Search results for: membrane resistance

Authors: Daniel Osorio, Andreas Klenk, Stefan Weihe, Andreas Kopp, Frank Rödiger

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Future power plants currently face high design requirements due to worsening climate change and environmental restrictions, which demand high operational flexibility, superior thermal performance, minimal emissions, and higher cyclic capability. The aim of the paper is, therefore, to investigate the creep and thermo-mechanical material behavior of improved materials experimentally and welded joints at component scale under near-to-service operating conditions, which are promising for application in highly efficient and flexible future power plants. These materials promise an increase in flexibility and a reduction in manufacturing costs by providing enhanced creep strength and, therefore, the possibility for wall thickness reduction. At the temperature range between 550°C and 625°C, the investigation focuses on the in-phase thermo-mechanical fatigue behavior of dissimilar welded joints of conventional materials (ferritic and martensitic material T24 and T92) to nickel-based alloys (A617B and HR6W) by means of membrane test panels. The temperature and external load are varied in phase during the test, while the internal pressure remains constant. At the temperature range between 650°C and 750°C, it focuses on the creep behavior under multiaxial stress loading of similar and dissimilar welded joints of high temperature resistant nickel-based alloys (A740H, A617B, and HR6W) by means of a thick-walled-component test. In this case, the temperature, the external axial load, and the internal pressure remain constant during testing. Numerical simulations are used for the estimation of the axial component load in order to induce a meaningful damage evolution without causing a total component failure. Metallographic investigations after testing will provide support for understanding the damage mechanism and the influence of the thermo-mechanical load and multiaxiality on the microstructure change and on the creep and TMF- strength.

Keywords: creep, creep-fatigue, component behaviour, weld joints, high temperature material behaviour, nickel-alloys, high temperature resistant steels

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Authors: Osman Yildiz

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As it is predicted 2559 years before there is nothing permanent except change. In our turbulent World, Organizations will always be faced with the challenge of determining the path that will always keep them on balance en route that will bring success. That means from top to bottom, every organisation is exposed to fight to stay afloat and compete while they face the continuous prospect of change in an increasingly competitive and globalized World. Otherwise, they would fail to realize their goals and targets, and ultimately would disappear. But the organizations that will celebrate success five or ten years from now will be the winners of the fight by having recognizing that planning the change was only the first step in the journey and put sufficient efforts into the task of leading change. Increasingly unpredictable and competitive organizational environments have put pressure on leaders across all industries to better manage the change. The key of establishing effective change and transformation in organisations lies on the steps taken before the change happens depending to the quality of the human sources; readiness for change, acknowledgement by management, prepared leaders, motivated employees, overcoming the resistance to change and ultimately adapting change into the organization. Due to these factors, leaders managing the organisational development can ensure organizations and employees to meet new performance targets, motivation and skills rapidly and effectively. Finally, this article will provide some tools for leaders, and discuss how to catch organisational development and manage the innovations in effective ways.

Keywords: managing the change, organizational change, human factor, leaders, globalization, organisational development

Procedia PDF Downloads 275

Authors: Nicholas Fletcher, Zachary Houston, Yongmei Zhao, Christopher Howard, Kristofer Thurecht

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One promising approach to enhance nanomedicine therapeutic efficacy is to include a targeting agent, such as an antibody, to increase accumulation at the tumor site. However, the application of such targeted nanomedicines remains limited, in part due to difficulties involved with biomolecule conjugation to synthetic nanomaterials. One approach recently developed to overcome this has been to engineer bispecific antibodies (BsAbs) with dual specificity, whereby one portion binds to methoxy polyethyleneglycol (mPEG) epitopes present on synthetic nanomedicines, while the other binds to molecular disease markers of interest. In this way, noncovalent complexes of nanomedicine core, comprising a hyperbranched polymer (HBP) of primarily mPEG, decorated with targeting ligands are able to be produced by simple mixing. Further work in this area has now demonstrated such complexes targeting the breast cancer marker epidermal growth factor receptor (EGFR) to show enhanced binding to tumor cells both in vitro and in vivo. Indeed the enhanced accumulation at the tumor site resulted in improved therapeutic outcomes compared to untargeted nanomedicines and free chemotherapeutics. The current work on these BsAb-HBP conjugates focuses on further probing antibody-nanomaterial interactions and demonstrating broad applicability to a range of cancer types. Herein are reported BsAb-HBP materials targeted towards prostate-specific membrane antigen (PSMA) and study of their behavior in vivo using ⁸⁹Zr positron emission tomography (PET) in a dual-tumor prostate cancer xenograft model. In this model mice bearing both PSMA+ and PSMA- tumors allow for PET imaging to discriminate between nonspecific and targeted uptake in tumors, and better quantify the increased accumulation following BsAb conjugation. Also examined is the potential for formation of these targeted complexes in situ following injection of individual components? The aim of this approach being to avoid undesirable clearance of proteinaceous complexes upon injection limiting available therapeutic. Ultimately these results demonstrate BsAb functionalized nanomaterials as a powerful and versatile approach for producing targeted nanomedicines for a variety of cancers.

