Search results for: random matrix theory
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 8363

Search results for: random matrix theory

1583 Enhancing the Pricing Expertise of an Online Distribution Channel

Authors: Luis N. Pereira, Marco P. Carrasco

Abstract:

Dynamic pricing is a revenue management strategy in which hotel suppliers define, over time, flexible and different prices for their services for different potential customers, considering the profile of e-consumers and the demand and market supply. This means that the fundamentals of dynamic pricing are based on economic theory (price elasticity of demand) and market segmentation. This study aims to define a dynamic pricing strategy and a contextualized offer to the e-consumers profile in order to improve the number of reservations of an online distribution channel. Segmentation methods (hierarchical and non-hierarchical) were used to identify and validate an optimal number of market segments. A profile of the market segments was studied, considering the characteristics of the e-consumers and the probability of reservation a room. In addition, the price elasticity of demand was estimated for each segment using econometric models. Finally, predictive models were used to define rules for classifying new e-consumers into pre-defined segments. The empirical study illustrates how it is possible to improve the intelligence of an online distribution channel system through an optimal dynamic pricing strategy and a contextualized offer to the profile of each new e-consumer. A database of 11 million e-consumers of an online distribution channel was used in this study. The results suggest that an appropriate policy of market segmentation in using of online reservation systems is benefit for the service suppliers because it brings high probability of reservation and generates more profit than fixed pricing.

Keywords: dynamic pricing, e-consumers segmentation, online reservation systems, predictive analytics

Procedia PDF Downloads 203
1582 Foreign Policy and National Security Dilemma: Examining Nigerian Experience

Authors: Shuaibu Umar Abdul

Abstract:

The essence of any state as well as government is to ensure and advance the security of lives and property of its citizens. As a result, providing security in all spheres ranging from safeguarding the territorial integrity, security of lives and property of the citizens as well as economic emancipation have constitute the core objectives cum national interest of virtually all country’s foreign policy in the world. In view of this imperative above, Nigeria has enshrined in the early part of her 1999 constitution as amended, as its duty and responsibility as a state, to ensure security of lives and property of its citizens. Yet, it does not make any significant shift as it relates to the country’s fundamental security needs as exemplified by the current enormous security challenges that reduced the country’s fortune to the background in all ramifications. The study chooses realist paradigm as theoretical underpinning which emphasizes that exigency of the moment should always take priority in the pursuit of foreign policy. The study is historical, descriptive and narrative in method and character. Data for the study was sourced from secondary sources and analysed via content analysis. The study found out that it is lack of political will on the side of the government to guarantee a just and egalitarian society that will be of benefit to all citizens. This could be more appreciated when looking at the gaps between the theory in Nigerian foreign policy and the practice as exemplified by the action or inaction of the government to ensure security in the state. On this account, the study recommends that until the leaderships in Nigerian foreign policy recognized the need for political will and respect for constitutionalism to ensure security of its citizens and territory, otherwise achieving great Nigeria will remain an illusion.

Keywords: foreign policy, nation, national security, Nigeria, security

Procedia PDF Downloads 477
1581 Uncertainty Assessment in Building Energy Performance

Authors: Fally Titikpina, Abderafi Charki, Antoine Caucheteux, David Bigaud

Abstract:

The building sector is one of the largest energy consumer with about 40% of the final energy consumption in the European Union. Ensuring building energy performance is of scientific, technological and sociological matter. To assess a building energy performance, the consumption being predicted or estimated during the design stage is compared with the measured consumption when the building is operational. When valuing this performance, many buildings show significant differences between the calculated and measured consumption. In order to assess the performance accurately and ensure the thermal efficiency of the building, it is necessary to evaluate the uncertainties involved not only in measurement but also those induced by the propagation of dynamic and static input data in the model being used. The evaluation of measurement uncertainty is based on both the knowledge about the measurement process and the input quantities which influence the result of measurement. Measurement uncertainty can be evaluated within the framework of conventional statistics presented in the \textit{Guide to the Expression of Measurement Uncertainty (GUM)} as well as by Bayesian Statistical Theory (BST). Another choice is the use of numerical methods like Monte Carlo Simulation (MCS). In this paper, we proposed to evaluate the uncertainty associated to the use of a simplified model for the estimation of the energy consumption of a given building. A detailed review and discussion of these three approaches (GUM, MCS and BST) is given. Therefore, an office building has been monitored and multiple sensors have been mounted on candidate locations to get required data. The monitored zone is composed of six offices and has an overall surface of 102 $m^2$. Temperature data, electrical and heating consumption, windows opening and occupancy rate are the features for our research work.

Keywords: building energy performance, uncertainty evaluation, GUM, bayesian approach, monte carlo method

Procedia PDF Downloads 427
1580 Determining G-γ Degradation Curve in Cohesive Soils by Dilatometer and in situ Seismic Tests

Authors: Ivandic Kreso, Spiranec Miljenko, Kavur Boris, Strelec Stjepan

Abstract:

This article discusses the possibility of using dilatometer tests (DMT) together with in situ seismic tests (MASW) in order to get the shape of G-g degradation curve in cohesive soils (clay, silty clay, silt, clayey silt and sandy silt). MASW test provides the small soil stiffness (Go from vs) at very small strains and DMT provides the stiffness of the soil at ‘work strains’ (MDMT). At different test locations, dilatometer shear stiffness of the soil has been determined by the theory of elasticity. Dilatometer shear stiffness has been compared with the theoretical G-g degradation curve in order to determine the typical range of shear deformation for different types of cohesive soil. The analysis also includes factors that influence the shape of the degradation curve (G-g) and dilatometer modulus (MDMT), such as the overconsolidation ratio (OCR), plasticity index (IP) and the vertical effective stress in the soil (svo'). Parametric study in this article defines the range of shear strain gDMT and GDMT/Go relation depending on the classification of a cohesive soil (clay, silty clay, clayey silt, silt and sandy silt), function of density (loose, medium dense and dense) and the stiffness of the soil (soft, medium hard and hard). The article illustrates the potential of using MASW and DMT to obtain G-g degradation curve in cohesive soils.

