Search results for: thermorheological complex
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 5030

Search results for: thermorheological complex

3440 Effects of Variable Viscosity on Radiative MHD Flow in a Porous Medium Between Twovertical Wavy Walls

Authors: A. B. Disu, M. S. Dada

Abstract:

This study was conducted to investigate two dimensional heat transfer of a free convective-radiative MHD (Magneto-hydrodynamics) flow with temperature dependent viscosity and heat source of a viscous incompressible fluid in a porous medium between two vertical wavy walls. The fluid viscosity is assumed to vary as an exponential function of temperature. The flow is assumed to consist of a mean part and a perturbed part. The perturbed quantities were expressed in terms of complex exponential series of plane wave equation. The resultant differential equations were solved by Differential Transform Method (DTM). The numerical computations were presented graphically to show the salient features of the fluid flow and heat transfer characteristics. The skin friction and Nusselt number were also analyzed for various governing parameters.

Keywords: differential transform method, MHD free convection, porous medium, two dimensional radiation, two wavy walls

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3439 Shock Formation for Double Ramp Surface

Authors: Abdul Wajid Ali

Abstract:

Supersonic flight promises speed, but the design of the air inlet faces an obstacle: shock waves. They prevent air flow in the mixed compression ports, which reduces engine performance. Our research investigates this using supersonic wind tunnels and schlieren imaging to reveal the complex dance between shock waves and airflow. The findings show clear patterns of shock wave formation influenced by internal/external pressure surfaces. We looked at the boundary layer, the slow-moving air near the inlet walls, and its interaction with shock waves. In addition, the study emphasizes the dependence of the shock wave behaviour on the Mach number, which highlights the need for adaptive models. This knowledge is key to optimizing the combined compression inputs, paving the way for more powerful and efficient supersonic vehicles. Future engineers can use this knowledge to improve existing designs and explore innovative configurations for next-generation ultrasonic applications.

Keywords: oblique shock formation, boundary layer interaction, schlieren images, double wedge surface

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3438 Designing a Method to Control and Determine the Financial Performance of the Real Cost Sub-System in the Information Management System of Construction Projects

Authors: Alireza Ghaffari, Hassan Saghi

Abstract:

Project management is more complex than managing the day-to-day affairs of an organization. When the project dimensions are broad and multiple projects have to be monitored in different locations, the integrated management becomes even more complicated. One of the main concerns of project managers is the integrated project management, which is mainly rooted in the lack of accurate and accessible information from different projects in various locations. The collection of dispersed information from various parts of the network, their integration and finally the selective reporting of this information is among the goals of integrated information systems. It can help resolve the main problem, which is bridging the information gap between executives and senior managers in the organization. Therefore, the main objective of this study is to design and implement an important subset of a project management information system in order to successfully control the cost of construction projects so that its results can be used to design raw software forms and proposed relationships between different project units for the collection of necessary information.

Keywords: financial performance, cost subsystem, PMIS, project management

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3437 Homoleptic Complexes of a Tetraphenylporphyrinatozinc(II)-conjugated 2,2':6',6"-Terpyridine

Authors: Angelo Lanzilotto, Martin Kuss-Petermann, Catherine E. Housecroft, Edwin C. Constable, Oliver S. Wenger

Abstract:

We recently described the synthesis of a new tetraphenylporphyrinatozinc(II)-conjugated 2,2':6',6"-terpyridine (1) in which the tpy domain enables the molecule to act as a metalloligand. The synthetic route to 1 has been optimized, the importance of selecting a particular sequence of synthetic steps will be discussed. Three homoleptic complexes have been prepared, [Zn(1)₂]²⁺, [Fe(1)₂]²⁺ and [Ru(1)₂]²⁺, and have been isolated as the hexafluoridophosphate salts. Spectroelectrochemical measurements have been performed and the spectral changes ascribed to redox processes are partitioned on either the porphyrin or the terpyridine units. Compound 1 undergoes a reversible one-electron oxidation/reduction. The removal/gain of a second electron leads to a further irreversible chemical transformation. For the homoleptic [M(1)₂]²⁺ complexes, a suitable potential can be chosen at which both the oxidation and the reduction of the {ZnTPP} core are reversible. When the homoleptic complex contains a redox active metal such as Fe or Ru, spectroelectrochemistry has been used to investigate the metal to ligand charge transfer (MLCT) transition. The latter is sensitive to the oxidation state of the metal, and electrochemical oxidation of the metal center suppresses it. Detailed spectroelectrochemical studies will be presented.

Keywords: homoleptic complexes, spectroelectrochemistry, tetraphenylporphyrinatozinc(II), 2, 2':6', 6"-terpyridine

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3436 Study of Treatment Plant of The City Chlef Study of Environmental Impact

Authors: Houmame Benbouali, Aboubakr Gribi

Abstract:

The risks, in general, exist in any project, one can hardly carry out a project without taking risks. The hydraulic works are rather complex projects in their design, realization and exploitation and are often subjected at the multiple risks being able to influence with their good performance and can have a negative impact on their environment. The present study was carried out to quote the impacts caused by purification plant STEP Chlef on the environment, it aims has studied the environmental impacts during construction and when designing this STEP, it is divided into two parts: The first part results from a research task bibliographer which contain three chapters (- cleansing of water-worn- general information on water worn-proceed of purification of waste water). The second part is an experimental part which is divided into four chapters (detailed state initial description of the station of purification-evaluation of the impacts of the project analyzes measurements and recommendations).

