Search results for: adhesively bonded concrete joints
746 The Immediate Effects of Thrust Manipulation for Thoracic Hyperkyphosis
Authors: Betul Taspinar, Eda O. Okur, Ismail Saracoglu, Ismail Okur, Ferruh Taspinar
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Thoracic hyperkyphosis, is a well-known spinal phenomenon, refers to an excessive curvature (> 40 degrees) of the thoracic spine. The aim of this study was to explore the effectiveness of thrust manipulation on thoracic spine alignment. 31 young adults with hyperkyphosis diagnosed with Spinal Mouse® device were randomly assigned either thrust manipulation group (n=16, 11 female, 5 male) or sham manipulation group (n=15, 8 female, 7 male). Thrust and sham manipulations were performed by a blinded physiotherapist who is a certificated expert in musculoskeletal physiotherapy. Thoracic kyphosis degree was measured after the interventions via Spinal Mouse®. Wilcoxon test was used to analyse the data obtained before and after the manipulation for each group, whereas Mann-Whitney U test was used to compare the groups. The mean of baseline thoracic kyphosis degrees in thrust and sham groups were 50.69 o ± 7.73 and 48.27o ± 6.43, respectively. There was no statistically significant difference between groups in terms of initial thoracic kyphosis degrees (p=0.51). After the interventions, the mean of thoracic kyphosis degree in thrust and sham groups were measured as 44.06o ± 6.99 and 48.93o ± 6.57 respectively (p=0.03). There was no statistically significant difference between before and after interventions in sham group (p=0.33), while the mean of thoracic kyphosis degree in thrust group decreased significantly (p=0.00). Thrust manipulation can attenuate thoracic hyperkyphosis immediately in young adults by not using placebo effect. Manipulation might provide accurate proprioceptive (sensory) input to the spine joints and reduce kyphosis by restoring normal segment mobility. Therefore thoracic manipulation might be included in the physiotherapy programs to treat hyperkyphosis.Keywords: hyperkyphosis, manual therapy, spinal mouse, physiotherapy
Procedia PDF Downloads 333745 Prioritization Ranking for Managing Moisture Problems in a Building
Authors: Sai Amulya Gollapalli, Dilip A. Patel, Parth Patel K., Lukman E. Mansuri
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Accumulation of moisture is one of the most worrisome aspects of a building. Architects and engineers tend to ignore its vitality during the designing and construction stage. Major fatalities in buildings can be caused by it. People avoid spending a lot of money on waterproofing. If the same mistake is repeated, no deep thinking is done. The quality of workmanship and construction is depleting due to negligence. It is important to do an analysis of the water maintenance issues happening in the current buildings and give a database for all the factors that are causing the defect. In this research, surveys are done with two waterproofing consultants, two client engineers, and two project managers. The survey was based on a matrix that was based on the causes of water maintenance issues. There were around 100 causes that were identified. The causes were categorized into six, namely, manpower, finance, method, management, environment, and material. In the matrices, the causes on the x-direction matched with the causes on the y-direction. 3 Likert scale was used to make a pairwise comparison between causes on each cell. Matrices were evaluated for the main categories and for each category separately. A final ranking was done by the weights achieved, and ‘cracks arriving from various construction joints’ was the highest with 0.57 relative significance, and ‘usage of the material’ was the lowest with 0.03 relative significance. Twelve defects due to water leakage were identified, and interviewees were asked to make a pairwise comparison of them, too, to understand the priorities. When the list of causes is achieved, the prioritization as per the stratification analysis is done. This will be beneficial to the consultants and contractors as they will get a primary idea of which causes to focus on.Keywords: water leakage, survey, causes, matrices, prioritization
Procedia PDF Downloads 90744 Ipsilateral Heterotopic Ossification in the Knee and Shoulder Post Long COVID-19
Authors: Raheel Shakoor Siddiqui, Calvin Mathias, Manikandar Srinivas Cheruvu, Bobin Varghese
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A 58 year old gentleman presented to accident and emergency at the district general hospital with worsening shortness of breath and a non-productive cough over a period of five days. He was initially admitted under the medical team for suspicion of SARS-CoV-2 (COVID-19) pneumonitis. Subsequently, upon deterioration of observations and a positive COVID-19 PCR, he was taken to intensive care for invasive mechanical ventilation. He required frequent proning, inotropic support and was intubated for thirty-three days. After successful extubation, he developed myopathy with a limited range of motion to his right knee and right shoulder. Plain film imaging of these limbs demonstrated an unusual formation of heterotopic ossification without any precipitating trauma or surgery. Current literature demonstrates limited case series portraying heterotopic ossification post-COVID-19. There has been negligible evidence of heterotopic ossification in the ipsilateral knee and shoulder post-prolonged immobility secondary to a critical illness. Physiotherapy and rehabilitation are post-intensive care can be prolonged due to the formation of heterotopic ossification around joints. Prolonged hospital stays may lead to a higher risk of developing infections of the chest, urine and pressure sores. This raises the question of whether a severe systemic inflammatory immune response from the SARS-CoV-2 virus results in histopathological processes leading to the formation of heterotopic ossification not previously seen, requiring prolonged physiotherapy.Keywords: orthopaedics, rehabilitation, physiotherapy, heterotopic ossification, COVID-19
Procedia PDF Downloads 66743 Design and Production of Thin-Walled UHPFRC Footbridge
Authors: P. Tej, P. Kněž, M. Blank
