Search results for: concrete-filled steel tube column

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

Procedia PDF Downloads 307

Authors: M. Bidi, H. Akhbari, S. Eslami, A. Bakhtiari

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Due to the high potential of solar energy utilization in Iran, development of related technologies is of great necessity. Linear parabolic collectors are among the most common and most efficient means to harness the solar energy. The main goal of this paper is design and construction of a parabolic trough collector to produce hot water and steam in Tehran. To provide precise and practical plans, 3D models of the collector under consideration were developed using Solidworks software. This collector was designed in a way that the tilt angle can be adjusted manually. To increase concentraion ratio, a small diameter absorber tube is selected and to enhance solar absorbtion, a shape of U-tube is used. One of the outstanding properties of this collector is its simple design and use of low cost metal and plastic materials in its manufacturing procedure. The collector under consideration was installed in Shahid Beheshti University of Tehran and the values of solar irradiation, ambient temperature, wind speed and collector steam production rate were measured in different days and hours of July. Results revealed that a 1×2 m parabolic trough collector located in Tehran is able to produce steam by the rate of 300ml/s under the condition of atmospheric pressure and without using a vacuum cover over the absorber tube.

Keywords: desalination, parabolic trough collector, direct steam production, solar water heater, design and construction

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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: Shagil Akhtar, Syed Muneeb Iqbal, Mohammed R. Rahim

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Common steel tubes with similar confines were used in simulation of tubes with distinctive type of corrugated sections. These corrugated cross-sections were arc-tangent, triangular, trapezoidal and square corrugated sections. The outcome of fluctuating structures of tube cross-section shape on the deformation feedback, collapse form and energy absorption characteristics of tubes under quasi-static axial compression have been prepared numerically. The finite element package of ANSYS Workbench was applied in the current analysis. The axial load-displacement products accompanied by the fold formation of disparate tubes were inspected and compared. Deviation of the initial peak load and the mean crushing force of the tubes with distinctive cross-sections were conscientiously examined.

Keywords: absorbed energy, axial loading, corrugated tubes, finite element, initial peak load, mean crushing force

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Authors: Mohamed K. El-Fawkhry, Ahmed Shash, Ahmed Ismail Zaki Farahat, Sherif Ali Abd El Rahman, Taha Mattar

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High-carbon, silicon-rich steels are commonly suggested to obtain very fine bainitic microstructure at low temperature ranged from 200 to 300°C. Thereby, the resulted microstructure consists of slender of bainitic-ferritic plates interwoven with retained austenite. The advanced strength and ductility package of this steel is much dependent on the fineness of bainitic ferrite, as well as the retained austenite phase. In this article, Aluminum to Silicon ratio, and the isothermal transformation temperature have been adopted to obtain ultra high strength high carbon steel. Optical and SEM investigation of the produced steels have been performed. XRD has been used to track the retained austenite development as a result of the change in the chemical composition of developed steels and heat treatment process. Mechanical properties in terms of hardness and microhardness of obtained phases and structure were investigated. It was observed that the increment of aluminum to silicon ratio has a great effect in promoting the bainitic transformation, in tandem with improving the stability and the fineness of retained austenite. Such advanced structure leads to enhancement in the whole mechanical properties of the high carbon steel.

Keywords: high-carbon steel, silicon-rich steels, fine bainitic microstructure, retained austenite, isothermal transformation

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Authors: Yuan Li, Yitao Han, Zhao Zhu

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In this paper, the effect of blasting loads on steel-concrete composite bridges has been investigated considering the slope reflection effect. Reasonable values of girder size, plate thickness, stiffening rib, and other design parameters were selected according to design specifications. Modified RHT (Riedel-Hiermaier-Thoma) was used as constitutive relation in analyses. In order to simulate the slope reflection effect, the slope of the bridge was precisely built in the model. Different blasting conditions, including top, middle, and bottom explosions, were simulated. The multi-Euler domain method based on fully coupled Lagrange and Euler models was adopted for the structural analysis of the explosion process using commercial software AUTODYN. The obtained results showed that explosion overpressure was increased by 3006, 879, and 449kPa, corresponding to explosions occurring at the top, middle, and bottom of the slope, respectively. At the same time, due to energy accumulation and transmission dissipation caused by slope reflection, the corresponding yield lengths of steel beams were increased by 8, 0, and 5m, respectively.