Keywords: treatment plant, waste water, waste water treatment, Chlef

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3435 Evaluation of Robust Feature Descriptors for Texture Classification

Authors: Jia-Hong Lee, Mei-Yi Wu, Hsien-Tsung Kuo

Abstract:

Texture is an important characteristic in real and synthetic scenes. Texture analysis plays a critical role in inspecting surfaces and provides important techniques in a variety of applications. Although several descriptors have been presented to extract texture features, the development of object recognition is still a difficult task due to the complex aspects of texture. Recently, many robust and scaling-invariant image features such as SIFT, SURF and ORB have been successfully used in image retrieval and object recognition. In this paper, we have tried to compare the performance for texture classification using these feature descriptors with k-means clustering. Different classifiers including K-NN, Naive Bayes, Back Propagation Neural Network , Decision Tree and Kstar were applied in three texture image sets - UIUCTex, KTH-TIPS and Brodatz, respectively. Experimental results reveal SIFTS as the best average accuracy rate holder in UIUCTex, KTH-TIPS and SURF is advantaged in Brodatz texture set. BP neuro network works best in the test set classification among all used classifiers.

Keywords: texture classification, texture descriptor, SIFT, SURF, ORB

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3434 Adaptive Neuro Fuzzy Inference System Model Based on Support Vector Regression for Stock Time Series Forecasting

Authors: Anita Setianingrum, Oki S. Jaya, Zuherman Rustam

Abstract:

Forecasting stock price is a challenging task due to the complex time series of the data. The complexity arises from many variables that affect the stock market. Many time series models have been proposed before, but those previous models still have some problems: 1) put the subjectivity of choosing the technical indicators, and 2) rely upon some assumptions about the variables, so it is limited to be applied to all datasets. Therefore, this paper studied a novel Adaptive Neuro-Fuzzy Inference System (ANFIS) time series model based on Support Vector Regression (SVR) for forecasting the stock market. In order to evaluate the performance of proposed models, stock market transaction data of TAIEX and HIS from January to December 2015 is collected as experimental datasets. As a result, the method has outperformed its counterparts in terms of accuracy.

Keywords: ANFIS, fuzzy time series, stock forecasting, SVR

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3433 Characterization of Retinal Pigmented Cell Epithelium Cell Sheet Cultivated on Synthetic Scaffold

Authors: Tan Yong Sheng Edgar, Yeong Wai Yee

Abstract:

Age-related macular degeneration (AMD) is one of the leading cause of blindness. It can cause severe visual loss due to damaged retinal pigment epithelium (RPE). RPE is an important component of the retinal tissue. It functions as a transducing boundary for visual perception making it an essential factor for sight. The RPE also functions as a metabolically complex and functional cell layer that is responsible for the local homeostasis and maintenance of the extra photoreceptor environment. Thus one of the suggested method of treating such diseases would be regenerating these RPE cells. As such, we intend to grow these cells using a synthetic scaffold to provide a stable environment that reduces the batch effects found in natural scaffolds. Stiffness of the scaffold will also be investigated to determine the optimal Young’s modulus for cultivating these cells. The cells will be generated into a monolayer cell sheet and their functions such as formation of tight junctions and gene expression patterns will be assessed to evaluate the cell sheet quality compared to a native RPE tissue.

Keywords: RPE, scaffold, characterization, biomaterials, colloids and nanomedicine

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3432 Ethnic Conflict Dynamics in the Ethiopian Federation: Case of the Oromo-Somali Conflict

Authors: Takele Bekele Bayu

Abstract:

Though Ethiopia is an ancient country with ethnocultural and linguistic diversity, modern Ethiopia came into being in the second half of the 19th century under the military expansion of King Menelik II. Since then, the subsequent political system in the country failed to recognize and accommodate the country’s ethnolinguistic diversity. However, in 1991 the new government led by the Ethiopian People's Revolutionary Democratic Front (EPRDF) adopted federal-state structuring whereby constitutionally recognized and institutionally accommodated the country’s diversity. This investigation aimed to analyze drivers of ethnic conflict and its dynamism along the Eastern shared border of the Somali and Oromia regional administrations within the federal framework. The paper employed a comparative research design, adopted mixed research methods, and used survey questionnaires and focus group discussions (FGDs) for data collection. The study found that the Somali-Oromo conflict is complex and the dynamics and the sources of conflict in the study areas are similar.