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The paper presents design and production of thin-walled U-profile footbridge made of UHPFRC. The main structure of the bridge is one prefabricated shell structure made of UHPFRC with dispersed steel fibers without any conventional reinforcement. The span of the bridge structure is 10 m and the clear width of 1.5 m. The thickness of the UHPFRC shell structure oscillated in an interval of 30-45 mm. Several calculations were made during the bridge design and compared with the experiments. For the purpose of verifying the calculations, a segment of 1.5 m was first produced, followed by the whole footbridge for testing. After the load tests were done, the design was optimized to cast the final footbridge.Keywords: footbridge, non-linear analysis, shell structure, UHPFRC, Ultra-High Performance Fibre Reinforced Concrete
Procedia PDF Downloads 221742 Use of Recycled PVB as a Protection against Carbonation
Authors: Michael Tupý, Vít Petránek
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The paper is focused on testing of the poly(vinyl butyral) (PVB) layer which had the function of a CO2 insulating protection against concrete and mortar carbonation. The barrier efficiency of PVB was verified by the measurement of diffusion characteristics. Two different types of PVB were tested; original extruded PVB sheet and PVB sheet made from PVB dispersion which was obtained from recycled windshields. The work deals with the testing CO2 diffusion when polymer sheets were exposed to a CO2 atmosphere (10% v/v CO2) with 0% RH. The excellent barrier capability against CO2 permeability of original and also recycled types of PVB layers was observed. This application of PVB waste can bring advantageous use in civil engineering and significant environmental contribution.Keywords: windshield, poly(vinyl butyral), mortar, diffusion, carbonatation, polymer waste
Procedia PDF Downloads 417741 Design of Reinforced Concrete (RC) Walls Considering Shear Amplification by Nonlinear Dynamic Behavior
Authors: Sunghyun Kim, Hong-Gun Park
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In the performance-based design (PBD), by using the nonlinear dynamic analysis (NDA), the actual performance of the structure is evaluated. Unlike frame structures, in the wall structures, base shear force which is resulted from the NDA, is greatly amplified than that from the elastic analysis. This shear amplifying effect causes repeated designs which make designer difficult to apply the PBD. Therefore, in this paper, factors which affect shear amplification were studied. For the 20-story wall model, the NDA was performed. From the analysis results, the base shear amplification factor was proposed.Keywords: performance based design, shear amplification factor, nonlinear dynamic analysis, RC shear wall
Procedia PDF Downloads 375740 Pushover Analysis of Masonry Infilled Reinforced Concrete Frames for Performance Based Design for near Field Earthquakes
Authors: Alok Madan, Ashok Gupta, Arshad K. Hashmi
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Non-linear dynamic time history analysis is considered as the most advanced and comprehensive analytical method for evaluating the seismic response and performance of multi-degree-of-freedom building structures under the influence of earthquake ground motions. However, effective and accurate application of the method requires the implementation of advanced hysteretic constitutive models of the various structural components including masonry infill panels. Sophisticated computational research tools that incorporate realistic hysteresis models for non-linear dynamic time-history analysis are not popular among the professional engineers as they are not only difficult to access but also complex and time-consuming to use. And, commercial computer programs for structural analysis and design that are acceptable to practicing engineers do not generally integrate advanced hysteretic models which can accurately simulate the hysteresis behavior of structural elements with a realistic representation of strength degradation, stiffness deterioration, energy dissipation and ‘pinching’ under cyclic load reversals in the inelastic range of behavior. In this scenario, push-over or non-linear static analysis methods have gained significant popularity, as they can be employed to assess the seismic performance of building structures while avoiding the complexities and difficulties associated with non-linear dynamic time-history analysis. “Push-over” or non-linear static analysis offers a practical and efficient alternative to non-linear dynamic time-history analysis for rationally evaluating the seismic demands. The present paper is based on the analytical investigation of the effect of distribution of masonry infill panels over the elevation of planar masonry infilled reinforced concrete (R/C) frames on the seismic demands using the capacity spectrum procedures implementing nonlinear static analysis (pushover analysis) in conjunction with the response spectrum concept. An important objective of the present study is to numerically evaluate the adequacy of the capacity spectrum method using pushover analysis for performance based design of masonry infilled R/C frames for near-field earthquake ground motions.Keywords: nonlinear analysis, capacity spectrum method, response spectrum, seismic demand, near-field earthquakes
Procedia PDF Downloads 398739 Seismic Performance Evaluation of the Composite Structural System with Separated Gravity and Lateral Resistant Systems
Authors: Zi-Ang Li, Mu-Xuan Tao
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During the process of the industrialization of steel structure housing, a composite structural system with separated gravity and lateral resistant systems has been applied in engineering practices, which consists of composite frame with hinged beam-column joints, steel brace and RC shear wall. As an attempt in steel structural system area, seismic performance evaluation of the separated composite structure is important for further application in steel housing. This paper focuses on the seismic performance comparison of the separated composite structural system and traditional steel frame-shear wall system under the same inter-story drift ratio (IDR) provision limit. The same architectural layout of a high-rise building is designed as two different structural systems at the same IDR level, and finite element analysis using pushover method is carried out. Static pushover analysis implies that the separated structural system exhibits different lateral deformation mode and failure mechanism with traditional steel frame-shear wall system. Different indexes are adopted and discussed in seismic performance evaluation, including IDR, safe factor (SF), shear wall damage, etc. The performance under maximum considered earthquake (MCE) demand spectrum shows that the shear wall damage of two structural systems are similar; the separated composite structural system exhibits less plastic hinges; and the SF index value of the separated composite structural system is higher than the steel frame shear wall structural system.Keywords: finite element analysis, new composite structural system, seismic performance evaluation, static pushover analysis