Keywords: dilatometer testing, MASW testing, shear wave, soil stiffness, stiffness reduction, shear strain

Procedia PDF Downloads 276
1579 Stochastic Pi Calculus in Financial Markets: An Alternate Approach to High Frequency Trading

Authors: Jerome Joshi

Abstract:

The paper presents the modelling of financial markets using the Stochastic Pi Calculus model. The Stochastic Pi Calculus model is mainly used for biological applications; however, the feature of this model promotes its use in financial markets, more prominently in high frequency trading. The trading system can be broadly classified into exchange, market makers or intermediary traders and fundamental traders. The exchange is where the action of the trade is executed, and the two types of traders act as market participants in the exchange. High frequency trading, with its complex networks and numerous market participants (intermediary and fundamental traders) poses a difficulty while modelling. It involves the participants to seek the advantage of complex trading algorithms and high execution speeds to carry out large volumes of trades. To earn profits from each trade, the trader must be at the top of the order book quite frequently by executing or processing multiple trades simultaneously. This would require highly automated systems as well as the right sentiment to outperform other traders. However, always being at the top of the book is also not best for the trader, since it was the reason for the outbreak of the ‘Hot – Potato Effect,’ which in turn demands for a better and more efficient model. The characteristics of the model should be such that it should be flexible and have diverse applications. Therefore, a model which has its application in a similar field characterized by such difficulty should be chosen. It should also be flexible in its simulation so that it can be further extended and adapted for future research as well as be equipped with certain tools so that it can be perfectly used in the field of finance. In this case, the Stochastic Pi Calculus model seems to be an ideal fit for financial applications, owing to its expertise in the field of biology. It is an extension of the original Pi Calculus model and acts as a solution and an alternative to the previously flawed algorithm, provided the application of this model is further extended. This model would focus on solving the problem which led to the ‘Flash Crash’ which is the ‘Hot –Potato Effect.’ The model consists of small sub-systems, which can be integrated to form a large system. It is designed in way such that the behavior of ‘noise traders’ is considered as a random process or noise in the system. While modelling, to get a better understanding of the problem, a broader picture is taken into consideration with the trader, the system, and the market participants. The paper goes on to explain trading in exchanges, types of traders, high frequency trading, ‘Flash Crash,’ ‘Hot-Potato Effect,’ evaluation of orders and time delay in further detail. For the future, there is a need to focus on the calibration of the module so that they would interact perfectly with other modules. This model, with its application extended, would provide a basis for researchers for further research in the field of finance and computing.

Keywords: concurrent computing, high frequency trading, financial markets, stochastic pi calculus

Procedia PDF Downloads 47
1578 The Predictive Utility of Subjective Cognitive Decline Using Item Level Data from the Everyday Cognition (ECog) Scales

Authors: J. Fox, J. Randhawa, M. Chan, L. Campbell, A. Weakely, D. J. Harvey, S. Tomaszewski Farias

Abstract:

Early identification of individuals at risk for conversion to dementia provides an opportunity for preventative treatment. Many older adults (30-60%) report specific subjective cognitive decline (SCD); however, previous research is inconsistent in terms of what types of complaints predict future cognitive decline. The purpose of this study is to identify which specific complaints from the Everyday Cognition Scales (ECog) scales, a measure of self-reported concerns for everyday abilities across six cognitive domains, are associated with: 1) conversion from a clinical diagnosis of normal to either MCI or dementia (categorical variable) and 2) progressive cognitive decline in memory and executive function (continuous variables). 415 cognitively normal older adults were monitored annually for an average of 5 years. Cox proportional hazards models were used to assess associations between self-reported ECog items and progression to impairment (MCI or dementia). A total of 114 individuals progressed to impairment; the mean time to progression was 4.9 years (SD=3.4 years, range=0.8-13.8). Follow-up models were run controlling for depression. A subset of individuals (n=352) underwent repeat cognitive assessments for an average of 5.3 years. For those individuals, mixed effects models with random intercepts and slopes were used to assess associations between ECog items and change in neuropsychological measures of episodic memory or executive function. Prior to controlling for depression, subjective concerns on five of the eight Everyday Memory items, three of the nine Everyday Language items, one of the seven Everyday Visuospatial items, two of the five Everyday Planning items, and one of the six Everyday Organization items were associated with subsequent diagnostic conversion (HR=1.25 to 1.59, p=0.003 to 0.03). However, after controlling for depression, only two specific complaints of remembering appointments, meetings, and engagements and understanding spoken directions and instructions were associated with subsequent diagnostic conversion. Episodic memory in individuals reporting no concern on ECog items did not significantly change over time (p>0.4). More complaints on seven of the eight Everyday Memory items, three of the nine Everyday Language items, and three of the seven Everyday Visuospatial items were associated with a decline in episodic memory (Interaction estimate=-0.055 to 0.001, p=0.003 to 0.04). Executive function in those reporting no concern on ECog items declined slightly (p <0.001 to 0.06). More complaints on three of the eight Everyday Memory items and three of the nine Everyday Language items were associated with a decline in executive function (Interaction estimate=-0.021 to -0.012, p=0.002 to 0.04). These findings suggest that specific complaints across several cognitive domains are associated with diagnostic conversion. Specific complaints in the domains of Everyday Memory and Language are associated with a decline in both episodic memory and executive function. Increased monitoring and treatment of individuals with these specific SCD may be warranted.

Keywords: alzheimer’s disease, dementia, memory complaints, mild cognitive impairment, risk factors, subjective cognitive decline

Procedia PDF Downloads 49
1577 Voting Behavior in an Era of Turbulent Race Relations: Revisiting Church Attendance and Turnout

Authors: JoVontae Butts

Abstract:

A central and enduring theme in the study of American politics is political participation, which indicates the health of a democracy, citizen buy-in, and fair political representation. Though voting push factors have been thoroughly researched and are becoming better understood, the effect of those same push factors often varies for marginalized people. Black voters begun to cast votes at a steadily increasing rate following the 1996 election, gradually growing to its highest level in the 2012 presidential election, even surpassing white voter participation rates. The thirty-year growth period of Black voter engagement concluded in the 2016 election, with the number of participating Black voters stumbling by approximately 7% while other demographics remained roughly the same. Theories for the shift in Black voter behavior range from vote suppression to discouragement due to Barack Obama’s concluding tenure in office. Furthermore, Black voter engagement rebounded in the 2020 election, leaving turnout and race scholars to speculate even further, predicting that disapproval of Trump energized the Black voter bloc. Though there is much conjecture regarding the changes in Black voter behavior, there is truly little empirical evidence to vet those suppositions. This study engages and quantifies speculations for the changes in Black voter engagement in recent elections using 2016 and 2020 American National Election Studies Pilot Study data. Additionally, this study expands upon McGregor’s theory of political hypervigilance by exploring differences in political engagement for church-attending Black voters and those that do not.

