Search results for: fiber characteristics

Authors: Sewon Kim, Chang Yeop Lee, Minjun Kwon

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This study is aiming at establishing the relationship between the optical signal of flame and an equivalent ratio of flame. In this experiment, flame optical signal in a furnace is measured using photodiode. The combustion system is composed of metal fiber burner and vertical furnace, and flame chemiluminescence is measured at various experimental conditions. In this study, the flame chemiluminescence of laminar premixed flame is measured using commercially available photodiode. It is experimentally investigated the relationship between equivalent ratio and photodiode signal. In addition, the strategy of combustion control method is proposed using the optical signal and fuel pressure. The results showed that certain relationship between optical data of photodiode and equivalence ratio exists, and this leads to the successful application of this system for instantaneous measurement of equivalence ration of the combustion system.

Keywords: Flame chemiluminescence, photo diode, equivalence ratio, combustion control.

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Authors: C. Amer, M. Sahin

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The design of an optimised horizontal axis 5-meter-long wind turbine rotor blade in according with IEC 61400-2 standard is a research and development project in order to fulfil the requirements of high efficiency of torque from wind production and to optimise the structural components to the lightest and strongest way possible. For this purpose, a research study is presented here by focusing on the structural characteristics of a composite wind turbine blade via finite element modelling and analysis tools. In this work, first, the required data regarding the general geometrical parts are gathered. Then, the airfoil geometries are created at various sections along the span of the blade by using CATIA software to obtain the two surfaces, namely; the suction and the pressure side of the blade in which there is a hat shaped fibre reinforced plastic spar beam, so-called chassis starting at 0.5m from the root of the blade and extends up to 4 m and filled with a foam core. The root part connecting the blade to the main rotor differential metallic hub having twelve hollow threaded studs is then modelled. The materials are assigned as two different types of glass fabrics, polymeric foam core material and the steel-balsa wood combination for the root connection parts. The glass fabrics are applied using hand wet lay-up lamination with epoxy resin as METYX L600E10C-0, is the unidirectional continuous fibres and METYX XL800E10F having a tri-axial architecture with fibres in the 0,+45,-45 degree orientations in a ratio of 2:1:1. Divinycell H45 is used as the polymeric foam. The finite element modelling of the blade is performed via MSC PATRAN software with various meshes created on each structural part considering shell type for all surface geometries, and lumped mass were added to simulate extra adhesive locations. For the static analysis, the boundary conditions are assigned as fixed at the root through aforementioned bolts, where for dynamic analysis both fixed-free and free-free boundary conditions are made. By also taking the mesh independency into account, MSC NASTRAN is used as a solver for both analyses. The static analysis aims the tip deflection of the blade under its own weight and the dynamic analysis comprises normal mode dynamic analysis performed in order to obtain the natural frequencies and corresponding mode shapes focusing the first five in and out-of-plane bending and the torsional modes of the blade. The analyses results of this study are then used as a benchmark prior to modal testing, where the experiments over the produced wind turbine rotor blade has approved the analytical calculations.

Keywords: Dynamic analysis, Fiber Reinforced Composites, Horizontal axis wind turbine blade, Hand-wet layup, Modal Testing.

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Authors: Rezaul Azim, A. Toaha Mobashsher, M. Tariqul Islam

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In this paper a novel ultra-wideband (UWB) slot antenna with band notch characteristics for world interoperability for microwave access (WiMAX) is proposed. The designed antenna consists of a rectangular radiating patch and a ground plane with tapered shape slot. To realize a notch band, a curved parasitic element has been etched out along with the radiating patch. It is observed that by adjusting the length, thickness and position of the parasitic element, the proposed antenna can achieved an impedance bandwidth of 8.01GHz (2.84 to 10.85GHz) with a notched band of 3.28-3.85GHz. Compared to the recently reported band notch antennas, the proposed antenna has a simple configuration to realize band notch characteristics in order to mitigate the potential interference between WiMAX and UWB system. Furthermore, a stable radiation pattern and moderate gain except at the notched band makes the proposed antenna suitable for various UWB applications. 

Keywords: Band notch, Filter element, Ultra-wideband (UWB), WiMAX.