Keywords: bioengineering, cancer, nanomedicine, polymer chemistry

Procedia PDF Downloads 141

Authors: Chun-Ying Lee, Kuan-Hui Cheng, Mei-Wen Wu

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The nickel-manganese (Ni-Mn) alloy coating prepared from DC electrodeposition process in sulphamate bath was studied. The effects of process parameters, such as current density and electrolyte composition, on the cathodic current efficiency, microstructure, internal stress and mechanical properties were investigated. Because of its crucial effect on the application to the electroforming of microelectronic components, the development of low internal stress coating with high leveling power was emphasized. It was found that both the coating’s manganese content and the cathodic current efficiency increased with the raise in current density. In addition, the internal stress of the deposited coating showed compressive nature at low current densities while changed to tensile one at higher current densities. Moreover, the metallographic observation, X-ray diffraction measurement, transmission electron microscope (TEM) examination, and polarization curve measurement were conducted. It was found that the Ni-Mn coating consisted of nano-sized columnar grains and the maximum hardness of the coating was associated with (111) preferred orientation in the microstructure. The grain size was refined along with the increase in the manganese content of the coating, which accordingly, raised its hardness and mechanical tensile strength. In summary, the Ni-Mn coating prepared at lower current density of 1-2 A/dm2 had low internal stress, high leveling power, and better corrosion resistance.

Keywords: Ni-Mn coating, DC plating, internal stress, leveling power

Procedia PDF Downloads 369

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

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Microbiologically influenced corrosion (MIC) is a major cause of pipeline failure in the oil and gas industry, particularly affecting carbon steel, which is widely used for its cost-effectiveness and mechanical properties. This study investigates the adhesion of sulfate-reducing bacteria (SRB) and other corrosive microbial species on API 5L X52 carbon steel in crude oil and injection water environments. Experimental results showed that after 72 hours of exposure, biofilm formed extensively, leading to significant corrosion rates. Weight loss measurements indicated a corrosion rate of 0.39 mm/year, with localized pitting observed at depths reaching 120 μm. Electrochemical impedance spectroscopy (EIS) revealed a drastic decrease in charge transfer resistance, from 1200 Ω/cm² for sterile samples to 240 Ω/cm² in the presence of SRB biofilm. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) analyses confirmed the presence of iron sulfide deposits, indicating active bacterial colonization and biofilm-induced pitting corrosion. This study highlights the severe impact of MIC on pipeline infrastructure, emphasizing the need for efficient microbial control strategies. Furthermore, the results provide a framework for the development of enhanced protective coatings and environmentally friendly biocides to mitigate the economic and environmental risks associated with MIC in oilfield operations in Algeria.

Keywords: MIC, corrosion, bacteria, API 5L X52

Procedia PDF Downloads 32

Authors: Gabriela C. Caldas, Fernanda C. Jacome, Arthur da C. Rasinhas, Ortrud M. Barth, Flavia B. dos Santos, Priscila C. G. Nunes, Yuli R. M. de Souza, Pedro Paulo de A. Manso, Marcelo P. Machado, Debora F. Barreto-Vieira

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The establishment of animal models for studies of DENV infections has been challenging, since circulating epidemic viruses do not naturally infect nonhuman species. Such studies are of great relevance to the various areas of dengue research, including immunopathogenesis, drug development and vaccines. In this scenario, the main objective of this study is to verify possible morphological changes, as well as the presence of antigens and viral RNA in lung samples from BALB/c mice experimentally infected with an epidemic and non-neuroadapted DENV-3 strain. Male BALB/c mice, 2 months old, were inoculated with DENV-3 by intravenous route. After 72 hours of infection, the animals were euthanized and the lungs were collected. Part of the samples was processed by standard technique for analysis by light and transmission electronic microscopies and another part was processed for real-time PCR analysis. Morphological analyzes of lungs from uninfected mice showed preserved tissue areas. In mice infected with DENV-3, the analyzes revealed interalveolar septum thickening with presence of inflammatory infiltrate, foci of alveolar atelectasis and hyperventilation, bleeding foci in the interalveolar septum and bronchioles, peripheral capillary congestion, accumulation of fluid in the blood capillary, signs of interstitial cell necrosis presence of platelets and mononuclear inflammatory cells circulating in the capillaries and/or adhered to the endothelium. In addition, activation of endothelial cells, platelets, mononuclear inflammatory cell and neutrophil-type polymorphonuclear inflammatory cell evidenced by the emission of cytoplasmic membrane prolongation was observed. DEN-like particles were seen in the cytoplasm of endothelial cells. The viral genome was recovered from 3 in 12 lung samples. These results demonstrate that the BALB / c mouse represents a suitable model for the study of the histopathological changes induced by DENV infection in the lung, with tissue alterations similar to those observed in human cases of DEN.

Keywords: BALB/c mice, dengue, histopathology, lung, ultrastructure

Procedia PDF Downloads 253

Authors: André C. Silva, Mariana R. Barros, Elenice M. S. Silva, Douglas. Y. Marinho, Diego F. Lopes, Débora N. Sousa, Raphael S. Tomáz

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Modern agriculture requires productivity, efficiency and quality. Therefore, there is need for agricultural limestone implementation that provides adequate amounts of calcium and magnesium carbonates in order to correct soil acidity. During the limestone process, fine particles (with average size under 400#) are generated. These particles do not have economic value in agricultural and metallurgical sectors due their size. When limestone is used for agriculture purposes, these fine particles can be easily transported by wind generated air pollution. Therefore, briquetting, a mineral processing technique, was used to mitigate this problem resulting in an agglomerated product suitable for agriculture use. Briquetting uses compressive pressure to agglomerate fine particles. It can be aided by agglutination agents, allowing adjustments in shape, size and mechanical parameters of the mass. Briquettes can generate extra profits for mineral industry, presenting as a distinct product for agriculture, and can reduce the environmental liabilities of the fine particles storage or disposition. The produced limestone briquettes were subjected to shatter and water action resistance tests. The results show that after six minutes completely submerged in water, the briquettes where fully diluted, a highly favorable result considering its use for soil acidity correction.

