Search results for: dispersed region growing algorithm (DRGA)
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 11451

Search results for: dispersed region growing algorithm (DRGA)

7731 Determinants of Investment in Vaca Muerta, Argentina

Authors: Ivan Poza Martínez

Abstract:

The international energy landscape has been significantly affected by the Covid-19 pandemic and te conflict in Ukraine. The Vaca Muerta sedimentary formation in Argentina´s Neuquén province has become a crucial area for energy production, specifically in the shale gas ad shale oil sectors. The massive investment required for theexploitation of this reserve make it essential to understand te determinants of the investment in the upstream sector at both local ad international levels. The aim of this study is to identify the qualitative and quantitative determinants of investment in Vaca Muerta. The research methodolody employs both quantiative ( econometrics ) and qualitative approaches. A linear regression model is used to analyze the impact in non-conventional hydrocarbons. The study highlights that, in addition to quantitative factors, qualitative variables, particularly the design of a regulatory framework, significantly influence the level of the investment in Vaca Muerta. The analysis reveals the importance of attracting both domestic and foreign capital investment. This research contributes to understanding the factors influencing investment inthe Vaca Muerta regioncomapred to other published studies. It emphasizes to role of qualitative varibles, such as regulatory frameworks, in the development of the shale gas and oil sectors. The study uses a combination ofquantitative data , such a investment figures, and qualitative data, such a regulatory frameworks. The data is collected from various rpeorts and industry publications. The linear regression model is used to analyze the relationship between the variables and the investment in Vaca Muerta. The research addresses the question of what factors drive investment in the Vaca Muerta region, both from a quantitative and qualitative perspective. The study concludes that a combination of quantitative and qualitative factors, including the design of a regulatory framework, plays a significant role in attracting investment in Vaca Muerta. It highlights the importance of these determinants in the developmentof the local energy sector and the potential economic benefits for Argentina and the Southern Cone region.

Keywords: vaca muerta, FDI, shale gas, shale oil, YPF

Procedia PDF Downloads 49
7730 Enhancing Project Management Performance in Prefabricated Building Construction under Uncertainty: A Comprehensive Approach

Authors: Niyongabo Elyse

Abstract:

Prefabricated building construction is a pioneering approach that combines design, production, and assembly to attain energy efficiency, environmental sustainability, and economic feasibility. Despite continuous development in the industry in China, the low technical maturity of standardized design, factory production, and construction assembly introduces uncertainties affecting prefabricated component production and on-site assembly processes. This research focuses on enhancing project management performance under uncertainty to help enterprises navigate these challenges and optimize project resources. The study introduces a perspective on how uncertain factors influence the implementation of prefabricated building construction projects. It proposes a theoretical model considering project process management ability, adaptability to uncertain environments, and collaboration ability of project participants. The impact of uncertain factors is demonstrated through case studies and quantitative analysis, revealing constraints on implementation time, cost, quality, and safety. To address uncertainties in prefabricated component production scheduling, a fuzzy model is presented, expressing processing times in interval values. The model utilizes a cooperative co-evolution evolution algorithm (CCEA) to optimize scheduling, demonstrated through a real case study showcasing reduced project duration and minimized effects of processing time disturbances. Additionally, the research addresses on-site assembly construction scheduling, considering the relationship between task processing times and assigned resources. A multi-objective model with fuzzy activity durations is proposed, employing a hybrid cooperative co-evolution evolution algorithm (HCCEA) to optimize project scheduling. Results from real case studies indicate improved project performance in terms of duration, cost, and resilience to processing time delays and resource changes. The study also introduces a multistage dynamic process control model, utilizing IoT technology for real-time monitoring during component production and construction assembly. This approach dynamically adjusts schedules when constraints arise, leading to enhanced project management performance, as demonstrated in a real prefabricated housing project. Key contributions include a fuzzy prefabricated components production scheduling model, a multi-objective multi-mode resource-constrained construction project scheduling model with fuzzy activity durations, a multi-stage dynamic process control model, and a cooperative co-evolution evolution algorithm. The integrated mathematical model addresses the complexity of prefabricated building construction project management, providing a theoretical foundation for practical decision-making in the field.

Keywords: prefabricated construction, project management performance, uncertainty, fuzzy scheduling

Procedia PDF Downloads 48
7729 Challenges Faced by Physician Leaders in Teaching Hospitals of Private Medical Schools in the National Capital Region, Philippines

Authors: Policarpio Jr. Joves

Abstract:

Physicians in most teaching hospitals are commonly promoted into managerial roles, yet their training is mostly in clinical and scientific skills but not in leadership competencies. When they shift into roles of physician leadership, the majority hold on to their primary identity of physicians. These conflicting roles affect their identity and eventually their work. The physician leaders also face additional challenges related to academics which include incorporation of new knowledge into the existing curriculum, use of technology in the delivery of teaching, the need to train medical students outside of hospital wards, etc. The study aims to explore how physician leaders in teaching hospitals of private medical schools enact their leadership roles and how they face the challenges as physician leaders. The study setting shall be teaching hospitals of three private medical schools situated in the National Capital Region, Philippines. A multiple case study design shall be adopted in this research. Physicians shall be eligible to participate in the study if they are practicing clinicians limited to the five major clinical specialty: Internal Medicine, Pediatrics, Family Medicine, Surgery, Obstetrics and Gynecology. They must be teaching in the College of Medicine prior to their appointments as physician leaders in both medical school and teaching hospital. Semi-structured face-to-face interviews shall be utilized as a means of data collection, with open-ended questions, enabling physician leaders to present narratives about their identity, role enactment, conflicts, reaction of colleagues, and the challenges encountered in their day-to-day work as physician leaders. Interviews shall be combined with observations and review of records to gain more insights into how the physician leaders are 'doing' management. Within-case analysis shall be done initially followed by a thematic analysis across the cases, referred to as cross–case analysis or cross-case synthesis.

Keywords: academic leaders, academic managers, physician leaders, physician managers

Procedia PDF Downloads 342
7728 Isolation, Characterization, and Optimization of Immobilized L-Asparginase- Anticancer Enzyme from Aspergillus.Niger

Authors: Supriya Chatla, Anjana Male, Srikala Kamireddy

Abstract:

L-asparaginase (E.C.3.5.1.1) is an anti-cancer enzyme that has been purified and characterized for decades to study and evaluate its anti-carcinogenic activity against Hodgkin’s lymphoma. The present investigation deals with screening, isolation and optimization of L-asparaginase giving fungal strain of soil samples from different areas of AP, India. L-Aspariginase activity was estimated on the basis of the pink color surrounding the growing colony. A total of 132 colonies were screened and isolated from different samples. Based on the zone diameter, L-asparaginase activity is determined, L- asparaginase activity is optimized at 28oc and Immobilized Aspariginase had more potency than the free enzymes.

