Search results for: concrete-filled steel tube column

Authors: Yang Gon Seo, Chang-Joon Kim, Dae Hyeok Kim

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It is estimated that 1.5 billion tires are produced worldwide each year which will eventually end up as waste tires representing a major potential waste and environmental problem. Pyrolysis has been great interest in alternative treatment processes for waste tires to produce valuable oil, gas and solid products. The oil and gas products may be used directly as a fuel or a chemical feedstock. The solid produced from the pyrolysis of tires ranges typically from 30 to 45 wt% and have high carbon contents of up to 90 wt%. However, most notably the solid have high sulfur contents from 2 to 3 wt% and ash contents from 8 to 15 wt% related to the additive metals. Upgrading tire pyrolysis products to high-value products has concentrated on solid upgrading to higher quality carbon black and to activated carbon. Hydrogen sulfide and ammonia are one of the common malodorous compounds that can be found in emissions from many sewages treatment plants and industrial plants. Therefore, removing these harmful gasses from emissions is of significance in both life and industry because they can cause health problems to human and detrimental effects on the catalysts. In this work, pyrolytic carbon black from waste tires was used to develop adsorbent with good adsorption capacity for removal of hydrogen and ammonia. Pyrolytic carbon blacks were prepared by pyrolysis of waste tire chips ranged from 5 to 20 mm under the nitrogen atmosphere at 600℃ for 1 hour. Pellet-type adsorbents were prepared by a mixture of carbon black, metal oxide and sodium hydroxide or hydrochloric acid, and their adsorption capacities were estimated by using the breakthrough curve of a continuous fixed bed adsorption column at ambient condition. The adsorbent was manufactured with a mixture of carbon black, iron oxide(III), and sodium hydroxide showed the maximum working capacity of hydrogen sulfide. For ammonia, maximum working capacity was obtained by the adsorbent manufactured with a mixture of carbon black, copper oxide(II), and hydrochloric acid.

Keywords: adsorbent, ammonia, pyrolytic carbon black, hydrogen sulfide, metal oxide

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Authors: Kei Kamada, Rikito Murakami, Masahiko Ito, Mototaka Arakawa, Yasuhiro Shoji, Toshiyuki Ueno, Masao Yoshino, Akihiro Yamaji, Shunsuke Kurosawa, Yuui Yokota, Yuji Ohashi, Akira Yoshikawa

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Techniques of energy harvesting y have been widely developed in recent years, due to high demand on the power supply for ‘Internet of things’ devices such as wireless sensor nodes. In these applications, conversion technique of mechanical vibration energy into electrical energy using magnetostrictive materials n have been brought to attention. Among the magnetostrictive materials, Fe-Ga and Fe-Al alloys are attractive materials due to the figure of merits such price, mechanical strength, high magnetostrictive constant. Up to now, bulk crystals of these alloys are produced by the Bridgman–Stockbarger method or the Czochralski method. Using these method big bulk crystal up to 2~3 inch diameter can be grown. However, non-uniformity of chemical composition along to the crystal growth direction cannot be avoid, which results in non-uniformity of magnetostriction constant and reduction of the production yield. The micro-pulling down (μ-PD) method has been developed as a shaped crystal growth technique. Our group have reported shaped crystal growth of oxide, fluoride single crystals with different shape such rod, plate tube, thin fiber, etc. Advantages of this method is low segregation due to high growth rate and small diffusion of melt at the solid-liquid interface, and small kerf loss due to near net shape crystal. In this presentation, we report the shaped long plate crystal growth of Fe-Ga and Fe-Al alloys using the μ-PD method. Alloy crystals were grown by the μ-PD method using calcium oxide crucible and induction heating system under the nitrogen atmosphere. The bottom hole of crucibles was 5 x 1mm² size. A <100> oriented iron-based alloy was used as a seed crystal. 5 x 1 x 320 mm³ alloy crystal plates were successfully grown. The results of crystal growth, chemical composition analysis, magnetostrictive properties and a prototype vibration energy harvester are reported. Furthermore, continuous crystal growth using powder supply system will be reported to minimize the chemical composition non-uniformity along the growth direction.

Keywords: crystal growth, micro-pulling-down method, Fe-Ga, Fe-Al

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Authors: James Kralj

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Commercial shellfish aquaculture makes significant contributions to the economy and culture of the Pacific Northwest United States. The industry faces intense pressure to minimize environmental impacts as a result of Federal policies like the Magnuson-Stevens Fisheries Conservation and Management Act and the Endangered Species Act. These policies demand the protection of essential fish habitat and declare several salmon species as endangered. Consequently, numerous projects related to the protection and rehabilitation of eelgrass beds, a crucial ecosystem for countless fish species, have been proposed at both state and federal levels. Both eelgrass beds and commercial shellfish farms occupy the same physical space, and therefore understanding the effects of shellfish aquaculture on eelgrass ecosystems has become a top ecological and economic priority of both government and industry. This study evaluates the organismal communities that eelgrass and oyster aquaculture habitats support. Water samples were collected from Willapa Bay, Washington; Tillamook Bay, Oregon; Humboldt Bay, California; and Sammish Bay, Washington to compare species diversity in eelgrass beds, oyster aquaculture plots, and boundary edges between these two habitats. Diversity was assessed using a novel technique: environmental DNA (eDNA). All organisms constantly shed small pieces of DNA into their surrounding environment through the loss of skin, hair, tissues, and waste. In the marine environment, this DNA becomes suspended in the water column allowing it to be easily collected. Once extracted and sequenced, this eDNA can be used to paint a picture of all the organisms that live in a particular habitat making it a powerful technology for environmental monitoring. Industry professionals and government officials should consider these findings to better inform future policies regulating eelgrass beds and oyster aquaculture. Furthermore, the information collected in this study may be used to improve the environmental sustainability of commercial shellfish aquaculture while simultaneously enhancing its growth and profitability in the face of ever-changing political and ecological landscapes.