Keywords: steel-concrete composite bridge, explosion damage, slope reflection, blasting loads, RHT

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Authors: Preeti Panthari, Harsha Kharkwal

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Myrica nagi belongs to Myricaceae family. It is known for its therapeutic use since ancient times. The leaves were extracted with methanol and further fractioned with different solvents with increasing polarity. The n-butanol fraction of methanol extract was passed through celite, on separation through silica gel column chromatography yielded ten fractions. For the first time we report isolation of Caffeic acid from n-butanol fraction of Myrica nagi leaves in Chloroform: methanol (70:30) fraction. The mobile phase used for analysis in HPLC was Methanol: water (60:40) at the flow rate of 1 ml/min at wavelength of 280 nm. The retention time was 2.66 mins.

Keywords: Myrica nagi, column chromatography, retention time, caffeic acid

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Authors: Ataollah Rabiee1, Amir Hossein Kamalinia, Alireza Atf

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One of the most important issues in the design of nuclear fusion power plants is the heat removal from the hottest region at the diverter. Various methods could be employed in order to improve the heat transfer efficiency, such as generating turbulent flow and injection of nanoparticles in the host fluid. In the current study, Water/AL₂O₃ nanofluid forced swirl flow boiling has been investigated by using a homogeneous thermophysical model within the Eulerian-Eulerian framework through a twisted tape tube, and the boiling phenomenon was modeled using the Rensselaer Polytechnic Institute (RPI) approach. In addition to comparing the results with the experimental data and their reasonable agreement, it was evidenced that higher flow mixing results in more uniform bulk temperature and lower wall temperature along the twisted tape tube. The presence of AL₂O₃ nanoparticles in the boiling flow field showed that increasing the nanoparticle concentration leads to a reduced vapor volume fraction and wall temperature. The Computational fluid dynamics (CFD) results show that the average heat transfer coefficient in the tube increases both by increasing the nanoparticle concentration and the insertion of twisted tape, which significantly affects the thermal field of the boiling flow.

Keywords: nanoparticle, boiling, CFD, two phase flow, alumina, ITER

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Authors: Ajay Biswas, Swapan Bhaumik, Abhijit Bhowmik

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Present experiment has been carried out to study the microstructure of weldment obtained by submerged arc welding on mild steel plate at zero degree Celsius. To study this, bead on plate welding is done by submerged arc welding on the sample plate of heavy duty mild steel of designation IS 2062 grade B, fitted on the special fixture ensuring the plate temperature at zero degree Celsius. Sixteen numbers of such samples are welded by varying the most influencing parameters viz. travel speed, voltage, wire feed rate and electrode stick-out at four different levels. Taguchi’s design of experiment is applied by selecting Taguchi's L16 orthogonal array to restrict the number of experimental runs. Cross sectioned samples are polished and etched to view the weldment. Finally, different zone of the weldment is observed by optical microscope. From the type of microstructure of weldment it is concluded that submerged arc welding is feasible at zero degree Celsius on mild steel plate.

Keywords: Submerged Arc Welding, zero degree Celsius, Taguchi’s design of experiment, microstructure of weldment

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Authors: Pankaj Chandna, Dinesh Kumar

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The present work analyses different parameters of end milling to minimize the surface roughness for AISI D2 steel. D2 Steel is generally used for stamping or forming dies, punches, forming rolls, knives, slitters, shear blades, tools, scrap choppers, tyre shredders etc. Surface roughness is one of the main indices that determines the quality of machined products and is influenced by various cutting parameters. In machining operations, achieving desired surface quality by optimization of machining parameters, is a challenging job. In case of mating components the surface roughness become more essential and is influenced by the cutting parameters, because, these quality structures are highly correlated and are expected to be influenced directly or indirectly by the direct effect of process parameters or their interactive effects (i.e. on process environment). In this work, the effects of selected process parameters on surface roughness and subsequent setting of parameters with the levels have been accomplished by Taguchi’s parameter design approach. The experiments have been performed as per the combination of levels of different process parameters suggested by L9 orthogonal array. Experimental investigation of the end milling of AISI D2 steel with carbide tool by varying feed, speed and depth of cut and the surface roughness has been measured using surface roughness tester. Analyses of variance have been performed for mean and signal-to-noise ratio to estimate the contribution of the different process parameters on the process.