Keywords: aspariginase, anticancer enzyme, Isolation, optimization

Procedia PDF Downloads 76
7727 Blockchain-Based Decentralized Architecture for Secure Medical Records Management

Authors: Saeed M. Alshahrani

Abstract:

This research integrated blockchain technology to reform medical records management in healthcare informatics. It was aimed at resolving the limitations of centralized systems by establishing a secure, decentralized, and user-centric platform. The system was architected with a sophisticated three-tiered structure, integrating advanced cryptographic methodologies, consensus algorithms, and the Fast Healthcare Interoperability Resources (HL7 FHIR) standard to ensure data security, transaction validity, and semantic interoperability. The research has profound implications for healthcare delivery, patient care, legal compliance, operational efficiency, and academic advancements in blockchain technology and healthcare IT sectors. The methodology adapted in this research comprises of Preliminary Feasibility Study, Literature Review, Design and Development, Cryptographic Algorithm Integration, Modeling the data and testing the system. The research employed a permissioned blockchain with a Practical Byzantine Fault Tolerance (PBFT) consensus algorithm and Ethereum-based smart contracts. It integrated advanced cryptographic algorithms, role-based access control, multi-factor authentication, and RESTful APIs to ensure security, regulate access, authenticate user identities, and facilitate seamless data exchange between the blockchain and legacy healthcare systems. The research contributed to the development of a secure, interoperable, and decentralized system for managing medical records, addressing the limitations of the centralized systems that were in place. Future work will delve into optimizing the system further, exploring additional blockchain use cases in healthcare, and expanding the adoption of the system globally, contributing to the evolution of global healthcare practices and policies.

Keywords: healthcare informatics, blockchain, medical records management, decentralized architecture, data security, cryptographic algorithms

Procedia PDF Downloads 52
7726 Improving the Penalty-free Multi-objective Evolutionary Design Optimization of Water Distribution Systems

Authors: Emily Kambalame

Abstract:

Water distribution networks necessitate many investments for construction, prompting researchers to seek cost reduction and efficient design solutions. Optimization techniques are employed in this regard to address these challenges. In this context, the penalty-free multi-objective evolutionary algorithm (PFMOEA) coupled with pressure-dependent analysis (PDA) was utilized to develop a multi-objective evolutionary search for the optimization of water distribution systems (WDSs). The aim of this research was to find out if the computational efficiency of the PFMOEA for WDS optimization could be enhanced. This was done by applying real coding representation and retaining different percentages of feasible and infeasible solutions close to the Pareto front in the elitism step of the optimization. Two benchmark network problems, namely the Two-looped and Hanoi networks, were utilized in the study. A comparative analysis was then conducted to assess the performance of the real-coded PFMOEA in relation to other approaches described in the literature. The algorithm demonstrated competitive performance for the two benchmark networks by implementing real coding. The real-coded PFMOEA achieved the novel best-known solutions ($419,000 and $6.081 million) and a zero-pressure deficit for the two networks, requiring fewer function evaluations than the binary-coded PFMOEA. In previous PFMOEA studies, elitism applied a default retention of 30% of the least cost-feasible solutions while excluding all infeasible solutions. It was found in this study that by replacing 10% and 15% of the feasible solutions with infeasible ones that are close to the Pareto front with minimal pressure deficit violations, the computational efficiency of the PFMOEA was significantly enhanced. The configuration of 15% feasible and 15% infeasible solutions outperformed other retention allocations by identifying the optimal solution with the fewest function evaluation

Keywords: design optimization, multi-objective evolutionary, penalty-free, water distribution systems

Procedia PDF Downloads 58
7725 The Crisis in Ukraine and the End of the Post Cold War Security Delusions in Europe

Authors: Georgios Siachamis

Abstract:

The main objective of this paper is to examine how the crisis in Ukraine can change our perception and understanding of the strategic challenges in Europe. It will try also to address the main factors behind the beginning of the conflict in Ukraine, the miscalculations and mistakes that lead towards the escalation of the crisis and what constructive initiatives are needed to be taken in order to avoid further instability in the region. Furthermore, measures in order to develop a more stable relation with Russia are also going to be presented. Finally the implementation of a new strategic outlook for the EU is also going to be analysed.

Keywords: crisis management, European grand strategy, crisis in Ukraine, Russian policy

Procedia PDF Downloads 366
7724 Towards a Critical Disentanglement of the ‘Religion’ Nexus in the Global East

Authors: Daan F. Oostveen

Abstract:

‘Religion’ as a term is not native to the Global East. The concept ‘religion’ is both understood in its meaning of ‘religious traditions’, commonly referring to the ‘World Religions’ and in its adjective meaning ‘the religious’ or ‘religiosity’ as a separate domain of human culture, commonly contrasted to the secular. Though neither of these understandings are native to the historical worldviews of East Asia, their development in modern Western scholarship has had an enormous impact on the self-understanding of cultural diversity in the Global East as well. One example is the identification and therefore elevation to the status of World Religion of ‘Buddhism’ which connected formerly dispersed religious practices throughout the Global East and subsumed them under this powerful label. On the other hand, we see how popular religiosity, shamanism and hybrid cultural expressions have become excluded from genuine religion; this had an immense impact on the sense of legitimacy of these practices, which became sometimes labeled as superstition are rejected as magic. Our theoretical frameworks on religion in the Global East do not always consider the complex power dynamics between religious actors, both elites and lay expressions of religion in everyday life, governments and religious studies scholars. In order to get a clear image of how religiosity functions in the context of the Global East, we have to take into account these power dynamics. What is important in particular is the issue of religious identity or absence of religious identity. The self-understanding of religious actors in the Global East is often very different from what scholars of religion observe. Religious practice, from an etic perspective, is often unrelated to religious identification from an emic perspective. But we also witness the rise of Christian churches in the Global East, in which religious identity and belonging does play a pivotal role. Finally, religion in the Global East has since the beginning of the 20th Century been conceptualized as the ‘other’ or republicanism or Marxist-Maoist ideology. It is important not to deny the key role of colonial thinking in the process of religion formation in the Global East. In this paper, it is argued that religious realities constituted emerging as a result from our theory of religion, and that these religious realities in turn inform our theory. Therefore, the relationship between phenomenology of religion and theory of religion can never be disentangled. In fact, we have to acknowledge that our conceptualizations of religious diversity are always already influenced by our valuation of those cultural expressions that we have come to call ‘religious’.