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Authors: Suchi Barua, Narottam Das, Sven Nordholm, Mohammad Razaghi

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This paper presents nonlinear pulse propagation characteristics for different input optical pulse shapes with various input pulse energy levels in semiconductor optical amplifiers. For simulation of nonlinear pulse propagation, finite-difference beam propagation method is used to solve the nonlinear Schrödinger equation. In this equation, gain spectrum dynamics, gain saturation are taken into account which depends on carrier depletion, carrier heating, spectral-hole burning, group velocity dispersion, self-phase modulation and two photon absorption. From this analysis, we obtained the output waveforms and spectra for different input pulse shapes as well as for different input energies. It shows clearly that the peak position of the output waveforms are shifted toward the leading edge which due to the gain saturation of the SOA for higher input pulse energies. We also analyzed and compared the normalized difference of full-width at half maximum for different input pulse shapes in the SOA.

Keywords: Finite-difference beam propagation method, pulse shape, pulse propagation, semiconductor optical amplifier.

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Authors: E. Mello, C. Ribellato, E. Mohamedelhassan

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This study investigated the improvement in concrete properties with addition of cellulose, steel, carbon and PET fibers. Each fiber was added at four percentages to the fresh concrete, which was moist-cured for 28-days and then tested for compressive, flexural and tensile strengths. Changes in strength and increases in cost were analyzed. Results showed that addition of cellulose caused a decrease between 9.8% and 16.4% in compressive strength. This range may be acceptable as cellulose fibers can significantly increase the concrete resistance to fire, and freezing and thawing cycles. Addition of steel fibers to concreteincreased the compressive strength by up to 20%. Increases 121.5% and 80.7% were reported in tensile and flexural strengths respectively. Carbon fibers increased flexural and tensile strengths by up to 11% and 45%, respectively. Concrete strength properties decreased after the addition of PET fibers. Results showed that improvement in strength after addition of steel and carbon fibers may justify the extra cost of fibers.

Keywords: Concrete, compressive strength, fibers, flexural strength, tensile strength.

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Authors: Natural Frequency Analysis of a Porous Functionally Graded Shaft System

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The vibration characteristics of a functionally graded (FG) rotor model having porosities and micro-voids is investigated using three-dimensional finite element analysis. The FG shaft is mounted with a steel disc located at the midspan. The shaft ends are supported on isotropic bearings. The FG material is composed of a metallic (stainless-steel) and ceramic phase (zirconium oxide) as its constituent phases. The layer wise material property variation is governed by power law. Material property equations are developed for the porosity modelling. Python code is developed to assign the material properties to each layer including the effect of porosities. ANSYS commercial software is used to extract the natural frequencies and whirl frequencies for the FG shaft system. The obtained results show the influence of porosity volume fraction and power-law index, on the vibration characteristics of the ceramic-based FG shaft system.

Keywords: Finite element method, functionally graded material, porosity volume fraction, power law.

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Authors: Pakorn Uttayopas, Chawalit Kittichaikarn

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This paper presents an experimental investigation for the characteristics of an energy harvesting device exploiting flow-induced vibration in a wind tunnel. A stationary bluff body is connected with a downstream tip body via an aluminium cantilever beam. Various lengths of aluminium cantilever beam and different shapes of downstream tip body are considered. The results show that the characteristics of the energy harvester’s vibration depend on both the length of the aluminium cantilever beam and the shape of the downstream tip body. The highest ratio between vibration amplitude and bluff body diameter was found to be 1.39 for an energy harvester with a symmetrical triangular tip body and L/D₁ = 5 at 9.8 m/s of flow speed (Re = 20077). Using this configuration, the electrical energy was extracted with a polyvinylidene fluoride (PVDF) piezoelectric beam with different load resistances, of which the optimal value could be found on each Reynolds number. The highest power output was found to be 3.19 µW, at 9.8 m/s of flow speed (Re = 20077) and 27 MΩ of load resistance.

Keywords: Downstream structures, energy harvesting, flow-induced vibration, piezoelectric material, wind tunnel.

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Authors: Dowluru Ravi Kumar, Bhima Prabhakara Rao

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Propagation of solitons in single-mode birefringent fibers is considered under the presence of third-order dispersion (TOD). The behavior of two neighboring solitons and their interaction is investigated under the presence of third-order dispersion with different group velocity dispersion (GVD) parameters. It is found that third-order dispersion makes the resultant soliton to deviate from its ideal position and increases the interaction between adjacent soliton pulses. It is also observed that this deviation due to third-order dispersion is considerably small when the optical pulse propagates at wavelengths relatively far from the zerodispersion. Modified coupled nonlinear Schrödinger-s equations (CNLSE) representing the propagation of optical pulse in single mode fiber with TOD are solved using split-step Fourier algorithm. The results presented in this paper reveal that the third-order dispersion can substantially increase the interaction between the solitons, but large group velocity dispersion reduces the interaction between neighboring solitons.