Keywords: agglomeration, briquetting, limestone, soil acidity correction

Procedia PDF Downloads 390

Authors: Lynda Golea, Rachid Chebaki

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Schiff bases contain heterocyclic structural units with N and O donor atoms which plays an important role in coordination chemistry. Azomethine groups are a broad class of widely used compounds with applications in many fields, including analytical, inorganic chemistry and biological. Schiff's base is of promising research interest due to the widespread antibacterial resistance in medical science. In addition, the research is essential to generate Schiff base metal complexes with various applications. Schiff complexes have been used as drugs and have antibacterial, antifungal, antiviral, and anti-inflammatory properties. The various donor atoms they contain offer a special ability for metal binding. In this research on the physicochemical properties of azomethine groups, we synthesized and studied the Schiff base compounds by a condensation reaction of tryptamines and acetophenone in ethanol. The structure of the prepared compound was interpreted using 1H NMR, 13C NMR, UV-vis and FT-IR. A computational analysis at the level of DFT with functional B3LYP in conjunction with the base 6-311+G (d, p) was conducted to study its electronic and molecular structure. The biological study was performed on three bacterial strains usually causing infection, including Gram-positive and Gram-negative, for antibacterial activity. Results showed moderate biological activity and proportional activity with increasing concentration.

Keywords: azomethine, HOMO, LUMO, RMN, molecular docking

Procedia PDF Downloads 63

Authors: Erim Koyun

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This paper aim to construct a mathematical model for Underwater vehicles under load variation test conditions. Propeller effects on underwater vehicle are investigated. Body with counter rotating propeller model is analyzed by CFD methods, thus forces and moment are obtained. Propeller effects of vehicle’s hydrodynamic performance under load variation conditions will be investigated. Additionally, pressure contour is examined for differences between different load conditions. Axial force equation is established using hydrodynamic coefficients, which contains resistance, thrust, and additional coefficients occurs due to load variations. Additional coefficients helps to express completely axial force on underwater vehicle. When the vehicle accelerates, additional force occurs besides thrust force increment. This is propeller effect on the body. Hence, mathematical model cover this effect. For CFD analysis, the incompressible, three-dimensional, and unsteady Reynolds Averaged Navier-Stokes equations will be used Numerical results is verified with experimental results for verification. The overall goal of this study is to present complementary mathematical model for body with counter rotating propeller.

Keywords: counter rotating propeller, CFD, hydrodynamic mathematic model, hydrodynamics analysis, thrust deduction

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Authors: Pablo Lopez Hurtado, Antroine Rouilly, Virginie Vandenbossche

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Cellulose fibre insulation is an eco-friendly building material made from recycled paper fibres, treated with borates for fungal and fire resistance. It is comparable in terms of thermal and acoustic performance to mineral wool insulation and other insulation materials based on non-renewable resources. The main method of application consists in separating and blowing the fibres in attics or closed wall cavities. Another method, known as the “wet spray method” is gaining interest. With this method the fibres are projected with pulverized water, which stick to the wall cavities. The issue with the wet spray technique is that the water dosage could be difficult to control. A high water dosage implies not only a longer drying time, depending on ambient conditions, but also a change in the performance of the material itself. In our work we studied the thermal and mechanical properties of wet spray-cellulose insulation in order to understand how water dosage could affect these properties. The material was first characterized to study the chemical and physical properties of the fibres. Then representative samples of wet sprayed cellulose with varying applied water dosage were subject to thermal conductivity and compression testing in order to better understand how changes in the fibres induced by drying can affect these properties.

Keywords: cellulose fibre, recycled paper, moisture sorption, thermal insulation

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Authors: Min-Shiuan Liou, Yi Shan Yang, Yang-Zhan Huang, Chia-Wen Hsieh

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A high speed growing and butanol-tolerant Clostridium acetobutylicum HOL1 mutant was screened throughout continuous adaption culture with C. acetobutylicum ATCC 824. The HOL1 strain can grow well in 10 g/L butanol contained CGM medium and can produce about 12.8 g /L butanol during 24 hrs. The C. acetobutylicum HOL1 strain was able to produce 166 mM butanol with 21 mM acetone at pH 4.8, resulting in a butanol selectivity (a molar ratio of butanol to total solvents) of 0.79, which is much higher than that (0.6) of the wild-type strain C. acetobutylicum ATCC 824. The acetate and butyrate accumulation were not observed during fermentation of the HOL1 strain. A hyper-butanol producing C. acetobutylicum HOL1 (pBPHS-3), which was created to overexpress the Bacillus psychrosaccharolyticus originated specific heat-shock protein gene, hspX, from a clostridial phosphotransbutyrylase promoter, was studied for its potential to produce a high titer of butanol. Overexpression of hspX resulted in increased final butanol yield 47% and 30% higher than those of the the ATCC824 and the HOL1 strains, respectively. The remarkable high-speed growth and butanol tolerance of strain HOL1 (pBPHS-3) demonstrates that overexpression of heterogeneous stress protein-encoding gene, hspX, could help C. acetobutylicum to effectively produce a high concentration of butanol.