Keywords: global east, religion, religious belonging, secularity

Procedia PDF Downloads 131
7723 Reconstruction of Age-Related Generations of Siberian Larch to Quantify the Climatogenic Dynamics of Woody Vegetation Close the Upper Limit of Its Growth

Authors: A. P. Mikhailovich, V. V. Fomin, E. M. Agapitov, V. E. Rogachev, E. A. Kostousova, E. S. Perekhodova

Abstract:

Woody vegetation among the upper limit of its habitat is a sensitive indicator of biota reaction to regional climate changes. Quantitative assessment of temporal and spatial changes in the distribution of trees and plant biocenoses calls for the development of new modeling approaches based upon selected data from measurements on the ground level and ultra-resolution aerial photography. Statistical models were developed for the study area located in the Polar Urals. These models allow obtaining probabilistic estimates for placing Siberian Larch trees into one of the three age intervals, namely 1-10, 11-40 and over 40 years, based on the Weilbull distribution of the maximum horizontal crown projection. Authors developed the distribution map for larch trees with crown diameters exceeding twenty centimeters by deciphering aerial photographs made by a UAV from an altitude equal to fifty meters. The total number of larches was equal to 88608, forming the following distribution row across the abovementioned intervals: 16980, 51740, and 19889 trees. The results demonstrate that two processes can be observed in the course of recent decades: first is the intensive forestation of previously barren or lightly wooded fragments of the study area located within the patches of wood, woodlands, and sparse stand, and second, expansion into mountain tundra. The current expansion of the Siberian Larch in the region replaced the depopulation process that occurred in the course of the Little Ice Age from the late 13ᵗʰ to the end of the 20ᵗʰ century. Using data from field measurements of Siberian larch specimen biometric parameters (including height, diameter at root collar and at 1.3 meters, and maximum projection of the crown in two orthogonal directions) and data on tree ages obtained at nine circular test sites, authors developed a model for artificial neural network including two layers with three and two neurons, respectively. The model allows quantitative assessment of a specimen's age based on height and maximum crone projection values. Tree height and crown diameters can be quantitatively assessed using data from aerial photographs and lidar scans. The resulting model can be used to assess the age of all Siberian larch trees. The proposed approach, after validation, can be applied to assessing the age of other tree species growing near the upper tree boundaries in other mountainous regions. This research was collaboratively funded by the Russian Ministry for Science and Education (project No. FEUG-2023-0002) and Russian Science Foundation (project No. 24-24-00235) in the field of data modeling on the basis of artificial neural network.

Keywords: treeline, dynamic, climate, modeling

Procedia PDF Downloads 73
7722 Phone Number Spoofing Attack in VoLTE 4G

Authors: Joo-Hyung Oh

Abstract:

The number of service users of 4G VoLTE (voice over LTE) using LTE data networks is rapidly growing. VoLTE based on all-IP network enables clearer and higher-quality voice calls than 3G. It does, however, pose new challenges; a voice call through IP networks makes it vulnerable to security threats such as wiretapping and forged or falsified information. And in particular, stealing other users’ phone numbers and forging or falsifying call request messages from outgoing voice calls within VoLTE result in considerable losses that include user billing and voice phishing to acquaintances. This paper focuses on the threats of caller phone number spoofing in the VoLTE and countermeasure technology as safety measures for mobile communication networks.

Keywords: LTE, 4G, VoLTE, phone number spoofing

Procedia PDF Downloads 428
7721 Transfer Function Model-Based Predictive Control for Nuclear Core Power Control in PUSPATI TRIGA Reactor

Authors: Mohd Sabri Minhat, Nurul Adilla Mohd Subha

Abstract:

The 1MWth PUSPATI TRIGA Reactor (RTP) in Malaysia Nuclear Agency has been operating more than 35 years. The existing core power control is using conventional controller known as Feedback Control Algorithm (FCA). It is technically challenging to keep the core power output always stable and operating within acceptable error bands for the safety demand of the RTP. Currently, the system could be considered unsatisfactory with power tracking performance, yet there is still significant room for improvement. Hence, a new design core power control is very important to improve the current performance in tracking and regulating reactor power by controlling the movement of control rods that suit the demand of highly sensitive of nuclear reactor power control. In this paper, the proposed Model Predictive Control (MPC) law was applied to control the core power. The model for core power control was based on mathematical models of the reactor core, MPC, and control rods selection algorithm. The mathematical models of the reactor core were based on point kinetics model, thermal hydraulic models, and reactivity models. The proposed MPC was presented in a transfer function model of the reactor core according to perturbations theory. The transfer function model-based predictive control (TFMPC) was developed to design the core power control with predictions based on a T-filter towards the real-time implementation of MPC on hardware. This paper introduces the sensitivity functions for TFMPC feedback loop to reduce the impact on the input actuation signal and demonstrates the behaviour of TFMPC in term of disturbance and noise rejections. The comparisons of both tracking and regulating performance between the conventional controller and TFMPC were made using MATLAB and analysed. In conclusion, the proposed TFMPC has satisfactory performance in tracking and regulating core power for controlling nuclear reactor with high reliability and safety.

Keywords: core power control, model predictive control, PUSPATI TRIGA reactor, TFMPC

Procedia PDF Downloads 237
7720 Eating Behaviours in Islam and Mental Health: A Preventative Approach

Authors: Muhammad Rafiq, Lamae Zulfiqar, Nazish Idrees Chaudhary

Abstract:

A growing number of research focuses on healthy and unhealthy eating behaviors and their impact on health. It was intended to study the Islamic point of view on eating behavior, its impact on mental health and preventative strategies in the light of the Quran and Sunnah. Different articles and Islamic sayings related to eating behaviors and mental health were reviewed in detail. It was also revealed scientifically and through Islamic point of view that appropriate quantity, quality and timings of food have positive effects on mental health. Therefore, a 3Rs model of eating behaviors has been proposed.