Keywords: Ethiopia, Oromo, Somali, ethnic conflict, federalism

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3431 Mathematical Modeling of Bi-Substrate Enzymatic Reactions in the Presence of Different Types of Inhibitors

Authors: Rafayel Azizyan, Valeri Arakelyan, Aram Gevorgyan, Varduhi Balayan, Emil Gevorgyan

Abstract:

Currently, mathematical and computer modeling are widely used in different biological studies to predict or assess behavior of such complex systems as biological ones. This study deals with mathematical and computer modeling of bi-substrate enzymatic reactions, which play an important role in different biochemical pathways. The main objective of this study is to represent the results from in silico investigation of bi-substrate enzymatic reactions in the presence of uncompetitive inhibitors, as well as to describe in details the inhibition effects. Four models of uncompetitive inhibition were designed using different software packages. Particularly, uncompetitive inhibitor to the first [ES1] and the second ([ES1S2]; [FS2]) enzyme-substrate complexes have been studied. The simulation, using the same kinetic parameters for all models allowed investigating the behavior of reactions as well as determined some interesting aspects concerning influence of different cases of uncompetitive inhibition. Besides that shown, that uncompetitive inhibitors exhibit specific selectivity depending on mechanism of bi-substrate enzymatic reaction.

Keywords: mathematical modeling, bi-substrate enzymatic reactions, reversible inhibition

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3430 Revealing Insights into the Mechanisms of Biofilm Adhesion on Surfaces in Crude Oil Environments

Authors: Hadjer Didouh, Mohammed Hadj Meliani, Izzaddine Sameut Bouhaik

Abstract:

This study employs a multidisciplinary approach to investigate the intricate processes governing biofilm-surface interactions. Results indicate that surface properties significantly influence initial microbial attachment, with materials characterized by increased roughness and hydrophobicity promoting enhanced biofilm adhesion. Moreover, the chemical composition of materials plays a crucial role in impacting the development of biofilms. Environmental factors, such as temperature fluctuations and nutrient availability, were identified as key determinants affecting biofilm formation dynamics. Advanced imaging techniques revealed complex three-dimensional biofilm structures, emphasizing microbial communication and cooperation within these networks. These findings offer practical implications for industries operating in crude oil environments, guiding the selection and design of materials to mitigate biofilm-related challenges and enhance operational efficiency in such settings.

Keywords: biofilm adhesion, surface properties, crude oil environments, microbial interactions, multidisciplinary investigation

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3429 Effect of Structure on Properties of Incrementally Formed Titanium Alloy Sheets

Authors: Lucie Novakova, Petr Homola, Vaclav Kafka

Abstract:

Asymmetric incremental sheet forming (AISF) could significantly reduce costs incurred by the fabrication of complex industrial components with a minimal environmental impact. The AISF experiments were carried out on commercially pure titanium (Ti-Gr2), Timetal (15-3-3-3) alloy, and Ti-6Al-4V (Ti-Gr5) alloy. A special testing geometry was used to characterize the titanium alloys properties from the point of view of the forming zone and titanium structure effect. The structure and properties of the materials were assessed by means of metallographic analyses and microhardness measurements.The highest differences in the parameters assessed as a function of the sampling zone were observed in the case of alpha-phase Ti-Gr2at the expense of the most substantial sheet thinning occurrence. A springback causes a smaller stored deformation in Timetal (β alloy) resulting in less pronounced microstructure refinement and microhardness increase. Ti-6Al-4V alloy exhibited early failure due to its poor formability at ambient temperature.

Keywords: incremental forming, metallography, hardness, titanium alloys

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3428 Yeasts Associated to Spontaneous Date Vinegar Process

Authors: F. Halladj, H. Amellal, S. Benamara

Abstract:

Current consumer trends go towards natural products defined as the products obtained by a traditional manufacturing method. Vinegar is one of those products marketed; it may be industrially obtained by a submerged (fast) or traditional (slow) processes. The latter exhibited a high quality because of its complex microbiological transformations (or two-stage fermentation) by the native must flora. Moreover, although that Acetic acid bacteria have traditionally been considered to play the leading role in vinegar production, some studies have recently highlighted that also yeasts metabolism can affect traditional vinegar chemical properties in a remarkable way. Thus, the aim of this study was to monitor a traditional slow process of vinegar as applied in the south of Algeria using date with hard texture (Degla-Beida variety) to isolate and identify the involved yeasts in order to select them as starter culture. Phenotypic and molecular analysis show that the non-Saccharomyces were the main yeasts species isolated throughout the alcoholic spontaneous fermentation and they included Hanseniaspora guilliermondii and Torulaspora delbrueckii.

Keywords: date vinegar, traditional production, yeasts, Phenotypic, Algeria

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3427 The Effects of Infographics as a Supplementary Tool in Promoting Academic Reading Skill in an EFL Class

Authors: Niracha Chompurach, Dararat Khampusaen

Abstract:

EFL students have to be able to synthesize the texts they are reading critically to compose and connect the information. This study focuses on the effects of the application of Infographics as a supplementary tool to improve Thai EFL students’ Academic reading skills. Infographics are graphic visual representations of information, data, and knowledge offering students to work on gathering multiple types of information, such as pictures, texts, graphs, mapping, and charts. The study aims to investigate if the Infographics as a supplementary tool in academic reading lessons can make a difference in students’ reading skills, and the students’ opinions toward the application of infographics as a reading tool. The participants of this study were 3rd year Thai EFL Khon Kaen University students who took English Academic Reading course. This study employed Infographics assignments, Infographics rubric, and Gucus group interview. This study would advantage for both EFL teachers and students as a means to engage the students to handle the larger load of and represents the complex information in visible and comprehensible way.

