Search results for: asymptotic behavior

Authors: A. Nourbakhsh

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A finite difference/front tracking method is used to study the motion of three-dimensional deformable drops suspended in plane Poiseuille flow at non-zero Reynolds numbers. A parallel version of the code was used to study the behavior of suspension on a reasonable grid resolution (grids). The viscosity and density of drops are assumed to be equal to that of the suspending medium. The effect of the Reynolds number is studied in detail. It is found that drops with small deformation behave like rigid particles and migrate to an equilibrium position about half way between the wall and the center line (the Segre-Silberberg effect). However, for highly deformable drops there is a tendency for drops to migrate to the middle of the channel, and the maximum concentration occurs at the center line. The effective viscosity of suspension and the fluctuation energy of the flow across the channel increases with the Reynolds number of the flow.

Keywords: suspensions, Poiseuille flow, effective viscosity, Reynolds number

Procedia PDF Downloads 355

Authors: Marie Kudrnova, Jana Petru

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This study is part of the international research - Materials for Molten Salt Reactors (MSR) and addresses the part of the project dealing with the corrosion behavior of candidate construction materials. Inconel 625 was characterized by x-ray photoelectron spectroscopy (XPS) before and after high–temperature experiment in molten salt. The experiment was performed in a horizontal tube furnace molten salt reactor, at 450 °C in argon, at atmospheric pressure, for 150 hours. Industrially produced HITEC salt was used (NaNO3, KNO3, NaNO2). The XPS study was carried out using the ESCAProbe P apparatus (Omicron Nanotechnology Ltd.) equipped with a monochromatic Al Kα (1486.6 eV) X-ray source. The surface layer on alloy 625 after exposure contains only Na, C, O, and Ni (as NiOx) and Nb (as NbOx BE 206.8 eV). Ni was detected in the metallic state (Ni0 – Ni 2p BE-852.7 eV, NiOx - Ni 2p BE-854.7 eV) after a short Ar sputtering because the oxide layer on the surface was very thin. Nickel oxides can form a protective layer in the molten salt, but only future long-term exposures can determine the suitability of Inconel 625 for MSR.

Keywords: Inconel 625, molten salt, oxide layer, XPS

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Authors: Mohammad Hadi Khorashadi Zadeh

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Many new applications and internet services have been emerged since the innovation of mobile networks and devices. However, these applications have problems of security, management, and performance in business environments. Cloud systems provide information transfer, management facilities, and security for virtual environments. Therefore, an innovative internet service and a business model are proposed in the present study for creating a secure and consolidated environment for managing the mobile information of organizations based on cloud virtual phones (CVP) infrastructures. Using this method, users can run Android and web applications in the cloud which enhance performance by connecting to other CVP users and increases privacy. It is possible to combine the CVP with distributed protocols and central control which mimics the behavior of human societies. This mix helps in dealing with sensitive data in mobile devices and facilitates data management with less application overhead.

Keywords: BYOD, mobile cloud computing, mobile security, information management

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Authors: Vicent Lwanga

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Background: Despite sensitization workshops that have been going on in rural areas in Kapchorwa District in Uganda to prevent stigmatization of People Living With HIV/AIDS (PLWHA), interview with PLWHA sows that they are still being stigmatized. This behavior of some people within the community possesses a serious danger to the successful prevention and control of HIV in our society. Evidence exists that some people still believe that eating, living together, and even discussing with PLWHA might make them infected, too, despite all persuasions against such attitude. Description: A face to face interview with some selected PLWHA in Kapchorwa, testified that stigmatization against those who have disclosed their status still lingers on. The interviews with the PLWHA reveals that people still believe that they are being bewitched and cursed by God for their sins, and as such, people keep away from them to avoid the wrath of God. Findings: The more the stigmatization against the PLWHA persists, the more difficult it will be to successfully prevent, control, and eradicate HIV in the society. This is because many PLWHA would prefer not to be identified if they are not shown love and care. Conclusion: A more continuous campaign to stop the stigmatization of PLWHA needs to be on-going. This could be done more effectively by Community-Based Organisations (CBOs) with workshops, print media, and seminars.