Keywords: aquaculture, environmental DNA, shellfish, sustainability

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Authors: B. Almassri, F. Almahmoud, R. Francois

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Near surface mounted reinforcement (NSM) technique is one of the promising techniques used nowadays to strengthen reinforced concrete (RC) structures. In the NSM technique, the Carbon Fibre Reinforced Polymer (CFRP) rods are placed inside pre-cut grooves and are bonded to the concrete with epoxy adhesive. This paper studies the non-classical mode of failure ‘the separation of concrete cover’ according to experimental and numerical FE modelling results. Experimental results and numerical modelling results of a 3D finite element (FE) model using the commercial software Abaqus and 2D FE model FEMIX were obtained on two beams, one corroded (25 years of corrosion procedure) and one control (A1CL3-R and A1T-R) were each repaired in bending using NSM CFRP rod and were then tested up to failure. The results showed that the NSM technique increased the overall capacity of control and corroded beams despite a non-classical mode of failure with separation of the concrete cover occurring in the corroded beam due to damage induced by corrosion. Another FE model used external steel stirrups around the repaired corroded beam A1CL3-R which failed with the separation of concrete cover, this model showed a change in the mode of failure form a non-classical mode of failure by the separation of concrete cover to the same mode of failure of the repaired control beam by the crushing of compressed concrete.

Keywords: corrosion, repair, Reinforced Concrete, FEM, CFRP, FEMIX

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Authors: Chayan Gupta, Arun Prasad

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The quick evolution of industrialization causes the scarcity of precious land. Thus, it is vital need to influence the R&D societies to achieve sustainable, economic and social benefits from huge utilization of waste for universal aids. The current study promotes the influence of steel industries waste i.e. ground granulated blast furnace slag (GGBS) in geotechnical properties of jarosite waste (solid waste residues produced from hydrometallurgy operations involved in extraction of Zinc). Numerous strengths tests (unconfined compression (qu) and splitting tensile strength (qt)) are conducted on jarosite-GGBS blends (GGBS, 10-30%) with different curing periods (7, 28 & 90 days). The results indicate that both qu and qt increase with the increase in GGBS content along with curing periods. The increased strength with the addition of GGBS is also observed from microstructural study, which illustrates the occurrence of larger agglomeration of jarosite-GGBS blend particles. The Freezing-Thawing (F-T) durability analysis is also conducted for all the jarosite-GGBS blends and found that the reduction in unconfined compressive strength after five successive F-T cycles enhanced from 62% (natural jarosite) to 48, 42 and 34% at 7, 14 and 28 days curing periods respectively for stabilized jarosite-GGBS samples containing 30% GGBS content. It can be concluded from this study that blending of cementing additives (GGBS) with jarosite waste resulted in a significant improvement in geotechnical characteristics.

Keywords: jarosite, GGBS, strength characteristics, microstructural study, durability analysis

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Authors: Asmae Tafraouti, Yasmina Layouni, Pascal Kleimann

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The growing market for Microsystems (MST) and Micro-Electromechanical Systems (MEMS) is driving the research for alternative manufacturing techniques to microelectronics-based technologies, which are generally expensive and time-consuming. Hot-embossing and micro-injection modeling of thermoplastics appear to be industrially viable processes. However, both require the use of master models, usually made in hard materials such as steel. These master models cannot be fabricated using standard microelectronics processes. Thus, other micromachining processes are used, as laser machining or micro-electrical discharge machining (µEDM). In this work, µEDM has been used. The principle of µEDM is based on the use of a thin cylindrical micro-tool that erodes the workpiece surface. The two electrodes are immersed in a dielectric with a distance of a few micrometers (gap). When an electrical voltage is applied between the two electrodes, electrical discharges are generated, which cause material machining. In order to produce master models with high resolution and smooth surfaces, it is necessary to well control the discharge mechanism. However, several problems are encountered, such as a random electrical discharge process, the fluctuation of the discharge energy, the electrodes' polarity inversion, and the wear of the micro-tool. The effect of different parameters, such as the applied voltage, the working capacitor, the micro-tool diameter, the initial gap, has been studied. This analysis helps to improve the machining performances, such: the workpiece surface condition and the lateral crater's gap.

Keywords: craters, electrical discharges, micro-electrical discharge machining (µEDM), microsystems

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Authors: Muna K. Abbass, Laith A. Mohammed, Muntaha K. Abbas

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The oxidation of Al-Li base alloy containing small amounts of rare earth (RE) oxides such as 0.2 wt% Y2O3 and 0.2wt% Nd2O3 particles have been studied at temperatures: 400ºC, 500ºC and 550°C for 60hr in a dry air. Alloys used in this study were prepared by melting and casting in a permanent steel mould under controlled atmosphere. Identification of oxidation kinetics was carried out by using weight gain/surface area (∆W/A) measurements while scanning electron microscopy (SEM) and x-ray diffraction analysis were used for micro structural morphologies and phase identification of the oxide scales. It was observed that the oxidation kinetic for all studied alloys follows the parabolic law in most experimental tests under the different oxidation temperatures. It was also found that the alloy containing 0.2 wt %Y 2O3 particles possess the lowest oxidation rate and shows great improvements in oxidation resistance compared to the alloy containing 0.2 wt % Nd2O3 particles and Al-Li base alloy. In this work, Taguchi method is performed to estimate the optimum weight gain /area (∆W/A) parameter in oxidation process of Al-Li base alloys to obtain a minimum thickness of oxidation layer. Taguchi method is used to formulate the experimental layout, to analyses the effect of each parameter (time, temperature and alloy type) on the oxidation generation and to predict the optimal choice for each parameter and analyzed the effect of these parameters on the weight gain /area (∆W/A) parameter. The analysis shows that, the temperature significantly affects on the (∆W/A) parameter.