Keywords: EFL, e-learning, infographics, language education

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3426 Biophysical and Structural Characterization of Transcription Factor Rv0047c of Mycobacterium Tuberculosis H37Rv

Authors: Md. Samsuddin Ansari, Ashish Arora

Abstract:

Every year 10 million people fall ill with one of the oldest diseases known as tuberculosis, caused by Mycobacterium tuberculosis. The success of M. tuberculosis as a pathogen is because of its ability to persist in host tissues. Multidrug resistance (MDR) mycobacteria cases increase every day, which is associated with efflux pumps controlled at the level of transcription. The transcription regulators of MDR transporters in bacteria belong to one of the following four regulatory protein families: AraC, MarR, MerR, and TetR. Phenolic acid decarboxylase repressor (PadR), like a family of transcription regulators, is closely related to the MarR family. Phenolic acid decarboxylase repressor (PadR) was first identified as a transcription factor involved in the regulation of phenolic acid stress response in various microorganisms (including Mycobacterium tuberculosis H37Rv). Recently research has shown that the PadR family transcription factors are global, multifunction transcription regulators. Rv0047c is a PadR subfamily-1 protein. We are exploring the biophysical and structural characterization of Rv0047c. The Rv0047 gene was amplified by PCR using the primers containing EcoRI and HindIII restriction enzyme sites cloned in pET-NH6 vector and overexpressed in DH5α and BL21 (λDE3) cells of E. coli following purification with Ni2+-NTA column and size exclusion chromatography. We did DSC to know the thermal stability; the Tm (transition temperature) of protein is 55.29ºC, and ΔH (enthalpy change) of 6.92 kcal/mol. Circular dichroism to know the secondary structure and conformation and fluorescence spectroscopy for tertiary structure study of protein. To understand the effect of pH on the structure, function, and stability of Rv0047c we employed spectroscopy techniques such as circular dichroism, fluorescence, and absorbance measurements in a wide range of pH (from pH-2.0 to pH-12). At low and high pH, it shows drastic changes in the secondary and tertiary structure of the protein. EMSA studies showed the specific binding of Rv0047c with its own 30-bp promoter region. To determine the effect of complex formation on the secondary structure of Rv0047c, we examined the CD spectra of the complex of Rv0047c with promoter DNA of rv0047. The functional role of Rv0047c was characterized by over-expressing the Rv0047c gene under the control of hsp60 promoter in Mycobacterium tuberculosis H37Rv. We have predicted the three-dimensional structure of Rv0047c using the Swiss Model and Modeller, with validity checked by the Ramachandra plot. We did molecular docking of Rv0047c with dnaA, through PatchDock following refinement through FireDock. Through this, it is possible to easily identify the binding hot-stop of the receptor molecule with that of the ligand, the nature of the interface itself, and the conformational change undergone by the protein pattern. We are using X-crystallography to unravel the structure of Rv0047c. Overall the studies show that Rv0047c may have transcription regulation along with providing an insight into the activity of Rv0047c in the pH range of subcellular environment and helps to understand the protein-protein interaction, a novel target to kill dormant bacteria and potential strategy for tuberculosis control.

Keywords: mycobacterium tuberculosis, phenolic acid decarboxylase repressor, Rv0047c, Circular dichroism, fluorescence spectroscopy, docking, protein-protein interaction

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3425 Genetic Algorithms for Feature Generation in the Context of Audio Classification

Authors: José A. Menezes, Giordano Cabral, Bruno T. Gomes

Abstract:

Choosing good features is an essential part of machine learning. Recent techniques aim to automate this process. For instance, feature learning intends to learn the transformation of raw data into a useful representation to machine learning tasks. In automatic audio classification tasks, this is interesting since the audio, usually complex information, needs to be transformed into a computationally convenient input to process. Another technique tries to generate features by searching a feature space. Genetic algorithms, for instance, have being used to generate audio features by combining or modifying them. We find this approach particularly interesting and, despite the undeniable advances of feature learning approaches, we wanted to take a step forward in the use of genetic algorithms to find audio features, combining them with more conventional methods, like PCA, and inserting search control mechanisms, such as constraints over a confusion matrix. This work presents the results obtained on particular audio classification problems.

Keywords: feature generation, feature learning, genetic algorithm, music information retrieval

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3424 Modeling of the Friction Behavior of Carbon/Epoxy Prepreg Composite

Authors: David Aveiga, Carlos Gonzalez

Abstract:

Thermoforming of pre-impregnated composites (prepreg) is the most employed process to build high-performance composite structures due to their visible advantage over alternative manufacturing techniques. This method allows easy shape moulding with a simple manufacturing system and a more refined outcome. The achievement of complex geometries can be exposed to undesired defects such as wrinkles. It is known that interply and ply-mould sliding behavior governs this defect generation. This work analyses interply and ply-mould friction coefficients for UD AS4/8552 Carbon/Epoxy prepreg. Friction coefficients are determined by a pull-out test method considering actual velocity, pressure and temperature conditions employed in a thermoforming process of an aeronautical composite component. A Stribeck curve is then constructed to find a mathematical expression that relates all the friction coefficients with the test variables through the Hersey number parameter. Two expressions are proposed to model ply-ply and ply-tool friction behaviors.

