity and adult emergence were a bit lower in silicon treated whitefly treatment. This may be due to the fact that silicon reduces the nutritional quality of host because of reduced whitefly feeding on silicon treated cotton. No significant difference in 1st and 2nd larval instars and then increased larval duration in later instars suggested that the effect of silicon treated host should be checked on more than 1 generation of C. carnea to get better findings.

Keywords: Chrysoperla carnea, silicon, tritrophic, whitefly

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Authors: Xiaodong Xu, Dan Zhao, Xiujuan Chang, Chunming Li, Huiyun Zhou, Xin Li, Qiang Shi, Shifang Luan, Jinghua Yin

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Polypropylene (PP) is one of the most commonly used plastics because of its low density, outstanding mechanical properties, and low cost. However, its drawbacks such as low surface energy, poor dyeability, lack of chemical functionalities, and poor compatibility with polar polymers and inorganic materials, have restricted the application of PP. To expand its application in biomedical materials, functionalization is considered to be the most effective way. In this study, PP was functionalized with a chiral monomer, (S)-1-acryloylpyrrolidine-2-carboxylic acid ((S)-APCA), by free-radical grafting in the solid phase. The grafting degree of PP-g-APCA was determined by chemical titration method, and the chemical structure of functionalized PP was characterized by FTIR spectroscopy, which confirmed that the chiral monomer (S)-APCA was successfully grafted onto PP. Static water contact angle results suggested that the surface hydrophilicity of PP was significantly improved by solid phase grafting and assistance of surface water treatment. Protein adsorption and platelet adhesion results showed that hemocompatibility of PP was greatly improved by grafting the chiral monomer.

Keywords: functionalization, polypropylene, chiral monomer, hemocompatibility

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Authors: Riya Bose, Ashok Bera, Manas R. Parida, Anirudhha Adhikari, Basamat S. Shaheen, Erkki Alarousu, Jingya Sun, Tom Wu, Osman M. Bakr, Omar F. Mohammed

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This work reports visualization of charge carrier dynamics on the surface of copper indium gallium selenide (CIGSe) nanocrystals in real space and time using four-dimensional scanning ultrafast electron microscopy (4D S-UEM) and correlates it with the optoelectronic properties of the nanocrystals. The surface of the nanocrystals plays a key role in controlling their applicability for light emitting and light harvesting purposes. Typically for quaternary systems like CIGSe, which have many desirable attributes to be used for optoelectronic applications, relative abundance of surface trap states acting as non-radiative recombination centre for charge carriers remains as a major bottleneck preventing further advancements and commercial exploitation of these nanocrystals devices. Though ultrafast spectroscopic techniques allow determining the presence of picosecond carrier trapping channels, because of relative larger penetration depth of the laser beam, only information mainly from the bulk of the nanocrystals is obtained. Selective mapping of such ultrafast dynamical processes on the surfaces of nanocrystals remains as a key challenge, so far out of reach of purely optical probing time-resolved laser techniques. In S-UEM, the optical pulse generated from a femtosecond (fs) laser system is used to generate electron packets from the tip of the scanning electron microscope, instead of the continuous electron beam used in the conventional setup. This pulse is synchronized with another optical excitation pulse that initiates carrier dynamics in the sample. The principle of S-UEM is to detect the secondary electrons (SEs) generated in the sample, which is emitted from the first few nanometers of the top surface. Constructed at different time delays between the optical and electron pulses, these SE images give direct and precise information about the carrier dynamics on the surface of the material of interest. In this work, we report selective mapping of surface dynamics in real space and time of CIGSe nanocrystals applying 4D S-UEM. We show that the trap states can be considerably passivated by ZnS shelling of the nanocrystals, and the carrier dynamics can be significantly slowed down. We also compared and discussed the S-UEM kinetics with the carrier dynamics obtained from conventional ultrafast time-resolved techniques. Additionally, a direct effect of the state trap removal can be observed in the enhanced photoresponse of the nanocrystals after shelling. Direct observation of surface dynamics will not only provide a profound understanding of the photo-physical mechanisms on nanocrystals’ surfaces but also enable to unlock their full potential for light emitting and harvesting applications.