Keywords: Al-Li base alloy, oxidation, Taguchi method, temperature

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Authors: Sifatullah Bahij, Safiullah Omary, Francoise Feugeas, Amanullah Faqiri

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Reinforced concrete (RC) is commonly used material in the construction sector, due to its low-cost and durability, and allowed the architectures and designers to construct structural members with different shapes and finishing. Usually, RC members are designed to sustain service loads efficiently without any destruction. However, because of the faults in the design phase, overloading, materials deficiencies, and environmental effects, most of the structural elements will require maintenance and repairing over their lifetime. Therefore, strengthening and repair of the deteriorated and/or existing RC structures are much important to extend their life cycle. Various techniques are existing to retrofit and strengthen RC structural elements such as steel plate bonding, external pre-stressing, section enlargement, fiber reinforced polymer (FRP) wrapping, etc. Although these configurations can successfully improve the load bearing capacity of the beams, they are still prone to corrosion damage which results in failure of the strengthened elements. Therefore, many researchers used fiber reinforced cementitious materials due to its low-cost, corrosion resistance, and result in improvement of the tensile and fatigue behaviors. Various types of cementitious materials have been used to strengthen or repair structural elements. This paper has summarized to accumulate data regarding on previously published research papers concerning the torsional behaviors of RC beams strengthened by various types of cementitious materials.

Keywords: reinforced concrete beams, strengthening techniques, cementitious materials, torsional strength, twisting angle

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Authors: Zainab Fadhil Al Toki, Nader Ghareeb

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This study investigates how lightweight a fire resistance door will perform with under types of insulation materials. Data is initially collected from various websites, scientific books and research papers. Results show that different layers of insulation in a single door can perform better than one insulator. Furthermore, insulation materials that are lightweight, high strength and low thermal conductivity are the most preferred for fire-rated doors. Whereas heavy weight, low strength, and high thermal conductivity are least preferred for fire resistance doors. Fire-rated door specifications, theoretical test methodology, structural analysis, and comparison between five different models with diverse layers insulations are presented. Five different door models are being investigated with different insulation materials and arrangements. Model 1 contains an air gap between door layers. Model 2 includes phenolic foam, mild steel and polyurethane. Model 3 includes phenolic foam and glass wool. Model 4 includes polyurethane and glass wool. Model 5 includes only rock wool between the door layers. It is noticed that model 5 is the most efficient model, and its design is simple compared to other models. For this model, numerical calculations are performed to check its efficiency and the results are compared to data from experiments for validation. Good agreement was noticed.

Keywords: fire resistance, insulation, strength, thermal conductivity, lightweight, layers

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Authors: Sang Chul Lee, Gi-Young Park, Dong Rak Kwon

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Objective: The aim of this study was to investigate regenerative effects of ultrasound (US)-guided injection with human umbilical cord blood-derived mesenchymal stem cells (UCB-MSCs) and/or polydeoxyribonucleotide (PDRN) injection in a chronic traumatic full-thickness rotator cuff tendon tear (FTRCTT) in a rabbit model. Material and Methods: Rabbits (n = 32) were allocated into 4 groups. After a 5-mm sized FTRCTT just proximal to the insertion site on the subscapularis tendon was created by excision, the wound was immediately covered by silicone tube to prevent natural healing. After 6 weeks, 4 injections (0.2 mL normal saline, G1; 0.2 mL PDRN, G2; 0.2 mL UCB-MSCs, G3; and 0.2 mL UCB-MSCs with 0.2ml PDRN, G4) were injected into FTRCTT under US guidance. We evaluated gross morphologic changes on all rabbits after sacrifice. Masson’s trichrome, anti-type 1 collagen antibody, bromodeoxyuridine, proliferating cell nuclear antigen, vascular endothelial growth factor and platelet endothelial cell adhesion molecule stain were performed to evaluate histological changes. Motion analysis was also performed. Results: The gross morphologic mean tendon tear size in G3 and 4 was significantly smaller than that of G1 and 2 (p < .05). However, there were no significant differences in tendon tear size between G3 and 4. In G4, newly regenerated collagen type 1 fibers, proliferating cells activity, angiogenesis, walking distance, fast walking time, and mean walking speed were greater than in the other three groups on histological examination and motion analysis. Conclusion: Co-injection of UCB-MSCs and PDRN was more effective than UCB-MSCs injection alone in histological and motion analysis in a rabbit model of chronic traumatic FTRCTT. However, there was no significant difference in gross morphologic change of tendon tear between UCB-MSCs with/without PDRN injection. The results of this study regarding the combination of UCB-MSCs and PDRN are worth additional investigations.

Keywords: mesenchymal stem cell, umbilical cord, polydeoxyribonucleotides, shoulder, rotator cuff, ultrasonography, injections

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Authors: Ahilya Singh, Brad Carte, Ramesh Subramani, William Aalbersberg

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A total of 37 actinomycete strains were purified from 25 Solomon Islands marine sediments using four different types of isolation media. Among them, 54% of the strains had obligate requirement of seawater for growth. The ethyl acetate extract of 100 ml fermentation product of each strain was screened for antimicrobial activity against multidrug resistant human pathogens and cytotoxic activity against brine shrimps. A total of 67% of the ethyl acetate extracts showed antimicrobial and/or cytotoxic activities. A strain F-1915 was selected for isolation and evaluation of bioactive compound(s) based on its bioactive properties and chemical profile analysis using the LC-MS. The strain F-1915 was identified to have 96% sequence similarity to Streptomyces violaceusniger on the basis of 16S rDNA sequences using BLAST analysis. The 16S rDNA revealed that the strain F-1915 is a new member of MAR4 clade of actinomycetes. The MAR4 clade is an interesting clade of actinomycetes known for the production of pharmaceutically important hybrid isoprenoid compounds. The ethyl acetate extract of the fermentation product of this strain was purified by silica gel column chromatography and afforded the isolation of one bioactive pure compound. Based on the 1D and 2D NMR spectral data of compound 1 it was identified as a new mono-brominated phenazinone, Marinophenazimycin A, a structure which has already been studied by external collaborators at Scripps Institution of Oceanography but is yet to be published. Compound 1 displayed significant antimicrobial activity against drug resistant human pathogens. The minimum inhibitory concentration (MIC) of compound 1 was against Methicillin Resistant Staphylococcus aureus (MRSA) was about 1.9 μg/ml and MIC recorded against Amphotericin Resistant Candida albicans (ARCA) was about 0.24 μg/ml. The bioactivity of compound 1 against ARCA was found to be better than the standard antifungal agent amphotericin B. Compound 1 however did not show any cytotoxic activity against brine shrimps.