Procedia PDF Downloads 129738 Teachers' Perceptions of Physical Education and Sports Calendar and Conducted in the Light of the Objective of the Lesson Approach Competencies
Authors: Chelali Mohammed
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In the context of the application of the competency-based approach in the system educational Algeria, the price of physical education and sport must privilege the acquisition of learning approaches and especially the approach science, which from problem situations, research and develops him information processing and application of knowledge and know-how in new situations in the words of ‘JOHN DEWEY’ ‘learning by practice’. And to achieve these goals and make teaching more EPS motivating, consistent and concrete, it is appropriate to perform a pedagogical approach freed from the constraints and open to creativity and student-centered in the light of the competency approach adopted in the formal curriculum. This approach is not unusual, but we think it is a highly professional nature requires the competence of the teacher.Keywords: approach competencies, physical, education, teachers
Procedia PDF Downloads 597737 Effect of Sintering Time and Porosity on Microstructure, Mechanical and Corrosion Properties of Ti6Al15Mo Alloy for Implant Applications
Authors: Jyotsna Gupta, S. Ghosh, S. Aravindan
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The requirement of artificial prostheses (such as hip and knee joints) has increased with time. Many researchers are working to develop new implants with improved properties such as excellent biocompatibility with no tissue reactions, corrosion resistance in body fluid, high yield strength and low elastic modulus. Further, the morphological properties of the artificial implants should also match with that of the human bone so that cell adhesion, proliferation and transportation of the minerals and nutrition through body fluid can be obtained. Present study attempts to make porous Ti6Al15Mo alloys through powder metallurgy route using space holder technique. The alloy consists of 6wt% of Al which was taken as α phase stabilizer and 15wt% Mo was taken as β phase stabilizer with theoretical density 4.708. Ammonium hydrogen carbonate is used as a space holder in order to generate the porosity. The porosity of these fabricated porous alloys was controlled by adding the 0, 50, 70 vol.% of the space holder content. Three phases were found in the microstructure: α, α_2 and β phase of titanium. Kirkendall pores are observed to be decreased with increase of holding time during sintering and parallelly compressive strength and elastic modulus value increased slightly. Compressive strength and elastic modulus of porous Ti-6Al-15Mo alloy (1.17 g/cm3 density) is found to be suitable for cancellous bone. Released ions from Ti-6Al-15Mo alloy are far below from the permissible limits in human body.Keywords: bone implant, powder metallurgy, sintering time, Ti-6Al-15Mo
Procedia PDF Downloads 142736 Assessment and Analysis of Literary Criticism and Consumer Research
Authors: Mohammad Mirzaei
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This article proposes literary criticism as a source of insight into consumer behavior, provides an extensive overview of literary criticism, provides concrete illustrative analysis, and offers suggestions for further research. To do, a literary analysis of advertising copy identifies elements that provide additional information to consumer researchers and discusses the contribution of literary criticism to consumer research. Important post-war critical schools of thought are reviewed, and relevant theoretical concepts are summarized. Ivory Flakes' advertisements are analyzed using a variety of concepts drawn from literary schools, primarily sociocultural and reader responses. Suggestions for further research on content analysis, image analysis, and consumption history are presented.Keywords: consumer behaviour, consumer research, consumption history, criticism
Procedia PDF Downloads 91735 Osteoarthritis (OA): A Total Knee Replacement Surgery
Authors: Loveneet Kaur
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Introduction: Osteoarthritis (OA) is one of the leading causes of disability, and the knee is the most commonly affected joint in the body. The last resort for treatment of knee OA is Total Knee Replacement (TKR) surgery. Despite numerous advances in prosthetic design, patients do not reach normal function after surgery. Current surgical decisions are made on 2D radiographs and patient interviews. Aims: The aim of this study was to compare knee kinematics pre and post-TKR surgery using computer-animated images of patient-specific models under everyday conditions. Methods: 7 subjects were recruited for the study. Subjects underwent 3D gait analysis during 4 everyday activities and medical imaging of the knee joint pre- and one-month post-surgery. A 3D model was created from each of the scans, and the kinematic gait analysis data was used to animate the images. Results: Improvements were seen in a range of motion in all 4 activities 1-year post-surgery. The preoperative 3D images provide detailed information on the anatomy of the osteoarthritic knee. The postoperative images demonstrate potential future problems associated with the implant. Although not accurate enough to be of clinical use, the animated data can provide valuable insight into what conditions cause damage to both the osteoarthritic and prosthetic knee joints. As the animated data does not require specialist training to view, the images can be utilized across the fields of health professionals and manufacturing in the assessment and treatment of patients pre and post-knee replacement surgery. Future improvements in the collection and processing of data may yield clinically useful data. Conclusion: Although not yet of clinical use, the potential application of 3D animations of the knee joint pre and post-surgery is widespread.Keywords: Orthoporosis, Ortharthritis, knee replacement, TKR
Procedia PDF Downloads 39734 Computer Aided Shoulder Prosthesis Design and Manufacturing
Authors: Didem Venus Yildiz, Murat Hocaoglu, Murat Dursun, Taner Akkan