Keywords: 4D scanning ultrafast microscopy, charge carrier dynamics, nanocrystals, optoelectronics, surface passivation, trap states

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Authors: Sonia Besbes, Mahmoud El Hajem, Habib Ben Aissia, Jean Yves Champagne, Jacques Jay

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In this work, we present a computational study for the characterization of the flow in a rectangular bubble column. To simulate the dynamic characteristics of the flow, a three-dimensional transient numerical simulations based on a coupled discrete phase model (DPM) and Volume of Fluid (VOF) model are performed. Modeling of bubble column reactor is often carried out under the assumption of a flat liquid surface with a degassing boundary condition. However, the dynamic behavior of the top surface surmounting the liquid phase will to some extent influence the meandering oscillations of the bubble plume. Therefore it is important to capture the surface behavior, and the assumption of a flat surface may not be applicable. So, the modeling approach needs to account for a dynamic liquid surface induced by the rising bubble plume. The volume of fluid (VOF) model was applied for the liquid and top gas which both interacts with bubbles implemented with a discrete phase model. This model treats the bubbles as Lagrangian particles and the liquid and the top gas as Eulerian phases with a sharp interface. Two-way coupling between Eulerian phases and Lagrangian bubbles are accounted for in a single set continuous phase momentum equation for the mixture of the two Eulerian phases. The effect of gas flow rate on the dynamic and time-averaged flow properties was studied. The time averaged liquid velocity field predicted from simulations and from our previous PIV measurements shows that the liquid is entrained up flow in the wake of the bubbles and down flow near the walls. The simulated and measured vertical velocity profiles exhibit a reasonable agreement looking at the minimum velocity values near the walls and the maximum values at the column center.

Keywords: bubble column, computational fluid dynamics (CFD), coupled DPM and VOF model, hydrodynamics

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Authors: Ishraq M. Anjum

Abstract:

Distributed Bragg reflectors are used in vertical-cavity surface-emitting lasers (VCSELs) in order to achieve very high reflectivity. Use of metamaterial in place of distributed Bragg reflector can reduce the device size significantly. A silicon-based metamaterial near perfect reflector is designed to be used in place of distributed Bragg reflectors in VCSELs. Mie resonance in dielectric microparticles is exploited in order to design the metamaterial. A reflectivity of 98.31% is achieved using finite-difference time-domain method. An 808nm double intra-cavity contacted VCSEL structure with 1.5 λ cavity is proposed using this metamaterial near perfect reflector. The active region is designed to be composed of seven GaAs/AlGaAs quantum wells. Upon numerical investigation of the designed VCSEL structure, the threshold current is found to be 2.96 mA at an aperture of 40 square micrometers and the maximum output power is found to be 71 mW at a current of 141 mA. Miniaturization of conventional VCSELs is possible using this design.

Keywords: GaAs, LASER, metamaterial, VCSEL, vertical cavity surface emitting laser

Procedia PDF Downloads 173

Authors: Balkar Singh, Gurpreet Singh, Vivek Aggarwal, Sehijpal Singh

Abstract:

The present research focused to improve the machinability of Hastelloy C-276 at different machining speeds such as 31, 55, and 79 m/min. The use of CO2 gas and Minimum quantity lubrication (MQL) was applied as coolant and lubrication purposes to enhance the machinability of the superalloy. The output in the form of surface roughness (S.R) and heat generation was monitored under dry, MQL, and MQL-CO2-cooled conditions. The Design of the Experiment was prepared using MINITAB software utilizing Taguchi L-27 orthogonal arrays followed by ANOVA analysis for finding the impact of input variables on output responses. At different speeds and lubrication conditions, different behavioral patterns for Surface Roughness and the temperature was observed. ANOVA analysis depicted that the cooling environment impacted the S.R. majorly (50%) followed by cutting speed (29.84%), feed rate (5.09%), and least through depth of cut (4.95%). On the other side, the temperature was greatly influenced by cutting speed (69.12%), Cryo-MQL (8.09%), feed rate (7.59%), and depth of cut (6.20%). Experimental results revealed that Cryo-MQL cooling enhanced the Surface roughness by 12% compared to MQL condition.