Keywords: actinomycetes, antimicrobial activity, brominated phenazine, MAR4 clade, marine natural products, multidrug resistent, 1D and 2D NMR

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Authors: A. M. Tiara, Sudipto Chakraborty, S. K. Pal

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Impinging jets and their different configurations are important from the viewpoint of the fluid flow characteristics and their influence on heat transfer from metal surfaces due to their complex flow characteristics. Such flow characteristics results in highly variable heat transfer from the surface, resulting in varying cooling rates which affects the mechanical properties including hardness and strength. The overall objective of the current research is to conduct a fundamental investigation of the heat transfer mechanisms for an impinging coolant jet. Numerical simulation of the cooling process gives a detailed analysis of the different parameters involved even though employing Computational Fluid Dynamics (CFD) to simulate the real time process, being a relatively new research area, poses many challenges. The heat transfer mechanism in the current research is actuated by jet cooling. The computational tool used in the ongoing research for simulation of the cooling process is ANSYS Workbench software. The temperature and heat flux distribution along the steel strip with the effect of various flow parameters on the heat transfer rate can be observed in addition to determination of the jet impingement patterns, which is the major aim of the present analysis. Modelling both jet and air atomized cooling techniques using CFD methodology and validating with those obtained experimentally- including trial and error with different models and comparison of cooling rates from both the techniques have been included in this work. Finally some concluding remarks are made that identify some gaps in the available literature that have influenced the path of the current investigation.

Keywords: CFD, heat transfer, impinging jets, numerical simulation

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Authors: Swanand Patil, Pankaj Agarwal

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In past few decades, seismic performance objectives have shifted from earthquake resistance to earthquake resilience of the structures, especially for the lifeline buildings. Features such as negligible post-earthquake damage and replaceable damaged components, makes energy dissipating systems a valid choice for a seismically resilient building. In this study, various energy dissipation devices are applied on an eight-storey moment resisting RC building model. The energy dissipating devices include both hysteresis-based and viscous type of devices. The seismic response of the building is obtained for different positioning and mechanical properties of the devices. The investigation is carried forward to the deficiently ductile RC frame also. The performance assessment is done on the basis of drift ratio, mode shapes and displacement response of the model structures. Nonlinear dynamic analysis shows largely improved displacement response. The damping devices improve displacement response more efficiently in the deficient ductile frames than that in the perfectly moment resisting frames. This finding is important considering the number of deficient buildings in India and the world. The placement and mechanical properties of the dampers prove to be a crucial part in modelling, analyzing and designing of the structures with supplemental energy dissipation.

Keywords: earthquake resilient structures, lifeline buildings, retrofitting of structures, supplemental energy dissipation

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Authors: A. Razavykia, A. Esmaeilzadeh, S. Iranmanesh

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Many orthopedic implants like proximal humerus cases require lower surface roughness and almost immediate/short lead time surgery. Thus, rapid response from the manufacturer is very crucial. Tool path strategy of milling process has a direct influence on the surface roughness and lead time of medical implant. High-speed milling as promised process would improve the machined surface quality, but conventional or super-abrasive grinding still required which imposes some drawbacks such as additional costs and time. Currently, many CAD/CAM software offers some different tool path strategies to milling free form surfaces. Nevertheless, the users must identify how to choose the strategies according to cutting tool geometry, geometry complexity, and their effects on the machined surface. This study investigates the effect of different tool path strategies for milling a proximal humerus head during finishing operation on stainless steel 316L. Experiments have been performed using MAHO MH700 S vertical milling machine and four machining strategies, namely, spiral outward, spiral inward, and radial as well as zig-zag. In all cases, the obtained surfaces were analyzed in terms of roughness and dimension accuracy compared with those obtained by simulation. The findings provide evidence that surface roughness, dimensional accuracy, and machining time have been affected by the considered tool path strategy.

Keywords: CAD/CAM software, milling, orthopedic implants, tool path strategy

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Authors: Krasimir Ivanov, Elitsa Kolentsova, Dimitar Dimitrov

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The development of active and stable catalysts without noble metals for low temperature oxidation of exhaust gases remains a significant challenge. The purpose of this study is to determine the influence of the preparation method on the catalytic activity of the supported copper-manganese mixed oxides in terms of VOCs oxidation. The catalysts were prepared by impregnation of γ-Al2O3 with copper and manganese nitrates and acetates and the possibilities for CO, CH3OH and dimethyl ether (DME) oxidation were evaluated using continuous flow equipment with a four-channel isothermal stainless steel reactor. Effect of the support, Cu/Mn mole ratio, heat treatment of the precursor and active component loading were investigated. Highly active alumina supported Cu-Mn catalysts for CO and VOCs oxidation were synthesized. The effect of preparation conditions on the activity behavior of the catalysts was discussed. The synergetic interaction between copper and manganese species increases the activity for complete oxidation over mixed catalysts. Type of support, calcination temperature and active component loading along with catalyst composition are important factors, determining catalytic activity. Cu/Mn molar ratio of 1:5, heat treatment at 450oC and 20 % active component loading are the best compromise for production of active catalyst for simultaneous combustion of CO, CH3OH and DME.

Keywords: copper-manganese catalysts, CO, VOCs oxidation, exhaust gases

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Authors: Viriyavudh Sim, SeungHyun Kim, JungKyu Choi, WooYoung Jung

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Glass Fiber Reinforced Polymer (GFRP) is a major evolution for energy dissipation when used as infill material for seismic retrofitting of steel frame, a basic PMC infill wall system consists of two GFRP laminates surrounding an infill of foam core. This paper presents numerical analysis in terms of buckling resistance of GFRP sandwich infill panels system under the influence of environment temperature and stacking sequence of laminate skin. Mode of failure under in-plane compression is studied by means of numerical analysis with ABAQUS platform. Parameters considered in this study are contact length between infill and frame, laminate stacking sequence of GFRP skin and variation of mechanical properties due to increment of temperature. The analysis is done with four cases of simple stacking sequence over a range of temperature. The result showed that both the effect of temperature and stacking sequence alter the performance of entire panel system. The rises of temperature resulted in the decrements of the panel’s strength. This is due to the polymeric nature of this material. Additionally, the contact length also displays the effect on the performance of infill panel. Furthermore, the laminate stiffness can be modified by orientation of laminate, which can increase the infill panel strength. Hence, optimal performance of the entire panel system can be obtained by comparing different cases of stacking sequence.