Keywords: Clostridium acetobutylicum, butanol, heat-shock protein, resistance

Procedia PDF Downloads 430

Authors: B. Chemani, H. Aknouche, A. Zerizer, R. Marchal

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The phenomena occurring during machining are related to the internal friction of the material that deforms and the friction the flake on the rake face of tool. Various researches have been conducted to improve the wear resistance of the tool by thin film deposition. This work aims to present an experimental approach related to wood machining technique to evaluate the wear for the case of ripping Aleppo pine, a species well established in the Mediterranean in general and in Algeria in particular. The study will be done on tungsten carbide cutting tools widely used in woodworking and coated with chrome nitride (CrN) and Chromium Nitride enriched Aluminium (CrAlN) with percentage different of aluminum sputtered through frame magnetron mark Nordiko 3500. The deposition conditions are already optimized by previous studies. The wear tests were performed in the laboratory of ENSAM Cluny (France) on a numerical control ripper of recordi type. This comparative study of the behavior of tools, coated and uncoated, showed that the addition of the aluminum chromium nitride films does not improve the tool ability to resist abrasive wear that is predominant when ripping the Aleppo pine. By against the aluminum addition improves the crystallization of chromium nitride films.

Keywords: Aleppo pine, PVD, coatings, CrAlN, wear

Procedia PDF Downloads 568

Authors: Cheba Ben Amar

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Bacillus and Paenibacillus are Gram-positive aerobic endospore-forming bacteria (AEFB) and most abundant in the rhizosphere, they mediated plant growth promotion and disease protection by several complex and interrelated processes involving direct and indirect mechanisms that include nitrogen fixation, phosphate solubilization, siderophores production, phytohormones production and plant diseases control. In addition to their multiple PGPR properties, high secretory capacity, spore forming ability and spore resistance to unfavorable conditions enabling their extended commercial applications for long shelf-life. Due to these unique advantages, Bacillus species were the most an ideal candidate for developing efficient PGPR products such as biopesticides, fungicides and fertilizers. This review list all studied and reported plant growth promoting Bacillus species and strains, discuss their capacities to enhance plant growth and protection with special focusing on the most frequent species Bacillus subtilis, B. pumilus ,B. megaterium, B. amyloliquefaciens , B. licheniformis and B. sphaericus, furthermore we recapitulate the beneficial activities and mechanisms of several species and strains of the genus Paenibacillus involved in plant growth stimulation and plant disease control.

Keywords: bacillus, paenibacillus, PGPR, beneficial activities, mechanisms, growth promotion, disease control, agrobiotechnology

Procedia PDF Downloads 400

Authors: Kazui Sasakii, Seira Mormune-Moriya, Hiroaki Tanahashi, Shigeji Kongaya

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Poly (3.4-ethylenedioxythiophene) doped with poly (4-styrene sulfonate) (PEDOT: PSS) attracted a great deal of attention because of its unique characteristics of flexibility, optical properties, heat resistance and colloidal dispersion in water. It is well known that when high boiling solvents such as ethylene glycol or dimethyl sulfoxide are added as a secondary dopant to the micellar structure, PEDOT microcrystallizes and becomes highly conductive. In previous study bis(4-hydroxyphenyl) sulfone (BPS) was used as a secondary dopant for PEDOT:PSS and the enhancement of the conductivity was revealed. However, ductility is one of the serious issues which limited the application of PEDOT:PSS/BPS. So far, the composition with polymer binders has been conducted, however, polymer binders decrease the conductivity of the materials. In this study, PEDOT: PSS composites with polyester (PEs) were prepared by a simple aqueous process using PEs emulsion. The structural studies revealed that PEDOT:PSS and PEs were homogeneously distributed in the composites. It was found that the properties of PEDOT:PSS were remarkably enhanced by the incorporation of PEs. According to the tensile test, the ductility of PEDOT:PSS was remarkably improved. Interestingly, the conductivity of PEDOT:PSS/PEs composites was higher than that of neat PEDOT:PSS. For example, the conductivity increased by 8% at PEs content of 25 wt%. Since PEDOT:PSS were homogeneously dispersed on the surface of PEs particles, it was assumed that the conductive pathway was constructed by PEs particles in the nanocomposites. Therefore, a significant increase in conductivity was achieved.

Keywords: polymer composites, conductivity, PEDOT:PSS, polyester

Procedia PDF Downloads 115

Authors: Vishavjeet Singh Goraya, Bashir Ahmed Dar

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Sikhism is one of the youngest religions which came into existence only 550 years ago with Guru Nanak Dev. Guru Nanak and his successors not only gave religious sermons but also made bold commentaries on the politico-social situations of their times. Sikhism has consistently stood against autocratic regimes and societal polarization. The Sikh Gurus envisioned a political system based on equality, brotherhood, freedom of conscience, justice, and secularism where there was no discrimination and human rights of all were protected. The Sikh Gurus visualized a society based on an amalgamation of politics and religion without compromising morality and resisting any form of oppression and tyranny. The fifth guru of the Sikhs, Guru Arjan Dev, compiled the verses of his predecessors and many other saints belonging to different religions and castes in the form of Adi Granth, highlighting the egalitarian and secular foundations of Sikhism. Later tenth guru, Guru Gobind Singh, gave a concrete shape to the concepts of the earlier gurus written in Adi Granth and created an openly political and sovereign community known as Khalsa Panth with a distinct identity. This paper will use the qualitative historical approach to highlight Sikhism’s enduring commitment to fight oppression and tyranny, and it also examines how Sikhism offers solutions to contemporary issues of authoritarianism and polarization.