Keywords: Hastelloy C-276, minimum quantity lubrication, olive oil, cryogenic Cooling (CO2)

Procedia PDF Downloads 132

Authors: Balakumar Pitchai, Xiang Llan Ang, Sunil Prajapati, Varatharajan Rajavel, Sundram Karupiah, Mohd Baidi Bahari

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The study examined the pretreatment and post-treatment effects of low-doses of fenofibrate and rosuvastatin in gentamicin-induced acute nephrotoxicity in rats. Gentamicin (100 mg/kg/day, i.p.) was administered to rats for 8 days. In the pretreatment protocol, low-dose fenofibrate (30 mg/kg/day, p.o.) or low-dose rosuvastatin (2 mg/kg/day, p.o.) treatments were started a day before the administration of gentamicin and continued for 8 days. In the post-treatment protocol, rats administered gentamicin were treated with low-dose fenofibrate (30 mg/kg/day, p.o.) or low-dose rosuvastatin (2 mg/kg/day, p.o.) for 6 days after the completion of 8 days protocol of gentamicin administration. Gentamicin-associated acute nephrotoxicity in rats was assessed in terms of biochemical analysis and renal histopathological studies. Gentamicin-administered rats showed marked renal functional changes as assessed in terms of a significant increase in serum creatinine and urea levels as compared to normal rats. The renal dysfunction noted in gentamicin administered rats was accompanied with elevated serum uric acid level as compared to normal rats while there was no significant change in lipid profile. Low-dose fenofibrate pretreatment in gentamicin-administered rats afforded a significant renal functional improvements and renoprotection while its post-treatment showed no significant renoprotection. On the other hand, pretreatment with low-dose rosuvastatin partially reduced gentamicin-induced increase in serum creatinine level, but its post-treatment did not afford renal functional improvements in gentamicin-administered rats. However, all pre and post-treatments with low-doses of fenofibrate or rosuvastatin significantly reduced the elevated serum uric acid concentration in gentamicin-administered rats. Renal histopathological analysis showed a discernible incidence of acute tubular necrosis in gentamicin-administered rats which were markedly reduced by low-dose fenofibrate or low-dose rosuvastatin pretreatments; but, not by their post-treatments. In conclusion, low-dose fenofibrate pretreatment considerably prevented gentamicin-induced acute tubular necrosis and renal functional abnormalities in rats while its post-treatment resulted in no significant renoprotective action. In spite of effective prevention of gentamicin-induced acute tubular necrosis, the pretreatment with low-dose rosuvastatin had only a partial and fractional protection on renal functional abnormalities. The post-treatment with low-dose rosuvastatin was ineffective in affording a renoprotection in gentamicin-administered rats.

Keywords: gentamicin-nephrotoxicity, low-dose fenofibrate, low-dose rosuvastatin, renoprotection

Procedia PDF Downloads 196

Authors: Hannah Riva, Sarah Mazal, Jessica L. Marquez, Michael Rains

Abstract:

A 70-year-old female with a Fitzpatrick skin phenotype II presented with a 13-year history of a scaly rash located on the left breast and bilateral pretibial regions. The patient’s past medical history was otherwise unremarkable, with the exception of surgery involving the left breast. Physical examination revealed infiltrative hyperpigmented scaly plaques and nodules located on the left breast and pretibial regions bilaterally. A negative systemic workup excluded organ involvement. A clinical diagnosis of cutaneous sarcoidosis was made. Prior treatments included triamcinolone 0.1% topical cream and clobetasol 0.05% ointment, which failed to show improvement. Full-body narrow-band UVB (NBUVB) treatment was performed on a tri-weekly basis for eight months. NBUVB dosage was slowly titrated from 300 mJ/cm2 to a final dose of 1800 mJ/cm2 to prevent discomfort and burning sensations. Throughout the duration of her treatment, the patient adhered to a regimen of clobetasol 0.05% topical ointment applied twice daily in two-week intervals. Improvement was noticed after two months, with continued improvement up to eight months. The patient is continuing NBUVB phototherapy treatments for maintenance. In our case, NBUVB phototherapy treatment demonstrated promising results with improvement after two months of treatment. Physicians should consider NBUVB phototherapy as an effective option for patients presenting with cutaneous sarcoidosis.