Keywords: race, religion, evangelicalism, political engagement

Procedia PDF Downloads 54
1576 Effect of Particle Aspect Ratio and Shape Factor on Air Flow inside Pulmonary Region

Authors: Pratibha, Jyoti Kori

Abstract:

Particles in industry, harvesting, coal mines, etc. may not necessarily be spherical in shape. In general, it is difficult to find perfectly spherical particle. The prediction of movement and deposition of non spherical particle in distinct airway generation is much more difficult as compared to spherical particles. Moreover, there is extensive inflexibility in deposition between ducts of a particular generation and inside every alveolar duct since particle concentrations can be much bigger than the mean acinar concentration. Consequently, a large number of particles fail to be exhaled during expiration. This study presents a mathematical model for the movement and deposition of those non-spherical particles by using particle aspect ratio and shape factor. We analyse the pulsatile behavior underneath sinusoidal wall oscillation due to periodic breathing condition through a non-Darcian porous medium or inside pulmonary region. Since the fluid is viscous and Newtonian, the generalized Navier-Stokes equation in two-dimensional coordinate system (r, z) is used with boundary-layer theory. Results are obtained for various values of Reynolds number, Womersley number, Forchsheimer number, particle aspect ratio and shape factor. Numerical computation is done by using finite difference scheme for very fine mesh in MATLAB. It is found that the overall air velocity is significantly increased by changes in aerodynamic diameter, aspect ratio, alveoli size, Reynolds number and the pulse rate; while velocity is decreased by increasing Forchheimer number.

Keywords: deposition, interstitial lung diseases, non-Darcian medium, numerical simulation, shape factor

Procedia PDF Downloads 147
1575 The Impact of Artificial Intelligence on Digital Construction

Authors: Omil Nady Mahrous Maximous

Abstract:

The construction industry is currently experiencing a shift towards digitisation. This transformation is driven by adopting technologies like Building Information Modelling (BIM), drones, and augmented reality (AR). These advancements are revolutionizing the process of designing, constructing, and operating projects. BIM, for instance, is a new way of communicating and exploiting technology such as software and machinery. It enables the creation of a replica or virtual model of buildings or infrastructure projects. It facilitates simulating construction procedures, identifying issues beforehand, and optimizing designs accordingly. Drones are another tool in this revolution, as they can be utilized for site surveys, inspections, and even deliveries. Moreover, AR technology provides real-time information to workers involved in the project. Implementing these technologies in the construction industry has brought about improvements in efficiency, safety measures, and sustainable practices. BIM helps minimize rework and waste materials, while drones contribute to safety by reducing workers' exposure to areas. Additionally, AR plays a role in worker safety by delivering instructions and guidance during operations. Although the digital transformation within the construction industry is still in its early stages, it holds the potential to reshape project delivery methods entirely. By embracing these technologies, construction companies can boost their profitability while simultaneously reducing their environmental impact and ensuring safer practices.

Keywords: architectural education, construction industry, digital learning environments, immersive learning BIM, digital construction, construction technologies, digital transformation artificial intelligence, collaboration, digital architecture, digital design theory, material selection, space construction

Procedia PDF Downloads 8
1574 Writing Hybridized Narratives to Enact Scientific Literacy and the Myth of the Scientific Method

Authors: Ajaz Shaheen, Jawaid Ahmed Siddqui

Abstract:

This world has purely become scientific and technological, and therefore it demands more from our young learners to be more intellectual in learning sciences. A point of concern that is dragging the attention of educationists is that young learners are gradually detaching from science and scientific theory. To deal with this matter, we must arrange such engaging activities that may improve the imaginative skills of our young learners. Our ongoing research program highlights the effects of such activities that demand the learners to interpret scientific information in the form of text they possess. These mixed stories are also known as what we call BioStories. Learners upload their narratives on different websites to let their peers go through their manuscripts. That, as a result, brings more refinement to their works. Moreover, stories allow the learners to read, understand and learn on a broader spectrum. We have conducted separate studies with learners from Grades 6, 9, and 12 that involve case studies and quasi-experimental designs. The conclusion we drew from the analysis of Grade 6 learners was that the alignment of stories helped them become more familiar with the scientific issue. Not only this but also the learners of the respective grade built up their interest in the subject and also developed a clear understanding of related subject topics. On the other hand, results from the 8th and 9th grades study support the argument that learners reflected a positive attitude toward writing scientific information. Lastly, we concluded from the 12th-grade learners that they took pride in their writing skills and built up their strength, determination, and interest. The students became self-conscious as they wrote hybridized scientific narratives in science.

Keywords: BioStories, hybridized writing, scientific literacy, scientific method

Procedia PDF Downloads 47
1573 Modeling Search-And-Rescue Operations by Autonomous Mobile Robots at Sea

Authors: B. Kriheli, E. Levner, T. C. E. Cheng, C. T. Ng

Abstract:

During the last decades, research interest in planning, scheduling, and control of emergency response operations, especially people rescue and evacuation from the dangerous zone of marine accidents, has increased dramatically. Until the survivors (called ‘targets’) are found and saved, it may cause loss or damage whose extent depends on the location of the targets and the search duration. The problem is to efficiently search for and detect/rescue the targets as soon as possible with the help of intelligent mobile robots so as to maximize the number of saved people and/or minimize the search cost under restrictions on the amount of saved people within the allowable response time. We consider a special situation when the autonomous mobile robots (AMR), e.g., unmanned aerial vehicles and remote-controlled robo-ships have no operator on board as they are guided and completely controlled by on-board sensors and computer programs. We construct a mathematical model for the search process in an uncertain environment and provide a new fast algorithm for scheduling the activities of the autonomous robots during the search-and rescue missions after an accident at sea. We presume that in the unknown environments, the AMR’s search-and-rescue activity is subject to two types of error: (i) a 'false-negative' detection error where a target object is not discovered (‘overlooked') by the AMR’s sensors in spite that the AMR is in a close neighborhood of the latter and (ii) a 'false-positive' detection error, also known as ‘a false alarm’, in which a clean place or area is wrongly classified by the AMR’s sensors as a correct target. As the general resource-constrained discrete search problem is NP-hard, we restrict our study to finding local-optimal strategies. A specificity of the considered operational research problem in comparison with the traditional Kadane-De Groot-Stone search models is that in our model the probability of the successful search outcome depends not only on cost/time/probability parameters assigned to each individual location but, as well, on parameters characterizing the entire history of (unsuccessful) search before selecting any next location. We provide a fast approximation algorithm for finding the AMR route adopting a greedy search strategy in which, in each step, the on-board computer computes a current search effectiveness value for each location in the zone and sequentially searches for a location with the highest search effectiveness value. Extensive experiments with random and real-life data provide strong evidence in favor of the suggested operations research model and corresponding algorithm.