Keywords: sikhism, Gurus, political thought, equality, scriptures

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Authors: K. Asemave, D. O. Abakpa, T. T. Ligom

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The ability of bacteria to develop resistance to many antibiotics cannot be undermined, given the multifaceted health challenges in the present times. For this reason, a lot of attention is on botanicals and their products in search of new antibacterial agents. On the other hand, mango kernel oils (MKO) can be heavily valorized by taking advantage of the myriads bioactive phytochemicals it contains. Herein, we validated the use of MKO as bioactive agent against bacteria. The MKOs for the study were extracted by soxhlet means with ethanol and hexane for 4 h from 3 different mango kernels, namely; 'local' (sample A), 'julie' (sample B), and 'john' (sample C). Prior to the extraction, ground fine particles of the kernels were obtained from the seed kernels dried in oven at 100 °C for 8 h. Hexane gave higher yield of the oils than ethanol. It was also qualitatively confirmed that the mango kernel oils contain some phytochemicals such as phenol, quinone, saponin, and terpenoid. The results of the antibacterial activities of the MKO against both gram positive (Staphylococcus aureus) and gram negative (Pseudomonas aeruginosa) at different concentrations showed that the oils extracted with ethanol gave better antibacterial properties than those of the hexane. More so, the bioactivities were best with the local mango kernel oil. Indeed this work has completely validated the previous claim that MKOs are effective antibacterial agents. Thus, these oils (especially the ethanol-derived ones) can be used as bacteriostatic and antibacterial agents in say food, cosmetics, and allied industries.

Keywords: bacteria, mango, kernel, oil, phytochemicals

Procedia PDF Downloads 153

Authors: A. M. Aminazad, A. M. Hadian, F. Ghasimakbari

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DHP (Deoxidized High Phosphorus )copper is widely used in various heat transfer units such as, air conditioners refrigerators, evaporators and condensers. Copper sheets and tubes (ISODHP) were brazed with four different brazing alloys. Corrosion resistances of the joints were examined by polarization and salt spray tests. The selected fillers consisted of three silver-based brazing alloys (hard solder); AWS-BCu5 BAg8, DINLAg30, and a copper-based filler AWS BCuP2. All the joints were brazed utilizing four different brazing processes including furnace brazing under argon, vacuum, air atmosphere and torch brazing. All of the fillers were used with and without flux. The microstructure of the brazed sheets was examined using both optical and scanning electron microscope (SEM). Hardness and leak tests were carried out on all the brazed tubes. In all three silver brazing alloys selective and galvanic corrosion were observed in filler metals, but in copper phosphor alloys the copper adjacent to the joints were noticeably corroded by pitting method. Microstructure of damaged area showed selective attack of copper lamellae as well. Interfacial attack was observed along boundaries as well as copper attack within the filler metal itself. It was found that the samples brazed with BAg5 filler metal using vacuum furnace show a higher resistance to corrosion. They also have a good ductility in the brazed zone.

Keywords: copper, brazing, corrosion, filler metal

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Authors: Naif Mohsen Alharbi

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This paper present failure occurred on flexible coupling installed at oil anf gas operation. Also it presents maintenance ideas implemented on the flexible coupling installed to transmit high torque from gearbox to pump. Basically, the machine train is including steam turbine which drives the pump and there is gearbox located in between for speed reduction. investigation are identifying the root causes, solving and developing the technology designs or bad actor. This report provides the study intentionally for continues operation optimization, utilize the advanced opportunity and implement a improvement. Objective: The main objectives of the investigation are identifying the root causes, solving and developing the technology designs or bad actor. Ultimately, fulfilling the operation productivity, also ensuring better technology, quality and design by solutions. This report provides the study intentionally for continues operation optimization, utilize the advanced opportunity and implemet improvement. Method: The method used in this project was a very focused root cause analysis procedure that incorporated engineering analysis and measurements. The analysis method extensively covers the measuring of the complete coupling dimensions. Including the membranes thickness, hubs, bore diameter and total length, dismantle flexible coupling to diagnose how deep the coupling has been affected. Also, defining failure modes, so that the causes could be identified and verified. Moreover, Vibration analysis and metallurgy test. Lastly applying several solutions by advanced tools (will be mentioned in detail). Results and observation: Design capacity: Coupling capacity is an inadequate to fulfil 100% of operating conditions. Therefore, design modification of service factor to be at least 2.07 is crucial to address this issue and prevent recurrence of similar scenario, especially for the new upgrading project. Discharge fluctuation: High torque flexible coupling encountered during the operation. Therefore, discharge valve behaviour, tuning, set point and general conditions revaluated and modified subsequently, it can be used as baseline for upcoming Coupling design project. Metallurgy test: Material of flexible coupling membrane (discs) tested at the lab, for a detailed metallurgical investigation, better material grade has been selected for our operating conditions,

Keywords: high speed machine, reliabilty, flexible coupling, rotating equipment

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Authors: Ming-Jong Tsai, T. M. Wu, R. C. Chu

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The purpose of this study is to develop an Advanced linear calibration Technique for air flow sensing by using CTA-based Hot wire Anemometry. It contains a host PC with Human Machine Interface, a wind tunnel, a wind speed controller, an automatic data acquisition module, and nonlinear calibration model. To improve the fitting error by using single fitting polynomial, this study proposes a Multiple three-order Polynomial Fitting Method (MPFM) for fitting the non-linear output of a CTA-based Hot wire Anemometry. The CTA-based anemometer with built-in fitting parameters is installed in the wind tunnel, and the wind speed is controlled by the PC-based controller. The Hot-Wire anemometer's thermistor resistance change is converted into a voltage signal or temperature differences, and then sent to the PC through a DAQ card. After completion measurements of original signal, the Multiple polynomial mathematical coefficients can be automatically calculated, and then sent into the micro-processor in the Hot-Wire anemometer. Finally, the corrected Hot-Wire anemometer is verified for the linearity, the repeatability, error percentage, and the system outputs quality control reports.