Keywords: Birefringence, Group velocity dispersion, Polarization mode dispersion, Soliton interaction, Third order dispersion.

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Authors: Martina Drdlová, Michal Frank, Jaroslav Buchar, Josef Krátký

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The main aim of the presented experiments is to improve behaviour of sandwich structures under dynamic loading, such as crash or explosion. Several cellular materials are widely used as core of the sandwich structures and their properties influence the response of the entire element under impact load. To optimize their performance requires the characterisation of the core material behaviour at high strain rates and identification of the underlying mechanism. This work presents the study of high strain-rate characteristics of a specific porous lightweight blast energy absorbing foam using a Split Hopkinson Pressure Bar (SHPB) technique adapted to perform tests on low strength materials. Two different velocities, 15 and 30 m.s-1 were used to determine the strain sensitivity of the material. Foams were designed using two types of porous lightweight spherical raw materials with diameters of 30- 100 *m, combined with polymer matrix. Cylindrical specimens with diameter of 15 mm and length of 7 mm were prepared and loaded using a Split Hopkinson Pressure Bar apparatus to assess the relation between the composition of the material and its shock wave attenuation capacity.

Keywords: Blast, foam, microsphere, resin.

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Authors: Ismail Hakki Kalyoncu, Nilda Ersoy, Ayse Yalcin Elidemir, Inci Tolay

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In this study, The physico-chemical and nutritional properties of `Musmula` Medlar (Mespilus germanica L.) fruit and seed grown in Northeast Anatolia was investigated. In the fruit, length, width, thickness, weight, total soluble solids, colour (1), colour (2) [L, a, b values], protein, crude ash, crude fiber, crude oil, texture and pH were determinated as 4.34 cm, 4.22 cm, 3.67 cm, 38.36 g, 23.97 %, S60O60Y41,, [53.85, 17.15, 33.75], 1.06 %, 0.79 %, 4.24 %, 0.005 %, 1.21 kg/cm2 and 4.26 respectively. Also, pulp ratio, seed ratio and pulp/seed ratio were found to be 92.88 %, 7.11 % and 14.07 %, respectively. In addition, the mineral composition of medlar fruit in Northeast Anatolia was studied. In the fruit, 23 minerals were analyzed and 19 minerals were present at detectable levels. The medlar fruit was richest in potassium (6962 ppm), calcium (1186.378 ppm), magnesium (1070.08 ppm) and phosphor (763.425 ppm).

Keywords: Fruits, Mespilus germanica L., mineral compounds, physico-chemical properties.

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Authors: Igor Shardakov, Anton Bykov, Alexey Shestakov, Irina Glot

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This article focuses on the cycle of experimental studies of the formation of cracks and debondings in the concrete reinforced with carbon fiber. This research was carried out in Perm National Research Polytechnic University. A series of CFRP-strengthened RC beams was tested to investigate the influence of preload and crack repairing factors on CFRP debonding. IRT was applied to detect the early stage of IC debonding during the laboratory bending tests. It was found that for the beams strengthened under load after crack injecting, СFRP debonding strain is 4-65% lower than for the preliminary strengthened beams. The beams strengthened under the load had a relative area of debonding of 2 times higher than preliminary strengthened beams. The СFRP debonding strain is weakly dependent on the strength of the concrete substrate. For beams with a transverse wrapping anchorage in support sections FRP debonding is not a failure mode.

Keywords: FRP, RC beams, strengthening, IC debonding, infrared thermography, quality control, non-destructive testing methods.

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Authors: Praveen Kumar S P, Bong-Su Sin, Kwon-Hee Lee

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Finned-tube heat exchangers are predominantly used in space conditioning systems, as well as other applications requiring heat exchange between two fluids. The design of finned-tube heat exchangers requires the selection of over a dozen design parameters by the designer such as tube pitch, tube diameter, tube thickness, etc… Finned-tube heat exchangers are common devices; however, their performance characteristics are complicated. In this paper numerical studies have been carried out to analyze the performances of finned tube heat exchanger (without fins considered for experimental purpose) by predicting the characteristics of temperature difference and pressure drop. In this study, a design considering 5 design variables and also maximizing the temperature difference and pressure drop was suggested by applying DOE. During this process, L₁₈ orthogonal array was adopted. Parametric analytical studies have been carried out using ANOVA to determine the relative importance of each variable with respect to the temperature difference and the pressure drop. Following the results, the final design was suggested by predicting the optimum design therefore confirming the optimized condition.