Keywords: friction, prepreg composite, stribeck curve, thermoforming.

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3423 Stochastic Matrices and Lp Norms for Ill-Conditioned Linear Systems

Authors: Riadh Zorgati, Thomas Triboulet

Abstract:

In quite diverse application areas such as astronomy, medical imaging, geophysics or nondestructive evaluation, many problems related to calibration, fitting or estimation of a large number of input parameters of a model from a small amount of output noisy data, can be cast as inverse problems. Due to noisy data corruption, insufficient data and model errors, most inverse problems are ill-posed in a Hadamard sense, i.e. existence, uniqueness and stability of the solution are not guaranteed. A wide class of inverse problems in physics relates to the Fredholm equation of the first kind. The ill-posedness of such inverse problem results, after discretization, in a very ill-conditioned linear system of equations, the condition number of the associated matrix can typically range from 109 to 1018. This condition number plays the role of an amplifier of uncertainties on data during inversion and then, renders the inverse problem difficult to handle numerically. Similar problems appear in other areas such as numerical optimization when using interior points algorithms for solving linear programs leads to face ill-conditioned systems of linear equations. Devising efficient solution approaches for such system of equations is therefore of great practical interest. Efficient iterative algorithms are proposed for solving a system of linear equations. The approach is based on a preconditioning of the initial matrix of the system with an approximation of a generalized inverse leading to a stochastic preconditioned matrix. This approach, valid for non-negative matrices, is first extended to hermitian, semi-definite positive matrices and then generalized to any complex rectangular matrices. The main results obtained are as follows: 1) We are able to build a generalized inverse of any complex rectangular matrix which satisfies the convergence condition requested in iterative algorithms for solving a system of linear equations. This completes the (short) list of generalized inverse having this property, after Kaczmarz and Cimmino matrices. Theoretical results on both the characterization of the type of generalized inverse obtained and the convergence are derived. 2) Thanks to its properties, this matrix can be efficiently used in different solving schemes as Richardson-Tanabe or preconditioned conjugate gradients. 3) By using Lp norms, we propose generalized Kaczmarz’s type matrices. We also show how Cimmino's matrix can be considered as a particular case consisting in choosing the Euclidian norm in an asymmetrical structure. 4) Regarding numerical results obtained on some pathological well-known test-cases (Hilbert, Nakasaka, …), some of the proposed algorithms are empirically shown to be more efficient on ill-conditioned problems and more robust to error propagation than the known classical techniques we have tested (Gauss, Moore-Penrose inverse, minimum residue, conjugate gradients, Kaczmarz, Cimmino). We end on a very early prospective application of our approach based on stochastic matrices aiming at computing some parameters (such as the extreme values, the mean, the variance, …) of the solution of a linear system prior to its resolution. Such an approach, if it were to be efficient, would be a source of information on the solution of a system of linear equations.

Keywords: conditioning, generalized inverse, linear system, norms, stochastic matrix

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3422 Active Power Flow Control Using a TCSC Based Backstepping Controller in Multimachine Power System

Authors: Naimi Abdelhamid, Othmane Abdelkhalek

Abstract:

With the current rise in the demand of electrical energy, present-day power systems which are large and complex, will continue to grow in both size and complexity. Flexible AC Transmission System (FACTS) controllers provide new facilities, both in steady state power flow control and dynamic stability control. Thyristor Controlled Series Capacitor (TCSC) is one of FACTS equipment, which is used for power flow control of active power in electric power system and for increase of capacities of transmission lines. In this paper, a Backstepping Power Flow Controller (BPFC) for TCSC in multimachine power system is developed and tested. The simulation results show that the TCSC proposed controller is capable of controlling the transmitted active power and improving the transient stability when compared with conventional PI Power Flow Controller (PIPFC).

Keywords: FACTS, thyristor controlled series capacitor (TCSC), backstepping, BPFC, PIPFC

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3421 Passenger Flow Characteristics of Seoul Metropolitan Subway Network

Authors: Kang Won Lee, Jung Won Lee

Abstract:

Characterizing the network flow is of fundamental importance to understand the complex dynamics of networks. And passenger flow characteristics of the subway network are very relevant for an effective transportation management in urban cities. In this study, passenger flow of Seoul metropolitan subway network is investigated and characterized through statistical analysis. Traditional betweenness centrality measure considers only topological structure of the network and ignores the transportation factors. This paper proposes a weighted betweenness centrality measure that incorporates monthly passenger flow volume. We apply the proposed measure on the Seoul metropolitan subway network involving 493 stations and 16 lines. Several interesting insights about the network are derived from the new measures. Using Kolmogorov-Smirnov test, we also find out that monthly passenger flow between any two stations follows a power-law distribution and other traffic characteristics such as congestion level and throughflow traffic follow exponential distribution.