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The shoulder joint is a more complex structure than the hip or knee joints. In addition to the overall complexity of the shoulder joint, two different factors influence the insufficient outcome of shoulder replacement: the shoulder prosthesis design is far from fully developed and it is difficult to place these shoulder prosthesis due to shoulder anatomy. The glenohumeral joint is the most complex joint of the human shoulder. There are various treatments for shoulder failures such as total shoulder arthroplasty, reverse total shoulder arthroplasty. Due to its reverse design than normal shoulder anatomy, reverse total shoulder arthroplasty has different physiological and biomechanical properties. Post-operative achievement of this arthroplasty is depend on improved design of reverse total shoulder prosthesis. Designation achievement can be increased by several biomechanical and computational analysis. In this study, data of human both shoulders with right side fracture was collected by 3D Computer Tomography (CT) machine in dicom format. This data transferred to 3D medical image processing software (Mimics Materilise, Leuven, Belgium) to reconstruct patient’s left and right shoulders’ bones geometry. Provided 3D geometry model of the fractured shoulder was used to constitute of reverse total shoulder prosthesis by 3-matic software. Finite element (FE) analysis was conducted for comparison of intact shoulder and prosthetic shoulder in terms of stress distribution and displacements. Body weight physiological reaction force of 800 N loads was applied. Resultant values of FE analysis was compared for both shoulders. The analysis of the performance of the reverse shoulder prosthesis could enhance the knowledge of the prosthetic design.Keywords: reverse shoulder prosthesis, biomechanics, finite element analysis, 3D printing
Procedia PDF Downloads 150733 Fast and Accurate Finite-Difference Method Solving Multicomponent Smoluchowski Coagulation Equation
Authors: Alexander P. Smirnov, Sergey A. Matveev, Dmitry A. Zheltkov, Eugene E. Tyrtyshnikov
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We propose a new computational technique for multidimensional (multicomponent) Smoluchowski coagulation equation. Using low-rank approximations in Tensor Train format of both the solution and the coagulation kernel, we accelerate the classical finite-difference Runge-Kutta scheme keeping its level of accuracy. The complexity of the taken finite-difference scheme is reduced from O(N^2d) to O(d^2 N log N ), where N is the number of grid nodes and d is a dimensionality of the problem. The efficiency and the accuracy of the new method are demonstrated on concrete problem with known analytical solution.Keywords: tensor train decomposition, multicomponent Smoluchowski equation, runge-kutta scheme, convolution
Procedia PDF Downloads 425732 Development of Earthquake and Typhoon Loss Models for Japan, Specifically Designed for Underwriting and Enterprise Risk Management Cycles
Authors: Nozar Kishi, Babak Kamrani, Filmon Habte
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Natural hazards such as earthquakes and tropical storms, are very frequent and highly destructive in Japan. Japan experiences, every year on average, more than 10 tropical cyclones that come within damaging reach, and earthquakes of moment magnitude 6 or greater. We have developed stochastic catastrophe models to address the risk associated with the entire suite of damaging events in Japan, for use by insurance, reinsurance, NGOs and governmental institutions. KCC’s (Karen Clark and Company) catastrophe models are procedures constituted of four modular segments: 1) stochastic events sets that would represent the statistics of the past events, hazard attenuation functions that could model the local intensity, vulnerability functions that would address the repair need for local buildings exposed to the hazard, and financial module addressing policy conditions that could estimates the losses incurring as result of. The events module is comprised of events (faults or tracks) with different intensities with corresponding probabilities. They are based on the same statistics as observed through the historical catalog. The hazard module delivers the hazard intensity (ground motion or wind speed) at location of each building. The vulnerability module provides library of damage functions that would relate the hazard intensity to repair need as percentage of the replacement value. The financial module reports the expected loss, given the payoff policies and regulations. We have divided Japan into regions with similar typhoon climatology, and earthquake micro-zones, within each the characteristics of events are similar enough for stochastic modeling. For each region, then, a set of stochastic events is developed that results in events with intensities corresponding to annual occurrence probabilities that are of interest to financial communities; such as 0.01, 0.004, etc. The intensities, corresponding to these probabilities (called CE, Characteristics Events) are selected through a superstratified sampling approach that is based on the primary uncertainty. Region specific hazard intensity attenuation functions followed by vulnerability models leads to estimation of repair costs. Extensive economic exposure model addresses all local construction and occupancy types, such as post-linter Shinand Okabe wood, as well as concrete confined in steel, SRC (Steel-Reinforced Concrete), high-rise.Keywords: typhoon, earthquake, Japan, catastrophe modelling, stochastic modeling, stratified sampling, loss model, ERM
Procedia PDF Downloads 261731 Strength Analysis of RCC Dams Subject to the Layer-by-Layer Construction Method
Authors: Archil Motsonelidze, Vitaly Dvalishvili
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Existing roller compacted concrete (RCC) dams indicate that the layer-by-layer construction method gives considerable economies as compared with the conventional methods. RCC dams have also gained acceptance in the regions of high seismic activity. Earthquake resistance analysis of RCC gravity dams based on nonlinear finite element technique is presented. An elastic-plastic approach is used to describe the material of a dam while it is under static conditions (period of construction). Seismic force, as an acceleration equivalent to that produced by a real earthquake, is supposed to act when the dam is completed. The materials of the dam and foundation may be nonhomogeneous and anisotropic. The “dam-foundation” system is idealized as a plain strain problem.Keywords: finite element method, layer-by-layer construction, RCC dams, strength analysis
Procedia PDF Downloads 542730 Role of Inflammatory Markers in Arthritic Rats Treated with Ethanolic Bark Extract of Albizia procera