Keywords: food intake, mental health, quality of food, quantity of food

Procedia PDF Downloads 233
7719 Morphological Studies of the Gills of the Red Swamp Freshwater Crayfish Procambarus clarkii (Crustacea: Decapoda: Cambarids) (Girard 1852) from the River Nile and Its Branches in Egypt

Authors: Mohamed M. A. Abumandour

Abstract:

The red swamp freshwater crayfish breathe through three types of feather-like trichobranchiate gills; podobranchiae, arthrobranchiae and pleurobranchiae. All gills have the same general structure and appearance; plume-like with single broad setiferous, and single axis. The gill consists of axis with numerous finger-like filaments, having three morphological types; round, pointed and somewhat hooked shaped. The direction of filaments vary according their position; in middle region were nearly perpendicular to gill axis while in the apex were nearly parallel to axis. There were characteristic system of gill spines on; central axis (two types were distinguishable by presence of socket), basal plate, setobranch (long non-branched and short multidenticulate) and on the bilobed epipodal plate. There are four shape of spinated-like distal region of setobranch seta; two pointed processes (longitudinal arrangement and irregular arranged) and two broad processes (transverse triangular and multidenticulate). The bilobed epipodal plate devoid from any filaments and extended from outer side of podobranchiae as triangular basal part then extended between the gills as cord-like middle part then pass under the gill to lies against the thoracic body wall. By SEM, the apical part of bilobed epipodal plate have serrated free border and corrugated surface while the middle part have none serrated free border. There are two methods of gill cleaning mechanism in crayfish; passive and active method. The passive method occurred by; setae of setobranch, branchiostegite, bilobed epipodal plate, setiferous arthrodial lamellae and reversing the respiratory water through a narrow spaced branchial chamber.

Keywords: crayfis, gill spines, setobranch, gill setae, cleaning mechanisms

Procedia PDF Downloads 406
7718 The Rise of Far-Right Political Parties: Future of Multiculturalism in Europe

Authors: Bharti Yadav

Abstract:

Global migration and the rise of far-right parties have expanded the significance of political discussions enclosing multiculturalism. This research paper will focus on the rise of far-right political parties in Europe over the last nearly two decades and how right-wing politics affect multiculturalism in a detrimental way; major European leaders have publicly stated that multiculturalism in their countries has failed. This paper also discusses the main reasons for right-wing politics is normalizing in Europe. Far-right political parties are the fastest-growing parties in Europe, and multiculturalism is an unescapable significant political issue. The rise of far-right anti-immigrant parties diminishes mainstream party support for multiculturalism. Mainstream parties are more receptive to both increasing in ethnic minorities’ electoral power and the rise of far-right parties.

Keywords: political parties, far-right, migration, multiculturalism

Procedia PDF Downloads 83
7717 Parallel Multisplitting Methods for Differential Systems

Authors: Malika El Kyal, Ahmed Machmoum

Abstract:

We prove the superlinear convergence of asynchronous multi-splitting methods applied to differential equations. This study is based on the technique of nested sets. It permits to specify kind of the convergence in the asynchronous mode.The main characteristic of an asynchronous mode is that the local algorithm not have to wait at predetermined messages to become available. We allow some processors to communicate more frequently than others, and we allow the communication delays to be substantial and unpredictable. Note that synchronous algorithms in the computer science sense are particular cases of our formulation of asynchronous one.

Keywords: parallel methods, asynchronous mode, multisplitting, ODE

Procedia PDF Downloads 521
7716 Development of DNDC Modelling Method for Evaluation of Carbon Dioxide Emission from Arable Soils in European Russia

Authors: Olga Sukhoveeva

Abstract:

Carbon dioxide (CO2) is the main component of carbon biogeochemical cycle and one of the most important greenhouse gases (GHG). Agriculture, particularly arable soils, are one the largest sources of GHG emission for the atmosphere including CO2.Models may be used for estimation of GHG emission from agriculture if they can be adapted for different countries conditions. The only model used in officially at national level in United Kingdom and China for this purpose is DNDC (DeNitrification-DeComposition). In our research, the model DNDC is offered for estimation of GHG emission from arable soils in Russia. The aim of our research was to create the method of DNDC using for evaluation of CO2 emission in Russia based on official statistical information. The target territory was European part of Russia where many field experiments are located. At the first step of research the database on climate, soil and cropping characteristics for the target region from governmental, statistical, and literature sources were created. All-Russia Research Institute of Hydrometeorological Information – World Data Centre provides open daily data about average meteorological and climatic conditions. It must be calculated spatial average values of maximum and minimum air temperature and precipitation over the region. Spatial average values of soil characteristics (soil texture, bulk density, pH, soil organic carbon content) can be determined on the base of Union state register of soil recourses of Russia. Cropping technologies are published by agricultural research institutes and departments. We offer to define cropping system parameters (annual information about crop yields, amount and types of fertilizers and manure) on the base of the Federal State Statistics Service data. Content of carbon in plant biomass may be calculated via formulas developed and published by Ministry of Natural Resources and Environment of the Russian Federation. At the second step CO2 emission from soil in this region were calculated by DNDC. Modelling data were compared with empirical and literature data and good results were obtained, modelled values were equivalent to the measured ones. It was revealed that the DNDC model may be used to evaluate and forecast the CO2 emission from arable soils in Russia based on the official statistical information. Also, it can be used for creation of the program for decreasing GHG emission from arable soils to the atmosphere. Financial Support: fundamental scientific researching theme 0148-2014-0005 No 01201352499 ‘Solution of fundamental problems of analysis and forecast of Earth climatic system condition’ for 2014-2020; fundamental research program of Presidium of RAS No 51 ‘Climate change: causes, risks, consequences, problems of adaptation and regulation’ for 2018-2020.

Keywords: arable soils, carbon dioxide emission, DNDC model, European Russia

Procedia PDF Downloads 186
7715 Molecular Identification and Genotyping of Human Brucella Strains Isolated in Kuwait

Authors: Abu Salim Mustafa

Abstract:

Brucellosis is a zoonotic disease endemic in Kuwait. Human brucellosis can be caused by several Brucella species with Brucella melitensis causing the most severe and Brucella abortus the least severe disease. Furthermore, relapses are common after successful chemotherapy of patients. The classical biochemical methods of culture and serology for identification of Brucellae provide information about the species and serotypes only. However, to differentiate between relapse and reinfection/epidemiological investigations, the identification of genotypes using molecular methods is essential. In this study, four molecular methods [16S rRNA gene sequencing, real-time PCR, enterobacterial repetitive intergenic consensus (ERIC)-PCR and multilocus variable-number tandem-repeat analysis (MLVA)-16] were evaluated for the identification and typing of 75 strains of Brucella isolated in Kuwait. The 16S rRNA gene sequencing suggested that all the strains were B. melitensis and real-time PCR confirmed their species identity as B. melitensis. The ERIC-PCR band profiles produced a dendrogram of 75 branches suggesting each strain to be of a unique type. The cluster classification, based on ~ 80% similarity, divided all the ERIC genotypes into two clusters, A and B. Cluster A consisted of 9 ERIC genotypes (A1-A9) corresponding to 9 individual strains. Cluster B comprised of 13 ERIC genotypes (B1-B13) with B5 forming the largest cluster of 51 strains. MLVA-16 identified all isolates as B. melitensis and divided them into 71 MLVA-types. The cluster analysis of MLVA-16-types suggested that most of the strains in Kuwait originated from the East Mediterranean Region, a few from the African group and one new genotype closely matched with the West Mediterranean region. In conclusion, this work demonstrates that B. melitensis, the most pathogenic species of Brucella, is prevalent in Kuwait. Furthermore, MLVA-16 is the best molecular method, which can identify the Brucella species and genotypes as well as determine their origin in the global context. Supported by Kuwait University Research Sector grants MI04/15 and SRUL02/13.