Keywords: disaster management, intelligent robots, scheduling algorithm, search-and-rescue at sea

Procedia PDF Downloads 144
1572 Bi-Criteria Vehicle Routing Problem for Possibility Environment

Authors: Bezhan Ghvaberidze

Abstract:

A multiple criteria optimization approach for the solution of the Fuzzy Vehicle Routing Problem (FVRP) is proposed. For the possibility environment the levels of movements between customers are calculated by the constructed simulation interactive algorithm. The first criterion of the bi-criteria optimization problem - minimization of the expectation of total fuzzy travel time on closed routes is constructed for the FVRP. A new, second criterion – maximization of feasibility of movement on the closed routes is constructed by the Choquet finite averaging operator. The FVRP is reduced to the bi-criteria partitioning problem for the so called “promising” routes which were selected from the all admissible closed routes. The convenient selection of the “promising” routes allows us to solve the reduced problem in the real-time computing. For the numerical solution of the bi-criteria partitioning problem the -constraint approach is used. An exact algorithm is implemented based on D. Knuth’s Dancing Links technique and the algorithm DLX. The Main objective was to present the new approach for FVRP, when there are some difficulties while moving on the roads. This approach is called FVRP for extreme conditions (FVRP-EC) on the roads. Also, the aim of this paper was to construct the solving model of the constructed FVRP. Results are illustrated on the numerical example where all Pareto-optimal solutions are found. Also, an approach for more complex model FVRP with time windows was developed. A numerical example is presented in which optimal routes are constructed for extreme conditions on the roads.

Keywords: combinatorial optimization, Fuzzy Vehicle routing problem, multiple objective programming, possibility theory

Procedia PDF Downloads 446
1571 Bread-Making Properties of Rice Flour Dough Using Fatty Acid Salt

Authors: T. Hamaishi, Y. Morinaga, H. Morita

Abstract:

Introduction: Rice consumption in Japan has decreased, and Japanese government has recommended use of rice flour in order to expand the consumption of rice. There are two major protein components present in flour, called gliadin and glutenin. Gluten forms when water is added to flour and is mixed. As mixing continues, glutenin interacts with gliadin to form viscoelastic matrix of gluten. Rice flour bread does not expand as much as wheat flour bread. Because rice flour is not included gluten, it cannot construct gluten network in the dough. In recent years, some food additives have been used for dough-improving agent in bread making, especially surfactants has effect in order to improve dough extensibility. Therefore, we focused to fatty acid salt which is one of anionic surfactants. Fatty acid salt is a salt consist of fatty acid and alkali, it is main components of soap. According to JECFA(FAO/WHO Joint Expert Committee on Food Additives), salts of Myristic(C14), Palmitic(C16) and Stearic(C18) could be used as food additive. They have been evaluated ADI was not specified. In this study, we investigated to improving bread-making properties of rice flour dough adding fatty acid salt. Materials and methods: The sample of fatty acid salt is myristic (C14) dissolved in KOH solution to a concentration of 350 mM and pH 10.5. Rice dough was consisted of 100 g of flour using rice flour and wheat gluten, 5 g of sugar, 1.7 g of salt, 1.7g of dry yeast, 80 mL of water and fatty acid salt. Mixing was performed for 500 times by using hand. The concentration of C14K in the dough was 10 % relative to flour weight. Amount of gluten in the dough was 20 %, 30 % relative to flour weight. Dough expansion ability test was performed to measure physical property of bread dough according to the methods of Baker’s Yeast by Japan Yeast Industry Association. In this test, 150 g of dough was filled from bottom of the cylinder and fermented at 30 °C,85 % humidity for 120 min on an incubator. The height of the expansion in the dough was measured and determined its expansion ability. Results and Conclusion: Expansion ability of rice dough with gluten content of 20 %, 30% showed 316 mL, 341 mL for 120 min. When C14K adding to the rice dough, dough expansion abilities were 314 mL, 368 mL for 120 min, there was no significant difference. Conventionally it has been known that the rice flour dough contain gluten of 20 %. The considerable improvement of dough expansion ability was achieved when added C14K to wheat flour. The experimental result shows that c14k adding to the rice dough with gluten content more than 20 % was not improving bread-making properties. In conclusion, rice bread made with gluten content more than 20 % without C14K has been suggested to contribute to the formation of the sufficient gluten network.

Keywords: expansion ability, fatty acid salt, gluten, rice flour dough

Procedia PDF Downloads 222
1570 Cross-Sectional Analysis of the Health Product E-Commerce Market in Singapore

Authors: Andrew Green, Jiaming Liu, Kellathur Srinivasan, Raymond Chua

Abstract:

Introduction: The size of Singapore’s online health product (HP) market (e-commerce) is largely unknown. However, it is recognized that a large majority comes from overseas and thus, unregulated. As buying HP from unauthorized sources significantly compromises public health safety, understanding e-commerce users’ demographics and their perceptions on online HP purchasing becomes a pivotal first step to form a basis for recommendations in Singapore’s pharmacovigilance efforts. Objective: To assess the prevalence of online HP purchasing behaviour among Singaporean e-commerce users. Methodology: This is a cross-sectional study targeting Singaporean e-commerce users recruited from various local websites and online forums. Participants were not randomized into study arms but instead stratified by random sampling method based on participants’ age. A self-administered anonymous questionnaire was used to explore participants' demographics, online HP purchasing behaviour, knowledge and attitude. The association of different variables with online HP purchasing behaviour was analysed using logistic regression statistics. Main outcome measures: Prevalence of HP e-commerce users in Singapore (%) and variables that contribute to the prevalence (adjusted prevalent ratio). Results: The study recruited 372 complete and valid responses. The prevalence of online HP consumers among e-commerce users in Singapore is estimated to be 55.9% (1.7 million consumers). Online purchasing of complementary HP (46.9%) was the most prevalent, followed by medical devices (21.6%) and Western medicine (20.5%). Multivariate analysis showed that age is an independent variable that correlates with the likelihood of buying HP online. The prevalence of HP e-commerce users is highest in the 35-44 age group (64.1%) and lowest among the 16-24 age group (36.4%). The most bought HP through the internet are vitamins and minerals (21.5%), non-herbal (15.9%), herbal (13.9%), weight loss (8.7%) and sports (8.4%) supplements. While the top 3 products are distributed equally between the genders, there is a skew towards female respondents (12.4% in females vs. 4.9% in males) for weight loss supplements and towards males (13.2% in males vs. 3.7% in females) for sports supplements. Even though online consumers are in the younger age brackets, our study found that up to 72.0% of HP bought online are bought for others (buyer’s family and/or friends). Multivariate analysis showed a statistically significant association between purchasing HP through online means and the perceptions that 'internet is safe' (adjusted Prevalence Ratio=1.15, CI 1.03-1.28), 'buying HP online is time saving' (PR=1.17, CI 1.01-1.36), and 'recognition of HP brand' (PR=1.21 CI 1.06-1.40). Conclusions: This study has provided prevalence data for online HP market in Singapore, and has allowed the country’s regulatory body to formulate a targeted pharmacovigilance approach to this growing problem.