Keywords: D2 steel, orthogonal array, optimization, surface roughness, Taguchi methodology

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Authors: R. Ziaie Moayed, B. Mohammadi-Haji

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Stone columns have been widely employing to improve the load-settlement characteristics of soft soils. The results of two small scale displacement control loading tests on stone columns were used in order to validate numerical finite element simulations. Additionally, a series of numerical calculations of static loading have been performed on strengthened raft footing to investigate the effects of using stone columns on bearing capacity of footings. The bearing capacity of single and group of stone columns under static loading compares with unimproved ground.

Keywords: circular raft footing, numerical analysis, validation, vertically encased stone column

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Authors: Viera Zatkalíková, Lenka Markovičová, Aneta Tor-Swiatek

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The effect of molybdate addition to chloride environment on resistance of AISI 316Ti stainless steel to pitting corrosion was studied. Potentiodynamic polarisation tests were performed in 1 M and 0.1 M chloride acidified solutions with various additions of sodium molybdate at room temperature. The presented results compare the effect of molybdate anions on quality of passive film (expressed by the pitting potential) in both chloride solutions. The pitting potential increases with the increase inhibitor concentration. The inhibitive effect of molybdate ions is stronger in chloride solution of lower aggressiveness (0.1M).

Keywords: AISI 316Ti steel, molybdate inhibitor, pitting corrosion, pitting potential, potentiodynamic polarisation

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Authors: Moshe Mello, Hilary Rutto, Tumisang Seodigeng

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Tires are extremely challenging to recycle due to the available chemically cross-linked polymer which constitutes their nature and therefore, they are neither fusible nor soluble and consequently, cannot be remoulded into other shapes without serious degradation. Pyrolysis of tires produces four valuable products namely; char, steel, tire pyrolytic oil (TPO) and non-condensable gases. TPO has been reported to have similar properties to commercial diesel fuel (CDF). In this study, distillation of TPO was carried out in a batch distillation column and biodiesel was produced from waste cooking oil. FTIR analysis proved that TPO can be used as a fuel due to the available compounds detected and GC analysis displayed 94% biodiesel concentration from waste cooking oil. Different blends of TPO/biodiesel, TPO/CDF and biodiesel/CDF were prepared at different ratios. Fuel properties such as viscosity, density, flash point, and calorific value were studied. Viscosity and density models were also studied to measure the quality of different blends.

Keywords: biodiesel, distillation, pyrolysis, tire

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Authors: Jaroslaw Gawryluk, Andrzej Teter

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Simply supported angle columns subjected to uniform shortening are tested. The experimental studies are conducted on a testing machine using additional Aramis and the acoustic emission system. The laminate samples are subjected to axial uniform shortening. The tested columns are loaded with the force values from zero to the maximal load destroying the L-shaped column, which allowed one to observe the column post-buckling behavior until its collapse. Laboratory tests are performed at a constant velocity of the cross-bar equal to 1 mm/min. In order to eliminate stress concentrations between sample and support, flexible pads are used. Analyzed samples are made with carbon-epoxy laminate using the autoclave method. The configurations of laminate layers are: [60,0₂,-60₂,60₃,-60₂,0₃,-60₂,0,60₂]T, where direction 0 is along the length of the profile. Material parameters of laminate are: Young’s modulus along the fiber direction - 170GPa, Young’s modulus along the fiber transverse direction - 7.6GPa, shear modulus in-plane - 3.52GPa, Poisson’s ratio in-plane - 0.36. The dimensions of all columns are: length-300 mm, thickness-0.81mm, width of the flanges-40mm. Next, two numerical models of the column with and without flexible pads are developed using the finite element method in Abaqus software. The L-profile laminate column is modeled using the S8R shell elements. The layup-ply technique is used to define the sequence of the laminate layers. However, the model of grips is made of the R3D4 discrete rigid elements. The flexible pad is consists of the C3D20R type solid elements. In order to estimate the moment of the first laminate layer damage, the following initiation criteria were applied: maximum stress criterion, Tsai-Hill, Tsai-Wu, Azzi-Tsai-Hill, and Hashin criteria. The best compliance of results was observed for the Hashin criterion. It was found that the use of the pad in the numerical model significantly influences the damage mechanism. The model without pads characterized a much more stiffness, as evidenced by a greater bifurcation load and damage initiation load in all analyzed criteria, lower shortening, and less deflection of the column in its center than the model with flexible pads. Acknowledgment: The project/research was financed in the framework of the project Lublin University of Technology-Regional Excellence Initiative, funded by the Polish Ministry of Science and Higher Education (contract no. 030/RID/2018/19).