Keywords: Brucella, ERIC-PCR, MLVA-16, RT-PCR, 16S rRNA gene sequencing

Procedia PDF Downloads 386
7714 Estimating the Traffic Impacts of Green Light Optimal Speed Advisory Systems Using Microsimulation

Authors: C. B. Masera, M. Imprialou, L. Budd, C. Morton

Abstract:

Even though signalised intersections are necessary for urban road traffic management, they can act as bottlenecks and disrupt traffic operations. Interrupted traffic flow causes congestion, delays, stop-and-go conditions (i.e. excessive acceleration/deceleration) and longer journey times. Vehicle and infrastructure connectivity offers the potential to provide improved new services with additional functions of assisting drivers. This paper focuses on one of the applications of vehicle-to-infrastructure communication namely Green Light Optimal Speed Advisory (GLOSA). To assess the effectiveness of GLOSA in the urban road network, an integrated microscopic traffic simulation framework is built into VISSIM software. Vehicle movements and vehicle-infrastructure communications are simulated through the interface of External Driver Model. A control algorithm is developed for recommending an optimal speed that is continuously updated in every time step for all vehicles approaching a signal-controlled point. This algorithm allows vehicles to pass a traffic signal without stopping or to minimise stopping times at a red phase. This study is performed with all connected vehicles at 100% penetration rate. Conventional vehicles are also simulated in the same network as a reference. A straight road segment composed of two opposite directions with two traffic lights per lane is studied. The simulation is implemented under 150 vehicles per hour and 200 per hour traffic volume conditions to identify how different traffic densities influence the benefits of GLOSA. The results indicate that traffic flow is improved by the application of GLOSA. According to this study, vehicles passed through the traffic lights more smoothly, and waiting times were reduced by up to 28 seconds. Average delays decreased for the entire network by 86.46% and 83.84% under traffic densities of 150 vehicles per hour per lane and 200 vehicles per hour per lane, respectively.

Keywords: connected vehicles, GLOSA, intelligent transport systems, vehicle-to-infrastructure communication

Procedia PDF Downloads 166
7713 Comparative Analysis of the Antioxidant Capacities of Pre-Germinated and Germinated Pigmented Rice (Oryza sativa L. Cv. Superjami and Superhongmi)

Authors: Soo Im Chung, Lara Marie Pangan Lo, Yao Cheng Zhang, Su Jin Nam, Xingyue Jin, Mi Young Kang

Abstract:

Rice (Oryza sativa L.) is one of the most widely consumed grains. Due to the growing number of demand as a potential functional food and nutraceutical source and the increasing awareness of people towards healthy diet and good quality of living, more researches dwell upon the development of new rice cultivars for population consumption. However, studies on the antioxidant capacities of newly developed rice were limited as well as the effects of germination in these rice cultivars. Therefore, this study aimed to focus on analysis of the antioxidant potential of pre-germinated and germinated pigmented rice cultivars in South Korea such as purple cultivar Superjami (SJ) and red cultivar Super hongmi (SH) in comparison with the non-pigmented Normal Brown (NB) Rice. The powdered rice grain samples were extracted with 80% methanol and their antioxidant activities were determined. The Results showed that pre-germinated pigmented rice cultivars have higher Fe2+ Chelating Ability (Fe2+), Reducing Power (RP), 2,2´-azinobis[3-ethylbenzthiazoline]-6-sulfonic acid (ABTS) radical scavenging and Superoxide Dismutase activity than the control NB rice. Moreover, it is revealed that germination process induced a significant increased in the antioxidant activities of all the rice samples regardless of their strains. Purple rice SJ showed greater Fe2+ (88.82 + 0.53%), RP (0.82 + 0.01) , ABTS (143.63 + 2.38 mg VCEAC/100 g) and SOD (59.31 + 0.48%) activities than the red grain SH and the control NB having the lowest antioxidant potential among the three (3) rice samples examined. The Effective concentration at 50% (EC50) of 1, 1-Diphenyl-2-picrylhydrazyl (DPPH) and Hydroxyradical (-OH) Scavenging activity for the rice samples were also obtained. SJ showed lower EC50 in terms of its DPPH (3.81 + 0.15 mg/mL) and –OH (5.19 + 0.08 mg/mL) radical scavenging activities than the red grain SH and control NB rice indicating that at lower concentrations, it can readily exhibit antioxidant effects against reactive oxygen species (ROS). These results clearly suggest the higher antioxidant potential of pigmented rice varieties as compared with the widely consumed NB rice. Also, it is revealed in the study that even at lower concentrations, pigmented rice varieties can exhibit their antioxidant activities. Germination process further enhanced the antioxidant capacities of the rice samples regardless of their types. With these results at hand, these new rice varieties can be further developed as a good source of bio functional elements that can help alleviate the growing number of cases of metabolic disorders.

Keywords: antioxidant capacity, germinated rice, pigmented rice, super hongmi, superjami

Procedia PDF Downloads 435
7712 The Curse of Oil: Unpacking the Challenges to Food Security in the Nigeria's Niger Delta

Authors: Abosede Omowumi Babatunde

Abstract:

While the Niger Delta region satisfies the global thirst for oil, the inhabitants have not been adequately compensated for the use of their ancestral land. Besides, the ruthless exploitation and destruction of the natural environment upon which the inhabitants of the Niger Delta depend for their livelihood and sustenance by the activities of oil multinationals, pose major threats to food security in the region and by implication, Nigeria in general, Africa, and the world, given the present global emphasis on food security. This paper examines the effect of oil exploitation on household food security, identify key gaps in measures put in place to address the changes to livelihoods and food security and explore what should be done to improve the local people access to sufficient, safe and culturally acceptable food in the Niger Delta. Data is derived through interviews with key informants and Focus Group Discussions (FGDs) conducted with respondents in the local communities in the Niger Delta states of Delta, Bayelsa and Rivers as well as relevant extant studies. The threat to food security is one important aspect of the human security challenges in the Niger Delta which has received limited scholarly attention. In addition, successive Nigerian governments have not meaningfully addressed the negative impacts of oil-induced environmental degradation on traditional livelihoods given the significant linkages between environmental sustainability, livelihood security, and food security. The destructive impact of oil pollution on the farmlands, crops, economic trees, creeks, lakes, and fishing equipment is so devastating that the people can no longer engage in productive farming and fishing. Also important is the limited access to modern agricultural methods for fishing and subsistence farming as fishing and farming are done using mostly crude implements and traditional methods. It is imperative and urgent to take stock of the negative implications of the activities of oil multinationals for environmental and livelihood sustainability, and household food security in the Niger Delta.