Keywords: aids, community, HIV, stigma

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Authors: Yuri Katz, Kun Liu, Arunram Atmacharan

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Due to illiquidity, mispricing on Credit Markets is inevitable. This creates huge challenges to banks and investors as they seek to find new ways of risk valuation and portfolio management in a post-credit crisis world. Here, we analyze the difference in behavior of the spread-to-maturity in investment and high-yield categories of US corporate bonds between 2014 and 2023. Deviation from the theoretical dependency of this measure in the universe under study allows to identify multiple cases of mispriced credit risk. Remarkably, we observe mispriced bonds in both categories of credit ratings. This identification is supported by the application of the state-of-the-art machine learning model in more than 90% of cases. Noticeably, the ML-driven model-based forecasting of a category of bond’s credit ratings demonstrate an excellent out-of-sample accuracy (AUC = 98%). We believe that these results can augment conventional valuations of credit portfolios.

Keywords: credit risk, credit ratings, bond pricing, spread-to-maturity, machine learning

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Authors: Robert J. Sutton, Jon Elvins, Sean Casey, Eifion Jewell, Justin R. Searle

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Thermochemical storage utilises chemical salts which store and release energy a fully reversible endo/exothermic chemical reaction. Highly porous vermiculite impregnated with CaCl2, LiNO3 and MgSO4 (SIMs – Salt In Matrices) are proposed as potential materials for long-term thermochemical storage. The behavior of these materials during typical hydration and dehydration cycles is investigated. A simple moisture experiment represents the hydration, whilst thermogravimetric analysis (TGA) represents the dehydration. Further experiments to approximate the energy density and to determine the peak output temperatures of the SIMs are conducted. The CaCl2 SIM is deemed the best performing SIM across most experiments, whilst the results of MgSO4 SIM indicate difficulty associated with energy recovery.

Keywords: hydrated states, inter-seasonal heat storage, moisture sorption, salt in matrix

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Authors: M. Fikriansyah Wicaksono, Rafael Arief Budiman, M. Very Setiawan

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Currently, a wide range of innovative mobile library (M-Library) service is provided for the users in the library. The M-Library service is an innovation that aims to bring the collections of the library to users who currently use their smartphone so often. With M-Library services, it is expected that the users can fulfill their information needs more conveniently and practically. This study aims to find out how users use M-Library services provided by UGM library. This study applied a quantitative approach to investigate how to use the application M-Library. The Technology Acceptance Model (TAM) theory is applied to perform the analysis in terms of perceived usefulness, perceived ease of use, attitude towards behavior, behavioral intention and actual system usage. The results show that overall the users found that the M-Library application is useful to meet their information needs. Such as facilitate user to access e-resources, search UGM library collections, online booking collections, and reminder for returning book.

Keywords: m-library, mobile library services, technology acceptance, library of UGM

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Authors: Shieh Shiow-fang

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Superstitious thoughts or actions often occur during athletic competitions. Often "superstitious rituals" have a positive impact on the performance of competitive athletes. Athletes affirm the many psychological benefits of religious beliefs mostly in a positive way. Method: By snowball sampling, we recruited 10 experienced competitive athletes as participants. We used in-person and online one-to-one in-depth interview to collect their experiences about sport superstition. The total interview time was 795 minutes. We analyzed the raw data with the grounded theory processes suggested by Strauss and Corbin (1990). Results: The factors affecting athlete performance are ritual beliefs, taboo awareness, learning norms, and spontaneous attribution behaviors. Conclusion: We concluded that sports superstition reflects several psychological implications. The analysis results of this paper can provide another research perspective for the future study of sports superstition behavior.