Keywords: Heat Exchanger, Fluid Analysis, Heat Transfer, Design of Experiment (DOE), Analysis of Variance (ANOVA).

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Authors: Erica Lima

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The objective of this paper is to discuss relevant points about teaching translation in Brazilian universities and the possible impacts of blogs and social networks to translator education today. It is intended to analyze the curricula of Brazilian translation courses, contrasting them to information obtained from two social networking groups of great visibility in the area concerning essential characteristics to become a successful profession. Therefore, research has, as its main corpus, a few undergraduate translation programs’ syllabuses, as well as a few postings on social networks groups that specifically share professional opinions regarding the necessity for a translator to obtain a degree in translation to practice the profession. To a certain extent, such comments and their corresponding responses lead to the propagation of discourses which influence the ideas that aspiring translators and recent graduates end up having towards themselves and their undergraduate courses. The postings also show that many professionals do not have a clear position regarding the translator education; while refuting it, they also encourage “free” courses. It is thus observed that cyberspace constitutes, on the one hand, a place of mobilization of people in defense of similar ideas. However, on the other hand, it embodies a place of tension and conflict, in view of the fact that there are many participants and, as in any other situation of interlocution, disagreements may arise. From the postings, aspects related to professionalism were analyzed (including discussions about regulation), as well as questions about the classic dichotomies: theory/practice; art/technique; self-education/academic training. As partial result, the common interest regarding the valorization of the profession could be mentioned, although there is no consensus on the essential characteristics to be a good translator. It was also possible to observe that the set of socially constructed representations in the group reflects characteristics of the world situation of the translation courses (especially in some European countries and in the United States), which, in the first instance, does not accurately reflect the Brazilian idiosyncrasies of the area.

Keywords: Cyberspace, teaching translation, translator education, university.

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Authors: Hossein Shokouhmand , Mohammad A. Esmaeili, Koohyar Vahidkhah

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This paper presents a numerical study on surface heat transfer characteristics of laminar air flows in parallel-plate dimpled channels. The two-dimensional numerical model is provided by commercial code FLUENT and the results are obtained for channels with symmetrically opposing hemi-cylindrical cavities onto both walls for Reynolds number ranging from 1000 to 2500. The influence of variations in relative depth of dimples (the ratio of cavity depth to the cavity curvature diameter), the number of them and the thermophysical properties of channel walls on heat transfer enhancement is studied. The results are evident for existence of an optimum value for the relative depth of dimples in which the largest wall heat flux and average Nusselt number can be achieved. In addition, the results of conjugation simulation indicate that the overall influence of the ratio of wall thermal conductivity to the one of the fluid on heat transfer rate is not much significant and can be ignored.

Keywords: cavity, conjugation, heat transfer, laminar air flow, Numerical, parallel-plate channel.

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Authors: J. H. Zhou, C. S. Cheung, C. W. Leung

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The present study conducted experimental investigation on combustion and emission characteristics of compression ignition engine using diesel as pilot fuel and methane, hydrogen and methane/hydrogen mixture as gaseous fuels at 1800 rev min-1. The effect of gaseous fuel on peak cylinder pressure and heat release is modest at low to medium loads. At high load, the high combustion temperature and high quantity of pilot fuel contribute to better combustion efficiency for all kinds of gaseous fuels and increases the peak cylinder pressure. Enrichment of hydrogen in methane gradually increases the peak cylinder pressure. The brake thermal efficiency increases with higher hydrogen fraction at lower loads. Hydrogen addition in methane contributed to a proportional reduction of CO/CO2/HC emission without penalty of NOx. For particulate emission, methane and hydrogen, could both suppress the particle emission. 30% hydrogen fraction in methane is observed to be best in reducing the particulate emission.

Keywords: Combustion characteristics, diesel engine, emissions, methane/hydrogen mixture.