Keywords: challenges, food security, Nigeria's Niger delta, oil

Procedia PDF Downloads 245
7711 Analysis of Structural and Photocatalytical Properties of Anatase, Rutile and Mixed Phase TiO2 Films Deposited by Pulsed-Direct Current and Radio Frequency Magnetron Co-Sputtering

Authors: S. Varnagiris, M. Urbonavicius, S. Tuckute, M. Lelis, K. Bockute

Abstract:

Amongst many water purification techniques, TiO2 photocatalysis is recognized as one of the most promising sustainable methods. It is known that for photocatalytical applications anatase is the most suitable TiO2 phase, however heterojunction of anatase/rutile phases could improve the photocatalytical activity of TiO2 even further. Despite the relative simplicity of TiO2 different synthesis methods lead to the highly dispersed crystal phases and photocatalytic activity of the corresponding samples. Accordingly, suggestions and investigations of various innovative methods of TiO2 synthesis are still needed. In this work structural and photocatalytical properties of TiO2 films deposited by the unconventional method of simultaneous co-sputtering from two magnetrons powered by pulsed-Direct Current (pDC) and Radio Frequency (RF) power sources with negative bias voltage have been studied. More specifically, TiO2 film thickness, microstructure, surface roughness, crystal structure, optical transmittance and photocatalytical properties were investigated by profilometer, scanning electron microscope, atomic force microscope, X-ray diffractometer and UV-Vis spectrophotometer respectively. The proposed unconventional two magnetron co-sputtering based TiO2 film formation method showed very promising results for crystalline TiO2 film formation while keeping process temperatures below 100 °C. XRD analysis revealed that by using proper combination of power source type and bias voltage various TiO2 phases (amorphous, anatase, rutile or their mixture) can be synthesized selectively. Moreover, strong dependency between power source type and surface roughness, as well as between the bias voltage and band gap value of TiO2 films was observed. Interestingly, TiO2 films deposited by two magnetron co-sputtering without bias voltage had one of the highest band gap values between the investigated films but its photocatalytic activity was superior compared to all other samples. It is suggested that this is due to the dominating nanocrystalline anatase phase with various exposed surfaces including photocatalytically the most active {001}.

Keywords: films, magnetron co-sputtering, photocatalysis, TiO₂

Procedia PDF Downloads 115
7710 Optimal MRO Process Scheduling with Rotable Inventory to Minimize Total Earliness

Authors: Murat Erkoc, Kadir Ertogral

Abstract:

Maintenance, repair and overhauling (MRO) of high cost equipment used in many industries such as transportation, military and construction are typically subject to regulations set by local governments or international agencies. Aircrafts are prime examples for this kind of equipment. Such equipment must be overhauled at certain intervals for continuing permission of use. As such, the overhaul must be completed by strict deadlines, which often times cannot be exceeded. Due to the fact that the overhaul is typically a long process, MRO companies carry so called rotable inventory for exchange of expensive modules in the overhaul process of the equipment so that the equipment continue its services with minimal interruption. The extracted module is overhauled and returned back to the inventory for future exchange, hence the name rotable inventory. However, since the rotable inventory and overhaul capacity are limited, it may be necessary to carry out some of the exchanges earlier than their deadlines in order to produce a feasible overhaul schedule. An early exchange results with a decrease in the equipment’s cycle time in between overhauls and as such, is not desired by the equipment operators. This study introduces an integer programming model for the optimal overhaul and exchange scheduling. We assume that there is certain number of rotables at hand at the beginning of the planning horizon for a single type module and there are multiple demands with known deadlines for the exchange of the modules. We consider an MRO system with identical parallel processing lines. The model minimizes total earliness by generating optimal overhaul start times for rotables on parallel processing lines and exchange timetables for orders. We develop a fast exact solution algorithm for the model. The algorithm employs full-delay scheduling approach with backward allocation and can easily be used for overhaul scheduling problems in various MRO settings with modular rotable items. The proposed procedure is demonstrated by a case study from the aerospace industry.

Keywords: rotable inventory, full-delay scheduling, maintenance, overhaul, total earliness

Procedia PDF Downloads 541
7709 Mental Health Clinicians’ Perceptions of Nature-Based Interventions Within Community Mental Health Services: Evidence from Australia

Authors: Rachel Tambyah, Katarzyna Olcoń, Julaine Allan, Pete Destry, Thomas Astell-Burt

Abstract:

The rising social and financial burden of mental illness indicates an urgent need to explore interventions that can be used as well as or instead of traditional treatments. Although there is growing evidence of the positive mental health outcomes of spending time in nature, the implementation of nature-based interventions (NBIs) within mental health services remains minimal. Based on interviews with mental health clinicians in Australia, this study demonstrated that clinicians supported the use of NBIs and would promote them to their clients.

Keywords: nature, nature-based interventions, mental health, mental health services, mental health clinicians

Procedia PDF Downloads 144
7708 Antioxidant Activity of Selected Medicinal Plants Used in Folk Medicine in Libya

Authors: Salmin Alshalmani, Ghazall M Benhusein, Ebtisam Alhadi Absomaha, Marwa I. Meshri, Hamdoon A. Mohammed, Jamal Mezogi

Abstract:

Eight wild medicinal plants used by Libyan and growing in Al-Jebel Al-Akhdar, Libya were suspected to estimate the antioxidant activity using 2,2-Diphenyl-1-Picrylhydrazyl stable free radical (DPPH). Incidences of purple colour reduction of the DPPH by testing extracts in addition to quercetin and vitamin C as positive controls reflect its ability to scavenge free radicals. All testing plants extract showed noticeable strength as antioxidant regarding its abilities to scavenge DPPH with an especial regards to Sarcopoterium spinosum.