Keywords: betweenness centrality, correlation coefficient, power-law distribution, Korea traffic DB

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3420 Dynamic Process Monitoring of an Ammonia Synthesis Fixed-Bed Reactor

Authors: Bothinah Altaf, Gary Montague, Elaine B. Martin

Abstract:

This study involves the modeling and monitoring of an ammonia synthesis fixed-bed reactor using partial least squares (PLS) and its variants. The process exhibits complex dynamic behavior due to the presence of heat recycling and feed quench. One limitation of static PLS model in this situation is that it does not take account of the process dynamics and hence dynamic PLS was used. Although it showed, superior performance to static PLS in terms of prediction, the monitoring scheme was inappropriate hence adaptive PLS was considered. A limitation of adaptive PLS is that non-conforming observations also contribute to the model, therefore, a new adaptive approach was developed, robust adaptive dynamic PLS. This approach updates a dynamic PLS model and is robust to non-representative data. The developed methodology showed a clear improvement over existing approaches in terms of the modeling of the reactor and the detection of faults.

Keywords: ammonia synthesis fixed-bed reactor, dynamic partial least squares modeling, recursive partial least squares, robust modeling

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3419 How to Improve Teaching and Learning Strategies Through Educational Research. An Experience of Peer Observation in Legal Education

Authors: Luigina Mortari, Alessia Bevilacqua, Roberta Silva

Abstract:

The experience presented in this paper aims to understand how educational research can support the introduction and optimization of teaching innovations in legal education. In this increasingly complex context, a strong need to introduce paths aimed at acquiring not only professional knowledge and skills but also transversal such as reflective, critical, and problem-solving skills emerges. Through a peer observation intertwined with an analysis of discursive practices, researchers and the teacher worked together through a process of participatory and transformative accompaniment whose objective was to promote the active participation and engagement of students in learning processes, an element indispensable to work in the more specific direction of strengthening key competences. This reflective faculty development path led the teacher to activate metacognitive processes, becoming thus aware of the strengths and areas of improvement of his teaching innovation.

Keywords: legal education, teaching innovation, peer observation, discursive analysis, faculty development

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3418 Machine Learning-Enabled Classification of Climbing Using Small Data

Authors: Nicholas Milburn, Yu Liang, Dalei Wu

Abstract:

Athlete performance scoring within the climbing do-main presents interesting challenges as the sport does not have an objective way to assign skill. Assessing skill levels within any sport is valuable as it can be used to mark progress while training, and it can help an athlete choose appropriate climbs to attempt. Machine learning-based methods are popular for complex problems like this. The dataset available was composed of dynamic force data recorded during climbing; however, this dataset came with challenges such as data scarcity, imbalance, and it was temporally heterogeneous. Investigated solutions to these challenges include data augmentation, temporal normalization, conversion of time series to the spectral domain, and cross validation strategies. The investigated solutions to the classification problem included light weight machine classifiers KNN and SVM as well as the deep learning with CNN. The best performing model had an 80% accuracy. In conclusion, there seems to be enough information within climbing force data to accurately categorize climbers by skill.

Keywords: classification, climbing, data imbalance, data scarcity, machine learning, time sequence

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3417 Outcomes of Combined Penetrating keratoplasty and Vitreo-Retinal Surgery in Management of Endophthalmitis with Obscured Corneal Clarity

Authors: Abhishek Dave, Manisha Singh

Abstract:

Purpose: The study aims to evaluate the outcomes of combined Penetrating keratoplasty (PKP) and Vitreo-Retinal (VR) surgery in patients having endophthalmitis with poor corneal clarity. Methods: PKP with VR Surgery was performed in 43 eyes. This is a retrospective analysis of their preoperative, intraoperative and microbiological characteristics and anatomical and functional outcomes. Results: Corneal opacification was due to corneal ulcer in 30 (69.7%), graft infection in 8 (18.6%), bullous keratopathy in 4 and corneal scar in 1 eye. Postoperative visual acuity improved in 20 (46.5%), not changed in 14 (32.5%) and deteriorated in 9 eyes (20.9%). Poor anatomic success was seen in 15 (34.88%) eyes (9-phthisis bulbi, 6-eviscerated). Graft remained clear in 24 eyes (1 year). Microbiology revealed bacteria in 26, fungus in 14 and no growth in 3 eyes. Six out of 11 patients having poor vision in the fellow eye, too, achieved functional success. Conclusion: PKP with VR surgery is a complex but globe-salvaging procedure for poor prognosis eyes, which otherwise would need evisceration.