Keywords: angle column, compression, experiment, FEM

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Authors: Kahil Amar, Nekmouche Aghiles, Titouche Billal, Hamizi Mohand, Hannachi Naceur Eddine

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The ductility is an important parameter in the nonlinear behavior of portal structures reinforced concrete. It may be explained by the ability of the structure to deform in the plastic range, or the geometric characteristics in the map may influence the overall ductility. Our study is based on the influence of geometric slenderness (Lx / Ly) on the overall ductility of these structures, a study is made on a structure has 05 floors with varying the column section of 900 cm², 1600 cm² and 1225 cm². A slight variation in global ductility is noticed as (Lx/Ly) varies; however, column sections can control satisfactorily the plastic behavior of buildings.

Keywords: ductility, nonlinear behavior, pushover analysis, geometric slenderness, structural behavior

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Authors: Mustafa Col, Funda Gul Koc, Merve Yangaz, Eylem Subasi, Can Akbasoglu

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G38NiCrMo8-4-4 steel is widely used in mining industries, machine parts, gears due to its high strength and toughness properties. In this study, microstructure, wear and mechanical properties of G38NiCrMo8-4-4 steel modified with boron used in the mining industry were investigated. For this purpose, cast materials were alloyed by melting in an induction furnace to include boron with the rates of 0 ppm, 15 ppm, and 50 ppm (wt.) and were formed in the dimensions of 150x200x150 mm by casting into the sand mould. Homogenization heat treatment was applied to the specimens at 1150˚C for 7 hours. Then all specimens were austenitized at 930˚C for 1 hour, quenched in the polymer solution and tempered at 650˚C for 1 hour. Microstructures of the specimens were investigated by using light microscope and SEM to determine the effect of boron and heat treatment conditions. Changes in microstructure properties and material hardness were obtained due to increasing boron content and heat treatment conditions after microstructure investigations and hardness tests. Wear tests were carried out using a pin-on-disc tribometer under dry sliding conditions. Charpy V notch impact test was performed to determine the toughness properties of the specimens. Fracture and worn surfaces were investigated with scanning electron microscope (SEM). The results show that boron element has a positive effect on the hardness and wear properties of G38NiCrMo8-4-4 steel.

Keywords: G38NiCrMo8-4-4 steel, boron, heat treatment, microstructure, wear, mechanical properties

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Authors: A. Yonetken, A. Erol, M. Cakmakkaya

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Intermetallic materials are among advanced technology materials that have outstanding mechanical and physical properties for high temperature applications. Especially creep resistance, low density and high hardness properties stand out in such intermetallics. The microstructure, mechanical properties of %88Ni-%10Cr and %2Mn powders were investigated using specimens produced by tube furnace sintering at 900-1300°C temperature. A composite consisting of ternary additions, a metallic phase, Fe ,Cr and Mn have been prepared under Ar shroud and then tube furnace sintered. XRD, SEM (Scanning Electron Microscope), were investigated to characterize the properties of the specimens. Experimental results carried out for composition %88Ni-%10Cr and %2Mn at 1300°C suggest that the best properties as 138,80HV and 6,269/cm3 density were obtained at 1300°C.