Keywords: e-commerce, pharmaceuticals, pharmacovigilance, Singapore

Procedia PDF Downloads 331
1569 Theoretical Modeling of Self-Healing Polymers Crosslinked by Dynamic Bonds

Authors: Qiming Wang

Abstract:

Dynamic polymer networks (DPNs) crosslinked by dynamic bonds have received intensive attention because of their special crack-healing capability. Diverse DPNs have been synthesized using a number of dynamic bonds, including dynamic covalent bond, hydrogen bond, ionic bond, metal-ligand coordination, hydrophobic interaction, and others. Despite the promising success in the polymer synthesis, the fundamental understanding of their self-healing mechanics is still at the very beginning. Especially, a general analytical model to understand the interfacial self-healing behaviors of DPNs has not been established. Here, we develop polymer-network based analytical theories that can mechanistically model the constitutive behaviors and interfacial self-healing behaviors of DPNs. We consider that the DPN is composed of interpenetrating networks crosslinked by dynamic bonds. bonds obey a force-dependent chemical kinetics. During the self-healing process, we consider the The network chains follow inhomogeneous chain-length distributions and the dynamic polymer chains diffuse across the interface to reform the dynamic bonds, being modeled by a diffusion-reaction theory. The theories can predict the stress-stretch behaviors of original and self-healed DPNs, as well as the healing strength in a function of healing time. We show that the theoretically predicted healing behaviors can consistently match the documented experimental results of DPNs with various dynamic bonds, including dynamic covalent bonds (diarylbibenzofuranone and olefin metathesis), hydrogen bonds, and ionic bonds. We expect our model to be a powerful tool for the self-healing community to invent, design, understand, and optimize self-healing DPNs with various dynamic bonds.

Keywords: self-healing polymers, dynamic covalent bonds, hydrogen bonds, ionic bonds

Procedia PDF Downloads 146
1568 The Factors Constitute the Interaction between Teachers and Students: An Empirical Study at the Notion of Framing

Authors: Tien-Hui Chiang

Abstract:

The code theory, proposed by Basil Bernstein, indicates that framing can be viewed as the core element in constituting the phenomenon of cultural reproduction because it is able to regulate the transmission of pedagogical information. Strong framing increases the social relation boundary between a teacher and pupils, which obstructs information transmission, so that in order to improve underachieving students’ academic performances, teachers need to reduce to strength of framing. Weak framing enables them to transform academic knowledge into commonsense knowledge in daily life language. This study posits that most teachers would deliver strong framing due to their belief mainly confined within the aspect of instrumental rationality that deprives their critical minds. This situation could make them view the normal distribution bell curve of students’ academic performances as a natural outcome. In order to examine the interplay between framing, instrumental rationality and pedagogical action, questionnaires were completed by over 5,000 primary school teachers in Henan province, China, who were stratified sample. The statistical results show that most teachers employed psychological concepts to measure students’ academic performances and, in turn, educational inequity was legitimatized as a natural outcome in the efficiency-led approach. Such efficiency-led minds made them perform as the agent practicing the mechanism of social control and in turn sustaining the phenomenon of cultural reproduction.

Keywords: code, cultural reproduction, framing, instrumental rationality, social relation and interaction

Procedia PDF Downloads 117
1567 Ideology and Lexicogrammar: Discourse Against the Power in Lyrical Texts (XIII, XVII and XX Centuries)

Authors: Ulisses Tadeu Vaz de Oliveira

Abstract:

The development of multifunctional studies in the theoretical-methodological perspective of the Systemic-Functional Grammar (SFG) and the increasing number of critical literary studies have introduced new opportunities for the study of ideologies and societies, but also brought up new challenges across and within many areas. In this regard, the Critical Linguistics researches allow a form of pairing a textual linguistic analysis method (micro level) with a social language theory in political and ideological processes (macro level), presented in the literature. This presentation will report on strategies to criticize power holders in literary productions from three distinct eras, namely: (a) Satirical Galego-Portuguese chants of Gil Pérez Conde (thirteenth century), (b) Poems of Gregorio de Matos Guerra (seventeenth century), and (c) Songs of Chico Buarque de Holanda (twentieth century). The analysis of these productions is based on the SFG proposals, which considers the clause as a social event. Therefore, the structure serves to realize three concurrent meanings (metafunctions): Ideational, Interpersonal and Textual. The presenter aims to shed light on the core issues relevant to the successes of the authors to criticize authorities in repressive times while caring about face-threatening and politeness. The effective and meaningful critical discourse was a way of moving the society`s chains towards new ideologies reflected in the lexicogrammatical choices made and the rhetorical functions of the persuasive structures used by the authors.

Keywords: ideology, literature, persuasion, systemic-functional grammar

Procedia PDF Downloads 384
1566 Evaluating the Extent to Which Higher Education in Creativity Match with Demands of the Industry in Istanbul

Authors: Büşra Güven, Ebru Kerimoğlu

Abstract:

Relevant departments of universities in creative fields are increasingly facing the challenge of developing curriculum for more employable creative workforce. In Turkey, as a developing country, the creative industries have not yet argued in the political axis and higher education also has not been addressed in this context. Istanbul has the highest creative and cultural industries share also provides both rooted and developing higher education institutes for these sectors in Turkey. With this in mind, the main purpose of the paper attempts to clarify that how does higher education in creative fields deal with the demands of creative industries in Istanbul? First, the paper elaborated creative class theory, second creative industries, employability and curriculum triangle is examined. The research methodology consisted of a qualitative model based on interview analysis. Data are collected by interviews with the head of the relevant departments and professional associations authorities in selected sectors. Four higher education institutes in Istanbul are selected according to the some clarified factors related to the literature. This also offered a comparing between public and private universities in terms of the adaptability of this changing concept of work. Industry expectations and content of educations were compared and found the blind spots in the education-industry relationships. As a consequence, produced inclusive policies for universities and industries to overcome these spots with collaboration, flexibility, adaptability, openness and feedback management and also for future policies in particular outcomes of university-industry collaborations.