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Authors: Rahim Ada, Mustafa Harmankaya, Sadiye Ayse Celik

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The safflower seed contains about 25-40% solvent extract and 20-33% fiber. It is well known that dietary phospholipids lower serum cholesterol levels effectively. The nutrient composition of safflower seed changes depending on region, soil and genotypes. This research was made by using of six natural selected (A22, A29, A30, C12, E1, F4, G8, G12, J27) and three commercial (Remzibey, Dincer, Black Sun1) varieties of safflower genotypes. The research was conducted on field conditions for two years (2009 and 2010) in randomized complete block design with three replications in Konya-Turkey ecological conditions. Oil contents, mineral contents and their correlations were determined in the research. According to the results, oil content was ranged from 22.38% to 34.26%, while the minerals were in between the following values: 1469, 04-2068.07 mg kg^-1 for Ca, 7.24-11.71 mg kg^-1 for B, 13.29-17.41 mg kg^-1 for Cu, 51.00-79.35 mg kg^-1 for Fe, 3988-6638.34 mg kg^-1 for K, 1418.61-2306.06 mg kg^-1 for Mg, 11.37-17.76 mg kg^-1 for Mn, 4172.33-7059.58 mg kg^-1 for P and 32.60-59.00 mg kg^-1 for Zn. Correlation analysis that was made separately for the commercial varieties and wild lines showed that high level of oil content was negatively affected by all the investigated minerals except for K and Zn in the commercial varieties.

Keywords: Safflower, oil, mineral content, quality.

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Authors: Dipak Sen, Rajdeep Ghosh

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This paper presents a computational study of steady state three dimensional very high turbulent flow and heat transfer characteristics in a constant temperature-surfaced circular duct fitted with 900 hemispherical inline baffles. The computations are based on realizable k-ɛ model with standard wall function considering the finite volume method, and the SIMPLE algorithm has been implemented. Computational Study are carried out for Reynolds number, Re ranging from 80000 to 120000, Prandtl Number, Pr of 0.73, Pitch Ratios, PR of 1,2,3,4,5 based on the hydraulic diameter of the channel, hydrodynamic entry length, thermal entry length and the test section. Ansys Fluent 15.0 software has been used to solve the flow field. Study reveals that circular pipe having baffles has a higher Nusselt number and friction factor compared to the smooth circular pipe without baffles. Maximum Nusselt number and friction factor are obtained for the PR=5 and PR=1 respectively. Nusselt number increases while pitch ratio increases in the range of study; however, friction factor also decreases up to PR 3 and after which it becomes almost constant up to PR 5. Thermal enhancement factor increases with increasing pitch ratio but with slightly decreasing Reynolds number in the range of study and becomes almost constant at higher Reynolds number. The computational results reveal that optimum thermal enhancement factor of 900 inline hemispherical baffle is about 1.23 for pitch ratio 5 at Reynolds number 120000.It also shows that the optimum pitch ratio for which the baffles can be installed in such very high turbulent flows should be 5. Results show that pitch ratio and Reynolds number play an important role on both fluid flow and heat transfer characteristics.

Keywords: Friction factor, heat transfer, turbulent flow, circular duct, baffle, pitch ratio.

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Authors: V. Endo, A. G. Silva Sobrinho, F. A. Almeida, N. L. L. Lima, G. M. Manzi, L. G. A. Cirne, N. M. B. L. Zeola

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We used 24 Ile de France lambs, weighing between 15 and 32 kg (BW). Treatments were supplemented with concentrate: “in nature” sugarcane (IN), sugarcane hydrolyzed using 0.6% calcium oxide (CaO) under aerobic condition (AER), and sugarcane hydrolyzed using 0.6% CaO under anaerobic condition (ANA), constituting a completely randomized design with eight repetitions per treatment. Lambs were housed in individual stalls and fed into the through, allowing 10% of leftovers. Lambs were slaughtered when body weight reached 32 kg. The following parameters were determined on Longissimu lumborum muscle of hot and cold carcasses: pH and color, 45 minutes and 24 hours after slaughtering. Qualitative analysis of the meat were performed in the loins, water-holding capacity (WHC), cooking loss (CL), and shear force (SF). We used a completely randomized design with three treatments and eight repetitions. Means were compared by Tukey test at 5% significance. A higher value for redness (a*) 45 minutes after slaughter (10.48) were found for lambs fed hydrolyzed under anaerobic conditions sugarcane. The other qualitative characteristics of meat were not affected by treatments (P >0.05). The comparison of meat quality resulting from the treatments shows that it is possible to feed in nature sugarcane to lambs, thus waiving hydrolyses process and the spending with alkalizing agent.

Keywords: Calcium oxide, hydrolysis, meat quality, pH.