Keywords: penetrating keratoplasty, VR surgery, endophthalmitis, corneal ulcer

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3416 Challenges in Self-Managing Vitality: A Qualitative Study about Staying Vital at Work among Dutch Office Workers

Authors: Violet Petit-Steeghs, Jochem J. R. Van Roon, Jacqueline E. W. Broerse

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Last decennia the retirement age in Europe is gradually increasing. As a result, people have to continue working for a longer period of time. Health problems due to increased sedentary behavior and mental conditions like burn-out, pose a threat in fulfilling employees’ working life. In order to stimulate the ability and willingness to work in the present and future, it is important to stay vital. Vitality is regarded in literature as a sense of energy, motivation and resilience. It is assumed that by increasing their vitality, employees will stay healthier and be more satisfied with their job, leading to a more sustainable employment and less absenteeism in the future. The aim of this project is to obtain insights into the experiences and barriers of employees, and specifically office workers, with regard to their vitality. These insights are essential in order to develop appropriate measures in the future. To get more insights in the experiences of office workers on their vitality, 8 focus group discussions were organized with 6-10 office workers from 4 different employers (an university, a national construction company and a large juridical and care service organization) in the Netherlands. The discussions were transcribed and analyzed via open coding. This project is part of a larger consortium project Provita2, and conducted in collaboration with University of Technology Eindhoven. Results showed that a range of interdependent factors form a complex network that influences office workers’ vitality. These factors can be divided in three overarching groups: (1) personal (2) organizational and (3) environmental factors. Personal intrinsic factors, relating to the office worker, comprise someone’s physical health, coping style, life style, needs, and private life. Organizational factors, relating to the employer, are the workload, management style and the structure, vision and culture of the organization. Lastly, environmental factors consist of the air, light, temperature at the workplace and whether the workplace is inspiring and workable. Office workers experienced barriers to improve their own vitality due to a lack of autonomy. On the one hand, because most factors were not only intrinsic but extrinsic, like work atmosphere or the temperature in the room. On the other hand, office workers were restricted in adapting both intrinsic as well as extrinsic factors. Restrictions to for instance the flexibility of working times and the workload, can set limitations for improving vitality through personal factors like physical activity and mental relaxation. In conclusion, a large range of interdependent factors influence the vitality of office workers. Office workers are often regarded to have a responsibility to improve their vitality, but are limitedly autonomous in adapting these factors. Measures to improve vitality should therefore not only focus on increasing awareness among office workers, but also on empowering them to fulfill this responsibility. A holistic approach that takes the complex mutual dependencies between the different factors and actors (like managers, employees and HR personnel) into account is highly recommended.

Keywords: occupational health, perspectives office workers, sustainable employment, vitality at work, work & wellbeing

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3415 Re-Framing Resilience Turn in Risk and Management with Anti-Positivistic Perspective of Holling's Early Work

Authors: Jose CanIzares

Abstract:

In the last decades, resilience has received much attention in relation to understanding and managing new forms of risk, especially in the context of urban adaptation to climate change. There are abundant concerns, however, on how to best interpret resilience and related ideas, and on whether they can guide ethically appropriate risk-related or adaptation efforts. Narrative creation and framing are critical steps in shaping public discussion and policy in large-scale interventions, since they favor or inhibit early decision and interpretation habits, which can be morally sensitive and then become persistent on time. This article adds to such framing process by contesting a conventional narrative on resilience and offering an alternative one. Conventionally, present ideas on resilience are traced to the work of ecologist C. S. Holling, especially to his article Resilience and Stability in Ecosystems. This article is usually portrayed as a contribution of complex systems thinking to theoretical ecology, where Holling appeals to resilience in order to challenge received views on ecosystem stability and the diversity-stability hypothesis. In this regard, resilience is construed as a “purely scientific”, precise and descriptive concept, denoting a complex property that allows ecosystems to persist, or to maintain functions, after disturbance. Yet, these formal features of resilience supposedly changed with Holling’s later work in the 90s, where, it is argued, Holling begun to use resilience as a more pragmatic “boundary term”, aimed at unifying transdisciplinary research about risks, ecological or otherwise, and at articulating public debate and governance strategies on the issue. In the conventional story, increased vagueness and degrees of normativity are the price to pay for this conceptual shift, which has made the term more widely usable, but also incompatible with scientific purposes and morally problematic (if not completely objectionable). This paper builds on a detailed analysis of Holling’s early work to propose an alternative narrative. The study will show that the “complexity turn” has often entangled theoretical and pragmatic aims. Accordingly, Holling’s primary aim was to fight what he termed “pathologies of natural resource management” or “pathologies of command and control management”, and so, the terms of his reform of ecosystem science are partly subordinate to the details of his proposal for reforming the management sciences. As regards resilience, Holling used it as a polysemous, ambiguous and normative term: sometimes, as an instrumental value that is closely related to various stability concepts; other times, and more crucially, as an intrinsic value and a tool for attacking efficiency and instrumentalism in management. This narrative reveals the limitations of its conventional alternative and has several practical advantages. It captures well the structure and purposes of Holling’s project, and the various roles of resilience in it. It helps to link Holling’s early work with other philosophical and ideological shifts at work in the 70s. It highlights the currency of Holling’s early work for present research and action in fields such as risk and climate adaptation. And it draws attention to morally relevant aspects of resilience that the conventional narrative neglects.

Keywords: resilience, complexity turn, risk management, positivistic, framing

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3414 Site Formation Processes at a New Kingdom Settlement at Sai Island, Sudan

Authors: Sean Taylor, Sayantani Neogi, Julia Budka

Abstract:

The important Egyptian New Kingdom settlement at Sai Island Sudan presents a complex stratigraphic archaeological record. This study takes the theoretic stance that it, not just the archaeological material being retrieved from the deposits but the sediments themselves that reflect human agency. These anthropogenic sediments reflect the use life of the buildings and spaces between and the post-depositional processes which operate to complicate the archaeological record. The application of soil micromorphology is a technique that takes intact block samples of sediment and analyses them in thin section under a petrological microscope. A detailed understanding of site formation processes and a contextualized knowledge of the material culture can be understood through careful and systematic observation of the changing facies. The major findings of the study are that soil and sedimentary information can provide valuable insights to the use of space during the New Kingdom and elucidate the complexities of site formation processes.