Keywords: buckling resistance, GFRP infill panel, stacking sequence, temperature dependent

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Authors: Vikas Teotia, Sanjay Malhotra, Elina Mishra, Prashant Kumar, R. R. Singh, Priti Ukarde, P. P. Marathe, Y. S. Mayya

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Bhabha Atomic Research Centre, Trombay is developing low energy high intensity Proton Accelerator (LEHIPA) as pre-injector for 1 GeV proton accelerator for accelerator driven sub-critical reactor system (ADSS). LEHIPA consists of RFQ (Radio Frequency Quadrupole) and DTL (Drift Tube Linac) as major accelerating structures. DTL is RF resonator operating in TM010 mode and provides longitudinal E-field for acceleration of charged particles. The RF design of drift tubes of DTL was carried out to maximize the shunt impedance; this demands the diameter of drift tubes (DTs) to be as low as possible. The width of the DT is however determined by the particle β and trade-off between a transit time factor and effective accelerating voltage in the DT gap. The array of Drift Tubes inside DTL shields the accelerating particle from decelerating RF phase and provides transverse focusing to the charged particles which otherwise tends to diverge due to Columbic repulsions and due to transverse e-field at entry of DTs. The magnetic lenses housed inside DTS controls the transverse emittance of the beam. Quadrupole magnets are preferred over solenoid magnets due to relative high focusing strength of former over later. The availability of small volume inside DTs for housing magnetic quadrupoles has motivated the usage of permanent magnet quadrupoles rather than Electromagnetic Quadrupoles (EMQ). This provides another advantage as joule heating is avoided which would have added thermal loaded in the continuous cycle accelerator. The beam dynamics requires uniformity of integral magnetic gradient to be better than ±0.5% with the nominal value of 2.05 tesla. The paper describes the magnetic design of the PMQ using Sm2Co17 rare earth permanent magnets. The paper discusses the results of five pre-series prototype fabrications and qualification of their prototype permanent magnet quadrupoles and a full scale DT developed with embedded PMQs. The paper discusses the magnetic pole design for optimizing integral Gdl uniformity and the value of higher order multipoles. A novel but simple method of tuning the integral Gdl is discussed.

Keywords: DTL, focusing, PMQ, proton, rate earth magnets

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Authors: Chunyue Liu, Hongxing Jiang

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Traditional water depth survey of wetland habitats used by waterbirds needs intensive labor, time and money. The optical remote sensing image relies on passive multispectral scanner data has been widely employed to study estimate water depth. This paper presents an innovative method for developing the water depth model based on the characteristics of visible and thermal infrared spectra of Landsat ETM+ image, combing with 441 field water depth data at Etoupao shallow wetland. The wetland is located at Momoge National Nature Reserve of Northeast China, where the largest stopover habitat along the eastern flyway of globally, critically-endangered Siberian Cranes are. The cranes mainly feed on the tubers of emergent aquatic plants such as Scirpus planiculmis and S. nipponicus. The effective water control is a critical step for maintaining the production of tubers and food availability for this crane. The model employing multi-band approach can effectively simulate water depth for this shallow wetland. The model parameters of NDVI and GREEN indicated the vegetation growth and coverage affecting the reflectance from water column change are uneven. Combining with the field-observed water level at the same date of image acquisition, the digital elevation model (DEM) for the underwater terrain was generated. The wetland area and water volume of different water levels were then calculated from the DEM using the function of Area and Volume Statistics under the 3D Analyst of ArcGIS 10.0. The findings provide good references to effectively monitor changes in water level and water demand, develop practical plan for water level regulation and water management, and to create best foraging habitats for the cranes. The methods here can be adopted for the bottom topography simulation and water management in waterbirds’ habitats, especially in the shallow wetlands.

Keywords: remote sensing, water depth reversion, shallow wetland habitat management, siberian crane

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Authors: Babak Sadeghi, Rony Snyders, Marie-Paule.Delplancke-Ogletree

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Nitrogen fixation (NF) is one of the crucial industrial processes. Many attempts have been made in order to artificially fix nitrogen, and among them, the Haber-Bosch’s (H-B) process is widely used. However, it presents two major drawbacks: huge fossil feedstock consumption and noticeable greenhouse gases emission. It is, therefore, necessary to develop alternatives. Plasma technology, as an inherent “green” technology, is considered to have a great potential for reducing the environmental impacts and improving the energy efficiency of the NF process. In this work, we have studied the catalyst assisted microwave plasma for NF application. Heterogeneous catalysts of MoO₃, with various loads 0, 5, 10, 20, and 30 wt%, supported on γ-alumina were prepared by conventional wet impregnation. Crystallinity, surface area, pore size, and microstructure were obtained by X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) adsorption isotherm, Scanning electron microscopy (SEM), and Transmission electron microscopy (TEM). The XRD patterns of calcined alumina confirm the γ- phase. Characteristic picks of MoO₃ could not be observed for low loads (< 20 wt%), likely indicating a high dispersion of metal oxide over the support. The specific surface area along with pores size are decreasing with increasing calcination temperature and MoO₃ loading. The MoO₃ loading does not modify the microstructure. TEM and SEM results for loading inferior to 20 wt% are coherent with a monolayer of MoO₃ on the support as proposed elsewhere. For loading of 20 wt% and more, TEM and Electron diffraction (ED) show nanocrystalline ₃-D MoO₃ particles. The catalytic performances of these catalysts were investigated in the post-discharge of a microwave plasma for NOx formation from N₂/O₂ mixtures. The plasma is sustained by a surface wave launched in a quartz tube via a surfaguide supplied by a 2.45 GHz microwave generator in pulse mode. In-situ identification and quantification of the products were carried out by Fourier-transform infrared spectroscopy (FTIR) in the post-discharge region. FTIR analysis of the exhausted gas reveal NO and NO₂ bands in presence of catalyst while only NO band were assigned without catalyst. On the other hand, in presence of catalyst, a 10% increase of NOₓ formation and of 20% increase in energy efficiency are observed.