Keywords: composite, high temperature, intermetallic, sintering

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Authors: Yoon Kyung Song, Seung Won Han, Sang Hyun Hwang, Do Hoon Lee

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Laboratory tests is a significant part for the diagnosis, prognosis, treatment of diseases. Blood collection is a simple process, but can be a potential cause of pre-analytical errors. Vacuum blood collection tubes used to collect and store the blood specimens is necessary for accurate test results. The purpose of this study was to validate Improve serum separator tube(SST) (Guanzhou Improve Medical Instruments Co., Ltd, China) for routine clinical chemistry laboratory testing. Blood specimens were collected from 100 volunteers in three different serum vacuum tubes (Greiner SST , Becton Dickinson SST , Improve SST). The specimens were evaluated for 16 routine chemistry tests using TBA-200FR NEO (Toshiba Medical Co. JAPAN). The results were statistically analyzed by paired t-test and Bland-Altman plot. For stability test, the initial results for each tube were compared with results of 72 hours preserved specimens. Their clinical availability was evaluated by biological Variation of Ricos data bank. Paired t-test analysis revealed that AST, ALT, K, Cl showed statistically same results but calcium (CA), phosphorus(PHOS), glucose(GLU), BUN, uric acid(UA), cholesterol(CHOL), total protein(TP), albumin(ALB), total bilirubin(TB), ALP, creatinine(CRE), sodium(NA) were different(P < 0.05) between Improve SST and Greiner SST. Also, CA, PHOS, TP, TB, AST, ALT, NA, K, Cl showed statistically the same results but GLU, BUN, UA, CHOL, ALB, ALP, CRE were different between Improve SST and Becton Dickinson SST. All statistically different cases were clinically acceptable by biological Variation of Ricos data bank. Improve SST tubes showed satisfactory results compared with Greiner SST and Becton Dickinson SST. We concluded that the tubes are acceptable for routine clinical chemistry laboratory testing.

Keywords: blood collection, Guanzhou Improve, SST, vacuum tube

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Authors: Huijuan Liu, Fukun Li, Hao Yuan

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The bolted spherical node is a common type of joint in space steel structures. The bolt-sphere joint portion almost always controls the bearing capacity of the bolted spherical node. The investigation of the bearing performance and progressive failure in service often requires high-fidelity numerical models. This paper focuses on the constitutive models of bolt steel and sphere steel used in China’s space structure construction. The elastoplastic model is determined by a standard tensile test and calibrated Voce saturated hardening rule. The ductile damage is found dominant based on the fractography analysis. Then Rice-Tracey ductile fracture rule is selected and the model parameters are calibrated based on tensile tests of notched specimens. These calibrated material models can benefit research or engineering work in similar fields.

Keywords: bolt-sphere joint, steel, constitutive model, ductile damage, model calibration

Procedia PDF Downloads 138

Authors: J. Thirunavukkarasu, M. Poulet, T. Turner, S. Pickering

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Composite waste from manufacturing can consist of different fiber materials, including blends of different fiber. Commercially, the recycling of composite waste is currently limited to carbon fiber waste and recycling glass fiber waste is currently not economically viable due to the low cost of virgin glass fiber and the reduced mechanical properties of the recovered fibers. For this reason, the recycling of hybrid fiber materials, where carbon fiber is combined with a proportion of glass fiber, cannot be processed economically. Therefore, a separation method is required to remove the glass fiber materials during the recycling process. An electrostatic separation method is chosen for this work because of the significant difference between carbon and glass fiber electrical properties. In this study, an experimental rig has been developed to measure the electrostatic charge achievable as the materials are passed through a tube. A range of particle lengths (80-100 µm, 6 mm and 12 mm), surface state conditions (0%SA, 2%SA and 6%SA), and several tube wall materials have been studied. A polytetrafluoroethylene (PTFE) tube and recycled without sizing agent was identified as the most suitable parameters for the electrical separation method. It was also found that shorter fiber lengths helped to encourage particle flow and attain higher charge values. These findings can be used to develop a separation process to enable the cost-effective recycling of hybrid fiber composite waste.