Keywords: creative industries, curriculum, employability, high education, Istanbul

Procedia PDF Downloads 200
1565 Structural Invertibility and Optimal Sensor Node Placement for Error and Input Reconstruction in Dynamic Systems

Authors: Maik Kschischo, Dominik Kahl, Philipp Wendland, Andreas Weber

Abstract:

Understanding and modelling of real-world complex dynamic systems in biology, engineering and other fields is often made difficult by incomplete knowledge about the interactions between systems states and by unknown disturbances to the system. In fact, most real-world dynamic networks are open systems receiving unknown inputs from their environment. To understand a system and to estimate the state dynamics, these inputs need to be reconstructed from output measurements. Reconstructing the input of a dynamic system from its measured outputs is an ill-posed problem if only a limited number of states is directly measurable. A first requirement for solving this problem is the invertibility of the input-output map. In our work, we exploit the fact that invertibility of a dynamic system is a structural property, which depends only on the network topology. Therefore, it is possible to check for invertibility using a structural invertibility algorithm which counts the number of node disjoint paths linking inputs and outputs. The algorithm is efficient enough, even for large networks up to a million nodes. To understand structural features influencing the invertibility of a complex dynamic network, we analyze synthetic and real networks using the structural invertibility algorithm. We find that invertibility largely depends on the degree distribution and that dense random networks are easier to invert than sparse inhomogeneous networks. We show that real networks are often very difficult to invert unless the sensor nodes are carefully chosen. To overcome this problem, we present a sensor node placement algorithm to achieve invertibility with a minimum set of measured states. This greedy algorithm is very fast and also guaranteed to find an optimal sensor node-set if it exists. Our results provide a practical approach to experimental design for open, dynamic systems. Since invertibility is a necessary condition for unknown input observers and data assimilation filters to work, it can be used as a preprocessing step to check, whether these input reconstruction algorithms can be successful. If not, we can suggest additional measurements providing sufficient information for input reconstruction. Invertibility is also important for systems design and model building. Dynamic models are always incomplete, and synthetic systems act in an environment, where they receive inputs or even attack signals from their exterior. Being able to monitor these inputs is an important design requirement, which can be achieved by our algorithms for invertibility analysis and sensor node placement.

Keywords: data-driven dynamic systems, inversion of dynamic systems, observability, experimental design, sensor node placement

Procedia PDF Downloads 121
1564 Relay-Augmented Bottleneck Throughput Maximization for Correlated Data Routing: A Game Theoretic Perspective

Authors: Isra Elfatih Salih Edrees, Mehmet Serdar Ufuk Türeli

Abstract:

In this paper, an energy-aware method is presented, integrating energy-efficient relay-augmented techniques for correlated data routing with the goal of optimizing bottleneck throughput in wireless sensor networks. The system tackles the dual challenge of throughput optimization while considering sensor network energy consumption. A unique routing metric has been developed to enable throughput maximization while minimizing energy consumption by utilizing data correlation patterns. The paper introduces a game theoretic framework to address the NP-complete optimization problem inherent in throughput-maximizing correlation-aware routing with energy limitations. By creating an algorithm that blends energy-aware route selection strategies with the best reaction dynamics, this framework provides a local solution. The suggested technique considerably raises the bottleneck throughput for each source in the network while reducing energy consumption by choosing the best routes that strike a compromise between throughput enhancement and energy efficiency. Extensive numerical analyses verify the efficiency of the method. The outcomes demonstrate the significant decrease in energy consumption attained by the energy-efficient relay-augmented bottleneck throughput maximization technique, in addition to confirming the anticipated throughput benefits.

Keywords: correlated data aggregation, energy efficiency, game theory, relay-augmented routing, throughput maximization, wireless sensor networks

Procedia PDF Downloads 31
1563 Photoluminescence and Spectroscopic Studies of Tm3+ Ions Doped Lead Tungsten Tellurite Glasses for Visible Red and Near-Ir Laser Applications

Authors: M. Venkateswarlu, Srinivasa Rao Allam, S. K. Mahamuda, K. Swapna, G. Vijaya Prakash

Abstract:

Lead Tungsten Tellurite (LTT) glasses doped with different concentrations of Tm3+ ions were prepared by using melt quenching technique and characterized through optical absorption, photoluminescence and decay spectral studies to know the feasibility of using these glasses as luminescent devices in visible Red and NIR regions. By using optical absorption spectral data, the energy band gaps for all the glasses were evaluated and were found to be in the range of 2.34-2.59 eV; which is very useful for the construction of optical devices. Judd-Ofelt (J-O)theory has been applied to the optical absorption spectral profiles to calculate the J-O intensity parameters Ωλ (λ=2, 4 and 6) and consecutively used to evaluate various radiative properties such as radiative transition probability (AR), radiative lifetimes (τ_R) and branching ratios (β_R) for the prominent luminescent levels. The luminescence spectra for all the LTT glass samples have shown two intense peaks in bright red and Near Infrared regions at 650 nm (1G4→3F4) and 800 nm (3H4→3H6) respectively for which effective bandwidths (〖Δλ〗_P), experimental branching ratios (β_exp) and stimulated emission cross-sections (σ_se) are evaluated. The decay profiles for all the glasses were also recorded to measure the quantum efficiency of the prepared LTT glasses by coupling the radiative and experimental lifetimes. From the measured emission cross-sections, quantum efficiency and CIE chromaticity coordinates, it was found that 0.5 mol% of Tm3+ ions doped LTT glass is most suitable for generating bright visible red and NIR lasers to operate at 650 and 800 nm respectively.

Keywords: glasses, JO parameters, optical materials, thullium

Procedia PDF Downloads 215
1562 Design of a Virtual Reality System for Children with Developmental Coordination Disorder

Authors: Ya-Ju Ju, Li-Chen Yang, Yi-Chun Du, Rong-Ju Cherng

Abstract:

Introduction: It is estimated that 5-6% of school-aged children may be diagnosed to have developmental coordination disorder (DCD). Children with DCD are characterized with motor skill difficulty which cannot be explained by any medical or intellectual reasons. Such motor difficulties limit children’s participation to sports activity, further affect their physical fitness, cardiopulmonary function and balance, and may lead to obesity. The purpose of the project was to develop an exergaming system for children with DCD aiming to improve their physical fitness, cardiopulmonary function and balance ability. Methods: This study took five steps to build up the system: system planning, tasks selection, tasks programming, system integration and usability test. The system basically adopted virtual reality technique to integrate self-developed training programs. The training programs were developed to brainstorm among team members and after literature review. The selected tasks for training in the system were a combination of fundamental movement tor skill. Results and Discussion: Based on the theory of motor development, we design the training task from easy ones to hard ones, from single tasks to dual tasks. The tasks included walking, sit to stand, jumping, kicking, weight shifting, side jumping and their combination. Preliminary study showed that the tasks presented an order of development. Further study is needed to examine its effect on motor skill and cardiovascular fitness in children with DCD.