Keywords: γ-Al2O₃-MoO₃, µ-waveplasma, N2 fixation, Plasma-catalysis, Plasma diagnostic

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Authors: Alan T. Sassler

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Biofouling is a significant issue for ships, especially those based in warm water ports. Biofouling damages hull coatings, degrades platform hydrodynamics, blocks cooling water intakes, and returns, reduces platform range and speed, and increases fuel consumption. Although platforms are protected to some degree by antifouling paints, these paints are much less effective on stationary platforms, and problematic biofouling can occur on antifouling paint-protected stationary platforms in some environments in as little as a matter of weeks. Remediation hull cleaning operations are possible, but they are very expensive, sometimes result in damage to the vessel’s paint or hull and are generally not completely effective. Ultrasound with sufficient intensity focused on specific frequency ranges can be used to prevent the growth of biofouling organisms. The use of ultrasound to prevent biofouling isn't new, but systems to date have focused on protecting platforms by shaking the hull using internally mounted transducers similar to those used in ultrasonic cleaning machines. While potentially effective, this methodology doesn't scale well to large platforms, and there are significant costs associated with installing and maintaining these systems, which dwarf the initial purchase price. An alternative approach has been developed, which uses highly directional pier-mounted transducers to project high-intensity spread-spectrum ultrasonic energy into the water column focused near the surface. This focused energy has been shown to prevent biofouling at ranges of up to 50 meters from the source. Spreading the energy out over a multi-kilohertz band makes the system both more effective and more environmentally friendly. This system has been shown to be both effective and inexpensive in small-scale testing and is now being characterized on a larger scale in selected marinas. To date, test results have been collected in Florida marinas suggesting that this approach can be used to keep ensonified areas of thousands of square meters free from biofouling, although care must be taken to minimize shaded areas.

Keywords: biofouling, ultrasonic, environmentally friendly antifoulant, marine protection, antifouling

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Authors: Debasis Sarkar

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Clean development mechanism (CDM) can act as an effective instrument for mitigating climate change. This mechanism can effectively reduce the emission of CO2 and other green house gases (GHG). Construction of a mega infrastructure project like underground corridor construction for metro rail operation involves in consumption of substantial quantity of concrete which consumes huge quantity of energy consuming materials like cement and steel. This paper is an attempt to develop an integrated clean development mechanism and risk management approach for sustainable development for an underground corridor metro rail project in India during its construction phase. It was observed that about 35% reduction in CO2 emission can be obtained by adding fly ash as a part replacement of cement. The reduced emission quantity of CO2 which is of the quantum of about 21,646.36 MT would result in cost savings of approximately INR 8.5 million (USD 1,29,878).But construction and operation of such infrastructure projects of the present era are subject to huge risks and uncertainties throughout all the phases of the project, thus reducing the probability of successful completion of the project within stipulated time and cost frame. Thus, an integrated approach of combining CDM with risk management would enable the metro rail authorities to develop a sustainable risk mitigation measure framework to ensure more cost and energy savings and lesser time and cost over-run.

Keywords: clean development mechanism (CDM), infrastructure transportation, project risk management, underground metro rail

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Authors: Yongyu Duo, Xiaogang Liu, Qingrui Yue

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The anchor plays a critical role in the utilization of the tensile strength of carbon fiber-reinforced polymer (CFRP) plate when it is applied for the prestressed retrofitted and cable structures. In this paper, the anchor behavior of planar clamping anchor (PCA) under different interface treatment forms and normal pressures was investigated by the uniaxial static tensile test. Two interface treatment forms were adopted, including pure friction and the coupling action of friction and bonding. The results indicated that the load-bearing capacity of PCA could be obviously improved by the coupling action of friction and bonding compared with the action of pure friction. Under the normal pressure of 11 MPa, 22 MPa, and 33 MPa, the load-bearing capacity of PCA was enhanced by 164.61%, 68.40%, and 52.78%, respectively, and the tensile strength of the CFRP plate was fully exploited when the normal pressure reached 44 MPa. In addition, the experimental coefficient of static friction between the galling CFRP plate and a sandblasted steel plate was in the range of 0.28-0.30, corresponding to various normal pressure. Moreover, the failure mode was determined by the interface treatment form and normal pressure. The research in this paper has important guiding significance to optimize the design of the mechanical clamping anchor, contributing to promoting the application of CFRP plate in reinforcement and cable structure.

Keywords: PCA, CFRP plate, interface treatment form, normal pressure, friction, coupling action

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Authors: Savvas Varitis, Panagiotis Kavouras, George Kaimakamis, Eleni Pavlidou, George Vourlias, Konstantinos Chrysafis, Philomela Komninou, Theodoros Karakostas

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Tannery industry produces high quantities of chromium containing waste which also have high organic content. Processing of this waste is important since the organic content is above the disposal limits and the containing trivalent chromium could be potentially oxidized to hexavalent in the environment. This work aims to fabricate new vitreous and glass ceramic materials which could incorporate the tannery waste in stabilized form either for safe disposal or for the production of useful materials. Tannery waste was incinerated at 500oC in anoxic conditions so most of the organic content would be removed and the chromium remained trivalent. Glass forming agents SiO2, Na2O and CaO were mixed with the resulting ash in different proportions with decreasing ash content. Considering the low solubility of Cr in silicate melts, the mixtures were melted at 1400oC and/or 1500oC for 2h and then casted on a refractory steel plate. The resulting vitreous products were characterized by X-Ray Diffraction (XRD), Differential Thermal Analysis (DTA), Scanning and Transmission Electron Microscopy (SEM and TEM). XRD reveals the existence of Cr2O3 (eskolaite) crystallites embedded in a glassy amorphous matrix. Such crystallites are not formed under a certain proportion of the waste in the ash-vitrified material. Reduction of the ash proportion increases chromium content in the silicate matrix. From these glassy products, glass-ceramics were produced via different regimes of thermal treatment.