Keywords: antioxidant, scavenging activity, folk medicine, methanol extracts

Procedia PDF Downloads 594
7707 Effect of Crown Gall and Phylloxera Resistant Rootstocks on Grafted Vitis Vinifera CV. Sultana Grapevine

Authors: Hassan Mahmoudzadeh

Abstract:

The bacterium of Agrobacterium vitis causes crown and root gall disease, an important disease of grapevine, Vitis vinifera L. Also, Phylloxera is one of the most important pests in viticulture. Grapevine rootstocks were developed to provide increased resistance to soil-borne pests and diseases, but rootstock effects on some traits remain unclear. The interaction between rootstock, scion and environment can induce different responses to the grapevine physiology. 'Sultsna' (Vitis vinifera L.) is one of the most valuable raisin grape cultivars in Iran. Thus, the aim of this study was to determine the rootstock effect on the growth characteristics and yield components and quality of 'Sultana' grapevine grown in the Urmia viticulture region. The experimental design was completely randomized blocks, with four treatments, four replicates and 10 vines per plot. The results show that all variables evaluated were significantly affected by the rootstock. The Sultana/110R and Sultana/Nazmieh were among other combinations influenced by the year and had a higher significant yield/vine (13.25 and 12.14, respectively). Indeed, they were higher than that of Sultana/5BB (10.56 kg/vine) and Sultana/Spota (10.25 kg/vine). The number of clusters per burst bud and per vine and the weight of clusters were affected by the rootstock as well. Pruning weight/vine, yield/pruning weight, leaf area/vine and leaf area index are variables related to the physiology of grapevine, which was also affected by the rootstocks. In general, rootstocks had adapted well to the environment where the experiment was carried out, giving vigor and high yield to Sultana grapevine, which means that they may be used by grape growers in this region. In sum, the study found the best rootstocks for 'Sultana' to be Nazmieh and 110R in terms of root and shoot growth. However, the choice of the right rootstock depends on various aspects, such as those related to soil characteristics, climate conditions, grape varieties, and even clones, and production purposes.

Keywords: grafting, vineyards, grapevine, succeptability

Procedia PDF Downloads 116
7706 Molecular Characterization of Major Isolated Organism Involved in Bovine Subclinical Mastitis

Authors: H. K. Ratre, M. Roy, S. Roy, M. S. Parmar, V. Bhagat

Abstract:

Mastitis is a common problem of dairy industries. Reduction in milk production and an irreparable damage to the udder associated with the disease are common causes of culling of dairy cows. Milk from infected animals is not suitable for drinking and for making different milk products. So, it has a major economic importance in dairy cattle. The aims of this study were to investigate the bacteriological panorama in milk from udder quarters with subclinical mastitis and to carried out for the molecular characterization of the major isolated organisms, from subclinical mastitis-affected cows in and around Durg and Rajnandgaon district of Chhattisgarh. Isolation and identification of bacteria from the milk samples of subclinical mastitis-affected cows were done by standard and routine culture procedures. A total of 78 isolates were obtained from cows and among the various bacteria isolated, Staphylococcus spp. occupied prime position with occurrence rate of 51.282%. However, other bacteria isolated includeStreptococcus spp. (20.512%), Micrococcus spp. (14.102%), E. coli (8.974%), Klebsiela spp. (2.564%), Salmonella spp. (1.282%) and Proteus spp. (1.282%). Staphylococcus spp. was isolated as the major causative agent of subclinical mastitis in the studied area. Molecular characterization of Staphylococus aureusisolates was done for genetic expression of the virulence genes like ‘nuc’ encoding thermonucleaseexoenzyme, coa and spa by PCR amplification of the respective genes in 25 Staphylococcus isolates. In the present study, 15 isolates (77.27%) out of 20 coagulase positive isolates were found to be genotypically positive for ‘nuc’ where as 20 isolates (52.63%) out of 38 CNS expressed the presence of the same virulence gene. In the present study, three Staphylococcus isolates were found to be genotypically positive for coa gene. The Amplification of the coa gene yielded two different products of 627, 710 bp. The amplification of the gene segment encoding the IgG binding region of protein A (spa) revealed a size of 220 and 253bp in twostaphylococcus isolates. The X-region binding of the spa gene produced an amplicon of 315 bp in one Staphylococcal isolates. Staphylococcus aureus was found to be major isolate (51.28%) responsible for causing subclinical mastitis in cows which also showed expression of virulence genesnuc, coa and spa.

Keywords: mastitis, bacteria, characterization, expression, gene

Procedia PDF Downloads 210
7705 Sustainable Capacity Building on Tourism Management of Touristic Destinations in Ghana: The Case of James and Ussher Forts in the Accra Metropolis

Authors: Fiona Gibson

Abstract:

This study is on sustainable capacity building in tourism management of the touristic destination of forts and castles within the Accra Metropolis, of the Greater Accra Region of Ghana, notably, the Christianbough Castle, the James and Ussher Forts. These forts and castle mentioned above have a rich colonial historical past that emerged from the 17th century onwards on the Gulf Coast of Guinea of the West Africa Sub-Region. Unfortunately, apart from the Christianbough Castle, which used to be the seat of government until recently, the environment of James and Ussher Forts are in a deployable state of decay due to years of neglect. Jamestown and Usshertown fishing communities with historical colonial past of a rich touristic heritage sites are predominantly indigenous Gas who speak only the Ga language, one of the languages of the six local languages spoken in Ghana, as a medium for sustainable tourism management. The purpose of this study is to investigate the reasons for years of decay and neglect, using both qualitative and quantitative research approach for individual interviews, to develop a rich picture of life situational story of the people of James and Ussher Forts environs and finding solutions to their predicaments through internal generated funds for sustainability of tourism management within the communities. The study recommends nation-wide educational campaigns and programmes on culture of maintenance and management for sustainable tourism development and management at all historical heritage sites in the country, specifically with the aim of promoting tourism in Ghana, using the indigenous local languages. The study also recommends formal and informal education for the residents, especially the youth to help them learn skills, either through local training or the formal education and this call for collaboration between the government of Ghana and other local and international bodies.