Authors: M. Sangeetha, D. Chamundeeswari, C. Saravanababu, C. Rose, V. Gopal
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Rheumatoid arthritis (RA) is a chronic, progressive, systemic inflammatory disorder affecting the synovial joints and typically producing symmetrical arthritis that leads to joint destruction, which is responsible for the deformity and disability. Despite improvements in the treatment of RA over the past decade, there still is a need for new therapeutic agents that are efficacious, less expensive, and free of severe adverse reactions. The present study aimed to investigate role of inflammatory markers in arthritic rats treated with ethanolic bark extract of Albizia procera. The protective effect of ethanolic bark extract of Albizia procera against complete Freund’s adjuvant (CFA) induced arthritis in rats. Arthritis was induced by an intradermal injection of 0.1 ml FCA in the foot pad of left hind limb of rats. ETBE (100 and 200 mg/kg b.wt./p.o) and the reference drug diclofenac (25 mg/kg b.wt./p.o) were administered to arthritic rats. Paw volume was measured for all the animals before inducing arthritis and thereafter once in seven days by using plethysmometer for 42 days. Gene expression of inflammatory markers such as IL-1β and IL-10 were investigated in paw tissues. Up regulation of IL-1β and Down regulation IL-10 were observed in CFA injected rats when compared to normal rats. ETBE attenuated these alterations dose dependently when compared to the vehicle treated rats. These results provide insights into the mechanism of anti-arthritic activity, and unravel potential therapeutic use of Albizia procera in arthritis.
Keywords: CFA-Complete Freund’s adjuvant, ETBE – ethanolic bark extract, IL- interleukins, RA-rheumatoid arthritis
Procedia PDF Downloads 278729 Synthesis of Microencapsulated Phase Change Material for Adhesives with Thermoregulating Properties
Authors: Christin Koch, Andreas Winkel, Martin Kahlmeyer, Stefan Böhm
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Due to environmental regulations on greenhouse gas emissions and the depletion of fossil fuels, there is an increasing interest in electric vehicles.To maximize their driving range, batteries with high storage capacities are needed. In most electric cars, rechargeable lithium-ion batteries are used because of their high energy density. However, it has to be taken into account that these batteries generate a large amount of heat during the charge and discharge processes. This leads to a decrease in a lifetime and damage to the battery cells when the temperature exceeds the defined operating range. To ensure an efficient performance of the battery cells, reliable thermal management is required. Currently, the cooling is achieved by heat sinks (e.g., cooling plates) bonded to the battery cells with a thermally conductive adhesive (TCA) that directs the heat away from the components. Especially when large amounts of heat have to be dissipated spontaneously due to peak loads, the principle of heat conduction is not sufficient, so attention must be paid to the mechanism of heat storage. An efficient method to store thermal energy is the use of phase change materials (PCM). Through an isothermal phase change, PCM can briefly absorb or release thermal energy at a constant temperature. If the phase change takes place in the transition from solid to liquid, heat is stored during melting and is released to the ambient during the freezing process upon cooling. The presented work displays the great potential of thermally conductive adhesives filled with microencapsulated PCM to limit peak temperatures in battery systems. The encapsulation of the PCM avoids the effects of aging (e.g., migration) and chemical reactions between the PCM and the adhesive matrix components. In this study, microencapsulation has been carried out by in situ polymerization. The microencapsulated PCM was characterized by FT-IR spectroscopy, and the thermal properties were measured by DSC and laser flash method. The mechanical properties, electrical and thermal conductivity, and adhesive toughness of the TCA/PCM composite were also investigated.Keywords: phase change material, microencapsulation, adhesive bonding, thermal management
Procedia PDF Downloads 65728 Production of Geopolymers for Structural Applications from Fluidized Bed Combustion Bottom Ash
Authors: Thapelo Aubrey Motsieng
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Fluidized bed combustion (FBC) is a clean coal technology used in the combustion of low-grade coals for power generation. The production of large solid wastes such as bottom ashes from this process is a problem. The bottom ash contains some toxic elements which can leach out soils and contaminate surface and ground water; for this reason, they can neither be disposed of in landfills nor lagoons anymore. The production of geopolymers from bottom ash for structural and concrete applications is an option for their disposal. In this study, the waste bottom ash obtained from the combustion of three low grade South African coals in a bubbling fluidized bed reactor was used to produce geopolymers. The geopolymers were cured in a household microwave. The results showed that the microwave curing enhanced the reactivity and strength of the geopolymers.Keywords: bottom ash, geopolymers, coal, compressive strength
Procedia PDF Downloads 313727 Parametric Study on the Development of Earth Pressures Behind Integral Bridge Abutments Under Cyclic Translational Movements
Authors: Lila D. Sigdel, Chin J. Leo, Samanthika Liyanapathirana, Pan Hu, Minghao Lu
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Integral bridges are a class of bridges with integral or semi-integral abutments, designed without expansion joints in the bridge deck of the superstructure. Integral bridges are economical alternatives to conventional jointed bridges with lower maintenance costs and greater durability, thereby improving social and economic stability for the community. Integral bridges have also been proven to be effective in lowering the overall construction cost compared to the conventional type of bridges. However, there is significant uncertainty related to the design and analysis of integral bridges in response to cyclic thermal movements induced due to deck expansion and contraction. The cyclic thermal movements of the abutments increase the lateral earth pressures on the abutment and its foundation, leading to soil settlement and heaving of the backfill soil. Thus, the primary objective of this paper is to investigate the soil-abutment interaction under the cyclic translational movement of the abutment. Results from five experiments conducted to simulate different magnitudes of cyclic translational movements of abutments induced by thermal changes are presented, focusing on lateral earth pressure development at the abutment-soil interface. Test results show that the cycle number and magnitude of cyclic translational movements have significant effects on the escalation of lateral earth pressures. Experimentally observed earth pressure distributions behind the integral abutment were compared with the current design approaches, which shows that the most of the practices has under predicted the lateral earth pressure.Keywords: integral bridge, cyclic thermal movement, lateral earth pressure, soil-structure interaction