Keywords: superstition, taboo awareness, learning norms, competitive athlete

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Authors: Praveen Kumar, R. Uma, R. P. Sharma

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This study investigates the generation of turbulence in a deep-fluid environment using a damped 1D-modified nonlinear Schrödinger equation model. The well-known damped modified nonlinear Schrödinger equation (d-MNLS) is solved using numerical methods. Artificial damping is added to the MNLS equation, and turbulence generation is investigated through a numerical simulation. The numerical simulation employs a finite difference method for temporal evolution and a pseudo-spectral approach to characterize spatial patterns. The results reveal a recurring periodic pattern in both space and time when the nonlinear Schrödinger equation is considered. Additionally, the study shows that the modified nonlinear Schrödinger equation disrupts the localization of structure and the recurrence of the Fermi-Pasta-Ulam (FPU) phenomenon. The energy spectrum exhibits a power-law behavior, closely following Kolmogorov's spectra steeper than k⁻⁵/³ in the inertial sub-range.

Keywords: water waves, modulation instability, hydrodynamics, nonlinear Schrödinger's equation

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Authors: Helen Bartsch, Markus Feldmann

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The dimensioning of steel structures subject to fatigue loads, such as wind turbines, bridges, masts and towers, crane runways and weirs or components in crane construction, is often dominated by fatigue verification. The fatigue details defined by the welded connections, such as butt or cruciform joints, longitudinal welds, welded-on or welded-in stiffeners, etc., are decisive. In Europe, the verification is usually carried out according to EN 1993-1-9 on a nominal stress basis. The basis is the detailed catalog, which specifies the fatigue strength of the various weld and construction details according to fatigue classes. Until now, a relation between fatigue classes and weld imperfection sizes is not included. Quality levels for imperfections in fusion-welded joints in steel, nickel, titanium and their alloys are regulated in EN ISO 5817, which, however, doesn’t contain direct correlations to fatigue resistances. The question arises whether some imperfections might be tolerable to a certain extent since they may be present in the test data used for detail classifications dating back decades ago. Although current standardization requires proof of satisfying limits of imperfection sizes, it would also be possible to tolerate welds with certain irregularities if these can be reliably quantified by non-destructive testing. Fabricators would be prepared to undertake carefully and sustained weld inspection in view of the significant economic consequences of such unfavorable fatigue classes. This paper presents investigations on the fatigue behavior of common welded details containing imperfections. In contrast to the common nominal stress concept, local fatigue concepts were used to consider the true stress increase, i.e., local stresses at the weld toe and root. The actual shape of a weld comprising imperfections, e.g., gaps or undercuts, can be incorporated into the fatigue evaluation, usually on a numerical basis. With the help of the effective notch stress concept, the fatigue resistance of detailed local weld shapes is assessed. Validated numerical models serve to investigate notch factors of fatigue details with different geometries. By utilizing parametrized ABAQUS routines, detailed numerical studies have been performed. Depending on the shape and size of different weld irregularities, fatigue classes can be defined. As well load-carrying welded details, such as the cruciform joint, as non-load carrying welded details, e.g., welded-on or welded-in stiffeners, are regarded. The investigated imperfections include, among others, undercuts, excessive convexity, incorrect weld toe, excessive asymmetry and insufficient or excessive throat thickness. Comparisons of the impact of different imperfections on the different types of fatigue details are made. Moreover, the influence of a combination of crucial weld imperfections on the fatigue resistance is analyzed. With regard to the trend of increasing efficiency in steel construction, the overall aim of the investigations is to include a more economical differentiation of fatigue details with regard to tolerance sizes. In the long term, the harmonization of design standards, execution standards and regulations of weld imperfections is intended.