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Authors: P. Saleh, G. Challita, R. Hazimeh, K. Khalil

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In this paper 3D FEM analysis was carried out on double lap bonded joint with composite adherents subjected to dynamic shear. The adherents are made of Carbon/Epoxy while the adhesive is epoxy Araldite 2031. The maximum average shear stress and the stress homogeneity in the adhesive layer were examined. Three fibers textures were considered: UD; 2.5D and 3D with same volume fiber then a parametric study based on changing the thickness and the type of fibers texture in 2.5D was accomplished. Moreover, adherents’ dissimilarity was also investigated. It was found that the main parameter influencing the behavior is the longitudinal stiffness of the adherents. An increase in the adherents’ longitudinal stiffness induces an increase in the maximum average shear stress in the adhesive layer and an improvement in the shear stress homogeneity within the joint. No remarkable improvement was observed for dissimilar adherents.

Keywords: Adhesive, Composite adherents, Impact shear, Finite element.

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Authors: Amin Almasi

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Composite laminates are relatively weak in out of plane loading, inter-laminar stress, stress concentration near the edge and stress singularities. This paper develops a new analytical formulation for laminated composite rotating disc fabricated from symmetric sequential quasi isotropic layers to predict three dimensional stress and deformation. This analysis is necessary to evaluate mechanical integrity of fiber reinforced multi-layer laminates used for high speed rotating applications such as high speed impellers. Three dimensional governing equations are written for rotating composite disc. Explicit solution is obtained with "Frobenius" expansion series. Based on analytical results, there are two separate zones of three dimensional stress fields in centre and edge of rotating disc. For thin discs, out of plane deformations and stresses are small in comparison with plane ones. For relatively thick discs deformation and stress fields are three dimensional.

Keywords: Composite Disc, Rotating Machine.

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Authors: Adrienn Novák

Abstract:

The field research was carried out at the Látókép AGTC KIT research area of the University of Debrecen in Eastern-Hungary, on the area of the aeolain loess of the Hajdúság. We examined the effects of the sowing time on the phytopathogenic characteristics and yield production by applying various fertilizer treatments on two different sunflower genotypes (NK Ferti, PR64H42) in 2012 and 2013. We applied three different sowing times (early, optimal, late) and two different treatment levels of fungicides (control = no fungicides applied, double fungicide protection).

During our investigations, the studied cropyears were of different sowing time optimum in terms of yield amount (2012: early, 2013: average). By Pearson’s correlation analysis, we have found that delaying the sowing time pronouncedly decreased the extent of infection in both crop years (Diaporthe: r=0.663**, r=0.681**, Sclerotinia: r=0.465**, r=0.622**). The fungicide treatment not only decreased the extent of infection, but had yield increasing effect too (2012: r=0.498**, 2013: r=0.603**). In 2012, delaying of the sowing time increased (r=0.600**), but in 2013, it decreased (r= 0.356*) the yield amount.

Keywords: Fungicide treatment, genotypes, sowing time, yield, sunflower.

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Authors: M. Alauddin, M. A. Ullah, M. Alom, M. N. Islam

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The rivers in Bangladesh are highly unstable having loose boundaries, mild slope of water surface and bed, irregular siltation of huge sediment coming from upstream, among others. The groins are installed in the river bank to deflect the flowing water away from the vulnerable zones. The conventional groins are found to be unstable and ineffective. The combined groin having both impermeable and permeable components in the same structure improves the flow field to function better over others. The main goal of this study is to analyze the hydraulic characteristics induced by the combined groins of different alignments by using a 2D numerical model, iRIC Nays2DH. In this numerical simulation, the K-ε model for turbulence and Cubic Interpolation Pseudo-particle (CIP) method for advective terms are utilized. A particular flow condition is applied in the channel for all sets of groins with different alignments. The simulation results reveal that the combined groins alter the flow patterns considerably, with no significant recirculation of flow in the groin field. The effect of different alignments of groins is found somewhat different. Based on hydraulic features caused by the groins, the combined groin that aligns the permeable component towards slightly downstream performs better over others.

Keywords: Combined groin, alignment, hydraulic characteristics, numerical model.