Keywords: virtual reality, virtual reality system, developmental coordination disorder, children

Procedia PDF Downloads 84
1561 Design of Digital IIR Filter Using Opposition Learning and Artificial Bee Colony Algorithm

Authors: J. S. Dhillon, K. K. Dhaliwal

Abstract:

In almost all the digital filtering applications the digital infinite impulse response (IIR) filters are preferred over finite impulse response (FIR) filters because they provide much better performance, less computational cost and have smaller memory requirements for similar magnitude specifications. However, the digital IIR filters are generally multimodal with respect to the filter coefficients and therefore, reliable methods that can provide global optimal solutions are required. The artificial bee colony (ABC) algorithm is one such recently introduced meta-heuristic optimization algorithm. But in some cases it shows insufficiency while searching the solution space resulting in a weak exchange of information and hence is not able to return better solutions. To overcome this deficiency, the opposition based learning strategy is incorporated in ABC and hence a modified version called oppositional artificial bee colony (OABC) algorithm is proposed in this paper. Duplication of members is avoided during the run which also augments the exploration ability. The developed algorithm is then applied for the design of optimal and stable digital IIR filter structure where design of low-pass (LP) and high-pass (HP) filters is carried out. Fuzzy theory is applied to achieve maximize satisfaction of minimum magnitude error and stability constraints. To check the effectiveness of OABC, the results are compared with some well established filter design techniques and it is observed that in most cases OABC returns better or atleast comparable results.

Keywords: digital infinite impulse response filter, artificial bee colony optimization, opposition based learning, digital filter design, multi-parameter optimization

Procedia PDF Downloads 443
1560 CSR Reporting, State Ownership, and Corporate Performance in China: Proof from Longitudinal Data of Publicly Traded Enterprises from 2006 to 2020

Authors: Wanda Luen-Wun Siu, Xiaowen Zhang

Abstract:

This paper offered the primary methodical proof on how CSR reporting related to enterprise earnings in listed firms in China in light of most evidence focusing on cross-sectional data or data in a short span of time. Using full economic and business panel data on China’s publicly listed enterprise from 2006 to 2020 over two decades in the China Stock Market and Accounting Research database, we found initial evidence of significant direct relations between CSR reporting and firm corporate performance in both state-owned and privately owned firms over this period, supporting the stakeholder theory. Results also revealed that state-owned enterprises performed as well as private enterprises in the current period. But private enterprises performed better than state-owned enterprises in the subsequent years. Moreover, the release of social responsibility reports had a more significant impact on the financial performance of state-owned and private enterprises in the current period than in the subsequent periods. Specifically, CSR release was not significantly associated with the financial performance of state-owned enterprises on the lag of the first, second, and third periods. But it had an impact on the lag of the first, second, and third periods among private enterprises. Such findings suggested that CSR reporting helped improve the corporate financial performance of state-owned and private enterprises in the current period, but this kind of effect was more significant among private enterprises in the lag periods.

Keywords: China’s listed firms, CSR reporting, financial performance, panel analysis

Procedia PDF Downloads 138
1559 Public Participation in Science: The Case of Genetic Modified Organisms in Brazil

Authors: Maria Luisa Nozawa Ribeiro, Maria Teresa Miceli Kerbauy

Abstract:

This paper aims to present the theories of public participation in order to understand the context of the public GMO (Genetic Modified Organisms) policies in Brazil, highlighting the characteristics of its configuration and the dialog with the experts. As a controversy subject, the commercialization of GMO provoked manifestation of some popular and environmental representative groups questioning the decisions of policy makers and experts on the matter. Many aspects and consequences of the plantation and consumption of this crops emerged and the safety of this technology was questioned. Environmentalists, Civil Right's movement, representatives of rural workers, farmers and organics producers, etc. demonstrated their point of view, also sustained by some experts of medical, genetical, environmental, agronomical sciences, etc. fields. Despite this movement, the precautionary principle (risk management), implemented in 1987, suggested precaution facing new technologies and innovations in the sustainable development society. This principle influenced many legislation and regulation on GMO around the world, including Brazil, which became a reference among the world regulatory GMO systems. The Brazilian legislation ensures the citizens participation on GMO discussion, characteristic that was important to establish the connection between the subject and the participation theory. These deliberation spaces materialized in Brazil through the "Public Audiences", which are managed by the National Biosafety Technical Commission (CTNBio), the department responsible for controlling the research, production and commercialization of GMOs in Brazil.

Keywords: public engagement, public participation, science and technology studies, transgenic politics

Procedia PDF Downloads 272
1558 Conceptual Solution and Thermal Analysis of the Final Cooling Process of Biscuits in One Confectionary Factory in Serbia

Authors: Duško Salemović, Aleksandar Dedić, Matilda Lazić, Dragan Halas

Abstract:

The paper presents the conceptual solution for the final cooling of the chocolate dressing of biscuits in one confectionary factory in Serbia. The proposed concept solution was derived from the desired technological process of final cooling of biscuits and the required process parameters that were to be achieved, and which were an integral part of the project task. The desired process parameters for achieving proper hardening and coating formation are the exchanged amount of heat in the time unit between the two media (air and chocolate dressing), the speed of air inside the tunnel cooler, and the surface of all biscuits in contact with the air. These parameters were calculated in the paper. The final cooling of chocolate dressing on biscuits could be optimized by changing process parameters and dimensions of the tunnel cooler and looking for the appropriate values for them. The accurate temperature predictions and fluid flow analysis could be conducted by using heat balance and flow balance equations, having in mind the theory of similarity. Furthermore, some parameters were adopted from previous technology processes, such as the inlet temperature of biscuits and input air temperature. A thermal calculation was carried out, and it was demonstrated that the percentage error between the contact surface of the air and the chocolate biscuit topping, which is obtained from the heat balance and geometrically through the proposed conceptual solution, does not exceed 0.67%, which is a very good agreement. This enabled the quality of the cooling process of chocolate dressing applied on the biscuit and the hardness of its coating.

Keywords: chocolate dressing, air, cooling, heat balance

Procedia PDF Downloads 41
1557 Analytical and Numerical Results for Free Vibration of Laminated Composites Plates

Authors: Mohamed Amine Ben Henni, Taher Hassaine Daouadji, Boussad Abbes, Yu Ming Li, Fazilay Abbes

Abstract:

The reinforcement and repair of concrete structures by bonding composite materials have become relatively common operations. Different types of composite materials can be used: carbon fiber reinforced polymer (CFRP), glass fiber reinforced polymer (GFRP) as well as functionally graded material (FGM). The development of analytical and numerical models describing the mechanical behavior of structures in civil engineering reinforced by composite materials is necessary. These models will enable engineers to select, design, and size adequate reinforcements for the various types of damaged structures. This study focuses on the free vibration behavior of orthotropic laminated composite plates using a refined shear deformation theory. In these models, the distribution of transverse shear stresses is considered as parabolic satisfying the zero-shear stress condition on the top and bottom surfaces of the plates without using shear correction factors. In this analysis, the equation of motion for simply supported thick laminated rectangular plates is obtained by using the Hamilton’s principle. The accuracy of the developed model is demonstrated by comparing our results with solutions derived from other higher order models and with data found in the literature. Besides, a finite-element analysis is used to calculate the natural frequencies of laminated composite plates and is compared with those obtained by the analytical approach.