Keywords: flow rate sensing, hot wire, constant temperature anemometry (CTA), linear calibration, multiple three-order polynomial fitting method (MPFM), temperature compensation

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Authors: E. Feulefack Songong, A. Zingoni

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A vibration is a mechanical phenomenon whereby oscillations occur about an equilibrium point. Although vibrations can be linear or nonlinear depending on the basic components of the system, the interest is mostly pointed towards nonlinear vibrations. This is because most structures around us are to some extent nonlinear and also because we need more accurate values in an analysis. The goal of this research is the integration of nonlinearities in the development and validation of structural models and to ameliorate the resistance of structures when subjected to loads. Although there exist many types of nonlinearities, this thesis will mostly focus on the vibration of free and undamped systems incorporating nonlinearity due to stiffness. Nonlinear stiffness has been a concern to many engineers in general and Civil engineers in particular because it is an important factor that can bring a good modification and amelioration to the response of structures when subjected to loads. The analysis of systems will be done analytically and then numerically to validate the analytical results. We will first show the benefit and importance of stiffness nonlinearity when it is implemented in the structure. Secondly, We will show how its integration in the structure can improve not only the structure’s performance but also its response when subjected to loads. The results of this study will be valuable to practicing engineers as well as industry practitioners in developing better designs and tools for their structures and mechanical devices. They will also serve to engineers to design lighter and stronger structures and to give good predictions as for the behavior of structures when subjected to external loads.

Keywords: elastic foundation, nonlinear, plates, stiffness, structures, vibration

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Authors: Priya Jaswal, Vivek, S. K. Sinha

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One of the most important and complicated factors influencing the functional performance of unpaved roads is traffic loading. The complexity of traffic loading is caused by the variable magnitude and frequency of load, which causes unpaved roads to fail prematurely. Unpaved roads are low-volume roads, and as peri-urbanization increases, unpaved roads act as a means to boost the rural economy. This has also increased traffic on unpaved roads, intensifying the issue of settlement, rutting, and fatigue failure. This is a major concern for unpaved roads built on poor subgrade soil, as excessive rutting caused by heavy loads can cause driver discomfort, vehicle damage, and an increase in maintenance costs. Some researchers discovered that when a consistent static load is exerted as opposed to a rapidly changing load, the rate of deformation of unpaved roads increases. Previously, some of the most common methods for overcoming the problem of rutting and fatigue failure included chemical stabilisation, fibre reinforcement, and so on. However, due to their high cost, engineers' attention has shifted to geotextiles which are used as reinforcement in unpaved roads. Geotextiles perform the function of filtration, lateral confinement of base material, vertical restraint of subgrade soil, and the tension membrane effect. The use of geotextiles in unpaved roads increases the strength of unpaved roads and is an economically viable method because it reduces the required aggregate thickness, which would need less earthwork, and is thus recommended for unpaved road applications. The majority of geotextiles used previously were polymeric, but with a growing awareness of sustainable development to preserve the environment, researchers' focus has shifted to natural fibres. Coir is one such natural fibre that possesses the advantage of having a higher tensile strength than other bast fibres, being eco-friendly, low in cost, and biodegradable. However, various researchers have discovered that the surface of coir fibre is covered with various impurities, voids, and cracks, which act as a plane of weakness and limit the potential application of coir geotextiles. To overcome this limitation, chemical surface modification of coir geotextiles is widely accepted by researchers because it improves the mechanical properties of coir geotextiles. The current paper reviews the effect of using treated coir geotextiles as reinforcement on the load-deformation behaviour of a two-layered unpaved road model.

Keywords: coir, geotextile, treated, unpaved

Procedia PDF Downloads 94

Authors: Fdhila Walid, Bayar Sihem, Khouidi Bochra, Maâtouk Fethi, Ben Amor Feten, Hajer Hentati, Mahdhi Abdelkarim

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The presence of resistant bacteria in the oral cavity can be the major cause of dental antibiotic prophylaxis failure. Multidrug efflux has been described for many organisms, including bacteria and fungi as part of their drugs resistance strategy. The potential use of probiotic bacteria can be considered as a new alternative in the prevention or cure of oral cavity diseases. In this study, different Bacillus strains isolated from the environment were isolated and characterized using biochemical and molecular procedures. The inhibitory activity against different pathogenic bacteria and yeast strains was tested using diffusion agar assay method. Our data revealed that the tested strains have an antimicrobial effect against the pathogenic strains such as Streptococcus mutants. The inhibitory effect was variable depending from the probiotic and pathogenic strains. The obtained result demonstrated that Bacillus can be used as a potential candidates probiotic and help in the prevention and treatment of oral infections, including dental caries, periodontal disease and halitosis. Our data, partly encourage the use of probiotic strains because they do not produce acid which can contribute to faster installation decay and these are spore-forming bacteria that can withstand the stress of the oral cavity (acids, alkalis, and salty foods).