Procedia PDF Downloads 112726 Parameter Optimization and Thermal Simulation in Laser Joining of Coach Peel Panels of Dissimilar Materials
Authors: Masoud Mohammadpour, Blair Carlson, Radovan Kovacevic
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The quality of laser welded-brazed (LWB) joints were strongly dependent on the main process parameters, therefore the effect of laser power (3.2–4 kW), welding speed (60–80 mm/s) and wire feed rate (70–90 mm/s) on mechanical strength and surface roughness were investigated in this study. The comprehensive optimization process by means of response surface methodology (RSM) and desirability function was used for multi-criteria optimization. The experiments were planned based on Box– Behnken design implementing linear and quadratic polynomial equations for predicting the desired output properties. Finally, validation experiments were conducted on an optimized process condition which exhibited good agreement between the predicted and experimental results. AlSi3Mn1 was selected as the filler material for joining aluminum alloy 6022 and hot-dip galvanized steel in coach peel configuration. The high scanning speed could control the thickness of IMC as thin as 5 µm. The thermal simulations of joining process were conducted by the Finite Element Method (FEM), and results were validated through experimental data. The Fe/Al interfacial thermal history evidenced that the duration of critical temperature range (700–900 °C) in this high scanning speed process was less than 1 s. This short interaction time leads to the formation of reaction-control IMC layer instead of diffusion-control mechanisms.Keywords: laser welding-brazing, finite element, response surface methodology (RSM), multi-response optimization, cross-beam laser
Procedia PDF Downloads 346725 Response Analysis of a Steel Reinforced Concrete High-Rise Building during the 2011 Tohoku Earthquake
Authors: Naohiro Nakamura, Takuya Kinoshita, Hiroshi Fukuyama
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The 2011 off The Pacific Coast of Tohoku Earthquake caused considerable damage to wide areas of eastern Japan. A large number of earthquake observation records were obtained at various places. To design more earthquake-resistant buildings and improve earthquake disaster prevention, it is necessary to utilize these data to analyze and evaluate the behavior of a building during an earthquake. This paper presents an earthquake response simulation analysis (hereafter a seismic response analysis) that was conducted using data recorded during the main earthquake (hereafter the main shock) as well as the earthquakes before and after it. The data were obtained at a high-rise steel-reinforced concrete (SRC) building in the bay area of Tokyo. We first give an overview of the building, along with the characteristics of the earthquake motion and the building during the main shock. The data indicate that there was a change in the natural period before and after the earthquake. Next, we present the results of our seismic response analysis. First, the analysis model and conditions are shown, and then, the analysis result is compared with the observational records. Using the analysis result, we then study the effect of soil-structure interaction on the response of the building. By identifying the characteristics of the building during the earthquake (i.e., the 1st natural period and the 1st damping ratio) by the Auto-Regressive eXogenous (ARX) model, we compare the analysis result with the observational records so as to evaluate the accuracy of the response analysis. In this study, a lumped-mass system SR model was used to conduct a seismic response analysis using observational data as input waves. The main results of this study are as follows: 1) The observational records of the 3/11 main shock put it between a level 1 and level 2 earthquake. The result of the ground response analysis showed that the maximum shear strain in the ground was about 0.1% and that the possibility of liquefaction occurring was low. 2) During the 3/11 main shock, the observed wave showed that the eigenperiod of the building became longer; this behavior could be generally reproduced in the response analysis. This prolonged eigenperiod was due to the nonlinearity of the superstructure, and the effect of the nonlinearity of the ground seems to have been small. 3) As for the 4/11 aftershock, a continuous analysis in which the subject seismic wave was input after the 3/11 main shock was input was conducted. The analyzed values generally corresponded well with the observed values. This means that the effect of the nonlinearity of the main shock was retained by the building. It is important to consider this when conducting the response evaluation. 4) The first period and the damping ratio during a vibration were evaluated by an ARX model. Our results show that the response analysis model in this study is generally good at estimating a change in the response of the building during a vibration.Keywords: ARX model, response analysis, SRC building, the 2011 off the Pacific Coast of Tohoku Earthquake
Procedia PDF Downloads 160724 Earthquake Resistant Sustainable Steel Green Building
Authors: Arup Saha Chaudhuri