Keywords: electrostatic charging, hybrid fiber composites, recycling, short fiber composites

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Authors: Sanjeev Kumar, S. K. Nath

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Proper selection of welding parameters for getting excellent weld is a challenge. HAZ simulation helps in identifying suitable welding parameters like heating rate, cooling rate, peak temperature, and energy input. In this study, the influence of weld thermal cycle of heat affected zone (HAZ) is simulated for Submerged Arc Welding (SAW) using Gleeble ® 3800 thermomechanical simulator. A (Micro-alloyed) MA steel plate of thickness 18 mm having yield strength 450MPa is used for making test specimens. Determination of the mechanical properties of weld simulated specimens including Charpy V-notch toughness and hardness is performed. Peak temperatures of 1300°C, 1150°C, 1000°C, 900°C, 800°C, heat energy input of 22KJ/cm and preheat temperatures of 30°C have been used with Rykalin-3D simulation model. It is found that the impact toughness (75J) is the best for the simulated HAZ specimen at the peak temperature 900ºC. For parent steel, impact toughness value is 26.8J at -50°C in transverse direction.

Keywords: HAZ simulation, mechanical properties, peak temperature, ship hull steel, weldability

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Authors: Vishwas Goel, Kapil Surve, Somnath Basu

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In-situ alloying in steel during the electro-slag remelting (ESR) process has already been achieved by the addition of necessary ferroalloys into the electro-slag remelting mold. However, the use of commercially available ferroalloys during ESR processing is often found to be financially less favorable, in comparison with the conventional alloying techniques. However, a process of alloying steel with elements like chromium and manganese using the electro-slag remelting route is under development without any ferrochrome addition. The process utilizes in-situ reduction of refined mineral chromite (Cr₂O₃) and resultant enrichment of chromium in the steel ingot produced. It was established in course of this work that this process can become more advantageous over conventional alloying techniques, both economically and environmentally, for applications which inherently demand the use of the electro-slag remelting process, such as manufacturing of superalloys. A key advantage is the lower overall CO₂ footprint of this process relative to the conventional route of production, storage, and the addition of ferrochrome. In addition to experimentally validating the feasibility of the envisaged reactions, a mathematical model to simulate the reduction of chromium (III) oxide and transfer to chromium to the molten steel droplets was also developed as part of the current work. The developed model helps to correlate the amount of chromite input and the magnitude of chromium alloying that can be achieved through this process. Experiments are in progress to validate the predictions made by this model and to fine-tune its parameters.

Keywords: alloying element, chromite, electro-slag remelting, ferrochrome

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Authors: Asmaa Mandour, Ramzia El-Bagary, Asmaa El-Zaher, Ehab Elkady

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Background: An UHPLC (ultra high performance liquid chromatography) method for the simultaneous determination of norfloxacin (NOR), metronidazole (MET) and tinidazole (TNZ) using monolithic column is presented. Purpose: The method is considered an environmentally friendly method with relatively low organic composition of the mobile phase. Methods: The chromatographic separation was performed using Phenomenex® Onyex Monolithic C18 (50mmx 20mm) column. An elution program of mobile phase consisted of 0.5% aqueous phosphoric acid : methanol (85:15, v/v). Where elution of all drugs was completed within 3.5 min with 1µL injection volume. The UHPLC method was applied for the stability indication of NOR in the presence of its acid degradation product ND. Results: Retention times were 0.69, 1.19 and 3.23 min for MET, TNZ and NOR, respectively. While ND retention time was 1.06 min. Linearity, accuracy, and precision were acceptable over the concentration range of 5-50µg mL-1for all drugs. Conclusions: The method is simple, sensitive and suitable for the routine quality control and dosage form assay of the three drugs and can also be used for the stability indication of NOR in the presence of its acid degradation product.

Keywords: antibacterial, monolithic cilumn, simultaneous determination, UHPLC

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Authors: Amrit Pal Singh Arora

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The paper reports the results of a study undertaken to study the effects of addition of steel fibres of different aspect ratios on the permeability and strength characteristics of steel fiber reinforced fly ash concrete (SFRC). Corrugated steel fibres having a diameter of 0.6 mm and lengths of 12.5 mm, 30 mm and 50 mm were used in this study. Cube samples of 100 mm x 100 mm x 100 mm were cast from mixes replacing 0%, 10%, 20% and 30% cement content by fly ash with and without fibres and tested for the determination of coefficient of water permeability, compressive and split tensile strengths after 7 and 28 days of curing. Plain concrete samples were also cast and tested for reference purposes. Permeability was observed to decrease significantly for all concrete mixes with the addition of steel fibers as compared to plain concrete. The replacement of cement content by fly ash results in an increase in the coefficient of water permeability. With the addition of fly ash to the plain mix the7 day compressive and split tensile strengths decreased, however both the compressive and split tensile strengths increased with increase in curing age.