Keywords: composites materials, laminated composite plate, finite-element analysis, free vibration

Procedia PDF Downloads 266
1556 The Impact of Online Advertising on Generation Y’s Purchase Decision in Malaysia

Authors: Mui Joo Tang, Eang Teng Chan

Abstract:

Advertising is commonly used to foster sales and reputation of an institution. It is at first the growth of print advertising that has increased the population and number of periodicals of newspaper and its circulation. The rise of Internet and online media has somehow blurred the role of media and advertising though the intention is still to reach out to audience and to increase sales. The relationship between advertising and audience on a product purchase through persuasion has been developing from print media to online media. From the changing media environment and audience, it is the concern of this research to study the impact of online advertising to such a relationship cycle. The content of online advertisements is much of text, multimedia, photo, audio and video. The messages of such content format may indeed bring impacts to its audience and its credibility. This study is therefore reflecting the effectiveness of online advertisement and its influences on generation Y in their purchasing behavior. This study uses Media Dependency Theory to analyze the relationship between the impact of online advertisement and media usage pattern of generation Y. Hierarchy of Effectiveness Model is used as a marketing communication model to study the effectiveness of advertising and further to determine the impact of online advertisement on generation Y in their purchasing decision making. This research uses online survey to reach out the sample of generation Y. The results have shown that online advertisements do not affect much on purchase decision making even though generation Y relies much on the media content including online advertisement for its information and believing in its credibility. There are few other external factors that may interrupt the effectiveness of online advertising. The very obvious influence of purchasing behavior is actually derived from the peers.

Keywords: generation Y, purchase decision, print media, online advertising, persuasion

Procedia PDF Downloads 494
1555 CSR Health Programs: A Supplementary Tool of a Government’s Role in a Developing Nation

Authors: Kristine Demilou Santiago

Abstract:

In a context of a developing nation, how important is the role of Corporate Social Responsibility health programs? Is there a possibility that this will render a large impact in a society where health benefits are insufficient? The Philippine government has been in an unceasing battle to provide its citizens competitive health benefits through launching various health programs. As the efforts are being claimed by the government, the numbers just show that all the health benefits being offered such as PhilHealth health cards, medical missions and other subsidized government health benefits are not effective and sufficient at the minimum level. This is a major characteristic of a developing nation which the Philippine government is focusing on addressing as it becomes a national concern under the effects of poverty. Industrial companies, through Corporate Social Responsibility, are playing an important role in the aspiration to resolve this problem on health programs as supposed to be basic services to citizens of the Philippine government. The rise of commitment by these industrial companies to render health programs to communities as part of their corporate citizenship has covered a large portion of the basic health services that the Filipino citizens are supposed to be receiving. This is the most salient subject that a developing nation should focus on determining the important contribution of industrial companies present in their country as part of the citizens’ access to basic health services. The use of survey forms containing quantitative and qualitative questions which aim to give numerical figures and support answers as to the role of CSR Health programs in helping the communities receive the basic health services they need was the methodological procedure followed in this research. A sample population in a community where the largest industrial company in a province of the Philippines was taken through simple random sampling. The assumption is that this sample population which represents the whole of the community has the highest opportunities to access both the government health services and the CSR health program services of the industrial company located in their community. Results of the research have shown a significant level of participation by industrial companies through their CSR health programs in the attainment of basic health services that should be rendered by the Philippine government to its citizens as part of the state’s health benefits. In a context of a developing nation such as the Philippines, the role of Corporate Social Responsibility is beyond the expectation of initiating to resolve environmental and social issues. It is moving deeper in the concept of the corporate industries being a pillar of the government in catering the support needed by the individuals in the community for its development. As such, the concept of the presence of an industrial company in a community is said to be a parallel progress: by which when an industrial company expands because it is becoming more profitable, so is the community gaining the same step of progress in terms of socioeconomic development.

Keywords: basic health services, CSR health program, health services in a developing nation, Philippines health benefits

Procedia PDF Downloads 168
1554 Investigation of Physical-Mechanical Characteristics of Granulated Artificial Aggregates Synthesized from Wood Ash Using Green Technology

Authors: Vitoldas Vidikas, Algirdas Augonis

Abstract:

Different ecological binders have been used to minimize the negative effects of cement production and use on the environment. Wood ash is one of these alternative binders, and there has been increasing research related to this topic recently. The incineration process in power plants produces numerous amounts of residues, the potential applications of which remain incompletely understood. However, it is established that wood ash improves concrete properties, serves as a fertilizer, and substitutes natural aggregates in artificial aggregate production. This study presents the production and properties of wood ash artificial aggregate, their integration into concrete, and the assessment of their strength. Due to the aforementioned large amount of incineration waste accumulating in landfills, the recovery of this waste is important, and reuse and recycling of this waste is necessary. Artificial aggregates stand out as a significant innovation in this effort. In this study, the artificial aggregate was carbonized using wood waste incineration ash and alkali activators, with the alkaline activator consisting of Ca(OH)2. Various mixtures were formulated, incorporating different materials and compositions of activators. Initially, fillers were created using wood ash, followed by formulations subsequently supplemented with wood ash. A series of tests, including XRD, SEM, and compression tests, were conducted. The artificial aggregate exhibits minimal water absorption and holds potential as a substitute for natural materials. Its prospective applications extend to agriculture, where it could function as a fertilizer, and construction, where it could serve as an artificial aggregate. Concrete incorporating the artificial aggregate demonstrates stability, stiffness, and relatively low density. In our research, a test was developed and applied to determine the compressive strength of a manufactured artificial aggregate, not by direct loading, but by subjecting a cementitious test specimen containing the aggregate under test to a load. In this way, the test not only determines the effect of the aggregate on the compressive behavior of such a specimen but also the characteristics of the fracture, which shows how these artificial aggregates adhere to the cement matrix. This testing methodology holds promise for evaluating the suitability of artificial aggregates in construction materials, not only in terms of their load-bearing capacity but also of their adhesion to the mineral binder. The results showed that the mechanical properties of granular artificial aggregates vary significantly with the amount of binder (lime), i.e. an increase of ~15% in the amount of binder resulted in an increase in the crushing strength of the carbonized aggregate by ~15-20%, while the compressive strength of the cementitious specimen with this aggregate increased by ~18%.

Keywords: wood ash, artificial aggregate, carbonization, compressive strength

Procedia PDF Downloads 13