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Structural steel is a very ductile material with high strength carrying capacity, thus it is very useful to make earthquake resistant buildings. It is a homogeneous material also. The member section and the structural system can be made very efficient for economical design. As the steel is recyclable and reused, it is a green material. The embodied energy for the efficiently designed steel structure is less than the RC structure. For sustainable green building steel is the best material nowadays. Moreover, pre-engineered and pre-fabricated faster construction methodologies help the development work to complete within the stipulated time. In this paper, the usefulness of Eccentric Bracing Frame (EBF) in steel structure over Moment Resisting Frame (MRF) and Concentric Bracing Frame (CBF) is shown. Stability of the steel structures against horizontal forces especially in seismic condition is efficiently possible by Eccentric bracing systems with economic connection details. The EBF is pin–ended, but the beam-column joints are designed for pin ended or for full connectivity. The EBF has several desirable features for seismic resistance. In comparison with CBF system, EBF system can be designed for appropriate stiffness and drift control. The link beam is supposed to yield in shear or flexure before initiation of yielding or buckling of the bracing member in tension or compression. The behavior of a 2-D steel frame is observed under seismic loading condition in the present paper. Ductility and brittleness of the frames are compared with respect to time period of vibration and dynamic base shear. It is observed that the EBF system is better than MRF system comparing the time period of vibration and base shear participation.Keywords: steel building, green and sustainable, earthquake resistant, EBF system
Procedia PDF Downloads 345723 A Novel Rapid Well Control Technique Modelled in Computational Fluid Dynamics Software
Authors: Michael Williams
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The ability to control a flowing well is of the utmost important. During the kill phase, heavy weight kill mud is circulated around the well. While increasing bottom hole pressure near wellbore formation, the damage is increased. The addition of high density spherical objects has the potential to minimise this near wellbore damage, increase bottom hole pressure and reduce operational time to kill the well. This operational time saving is seen in the rapid deployment of high density spherical objects instead of building high density drilling fluid. The research aims to model the well kill process using a Computational Fluid Dynamics software. A model has been created as a proof of concept to analyse the flow of micron sized spherical objects in the drilling fluid. Initial results show that this new methodology of spherical objects in drilling fluid agrees with traditional stream lines seen in non-particle flow. Additional models have been created to demonstrate that areas of higher flow rate around the bit can lead to increased probability of wash out of formations but do not affect the flow of micron sized spherical objects. Interestingly, areas that experience dimensional changes such as tool joints and various BHA components do not appear at this initial stage to experience increased velocity or create areas of turbulent flow, which could lead to further borehole stability. In conclusion, the initial models of this novel well control methodology have not demonstrated any adverse flow patterns, which would conclude that this model may be viable under field conditions.Keywords: well control, fluid mechanics, safety, environment
Procedia PDF Downloads 167722 Perception and Control in the Age of Surrealism: A Critical History and a Survey of Pita Amor’s Poetic Ontology
Authors: Oliver Arana
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Within the common vein of social understanding, surrealism is often understood to rely on disconcerting images and fragmented collage, both in its visual representation and literary manifestations. By tracing the history and literature of surrealism, the author makes the argument that there were certain factions within Latin America that employed characteristics of surrealism in order to reach some sense of understanding, and not to further complicate or disorient -an aim that most closely aligns to Freudian psychoanalysis. Psychoanalysis should, however, be a comparable practice only to understand how Latin American surrealism had more of a concrete goal than its European counterpart. The primary subject of the paper is the Mexican poet, Pita Amor, who has retroactively been associated with the movement; and therefore, it should be duly noted that the adjective, surrealism, only applies to her as something that describes traits within the literary lexicon.Keywords: Latin America, Pita Amor, poetry, surrealism
Procedia PDF Downloads 140721 The Study of X- Bracing on Limit State Behaviour of Buckling Restrained Brace (BRB) in Steel Frames Using Pushover Analysis
Authors: Peyman Shadman Heidari, Hamid Bastani, Pouya Shadman Heidari
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Nowadays, using energy dampers in structures is highly considered for the dissipation and absorption of earthquake energy. The main advantage of using energy damper is absorbing the earthquake energy in some sections apart from the structure frame. Among different types of dampers, hysteresis dampers are of special place because of low cost, high reliability and the lack of mechanical parts. In this paper, a special kind of hysteresis damper is considered under the name of buckling brace, which is provided with the aim of the study and investigation of cross braces in boundary behaviour of steel frames using nonlinear static analysis. In this paper, ninety three models of steel frames with cross braces of buckling type are processed with different bays and heights and their plasticity index, behaviour coefficient, distribution type and the number of plastic hinges formed were calculated. Finally, the mean behaviour coefficient was compared with standard behaviour coefficient of 2800 and the suitable mode of braces placing in improving nonlinear behaviour and suitable distribution of plastic hinges were presented. In addition, it was determined that for some placing mode of braces the behaviour coefficient will increase to 15 times of recommended 2800 standard coefficient and in some placing modes, the braced bays will show considerable difference with suggested 2800 standard behaviour coefficient relative to each other.Keywords: buckling restrained brace, plasticity index, behaviour coefficient, resistance coefficient, plastic joints
Procedia PDF Downloads 508720 The Flexural Strength of Fiber-Reinforced Polymer Cement Mortars Using UM Resin
Authors: Min Ho Kwon, Woo Young Jung, Hyun Su Seo