Keywords: effective notch stress, fatigue, fatigue design, weld imperfections

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Authors: Young Ik Suh, Tywan G. Martin

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Bundling strategy is a common marketing practice today. In the past decades, both academicians and practitioners have increasingly emphasized the strategic importance of bundling in today’s markets. The reason for increased interest in bundling strategy is that they normally believe that it can significantly increase profits on organization’s sales over time and it is convenient for the customer. However, little efforts has been made on ticket bundling and purchase considerations in hedonic and utilitarian options in sport consumer behavior context. Consumers often face choices between utilitarian and hedonic alternatives in decision making. When consumers purchase certain products, they are only interested in the functional dimensions, which are called utilitarian dimensions. On the other hand, others focus more on hedonic features such as fun, excitement, and pleasure. Thus, the current research examines how utilitarian and hedonic consumption can vary in typical ticket purchasing process. The purpose of this research is to understand the following two research themes: (1) the differential effect of discount framing on ticket bundling: utilitarian and hedonic options and (2) moderating effect of team identification on ticket bundling. In order to test the research hypotheses, an experimental study using a two-way ANOVA, 3 (team identification: low, medium, and high) X 2 (discount frame: ticket bundle sales with utilitarian product, and hedonic product), with mixed factorial design will be conducted to determine whether there is a statistical significance between purchasing intentions of two discount frames of ticket bundle sales within different team identification levels. To compare mean differences among the two different settings, we will create two conditions of ticket bundles: (1) offering a discount on a ticket ($5 off) if they would purchase it along with utilitarian product (e.g., iPhone8 case, t-shirt, cap), and (2) offering a discount on a ticket ($5 off) if they would purchase it along with hedonic product (e.g., pizza, drink, fans featured on big screen). The findings of the current ticket bundling study are expected to have many theoretical and practical contributions and implications by extending the research and literature pertaining to the relationship between team identification and sport consumer behavior. Specifically, this study can provide a reliable and valid framework to understanding the role of team identification as a moderator on behavioral intentions such as purchase intentions. From an academic perspective, the study will be the first known attempt to understand consumer reactions toward different discount frames related to ticket bundling. Even though the game ticket itself is the major commodity of sport event attendance and significantly related to teams’ revenue streams, most recent ticket pricing research has been done in terms of economic or cost-oriented pricing and not from a consumer psychological perspective. For sport practitioners, this study will also provide significant implications. The result will imply that sport marketers may need to develop two different ticketing promotions for loyal fan and non-loyal fans. Since loyal fans concern ticket price than tie-in products when they see ticket bundle sales, advertising campaign should be more focused on discounting ticket price.

Keywords: ticket bundling, hedonic, utilitarian, team identification

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Authors: A. Arabzadeh, H. R. Kazemi Nia Korrani

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Composite steel plate shear wall is a lateral loading resistance system, which is used especially in tall buildings. This wall is made of a thin steel plate with reinforced a concrete cover, which is attached to one or both sides of the steel plate. This system is similar to stiffened steel plate shear wall, in which reinforced concrete replaces the steel stiffeners. Composite shear wall have in-plane and out-plane significant strength. Also, they have appropriate ductility. The present numerical investigations were focused on the effects of opening on wall mode shapes. In addition, frequencies of composite shear wall with and without opening are compared. For analyzing composite shear wall, a new program will be developed using of finite element theory and the effects of shape, size and position openings on the behavior of composite shear wall will be studied. Results indicated that the existence of opening decreases wall frequency.

Keywords: composite shear wall, opening, finite element method, modal analysis

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Authors: Martin S. Mulyadi

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This research investigates the corporate governance disclosure behavior of Indonesian corporations with type II agency problems. The primary cause of the 1990s Asian financial crisis has been attributed to poor corporate governance practices in Indonesia. Most importantly, these poor practices were commonly found in family-owned and government-owned corporations. There are a lot of publicly listed family-owned and government-owned corporations in Indonesia. Agency theory refers to these corporations as corporations with type II agency problems. This research employs agency theory to analyzes corporate governance practice and disclosures in such settings and found that government-owned corporations perform better than family-owned corporations.