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Authors: Yasin Khan

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Overhead electrical insulators form an important link in an electric power system. Along with the traditional insulators (i.e. glass and porcelain, etc) presently the polymeric insulators are also used world widely. These polymeric insulators are very sensitive to various environmental parameters such temperature, environmental pollution, UV-radiations, etc. which seriously effect their electrical, chemical and hydrophobic properties. The UV radiation level in the central region of Saudi Arabia is high as compared to the IEC standard for the accelerated aging of the composite insulators. Commonly used suspension type of composite EPDM (Ethylene Propylene Diene Monomer) insulator was subjected to accelerated stress aging as per modified IEC standard simulating the inland arid deserts atmospheric condition and also as per IEC-61109 standard. The hydrophobic characteristics were studied by measuring the contact angle along the insulator surface before and after the accelerated aging of the samples. It was found that EPDM insulator loses it hydrophobic properties proportional to the intensity of UV irradiations and its rate of recovery is also very low as compared to Silicone Rubber insulator.KeywordsEPDM, composite insulators, accelerated aging, hydrophobicity, contact angle.

Keywords: EPDM, composite insulators, accelerated aging, hydrophobicity, contact angle.

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Authors: P. Weerachanchai, C. Tangsathitkulchai, M. Tangsathitkulchai

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Attempt was made to improve certain characteristics of bio-oil derived from palm kernel pyrolysis by blending it with diesel fuel and alcohols. Two types of alcohol, ethanol or butanol, was used as cosolvent to stabilize the phase of ternary systems. Phase behaviors and basic fuel properties of palm kernel bio-oildiesel- alcohol systems were investigated in this study. Alcohol types showed a significant influence on the phase characteristics with palm kernel bio-oil-diesel-butanol system giving larger soluble area than that of palm kernel bio-oil-diesel-ethanol system. For fuel properties, blended fuels showed superior properties including lower values of density (~860 kg/m3 at 25°C), viscosity (~4.12 mm2/s at 40°C), carbon residue (1.02-2.53 wt%), ash (0.018-0.034 wt%) and pour point (<-25 to -7 °C), increased pH (~ 6.4) and giving reasonable heating values of 32.5-41.2 MJ/kg. To enable the prediction of some properties of fuel mixtures, the measured fuel properties including heating value, density, ash content and pH were fitted by Kay-s mixing rule, whereas the viscosities of blended fuels at different temperatures were correlated by the modified Grunberg-Nissan equation and Andrade equation.

Keywords: Bio-oil, fuel blend, fuel properties, phase behaviour.

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Authors: Davood Mostofinejad, Seyed Amirali Mostafavizadeh, Amirhomayoon Tabatabaei Kashani

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One of the most common practices for strengthening the reinforced concrete structures is the application of FRP (Fiber Reinforce Plastic) sheets to increase the flexural and shear strengths of the member. The elastic modulus of FRP is considerably higher than that of concrete. This will result in debonding between the FRP sheets and concrete surface. With conventional surface preparation of concrete, the ultimate capacity of the FRP sheets can hardly be achieved. New methods for preparation of the bonding surface have shown improvements in reducing the premature debonding of FRP sheets from concrete surface. The present experimental study focuses on the application of grooving method to postpone debonding of the FRP sheets attached to the side faces of concrete beams for shear strengthening. Comparison has also been made with conventional surface preparation method. This study clearly shows the efficiency of grooving method compared to surface preparation method, in preventing the debonding phenomenon and in increasing the load carrying capacity of FRP.

Keywords: FRP composite, grooving, rehabilitation, reinforced concrete, shear strengthening, surface preparation.

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Authors: Senda Trabelsi, Sébastien Poncet, Michel Poirier

Abstract:

Ice slurries are considered as a promising phase-changing secondary fluids for air-conditioning, packaging or cooling industrial processes. An experimental study has been here carried out to measure the rheological characteristics of ice slurries. Ice slurries consist in a solid phase (flake ice crystals) and a liquid phase. The later is composed of a mixture of liquid water and an additive being here either (1) Propylene-Glycol (PG) or (2) Ethylene-Glycol (EG) used to lower the freezing point of water. Concentrations of 5%, 14% and 24% of both additives are investigated with ice mass fractions ranging from 5% to 85%. The rheological measurements are carried out using a Discovery HR-2 vane-concentric cylinder with four full-length blades. The experimental results show that the behavior of ice slurries is generally non-Newtonian with shear-thinning or shear-thickening behaviors depending on the experimental conditions. In order to determine the consistency and the flow index, the Herschel-Bulkley model is used to describe the behavior of ice slurries. The present results are finally validated against an experimental database found in the literature and the predictions of an Artificial Neural Network model.

Keywords: Ice slurry, propylene-glycol, ethylene-glycol, rheology, artificial neural network.