Keywords: curing age, fiber shape, fly ash, Darcy’s law, Ppermeability

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Authors: A.Kouidri, B.Madani

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The present work deals with the study of the heat transfer in a rectangular channel equipped with a metallic foam. The tested metallic foam sample is made from copper with 20 PPI (Pore per Inch Linear) and 93% of porosity and the working fluid used is the n-pentane. In the present work the independent variables are the velocity in the range from 0.02 to 0.06 m/s and a boiling heat flux rate varying between 30 and 70 kW/m2. The heat transfer coefficient is presented versus boiling heat flux, vapor quality and superheat ΔTsat. The thermal results are compared to those found for a plain tube for the same conditions. The comparison with the plain tube shows that the insert of a metallic foam enhances the heat transfer coefficient by a factor between 1.3 and 3.

Keywords: boiling, metallic foam, heat transfer, plate heat exchanger

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Authors: Rehan Waheed, Hasan Aftab Saeed, Wasim Tarar, Khalid Mahmood, Sajid Ullah Butt

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Electromagnetic Interference (EMI) shielded doors made from brass extruded channels need to be welded with shielded enclosures to attain optimum shielding performance. Control of welding induced distortion is a problem in welding dissimilar metals like steel and brass. In this research, soldering of the steel-brass joint has been proposed to avoid weld distortion. The material used for brass channel is UNS C36000. The thickness of brass is defined by the manufacturing process, i.e. extrusion. The thickness of shielded enclosure material (ASTM A36) can be varied to produce joint between the dissimilar metals. Steel sections of different gauges are soldered using (91% tin, 9% zinc) solder to the brass, and strength of joint is measured by standard test procedures. It is observed that thin steel sheets produce a stronger bond with brass. The steel sections further require to be welded with shielded enclosure steel sheets through TIG welding process. Stresses and deformation in the vicinity of soldered portion is calculated through FE simulation. Crack formation in soldered area is also studied through experimental work. It has been found that in thin sheets deformation produced due to applied force is localized and has no effect on soldered joint area whereas in thick sheets profound cracks have been observed in soldered joint. The shielding effectiveness of EMI shielded door is compromised due to these cracks. The shielding effectiveness of the specimens is tested and results are compared.

Keywords: dissimilar metal, EMI shielding, joint strength, soldering

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Authors: S. Chandrakaran, G. Govind

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Stone columns are effectively used to improve bearing strength of soils and also for many geotechnical applications. In soft soils when stone columns are loaded they undergo large settlements due to insufficient lateral confinement. Use of geosynthetics encasement has proved to be a solution for this problem. In this paper, results of a laboratory experimental study carried out with model stone columns with and without encasement. Sand was used for making test beds, and grain size of soil varies from 0.075mm to 4.75mm. Woven geotextiles produced by Gareware ropes India with mass per unit area of 240gm/M2 and having tensile strength of 52KN/m is used for the present investigation. Tests were performed with large scale direct shear box and also using scaled laboratory plate load tests. Stone column of 50mm and 75mm is used for the present investigation. Diameter of stone column, size of stones used for making stone columns is varied in making stone column in the present study. Two types of stone were used namely small and bigger in size. Results indicate that there is an increase in angle of internal friction and also an increase in the shear strength of soil when stone columns are encased. With stone columns with 50mm dia, an average increase of 7% in shear strength and 4.6 % in angle of internal friction was achieved. When large stones were used increase in the shear strength was 12.2%, and angle of internal friction was increased to 5.4%. When the stone column diameter has increased to 75mm increase in shear strength and angle of internal friction was increased with smaller size of stones to 7.9 and 7.5%, and with large size stones, it was 7.7 and 5.48% respectively. Similar results are obtained in plate load tests, also.