Keywords: corporate governance, corporate disclosures, agency theory, type II agency problems

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Authors: Kaltume Kabir Sharrif

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Teacher education is the bedrock of educational growth and development of any nation. With development in education all human problems can be overcome. Educational Psychology, on the other hand, is in a strategic position for any programme in teacher education to be successful hence other aspects of societal issues. In other words, no teacher education can be of any help in ensuring transformation and security without adequate study in Educational Psychology. Without adequate knowledge and skills in Educational Psychology the teacher may not function effectively in the course of discharging his duty. It is in view of this, that the paper discusses some aspects of Educational Psychology that are of paramount importance in teacher education for sustainable transformation and security of Nigeria. Some recommendations were offered on the role educational psychology play in resolving security challenges facing the country. These include enriching educational psychology with topics from forensic psychology that will provide the teacher the skills of fighting crime in the school, Behavioural Science Unit should be established in each school to monitor the behavior of students, among others.

Keywords: transformation, security challenges, teacher education, educational psychology

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Authors: Sadhana Ghnayiem

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This article deals with the issue of effective communication between parents and children and its impact on the family in general and on the child in particular. The aim of this article is to provide information to parents, students, anyone interested in family communication between parents and children, and to provide them with tools to deal with barriers to communication in the family unit. The article presented a literature review of the importance of effective communication in the family, the definition of the concept of communication, and was a reference to factors and barriers in communication between parents and children leading to conflict destructive to the extent that barriers to effective communication in the family unit. At the end of the article, strategies were introduced to motivate children to behave appropriately, and to equip parents best to foster the healthy development of their children when they can create an atmosphere of effective communication. From the literature review, it's found that effective communication between parents and children prevents problematic behavior and helps children understand how to communicate effectively with others. Communication between parents and children is the cornerstone of a happy family life and is the basis for positive interactions between parents and children and increases self-esteem in children.

Keywords: children, communication, conflict, family

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Authors: Meysam Naeimi, Zili Li, Rolf Dollevoet

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A new small–scale test rig developed for rolling contact fatigue (RCF) investigations in wheel–rail material. This paper presents the scaling strategy of the rig based on dimensional analysis and mechanical modelling. The new experimental rig is indeed a spinning frame structure with multiple wheel components over a fixed rail-track ring, capable of simulating continuous wheel-rail contact in a laboratory scale. This paper describes the dimensional design of the rig, to derive its overall scaling strategy and to determine the key elements’ specifications. Finite element (FE) modelling is used to simulate the mechanical behavior of the rig with two sample scale factors of 1/5 and 1/7. The results of FE models are compared with the actual railway system to observe the effectiveness of the chosen scales. The mechanical properties of the components and variables of the system are finally determined through the design process.

Keywords: new test rig, rolling contact fatigue, rail, small scale

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Authors: K. Harrat, M. Hidjeb, M. T’kint

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The aim of the present research work is to characterize a cement palm date fiber composite in order to be used in isolation and in the manufacture of new structural materials. This technique may possibly participate seriously in the preservation of the environment and develop a growing need for plant products. On one hand, It has been shown that the presence of natural fiber in the composite materials manufacture, based on hydraulic binder, has improved the mechanical behaviour of the material. On the Other hand, It has been proven that the durability of composite materials reinforced with untreated fibers was largely affected by the presence of organic matter. In order to extract the organic material, the fibers were treated with boiling water and then coated with different types of products. A considerable improvement in the sensitivity to water of the fibers, as well as in the mechanical strength and in the ductility of the composite material was observed. The fiber being sensitive to water, the study put the emphasis on its dimensional stability.

Keywords: cement composite, durability, heat treatment, mechanical behaviour, vegetal fiber

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Authors: Daniel Klimovský

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Slovakia belongs to the most fragmented countries if one looks at its local government structure. The Slovak central governments implemented both broad devolution and fiscal decentralization some decades ago. However, neither territorial consolidation nor size categorization of local competences and powers has been implemented yet. Taking this fact into account, it is clear that the local governments are challenged not only by their citizens as customers but also by effectiveness as well as efficiency of delivered services. The paper is focused on behavior of the local governments in Slovakia and their approaches towards other local partners, including other local governments. Analysis of set of interviews shows that inter-municipal cooperation is the most common local partnership in Slovakia, but due to diversity of the local governments, this kind of cooperation leads to both intended and unintended outcomes. While in many cases the local governments are more efficient as well as effective in delivery of local services thanks to inter-municipal cooperation, there are many cases where inter-municipal cooperation fails, and it brings rather questionable or even negative outcomes.