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Authors: M.M. Namazi, S.M. Saghaiannejad, A. Rashidi

Abstract:

In this paper by using the port-controlled Hamiltonian (PCH) systems theory, a full-order nonlinear controlled model is first developed. Then a nonlinear passivity-based robust adaptive control (PBRAC) of switched reluctance motor in the presence of external disturbances for the purpose of torque ripple reduction and characteristic improvement is presented. The proposed controller design is separated into the inner loop and the outer loop controller. In the inner loop, passivity-based control is employed by using energy shaping techniques to produce the proper switching function. The outer loop control is employed by robust adaptive controller to determine the appropriate Torque command. It can also overcome the inherent nonlinear characteristics of the system and make the whole system robust to uncertainties and bounded disturbances. A 4KW 8/6 SRM with experimental characteristics that takes magnetic saturation into account is modeled, simulation results show that the proposed scheme has good performance and practical application prospects.

Keywords: Switched Reluctance Motor, Port HamiltonianSystem, Passivity-Based Control, Torque Ripple Minimization

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Authors: N. Manoj

Abstract:

The aeroelastic behavior of engine nacelle strake when subjected to unsteady aerodynamic flows is investigated in this paper. Geometric nonlinear characteristics and modal parameters of nacelle strake are studied when it is under dynamic loading condition. Here, an N-S based Finite Volume solver is coupled with Finite Element (FE) based nonlinear structural solver to investigate the nonlinear characteristics of nacelle strake over a range of dynamic pressures at various phases of flight like takeoff, climb, and cruise conditions. The combination of high fidelity models for both aerodynamics and structural dynamics is used to predict the nonlinearities of strake (chine). The methodology adopted for present aeroelastic analysis is partitioned-based time domain coupled CFD and CSD solvers and it is validated by the consideration of experimental and numerical comparison of aeroelastic data for a cropped delta wing model which has a proven record. The present strake geometry is derived from theoretical formulation. The amplitude and frequency obtained from the coupled solver at various dynamic pressures is discussed, which gives a better understanding of its impact on aerodynamic design-sizing of strake.

Keywords: Aeroelasticity, finite volume, geometric nonlinearity, limit cycle oscillations, strake.

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Authors: Bi Bo, Kayoko Yamamoto

Abstract:

This study aims to identify processes, current situations, and issues of recycling systems for four home appliances, namely, air conditioners, television receivers, refrigerators, and washing machines, among e-wastes in China and Japan for understanding and comparison of their characteristics. In accordance with results of a literature search, review of information disclosed online, and questionnaire survey conducted, conclusions of the study boil down to: (1)The results show that in Japan most of the home appliances mentioned above have been collected through home appliance recycling tickets, resulting in an issue of “requiring some effort" in treatment and recycling stages, and most plants have contracted out their e-waste recycling. (2)It is found out that advantages of the recycling system in Japan include easiness to monitor concrete data and thorough environmental friendliness ensured while its disadvantages include illegal dumping and export. It becomes apparent that advantages of the recycling system in China include a high reuse rate, low treatment cost, and fewer illegal dumping while its disadvantages include less safe reused products, environmental pollution caused by e-waste treatment, illegal import, and difficulty in obtaining data.

Keywords: E-waste, Recycling Systems, Home Appliances, Japan and China.

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Authors: Mohsen Davarzani, Ehsan Lame, Mohammad Taghi Hassan Zadeh

Abstract:

Language is considered as a powerful and outstanding feature of ethnicity. However, humiliating and prohibiting using human language is one the most heinous and brutal acts in the form of racism. In other words, racism can be a product of physiological humiliations and discrimination, such as skin color, and can also be resulted from ethnic humiliation and discrimination such as language, customs and so on. Ethnic and racial discrimination is one of the main problems of the world that minorities and occasionally the majority have suffered from. Nowadays, few states can be found in which all individuals and its citizens are of the same race and ethnicity, culture and language. In these countries, referred to as the multinational states, (eg, Iran, Switzerland, India, etc.), there are the communities and groups which have their own linguistic, cultural and historical characteristics. Characteristics of human rights issues, diversity of issues and plurality of meanings indicate that they appear in various aspects. The states are obliged to respect, as per national and international obligations, the rights of all citizens from different angles, especially different groups that require special attention in order of the particular aspects such as ethnicity, religious and political minorities, children, women, workers, unions and in case the states are in breach of any of these items, they are faced with challenges in local, regional or international fields.

Keywords: Law, language, minorities, ethnicity.

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