Keywords: probiotic, pathogenic bacteria, yeast, oral cavity

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Authors: Suresh Vidyasagar Chevuri, D. B. Karunakar Chevuri

Abstract:

The main advantages of 'Metal Matrix Nano Composites (MMNCs)' include excellent mechanical performance, good wear resistance, low creep rate, etc. The method of fabrication of MMNCs is quite a challenge, which includes processing techniques like Spark Plasma Sintering (SPS), etc. The objective of the present work is to fabricate aluminum based MMNCs with the addition of small amounts of yttrium using Spark Plasma Sintering and to evaluate their mechanical and microstructure properties. Samples of 2024 AA with yttrium ranging from 0.1% to 0.5 wt% keeping 1 wt% TiB2 constant are fabricated by Spark Plasma Sintering (SPS). The mechanical property like hardness is determined using Vickers hardness testing machine. The metallurgical characterization of the samples is evaluated by Optical Microscopy (OM), Field Emission Scanning Electron Microscopy (FE-SEM) and X-Ray Diffraction (XRD). Unreinforced 2024 AA sample is also fabricated as a benchmark to compare its properties with that of the composite developed. It is found that the yttrium addition increases the above-mentioned properties to some extent and then decreases gradually when yttrium wt% increases beyond a point between 0.3 and 0.4 wt%. High density is achieved in the samples fabricated by spark plasma sintering when compared to any other fabrication route, and uniform distribution of yttrium is observed.

Keywords: spark plasma sintering, 2024 AA, yttrium addition, microstructure characterization, mechanical properties

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Authors: Abed Ahmed, Mehrdad Asadi, Jennifer Martay

Abstract:

Stainless steel pipelines are crucial components to transportation and storage in the oil and gas industry. However, the rise of random attacks and vandalism on these pipes for their valuable transport has led to more security and protection for incoming surface impacts. These surface impacts can lead to large global deformations of the pipe and place the pipe under strain, causing the eventual failure of the pipeline. Therefore, understanding how these surface impact loads affect the pipes is vital to improving the pipes’ security and protection. In this study, experimental test and finite element analysis (FEA) have been carried out on EN3B stainless steel specimens to study the impact behaviour. Low velocity impact tests at 9 m/s with 16 kg dome impactor was used to simulate for high momentum impact for localised failure. FEA models of clamped and deformable boundaries were modelled to study the effect of the boundaries on the pipes impact behaviour on its impact resistance, using experimental and FEA approach. Comparison of experimental and FE simulation shows good correlation to the deformable boundaries in order to validate the robustness of the FE model to be implemented in pipe models with complex anisotropic structure.

Keywords: dynamic impact, deformable boundary conditions, finite element modelling, LS-DYNA, stainless steel pipe

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Authors: Ayman Othman, Tallat Abd el Wahed

Abstract:

The current research is directed towards studying the creep compliance characteristics of asphalt concrete mixtures modified with cement dust. This study can aid in assessing the permanent deformation potential of asphalt concrete mixtures. Cement dust was added to the mixture as mineral filler and compared with regular lime stone filler. A power law model was used to characterize the creep compliance behavior of the studied mixtures. Creep testing results have revealed that the creep compliance power law parameters have a strong relationship with mixture type. Testing results of the studied mixtures, as indicated by the creep compliance parameters revealed an enhancement in the creep resistance, Marshall stability, indirect tensile strength and compressive strength for cement dust mixtures as compared to mixtures with traditional lime stone filler. It is concluded that cement dust can be successfully used to decrease the potential of asphalt concrete mixture to permanent deformation and improve its mechanical properties. This is in addition to the environmental benefits that can be gained when using cement dust in asphalt paving technology.

Keywords: cement dust, asphalt concrete mixtures, creep compliance, Marshall stability, indirect tensile strength, compressive strength

Procedia PDF Downloads 427

Authors: Santiranjan Shannigrahi, Mohit Sharma, Ivan Tan Chee Kiang, Yong Anna Marie

Abstract:

Polymer-ceramics composites are gaining importance due to their high specific strength, corrosion resistance, and high mechanical properties, as well as low cost. As a result, polymer composites are suitable for various industrial applications, like automobiles, aerospace, and biomedical areas. The present work comprises the development of polymer-ceramic composite films and is tested for the harsh environment including weatherability and UV barrier property. The polymer composite films are kept in weather chamber for a fixed period of time followed by tested for their physical, mechanical and chemical properties. The composite films are fabricated using compounding followed by hot pressing. UV-visible spectroscopy results reveal that the pure polymer polyethylene (PE) films are transparent in the visible range and do not absorb UV. However, polymer ceramic composite films start absorbing UV completely even at very low filler loading amount of 5 wt.%. The changes in tensile properties of the various composite films before and after UV illuminations for 40 hrs at 60 degC are analyzed. The tensile strength of neat PE film has been observed 8% reduction, whereas the remarkable increase in tensile strength has been observed (18% improvement for 10 wt. % filled composites films). The UV exposure leads to strengthen the crosslinking among PE polymer chains in the filled composite films, which contributes towards the incremented tensile strength properties.