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A Polymer Cement Mortar (PCM) has been widely used as the material of repair and restoration work for concrete structure; however a PCM usually induces an environmental pollutant. Therefore, there is a need to develop PCM which is less impact to environments. Usually, UM resin is known to be harmless to the environment. Accordingly, in this paper, the properties of the PCM using UM resin were studied. The general cement mortar and UM resin was mixed in the specified ratio. A certain percentage of PVA fibers, steel fibers and mixed fibers (PVA fiber and steel fiber) were added to enhance the flexural strength. The flexural tests were performed in order to investigate the flexural strength of each PCM. Experimental results showed that the strength of proposed PCM using UM resin is improved when they are compared with general cement mortar.Keywords: polymer cement mortar, UM resin, compressive strength, PVA fiber, steel fiber
Procedia PDF Downloads 336719 Influence of Brazing Process Parameters on the Mechanical Properties of Nickel Based Superalloy
Authors: M. Zielinska, B. Daniels, J. Gabel, A. Paletko
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A common nickel based superalloy Inconel625 was brazed with Ni-base braze filler material (AMS4777) containing melting-point-depressants such as B and Si. Different braze gaps, brazing times and forms of braze filler material were tested. It was determined that the melting point depressants B and Si tend to form hard and brittle phases in the joint during the braze cycle. Brittle phases significantly reduce mechanical properties (e. g. tensile strength) of the joint. Therefore, it is important to define optimal process parameters to achieve high strength joints, free of brittle phases. High ultimate tensile strength (UTS) values can be obtained if the joint area is free of brittle phases, which is equivalent to a complete isothermal solidification of the joint. Isothermal solidification takes place only if the concentration of the melting point depressant in the braze filler material of the joint is continuously reduced by diffusion into the base material. For a given brazing temperature, long brazing times and small braze filler material volumes (small braze gaps) are beneficial for isothermal solidification. On the base of the obtained results it can be stated that the form of the braze filler material has an additional influence on the joint quality. Better properties can be achieved by the use of braze-filler-material in form of foil instead of braze-filler-material in form of paste due to a reduced amount of voids and a more homogeneous braze-filler-material-composition in the braze-gap by using foil.Keywords: diffusion brazing, microstructure, superalloy, tensile strength
Procedia PDF Downloads 358718 Community Empowerment: The Contribution of Network Urbanism on Urban Poverty Reduction
Authors: Lucia Antonela Mitidieri
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This research analyzes the application of a model of settlements management based on networks of territorial integration that advocates planning as a cyclical and participatory process that engages early on with civic society, the private sector and the state. Through qualitative methods such as participant observation, interviews with snowball technique and an active research on territories, concrete results of community empowerment are obtained from the promotion of productive enterprises and community spaces of encounter and exchange. Studying the cultural and organizational dimensions of empowerment allows building indicators such as increase of capacities or community cohesion that can lead to support local governments in achieving sustainable urban development for a reduction of urban poverty.Keywords: community spaces, empowerment, network urbanism, participatory process
Procedia PDF Downloads 322717 Self-Sensing Concrete Nanocomposites for Smart Structures
Authors: A. D'Alessandro, F. Ubertini, A. L. Materazzi
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In the field of civil engineering, Structural Health Monitoring is a topic of growing interest. Effective monitoring instruments permit the control of the working conditions of structures and infrastructures, through the identification of behavioral anomalies due to incipient damages, especially in areas of high environmental hazards as earthquakes. While traditional sensors can be applied only in a limited number of points, providing a partial information for a structural diagnosis, novel transducers may allow a diffuse sensing. Thanks to the new tools and materials provided by nanotechnology, new types of multifunctional sensors are developing in the scientific panorama. In particular, cement-matrix composite materials capable of diagnosing their own state of strain and tension, could be originated by the addition of specific conductive nanofillers. Because of the nature of the material they are made of, these new cementitious nano-modified transducers can be inserted within the concrete elements, transforming the same structures in sets of widespread sensors. This paper is aimed at presenting the results of a research about a new self-sensing nanocomposite and about the implementation of smart sensors for Structural Health Monitoring. The developed nanocomposite has been obtained by inserting multi walled carbon nanotubes within a cementitious matrix. The insertion of such conductive carbon nanofillers provides the base material with piezoresistive characteristics and peculiar sensitivity to mechanical modifications. The self-sensing ability is achieved by correlating the variation of the external stress or strain with the variation of some electrical properties, such as the electrical resistance or conductivity. Through the measurement of such electrical characteristics, the performance and the working conditions of an element or a structure can be monitored. Among conductive carbon nanofillers, carbon nanotubes seem to be particularly promising for the realization of self-sensing cement-matrix materials. Some issues related to the nanofiller dispersion or to the influence of the nano-inclusions amount in the cement matrix need to be carefully investigated: the strain sensitivity of the resulting sensors is influenced by such factors. This work analyzes the dispersion of the carbon nanofillers, the physical properties of the fresh dough, the electrical properties of the hardened composites and the sensing properties of the realized sensors. The experimental campaign focuses specifically on their dynamic characterization and their applicability to the monitoring of full-scale elements. The results of the electromechanical tests with both slow varying and dynamic loads show that the developed nanocomposite sensors can be effectively used for the health monitoring of structures.Keywords: carbon nanotubes, self-sensing nanocomposites, smart cement-matrix sensors, structural health monitoring
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