Keywords: anthropogenic sediment, New Kingdom, site formation processes, soil micromorphology

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3413 Fiber Stiffness Detection of GFRP Using Combined ABAQUS and Genetic Algorithms

Authors: Gyu-Dong Kim, Wuk-Jae Yoo, Sang-Youl Lee

Abstract:

Composite structures offer numerous advantages over conventional structural systems in the form of higher specific stiffness and strength, lower life-cycle costs, and benefits such as easy installation and improved safety. Recently, there has been a considerable increase in the use of composites in engineering applications and as wraps for seismic upgrading and repairs. However, these composites deteriorate with time because of outdated materials, excessive use, repetitive loading, climatic conditions, manufacturing errors, and deficiencies in inspection methods. In particular, damaged fibers in a composite result in significant degradation of structural performance. In order to reduce the failure probability of composites in service, techniques to assess the condition of the composites to prevent continual growth of fiber damage are required. Condition assessment technology and nondestructive evaluation (NDE) techniques have provided various solutions for the safety of structures by means of detecting damage or defects from static or dynamic responses induced by external loading. A variety of techniques based on detecting the changes in static or dynamic behavior of isotropic structures has been developed in the last two decades. These methods, based on analytical approaches, are limited in their capabilities in dealing with complex systems, primarily because of their limitations in handling different loading and boundary conditions. Recently, investigators have introduced direct search methods based on metaheuristics techniques and artificial intelligence, such as genetic algorithms (GA), simulated annealing (SA) methods, and neural networks (NN), and have promisingly applied these methods to the field of structural identification. Among them, GAs attract our attention because they do not require a considerable amount of data in advance in dealing with complex problems and can make a global solution search possible as opposed to classical gradient-based optimization techniques. In this study, we propose an alternative damage-detection technique that can determine the degraded stiffness distribution of vibrating laminated composites made of Glass Fiber-reinforced Polymer (GFRP). The proposed method uses a modified form of the bivariate Gaussian distribution function to detect degraded stiffness characteristics. In addition, this study presents a method to detect the fiber property variation of laminated composite plates from the micromechanical point of view. The finite element model is used to study free vibrations of laminated composite plates for fiber stiffness degradation. In order to solve the inverse problem using the combined method, this study uses only first mode shapes in a structure for the measured frequency data. In particular, this study focuses on the effect of the interaction among various parameters, such as fiber angles, layup sequences, and damage distributions, on fiber-stiffness damage detection.

Keywords: stiffness detection, fiber damage, genetic algorithm, layup sequences

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3412 Analysis of Subordination: The Reproductive Sphere

Authors: Aneesa Shafi

Abstract:

Reproduction is a complex term in a setting where it is continuously being shaped by epistemological shifts in knowledge. It denotes not just fertility, birth and childcare related practices but also the ideas that shape those practices. These ideas and practices figure into understandings of social and cultural renewal. Patriarchy continues to be a dominating force in the formation of these ideas and practices. Contemporary times are characterized by the resurgence of the whims of patriarchal politics in delineating the margins of women’s health care. This has further emboldened the struggle for reproductive rights on the global stage. The paper examines the subordination of the right to bodily autonomy of women within the ambit of their reproductive rights. Reproductive rights are recognized human rights and women’s rights. Why these rights of women face stiff opposition is established, as is the structure that creates hurdles to their enjoyment. The negotiation of this structure in the everyday life through women’s agency is also established. The reproductive sphere includes not just the process of reproduction but also social reproduction- domestic work, spheres of production and reproduction, population and birth (control) issues.

Keywords: patriarchy, women, reproduction, gender

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3411 Interpretation of Ultrasonic Backscatter of Linear FM Chirp Pulses from Targets Having Frequency-Dependent Scattering

Authors: Stuart Bradley, Mathew Legg, Lilyan Panton

Abstract:

Ultrasonic remote sensing is a useful tool for assessing the interior structure of complex targets. For these methods, significantly enhanced spatial resolution is obtained if the pulse is coded, for example using a linearly changing frequency during the pulse duration. Such pulses have a time-dependent spectral structure. Interpretation of the backscatter from targets is, therefore, complicated if the scattering is frequency-dependent. While analytic models are well established for steady sinusoidal excitations applied to simple shapes such as spheres, such models do not generally exist for temporally evolving excitations. Therefore, models are developed in the current paper for handling such signals so that the properties of the targets can be quantitatively evaluated while maintaining very high spatial resolution. Laboratory measurements on simple shapes are used to confirm the validity of the models.

Keywords: linear FM chirp, time-dependent acoustic scattering, ultrasonic remote sensing, ultrasonic scattering

Procedia PDF Downloads 300