Keywords: chromium containing tannery ash, glass ceramic materials, thermal processing, vitrification

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Authors: Kanagarajah Ravishankar

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This paper describes a study performed for a project featuring an elevated steel bridge structure supported by various types of foundation systems. This project focused on rehabilitation or redesign of a portion of the bridge substructures founded on caisson foundations. The study that this paper focuses on is the evaluation of foundation and soil stiffnesses and interactions between the existing caissons and proposed foundations. The caisson foundations were founded on top of rock, where the depth to the top of rock varies from approximately 50 to 140 feet below ground surface. Based on a comprehensive investigation of the existing piers and caissons, the presence of ASR was suspected from observed whitish deposits on cracked surfaces as well as internal damages sustained through the entire depth of foundation structures. Reuse of existing piers and caissons was precluded and deemed unsuitable under the earthquake condition because of these defects on the structures. The proposed design of new foundations and substructures which was selected ultimately neglected the contribution from the existing caisson and pier columns. Due to the complicated configuration between the existing caisson and the proposed foundation system, three-dimensional finite element method (FEM) was employed to evaluate soil-structure interaction (SSI), to evaluate the effect of the existing caissons on the proposed foundations, and to compare the results with conventional group analysis. The FEM models include separate models for existing caissons, proposed foundations, and combining both.

Keywords: soil-structure interaction, foundation stiffness, finite element, seismic design

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Authors: Erwin Chan, Aravind Subramaniyan, Siti Abdullah Fatehah, Steve Lian Kuling

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Foam assisted lift technology is proven across the industry to provide efficient deliquification in gas wells. Such deliquification is typically achieved by delivering the foamer chemical downhole via capillary strings. In highly liquid loaded wells where capillary strings are not readily available, foamer can be delivered via batch injection or bull-heading. The latter techniques differ from the former in that cap strings allow for liquid to be unloaded continuously, whereas foamer batches require that periodic batching be conducted for the liquid to be unloaded. Although batch injection allows for liquid to be unloaded in wells with suitable water to gas (WGR) ratio and condensate to gas (CGR) ratio without well intervention for capillary string installation, this technique comes with its own set of challenges - for foamer to de-liquify liquids, the chemical needs to reach perforation locations where gas bubbling is observed. In highly scaled perforation zones in certain wells, foamer delivered in batches is unable to reach the gas bubbling zone, thus achieving poor lift efficiency. This paper aims to discuss the techniques and challenges for unloading liquid via batch injection in scaled perforation wells X and Y, whose WGR is 6bbl/MMscf, whose scale build-up is observed at the bottom of perforation interval, whose water column is 400 feet, and whose ‘bubbling zone’ is less than 100 feet. Variables such as foamer Z dosage, batching technique, and well flow control valve opening times are manipulated during the duration of the trial to achieve maximum liquid unloading and gas rates. During the field trial, the team has found optimal values between the three aforementioned parameters for best unloading results, in which each cycle’s gas and liquid rates are compared with baselines with similar flowing tubing head pressures (FTHP). It is discovered that amongst other factors, a good agitation technique is a primary determinant for efficient liquid unloading. An average increment of 2MMscf/d against an average production of 4MMscf/d at stable FTHP is recorded during the trial.

Keywords: foam, foamer, gas lift, liquid unloading, scale, batch injection

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Authors: Nika Botchorishvili, Olgha Giorgishvili

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Many-year investigations of the nature of damping creep of rigid bodies and materials led to the discovery of the fundamental character of this phenomenon. It occurs only when a rigid body comes in contact with a surface-active medium (liquid or gaseous), which brings about a decrease of the free surface energy of a rigid body as a result of adsorption, chemo-sorption or wetting. The reversibility of the process consists of a gradual disappearance of creep deformation when the action of a surface-active medium stops. To clarify the essence of processes, a physical model is constructed by using Griffith’s scheme and the well-known representation formulas of deformation origination and failure processes. The total creep deformation is caused by the formation and opening of microcracks throughout the material volume under the action of load. This supposedly happens in macroscopically homogeneous silicate and organic glasses, while in polycrystals (tuff, gypsum, steel) contacting with a surface-active medium micro crack are formed mainly on the grain boundaries. The creep of rubber is due to its swelling activated by stress. Acknowledgment: All experiments are financially supported by Shota Rustaveli National Science Foundation of Georgia. Study of Properties of Concretes (Both Ordinary and Compacted) Made of Local Building Materials and Containing Admixtures, and Their Further Introduction in Construction Operations and Road Building. DP2016_26. 22.12.2016.

Keywords: process reversibility, surface-active medium, Rebinder’s effect, micro crack, creep

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Authors: Bashar Tarawneh, Yasser Hakam

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Rapid Impact Compaction (RIC) is a modern dynamic compaction device mainly used to compact sandy soils, where silt and clay contents are low. The device uses the piling hammer technology to increase the bearing capacity of soils through controlled impacts. The RIC device uses "controlled impact compaction" of the ground using a 9-ton hammer dropped from the height between 0.3 m to 1.2 m onto a 1.5 m diameter steel patent foot. The delivered energy is about 26,487 to 105,948 Joules per drop. To evaluate the performance of this technique, three project sites in the United Arab Emirates were improved using RIC. In those sites, a loose to very loose fine to medium sand was encountered at a depth ranging from 1.0m to 4.0m below the ground level. To evaluate the performance of the RIC, Cone Penetration Tests (CPT) were carried out before and after improvement. Also, load tests were carried out post-RIC work to assess the settlements and bearing capacity. The soil was improved to a depth of about 5.0m below the ground level depending on the CPT friction ratio (the ratio between sleeve friction and tip resistance). CPT tip resistance was significantly increased post ground improvement work. Load tests showed enhancement in the soil bearing capacity and reduction in the potential settlements. This study demonstrates the successful application of the RIC for middle-deep improvement and compaction of the ground. Foundation design criteria were achieved in all site post-RIC work.