Keywords: local governments, local partnerships, inter-municipal cooperation, delivery of local services

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Authors: Ž. Nikolić, H. Smoljanović, N. Živaljić

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This paper presents numerical model based on finite-discrete element method for analysis of the structural response of dry stone masonry structures under static and dynamic loads. More precisely, each discrete stone block is discretized by finite elements. Material non-linearity including fracture and fragmentation of discrete elements as well as cyclic behavior during dynamic load are considered through contact elements which are implemented within a finite element mesh. The application of the model was conducted on several examples of these structures. The performed analysis shows high accuracy of the numerical results in comparison with the experimental ones and demonstrates the potential of the finite-discrete element method for modelling of the response of dry stone masonry structures.

Keywords: dry stone masonry structures, dynamic load, finite-discrete element method, static load

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Authors: Mohamed H. El-Newehy, Sameh M. Osman, Moamen S. Refat, Salem S. Al-Deyab, Ayman El-Faham

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The two copolymers itaconic acid-methyl methacrylate and itaconic acid-acrylamide have been prepared in different ratio by radical copolymerization in the presence of azobisisobutyronitrile (AIBN) as initiator and using 2-butanone as reaction medium using microwave irradiation. The microwave technique is safe, fast, and gives high yield of the products with high purity in an optimum time, comparing to the traditional conventional heating. All the prepared copolymers were characterized by FT-IR, thermal analysis and elemental microanalysis. The itaconic acid-based copolymers showed a good sensitivity in alkaline media for scavenging Cu (II) and Pb (II). The chelation behavior of both Cu (II) and Pb (II) complexes were checked using FT-IR, thermogravimetric analysis (TGA), and differential scanning calorimetery (DSC). The infrared data are in a good agreement with the coordination through carboxylate-to-metal, in which the copolymers acting as a bidentate ligand.

Keywords: microwave synthesis, itaconic acid, copolymerization, scavenging, thermal stability

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Authors: Doo Ki Lee, Kumaresh Selvakumar, Man Young Kim, In Jae Song

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The widespread utilization of mixer in selective catalytic reduction (SCR) system marks a remarkable advantage in diesel engines. In the automotive selective catalytic reduction (SCR) system, the de-NOX efficiency can be improved by highly uniform flow with effective turbulent mixing. In this paper, the exhaust pipe is complemented with the swirling mixers of three different vane angles installed at the upstream of the SCR reactor. The attributes of the mixer are established by the variation in flow behavior followed by the drawback owing to the absence of mixer. In particular, the information pertaining to the selection of proper static mixer is provided based on the correlation between the uniformity index (UI) and the pressure drop. The uniform distribution of the flow at the entrance of the SCR reactor aids to determine the configuration which gives high mixing performance and comprehend the function of the mixer.

Keywords: pressure drop, selective catalytic reduction, static mixer, turbulent mixing, uniformity index

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Authors: Neda Navidi, Rene Jr. Landry

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Vehicle tracking and accident recognizing are considered by many industries like insurance and vehicle rental companies. The main goal of this paper is to detect the location of a car accident by combining different methods. The methods, which are considered in this paper, are Global Navigation Satellite Systems/Inertial Measurement Units (GNSS/IMU)-based navigation and vehicle accident detection algorithms. They are expressed by a set of raw measurements, which are obtained from a designed integrator black box using GNSS and inertial sensors. Another concern of this paper is the definition of accident detection algorithm based on its jerk to identify the position of that accident. In fact, the results convinced us that, even in GNSS blockage areas, the position of the accident could be detected by GNSS/INS integration with 50% improvement compared to GNSS stand alone.