Keywords: sustainable capacity building, tourism management, forts, castles

Procedia PDF Downloads 488
7704 Effect of Papaverine on Developmental Neurotoxicity: Neurosphere as in vitro Model

Authors: Mohammed Y. Elsherbeny, Mohamed Salama, Ahmed Lotfy, Hossam Fareed, Nora Mohammed

Abstract:

Background: Developmental neurotoxicity (DNT) entails the toxic effects imparted by various chemicals on brain during the early childhood when human brains are vulnerable during this period. DNT study in vivo cannot determine the effect of the neurotoxins, as it is not applicable, so using the neurosphere cells of lab animals as an alternative is applicable and time saving. Methods: Cell culture: Rat neural progenitor cells were isolated from rat embryos’ brain. The cortices were aseptically dissected out and the tissues were triturated. The dispersed tissues were allowed to settle. The supernatant was then transferred to a fresh tube and centrifuged. The pellet was placed in Hank’s balanced salt solution and cultured as free-floating neurospheres in proliferation medium. Differentiation was initiated by growth factor withdrawal in differentiation medium and plating onto a poly-d-lysine/ laminin matrix. Chemical Exposure: Neurospheres were treated for 2 weeks with papaverine in proliferation medium. Proliferation analyses: Spheres were cultured. After 0, 4, 5, 11 and 14 days, sphere size was determined by software analyses (CellProfiler, version 2.1; Broad Institute). Diameter of each neurosphere was measured and exported to excel file further to statistical analysis. Viability test: Trypsin-EDTA solution was added to neurospheres to dissociate neurospheres into single cells suspension, then viability evaluated by the Trypan Blue exclusion test. Result: As regards proliferation analysis and percentage of viable cells of papaverin treated groups: There was no significant change in cells proliferation compared to control at 0, 4, 5, 11 and 14 days with concentrations 1, 5 and 10 µM of papaverine, but there is a significant change in cell viability compared to control after 1 week and 2 weeks with the same concentrations of papaverine. Conclusion: Papaverine has toxic effect on viability of neural cell, not on their proliferation, so it may produce focal neural lesions not growth morphological changes.

Keywords: developmental neurotoxicity, neurotoxin, papaverine, neuroshperes

Procedia PDF Downloads 381
7703 Use of Artificial Neural Networks to Estimate Evapotranspiration for Efficient Irrigation Management

Authors: Adriana Postal, Silvio C. Sampaio, Marcio A. Villas Boas, Josué P. Castro

Abstract:

This study deals with the estimation of reference evapotranspiration (ET₀) in an agricultural context, focusing on efficient irrigation management to meet the growing interest in the sustainable management of water resources. Given the importance of water in agriculture and its scarcity in many regions, efficient use of this resource is essential to ensure food security and environmental sustainability. The methodology used involved the application of artificial intelligence techniques, specifically Multilayer Perceptron (MLP) Artificial Neural Networks (ANNs), to predict ET₀ in the state of Paraná, Brazil. The models were trained and validated with meteorological data from the Brazilian National Institute of Meteorology (INMET), together with data obtained from a producer's weather station in the western region of Paraná. Two optimizers (SGD and Adam) and different meteorological variables, such as temperature, humidity, solar radiation, and wind speed, were explored as inputs to the models. Nineteen configurations with different input variables were tested; amidst them, configuration 9, with 8 input variables, was identified as the most efficient of all. Configuration 10, with 4 input variables, was considered the most effective, considering the smallest number of variables. The main conclusions of this study show that MLP ANNs are capable of accurately estimating ET₀, providing a valuable tool for irrigation management in agriculture. Both configurations (9 and 10) showed promising performance in predicting ET₀. The validation of the models with cultivator data underlined the practical relevance of these tools and confirmed their generalization ability for different field conditions. The results of the statistical metrics, including Mean Absolute Error (MAE), Mean Squared Error (MSE), Root Mean Squared Error (RMSE), and Coefficient of Determination (R²), showed excellent agreement between the model predictions and the observed data, with MAE as low as 0.01 mm/day and 0.03 mm/day, respectively. In addition, the models achieved an R² between 0.99 and 1, indicating a satisfactory fit to the real data. This agreement was also confirmed by the Kolmogorov-Smirnov test, which evaluates the agreement of the predictions with the statistical behavior of the real data and yields values between 0.02 and 0.04 for the producer data. In addition, the results of this study suggest that the developed technique can be applied to other locations by using specific data from these sites to further improve ET₀ predictions and thus contribute to sustainable irrigation management in different agricultural regions. The study has some limitations, such as the use of a single ANN architecture and two optimizers, the validation with data from only one producer, and the possible underestimation of the influence of seasonality and local climate variability. An irrigation management application using the most efficient models from this study is already under development. Future research can explore different ANN architectures and optimization techniques, validate models with data from multiple producers and regions, and investigate the model's response to different seasonal and climatic conditions.

Keywords: agricultural technology, neural networks in agriculture, water efficiency, water use optimization

Procedia PDF Downloads 40
7702 Boundary Layer Control Using a Magnetic Field: A Case Study in the Framework of Ferrohydrodynamics

Authors: C. F. Alegretti, F. R. Cunha, R. G. Gontijo

Abstract:

This work investigates the effects of an applied magnetic field on the geometry-driven boundary layer detachment flow of a ferrofluid over a sudden expansion. Both constitutive equation and global magnetization equation for a ferrofluid are considered. Therefore, the proposed formulation consists in a coupled magnetic-hydrodynamic problem. Computational simulations are carried out in order to explore, not only the viability to control flow instabilities, but also to evaluate the consistency of theoretical aspects. The unidirectional sudden expansion in a ferrofluid flow is investigated numerically under the perspective of Ferrohydrodynamics in a two-dimensional domain using a Finite Differences Method. The boundary layer detachment induced by the sudden expansion results in a recirculating zone, which has been extensively studied in non-magnetic hydrodynamic problems for a wide range of Reynolds numbers. Similar investigations can be found in literature regarding the sudden expansion under the magnetohydrodynamics framework, but none considering a colloidal suspension of magnetic particles out of the superparamagnetic regime. The vorticity-stream function formulation is implemented and results in a clear coupling between the flow vorticity and its magnetization field. Our simulations indicate a systematic decay on the length of the recirculation zone as increasing physical parameters of the flow, such as the intensity of the applied field and the volume fraction of particles. The results all are discussed from a physical point of view in terms of the dynamical non-dimensional parameters. We argue that the decrease/reduction in the recirculation region of the flow is a direct consequence of the magnetic torque balancing the action of the torque produced by viscous and inertial forces of the flow. For the limit of small Reynolds and magnetic Reynolds parameters, the diffusion of vorticity balances the diffusion of the magnetic torque on the flow. These mechanics control the growth of the recirculation region.

Keywords: boundary layer detachment, ferrofluid, ferrohydrodynamics, magnetization, sudden expansion

Procedia PDF Downloads 201