Keywords: compaction, RIC, ground improvement, CPT

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Authors: Huseyin Zengin, Muhammet Emre Turan, Yunus Turen, Hayrettin Ahlatci, Yavuz Sun

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This study aimed for understanding the effects of dilute Nb additions on the austenite microstructure of microalloyed steels at five different reheating temperatures from 950 °C to 1300 °C. Four microalloyed high-carbon steels having 0.8 %wt C were examined in which three of them had varying Nb concentrations from 0.005 wt% to 0.02 wt% and one of them had no Nb concentration. The quantitative metallographic techniques were used to measure the average prior austenite grain size in order to compare the grain growth pinning effects of Nb precipitates as a function of reheating temperature. Due to the higher stability of the precipitates with increasing Nb concentrations, the grain coarsening temperature that resulted in inefficient grain growth impediment and a bimodal grain distribution in the microstructure, showed an increase with increasing Nb concentration. The respective grain coarsening temperatures (T_GC) in an ascending order for the steels having 0.005 wt% Nb, 0.01 wt% Nb and 0.02 wt% Nb were 950 °C, 1050 °C and 1150 °C. According to these observed grain coarsening temperatures, an approximation was made considering the complete dissolution temperature (T_DISS) of second phase particles as T_GC=T_DISS-300. On the other hand, the plain carbon steel did not show abnormal grain growth behaviour due to the absence of second phase particles. It was also observed that the higher the Nb concentration, the smaller the average prior austenite grain size although the small increments in Nb concenration did not change the average grain size considerably.

Keywords: microalloyed steels, prior austenite grains, second phase particles, grain coarsening temperature

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Authors: Amira Rjiba, Mohamed Ghanmi, Tahar Aifa, Achref Boulares

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This study, involving the interpretation of geological outcrops data (structures, and lithostratigraphiec colones) and subsurface structures (seismic and gravimetric data) help us to identify and precise (i) the lithology of the sedimentary formations between the Aptian and the recent formations, (ii) to differentiate the sedimentary formations it from the salt-bearing Triassic (iii) and to specify the major structures though the tectonics effects having affected the region during its geological evolution. By placing our study area placed in the context of Tunisia, located on the southern margin of the Tethys show us through tectonic traces and structural analysis conducted, that this area was submitted during the Triassic perio at an active rifting triggered extensional tectonic events and extensive respectively in the Cretaceous and Paleogene. Lithostratigraphic correlations between outcrops and seismic data sets on those of six oil wells conducted in the region have allowed us to better understand the structural complexity and the role of different tectonic faults having contributed to the current configuration, and marked by the current rifts. Indeed, three directions of NW-SE faults, NNW-SSE to NS and NE-SW to EW had a major role in the genesis of folds and open ditches collapse of NW-SE direction. These results were complemented by seismic reflection data to clarify the geometry of the southern and western areas of Kalaa Khasba ditch. The eight selected seismic lines for this study allowed to characterize the main structures, with isochronous maps, contour and isovitesse of Serdj horizon that presents the main reservoir in the region. The line L2, keyed by the well 6, helped highlight the NW-SE compression that has resulted in persistent discrepancies widely identifiable in its lithostratigraphic column. The gravity survey has confirmed the extension of most of the accidents deep subsurface whose activity seems to go far. Gravimetry also reinforced seismic interpretation confirming, at the L2 well, that both SW and NE flank of the moat are two opposite faults and trace the boundaries of NNW-SSE direction graben whose sedimentation of Mio-Pliocene age and Quaternary.

Keywords: graben, graben collapse, gravity, Kalat Es Senan, seismic, tectogenesis

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Authors: Shakti S. Acharya, V. R. R. Medicherla, Rajeev Rawat, Komal Bapna, Deepnarayan Biswas, Khadija Ali, K. Maiti

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The discovery of invar effect in 35% Ni concentration Fe1-xNix alloy has stimulated enormous experimental and theoretical research. Elemental Fe and low Ni concentration Fe1-xNix alloys which possess body centred cubic (bcc) crystal structure at ambient temperature and pressure transform to hexagonally close packed (hcp) phase at around 13 GPa. Magnetic order was found to be absent at 11K for Fe92Ni8 alloy when subjected to a high pressure of 26 GPa. The density functional theoretical calculations predicted substantial hyperfine magnetic fields, but were not observed in Mossbaur spectroscopy. The bulk modulus of fcc Fe1-xNix alloys with Ni concentration more than 35%, is found to be independent of pressure. The magnetic moment of Fe is also found be almost same in these alloys from 4 to 10 GPa pressure. Fe1-xNix alloys exhibit a complex microstructure which is formed by a series of complex phase transformations like martensitic transformation, spinodal decomposition, ordering, mono-tectoid reaction, eutectoid reaction at temperatures below 400°C. Despite the existence of several theoretical models the field is still in its infancy lacking full knowledge about the anomalous properties exhibited by these alloys. Fe1-xNix alloys have been prepared by arc melting the high purity constituent metals in argon ambient. These alloys have annealed at around 3000C in vacuum sealed quartz tube for two days to make the samples homogeneous. These alloys have been structurally characterized by x-ray diffraction and were found to exhibit a transition from bcc to fcc for x > 0.3. Ni 2p core levels of the alloys have been measured using high resolution (0.45 eV) x-ray photoelectron spectroscopy. Ni 2p core level shifts to lower binding energy with respect to that of pure Ni metal giving rise to negative core level shifts (CLSs). Measured CLSs exhibit a linear dependence in fcc region (x > 0.3) and were found to deviate slightly in bcc region (x < 0.3). ESCA potential model fails correlate CLSs with site potentials or charges in metallic alloys. CLSs in these alloys occur mainly due to shift in valence bands with composition due to intra atomic charge redistribution.

Keywords: arc melting, core level shift, ESCA potential model, valence band

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