Keywords: polymer ceramic composite, processing, harsh environment, mechanical properties

Procedia PDF Downloads 383

Authors: Zahid Iqbal, Ijaz Javed, Riaz Hussain, Ibadullah Jan, Amir Ali Khan

Abstract:

This study was conducted to investigate the disposition kinetics of ciprofloxacin and calculate its optimal dosage in Pakistani sheep of Lohi breed. Injectable preparation of ciprofloxacin was given intramuscularly to eight sheep at a dose of 5 mg/Kg. Before administration of drug blood sample was drawn from each animal. Post drug administration, blood samples were also drawn at various predetermined time periods. Drug concentration in the blood samples was assessed through high performance liquid chromatograph (HPLC). Data were best described by two compartment open model and different pharmacokinetic (PK) parameters were calculated. Cmax of 1.97 ± 0.15 µg/ml was reached at Tmax of 0.88 ± 0.09 hours. Half life of absorption (t1/2 abs) was observed to be 0.63 ± 0.16 hours while t1/2 α (distribution half life) and t1/2 ß (elimination half life) were found to be 0.46 ± 0.05 and 2.93 ± 0.45 hours, respectively. Vd (apparent volume of distribution) was calculated as 2.89 ± 0.30 L/kg while AUC (area under the curve) was 7.19 ± 0.38 µg.hr/mL and CL (total body clearance) was 0.75 ± 0.04 L/hr/kg. Using these parameters, an optimal intramuscular dosage of ciprofloxacin in adult Lohi sheep was calculated as 21.43 mg/kg, advised to be repeated after 24 hours. From this, we came to the conclusion that calculated dose was much higher than the dose advised by the foreign manufacturer and to avoid antimicrobial resistance, it is advised that this locally investigated dosage regimen should be strictly followed in local sheep.

Keywords: pharmacokinetics, dosage regimen, ciprofloxacin, HPLC, sheep

Procedia PDF Downloads 539

Authors: M. Mert, M. T. Ozkan

Abstract:

Pile load tests should be applied to check the bearing capacity calculations and to determine the settlement of the pile corresponding to test load. Strain gauges can be installed into pile in order to determine the shaft resistance of the piles for every soil layer respectively. Detailed results can be obtained by means of strain gauges placed at certain levels into test piles. In the scope of this study, pile load test data obtained from two different projects are examined.  Instrumented static pile load tests were applied on totally 7 test bored piles of different diameters (80 cm, 150 cm, and 200 cm) and different lengths (between 30-76 m) in two different project site. Settlement analysis of test piles is done by using some of load transfer methods and finite element method. Plaxis 3D which is a three-dimensional finite element program is also used for settlement analysis of the test piles. In this study, firstly bearing capacity of test piles are determined and compared with strain gauge data which is required for settlement analysis. Then, settlement values of the test piles are estimated by using load transfer methods developed in recent years and finite element method. The aim of this study is to show similarities and differences between the results obtained from settlement analysis methods and instrumented pile load tests.

Keywords: failure, finite element method, monitoring and instrumentation, pile, settlement

Procedia PDF Downloads 167

Authors: Hyunki Kang, Hi Won Jeong

Abstract:

The gas turbine operates for a long period of time under harsh, cyclic conditions of high temperature and pressure, where high turbine inlet temperature (TIT) can range from 1273 to 1873K. Therefore, Ni-base superalloys such as IN738, IN939, Rene 45, Rene 71, Rene 80, Mar M 247, CM 247, and CMSX-4 with excellent mechanical properties and resistance to creep, corrosion and oxidation at high temperatures are indeed used. Among the alloying additions for these alloys, aluminum (Al) and titanium (Ti) form gamma prime and enhance the high-temperature properties. However, when crack-damaged high-temperature turbine components such as blade and vane are repaired by fusion welding, they cause cracks. For example, when arc welding is applied to certain superalloys that contain Al and Ti with more than 3 wt.% and T3.5 wt%, respectively, such as IN738, IN939, Rene 80, Mar M 247, and CM 247, aging cracks occur. Therefore, repair technologies using diffusion brazing, which has less heat input into the base material, are being developed. Analysis of microstructural evolution of the brazed joints with a base metal of IN 939 Ni-base superalloy using brazing different filler metals was also carried out using X-ray diffraction, OEM, SEM-EDS, and EPMA. Stress rupture and high-temperature tensile strength properties were also measured to analyze the effects of different brazing heat cycles. The boron amount in the diffusion-affected zone (DAZ) was decreased towards the base metal and the formation of borides at grain boundaries was detected through EPMA.

Keywords: gas turbine, diffusion brazing, superalloy, gas turbine repair

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Authors: Qudama Albu-Jasim, Majdi Kanaan

Abstract:

A case study about the load rating and strengthening evaluation of the six-span of steel girders bridge in Colton city of State of California is investigated. To simulate the load rating strengthening assessment for the Colton Overhead bridge, a three-dimensional finite element model built in the CSiBridge program is simulated. Three-dimensional finite-element models of the bridge are established considering the nonlinear behavior of critical bridge components to determine the feasibility and strengthening capacity under load rating analysis. The bridge was evaluated according to Caltrans Bridge Load Rating Manual 1st edition for rating the superstructure using the Load and Resistance Factor Rating (LRFR) method. The analysis for the bridge was based on load rating to determine the largest loads that can be safely placed on existing I-girder steel members and permitted to pass over the bridge. Through extensive numerical simulations, the bridge is identified to be deficient in flexural and shear capacities, and therefore strengthening for reducing the risk is needed. An in-depth parametric study is considered to evaluate the sensitivity of the bridge’s load rating response to variations in its structural parameters. The parametric analysis has exhibited that uncertainties associated with the steel’s yield strength, the superstructure’s weight, and the diaphragm configurations should be considered during the fragility analysis of the bridge system.

Keywords: load rating, CSIBridge, strengthening, uncertainties, case study

Procedia PDF Downloads 211