Keywords: dermatology, sarcoidosis, phototherapy, ultraviolet

Procedia PDF Downloads 67

Authors: Wei-Kuo Soong

Abstract:

The forecasting of typhoon tracks remains a formidable challenge, primarily attributable to the paucity of observational data in the open sea and the intricate influence of weather systems at varying scales. This study investigates the case of Typhoon Hinnamnor in 2022, examining its trajectory and intensity fluctuations in relation to the interaction with a concurrent tropical cyclone and sea surface temperatures (SST). Utilizing the Weather Research and Forecasting Model (WRF), to simulate and analyze the interaction between Typhoon Hinnamnor and its environmental factors, shedding light on the mechanisms driving typhoon development and enhancing forecasting capabilities.

Keywords: typhoon, sea surface temperature, forecasting, WRF

Procedia PDF Downloads 45

Authors: T. Abohalkuma, J. Telegdi

Abstract:

Preparation, characterization, and application of self-assembled monolayers (SAM) formed by fluorophosphonic and undecenyl phosphonic acids on carbon steel surfaces as anticorrosive nanocoatings were demonstrated. The anticorrosive efficacy of these SAM layers was followed by atomic force microscopy, as the change in the surface morphology caused by layer deposition and corrosion processes was monitored. The corrosion process was determined by electrochemical potentiodynamic polarization, whereas the surface wettability of the carbon steel samples was tested with the use of static and dynamic contact angle measurements. Results showed that both chemicals produced good protection against corrosion as they performed as anodic inhibitors, especially with increasing the time of layer formation, which results in a more compact molecular film. According to the atomic force microscope (AFM) images, the fluoro-phosphonic acid self-assembled molecular layer can control the general as well as the pitting corrosion, but the SAM layers of the undecenyl-phosphonic acid cannot inhibit the pitting corrosion. The AFM and the contact angle measurements confirmed the results achieved by electrochemical measurements.

Keywords: nanolayers, corrosion, phosphonic acids, coatings

Procedia PDF Downloads 164

Authors: Kamal Upadhyay, Zhou Hua, Yu Rui

Abstract:

This paper aims to improve the streamline linked with the flow field and cavitation on the valve sleeve. We observed that local pressure fluctuation produces a low-pressure zone, central to the formation of vapor volume fraction within the valve chamber led to air-bubbles (or cavities). Thus, it allows simultaneously to a severe negative impact on the inner surface and lifespan of the valve sleeves. Cavitation reduction is a vitally important issue to pressure control valves. The optimization of the flow field is proposed in this paper to reduce the cavitation of valve sleeves. In this method, the inner wall of the valve sleeve is changed from a cylindrical surface to the conical surface, leading to the decline of the fluid flow velocity and the rise of the outlet pressure. Besides, the streamline is distributed inside the sleeve uniformly. Thus, the bubble generation is lessened. The fluid models are built and analysis of flow field distribution, pressure, vapor volume and velocity was carried out using computational fluid dynamics (CFD) and numerical technique. The results indicate that this structure can suppress the cavitation of valve sleeves effectively.

Keywords: streamline, cavitation, optimization, computational fluid dynamics

Procedia PDF Downloads 134

Authors: Shreekumari Patel, Prabhjot Kaur, Paras Solanki

Abstract:

Moon Mineralogy Mapper (M3), Miniature Radio Frequency (Mini-RF), Kaguya Terrain Camera images, Lunar Orbiter Laser Altimeter (LOLA) digital elevation model (DEM) and Lunar Reconnaissance Orbiter Camera (LROC)- Narrow angle camera (NAC) and Wide angle camera (WAC) images were used to study mineralogy, surface physical properties, and age of the 42 km diameter Kopff crater. M3 indicates the low albedo crater floor to be high-Ca pyroxene dominated associated with floor fracture suggesting the igneous activity of the gabbroic material. Signature of anorthositic material is sampled on the eastern edge as target material is excavated from ~3 km diameter impact crater providing access to the crustal composition. Several occurrences of spinel were detected in northwestern rugged terrain. Our observation can be explained by exposure of spinel by this crater that impacted onto the inner rings of Orientale basin. Spinel was part of the pre-impact target, an intrinsic unit of basin ring. Crater floor was dated by crater counts performed on Kaguya TC images. Nature of surface was studied in detail with LROC NAC and Mini-RF. Freshly exposed surface and boulder or debris seen in LROC NAC images have enhanced radar signal in comparison to mature terrain of Kopff crater. This multidisciplinary analysis of remote sensing data helps to assess lunar surface in detail.

Keywords: crater, mineralogy, moon, radar observations

Procedia PDF Downloads 151