Keywords: driver behavior monitoring, integration, IMU, GNSS, monitoring, tracking

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Authors: Raj Kumari Bahl, Sotirios Sabanis

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In this paper, we are concerned with the valuation of the first Catastrophic Mortality Bond that was launched in the market namely the Swiss Re Mortality Bond 2003. This bond encapsulates the behavior of a well-defined mortality index to generate payoffs for the bondholders. Pricing this bond is a challenging task. We adapt the payoff of the terminal principal of the bond in terms of the payoff of an Asian put option and present an approach to derive model-independent bounds exploiting comonotonic theory. We invoke Jensen’s inequality for the computation of lower bounds and employ Lagrange optimization technique to achieve the upper bound. The success of these bounds is based on the availability of compatible European mortality options in the market. We carry out Monte Carlo simulations to estimate the bond price and illustrate the strength of these bounds across a variety of models. The fact that our bounds are model-independent is a crucial breakthrough in the pricing of catastrophic mortality bonds.

Keywords: mortality bond, Swiss Re Bond, mortality index, comonotonicity

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Authors: F. Husem, M. E. Turan, Y. Sun, H. Ahlatci, I. Tozlu

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Residual stress and fatigue crack growth rates are important to determine mechanical behavior of rails. This study aims to make relationship between residual stress and fatigue crack growth values in rails. For this purpose, three R260 quality rails (0.6-0.8% C, 0.6-1.25 Mn) were chosen. Residual stress of samples was measured by cutting method that is related in railway standard. Then samples were machined for fatigue crack growth test and analyze was completed according to the ASTM E647 standard which gives information about parameters of rails for this test. Microstructure characterizations were examined by Light Optic Microscope (LOM). The results showed that residual stress change with fatigue crack growth rate. The sample has highest residual stress exhibits highest crack growth rate and pearlitic structure can be seen clearly for all samples by microstructure analyze.

Keywords: residual stress, fatigue crack growth, R260, SEM, ASTM E647

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Authors: S. A. Naeini, A. Khalili

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Nowadays, tunnels with different applications are developed, and most of them are related to subway tunnels. The excavation of shallow tunnels that pass under municipal utilities is very important, and the surface settlement control is an important factor in the design. The study sought to analyze the settlement and also to find an appropriate model in order to predict the behavior of the tunnel in Tehran subway line-3. The displacement in these sections is also determined by using numerical analyses and numerical modeling. In addition, the Adaptive Neuro-Fuzzy Inference System (ANFIS) method is utilized by Hybrid training algorithm. The database pertinent to the optimum network was obtained from 46 subway tunnels in Iran and Turkey which have been constructed by the new Austrian tunneling method (NATM) with similar parameters based on type of their soil. The surface settlement was measured, and the acquired results were compared to the predicted values. The results disclosed that computing intelligence is a good substitute for numerical modeling.

Keywords: settlement, Subway Line, FLAC3D, ANFIS Method

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Authors: Jhoanne Pedres Boñgol, Zhang Liu, Yuyin Qiu, King Lun Yeung

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Flexible ceramic sorbent material can be a viable technology to capture and recover emulsified fats, oils, and grease (FOG) that often cause sanitary sewer overflows. This study investigates the sorption capacity and recovery rate of ceramic material in surfactant-stabilized oil-water emulsion by synthesizing silica aerogel: SiO₂–X via acid-base sol-gel method followed by ambient pressure drying. The SiO₂–X is amorphous, microstructured, lightweight, flexible, and highly oleophilic. It displays spring-back behavior apparent at 80% compression with compressive strength of 0.20 MPa and can stand a weight of 1000 times its own. The contact angles measured at 0° and 177° in oil and water, respectively, confirm its oleophilicity and hydrophobicity while its thermal stability even at 450 °C is confirmed via TGA. In pure oil phase, the qe,AV. of 1x1 mm SiO₂–X is 7.5 g g⁻¹ at tqe= 10 min, and a qe,AV. of 6.05 to 6.76 g g⁻¹ at tqe= 24 hrs in O/W emulsion. The filter ceramic can be reused 50 x with 75-80 % FOG recovery by manual compression.