Keywords: stone columns, encasement, shear strength, plate load test

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Authors: WonHo Lee, Hyo-Gyoung Kwak

Abstract:

A numerical model considering slip behavior of steel-concrete composite structure is introduced. This model is based on a linear bond stress-slip relation along the interface. Single node was considered at the interface of steel and concrete member in finite element analysis, and it improves analytical problems of model that takes double nodes at the interface by adopting spring elements to simulate the partial interaction. The slip behavior is simulated by modifying material properties of steel element contacting concrete according to the derived formulation. Decreased elastic modulus simulates the slip occurrence at the interface and decreased yield strength simulates drop in load capacity of the structure. The model is verified by comparing numerical analysis applying this model with experimental studies. Acknowledgment—This research was supported by a grant(13SCIPA01) from Smart Civil Infrastructure Research Program funded by Ministry of Land, Infrastructure and Transport(MOLIT) of Korea government and Korea Agency for Infrastructure Technology Advancement(KAIA) and financially supported by Korea Ministry of Land, Infrastructure and Transport(MOLIT) as U-City Master and Doctor Course Grant Program.

Keywords: bond-slip, composite structure, partial interaction, steel-concrete structure

Procedia PDF Downloads 178

Authors: Sameer Gupta, Prant Gupta

Abstract:

Context: Fractures in the distal humerus are complex and challenging injuries for orthopaedic surgeons that can be effectively treated with open reduction and internal fixation. Aims: The study analyses clinical outcomes in patients with intra-articular distal humerus fractures (AO type 13 C3 excluded) treated using a different method of fixation ( LCPMS). Subject and Methods: A study was performed, and the author's personal experiences were reported. Thirty patients were treated using an intercondylar screw with lateral column plating and percutaneous medial column screw fixation. Detailed analysis was done for functional outcomes (average arc of motion, union rate, and complications). Statistical Analysis Used: SPSS software version 22.0 was used for statistical analysis. Results: In our study, at the end of 6 months, Overall good to excellent results were achieved in 28 patients out of 30 after analysis on the basis of MEP score. The majority of patients regained full arc of motion, achieved fracture union without any major complications, and were able to perform almost all activities of daily living (which required good elbow joint movements and functions). Conclusion: We concluded that this novel method provides adequate stability and anatomical reconstruction with an early union rate observed at the end of 6 months. Excellent functional outcome was observed in almost all the patients because of less operating time and initiation of early physiotherapy, as most of the patients experienced mild nature of pain post-surgery.

Keywords: intra arricular distal humerus fracture, percutaneous medial screw, lateral column plate, arc of motion

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Authors: Hadjer Didouh, Mohammed Hadj Melliani, Izzeddine Sameut Bouhaik

Abstract:

Corrosion is a serious problem in industrial installations or metallic transport pipes. Corrosion is an interfacial process controlled by several parameters. The presence of microorganisms affects the kinetics of corrosion. This type of corrosion is often referred as bio-corrosion or corrosion influenced by microorganisms (MIC). The action of a microorganism or a bacterium is carried out by the formation of biofilm following its attachment to the metal surface. The formation of biofilm isolates the metal surface from its environment and allows the bacteria to control the parameters of the metal/bacteria interface. Biofilm formation by sulfate-reducing bacteria (SRB) X52 steel, poses substantial challenges in oil and gas industry SONATRACH of Algeria. This research delves into the complex attachment mechanisms employed by SRB biofilm on X52 carbon steel and investigates strategies for effective mitigation using biocides. The exploration commences by elucidating the underlying mechanisms facilitating SRB biofilm adhesion to X52 carbon steel, considering factors such as surface morphology, electrostatic interactions, and microbial extracellular substances. Advanced microscopy and spectroscopic techniques provide a support to the attachment processes, laying the foundation for targeted mitigation strategies. The use of 100 ppm of Moringa Oleifera extract biocide as a promising approach to control and prevent SRB biofilm formation on X52 carbon steel surfaces. Green extract undergo evaluation for their effectiveness in disrupting biofilm development while ensuring the integrity of the steel substrate. Systematic analysis is conducted on the biocide's impact on the biofilm's structural integrity, microbial viability, and overall attachment strength. This two-pronged investigation aims to deepen our comprehension of SRB biofilm dynamics and contribute to the development of effective strategies for mitigating its impact on X52 carbon steel.

Keywords: bio-corrosion, biofilm, attachement, metal/bacteria interface

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