Keywords: adsorption, aerogel, emulsion, FOG

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Authors: Bharat Kumar, Deepak Kumar, Vijay Chaudhry

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Zirconium alloys are generally used for designing the core components of nuclear reactors due to their good mechanical and tribological properties. Some core components are subjected to flow-induced vibrations resulting in wear of these components due to their interaction with one another. To simulate these conditions, low amplitude reciprocating wear tests are conducted at room temperature and high temperature (260 degrees Celsius) between Zr-2.5Nb alloy and SS-410. The tests are conducted at a frequency range of 5 Hz to 25 Hz and an amplitude range of 200 µm to 600 µm. Friction and wear responses were recorded and correlated with the change in parameters. Worn surfaces are analysed using scanning electron microscopy (SEM) and optical profilometer. Elemental changes on the worn surfaces were determined using energy dispersive spectroscopy (EDS). The coefficient of friction (COF) increases with increasing temperature and decreases with increasing frequency. Adhesive wear is found to be the dominant wear mechanism which increases at high temperature.

Keywords: nuclear reactor, Zr-2.5Nb, SS-410, friction and wear

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Authors: Jayesh M. Patel, Bharat P. Modi

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The availability of on mobile devices that can invoke the demonstrated that the total data demand from users is far higher than previously articulated by measurements based solely on a cellular-centric view of smart-phone usage. The ratio of Wi-Fi to cellular traffic varies significantly between countries, This paper is shown the compression between the cellular data usage and Wi-Fi data usage by the user. This strategy helps operators to understand the growing importance and application of yield management strategies designed to squeeze maximum returns from their investments into the networks and devices that enable the mobile data ecosystem. The transition from unlimited data plans towards tiered pricing and, in the future, towards more value-centric pricing offers significant revenue upside potential for mobile operators, but, without a complete insight into all aspects of smartphone customer behavior, operators will unlikely be able to capture the maximum return from this billion-dollar market opportunity.

Keywords: cellular, Wi-Fi, mobile, smart phone

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Authors: R. J. Chang

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A cyclostationary Gaussian linearization method is formulated for investigating the time average response of nonlinear system under sinusoidal signal and white noise excitation. The quantitative measure of cyclostationary mean, variance, spectrum of mean amplitude, and mean power spectral density of noise is analyzed. The qualitative response behavior of stochastic jump and bifurcation are investigated. The validity of the present approach in predicting the quantitative and qualitative statistical responses is supported by utilizing Monte Carlo simulations. The present analysis without imposing restrictive analytical conditions can be directly derived by solving non-linear algebraic equations. The analytical solution gives reliable quantitative and qualitative prediction of mean and noise response for the Duffing system subjected to both sinusoidal signal and white noise excitation.

Keywords: cyclostationary, duffing system, Gaussian linearization, sinusoidal, white noise

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Authors: Mohamed Omar

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Steel bracing members are widely used in steel structures to reduce lateral displacement and dissipate energy during earthquake motions. Concentric steel bracing provide an excellent approach for strengthening and stiffening steel buildings. Using these braces the designer can hardly adjust the stiffness together with ductility as needed because of buckling of braces in compression. In this study the use of SMA bracing and steel bracing (Mega) utilized in steel frames are investigated. The effectiveness of these two systems in rehabilitating a mid-rise eight-storey steel frames were examined using time-history nonlinear analysis utilizing Seismo-Struct software. Results show that both systems improve the strength and stiffness of the original structure but due to excellent behavior of SMA in nonlinear phase and under compressive forces this system shows much better performance than the rehabilitation system of Mega bracing.

Keywords: finite element analysis, seismic response, shapes memory alloy, steel frame, mega bracing

Procedia PDF Downloads 325