Search results for: critical frequency
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 9281

Search results for: critical frequency

5651 Impedance Matching of Axial Mode Helical Antennas

Authors: Hossein Mardani, Neil Buchanan, Robert Cahill, Vincent Fusco

Abstract:

In this paper, we study the input impedance characteristics of axial mode helical antennas to find an effective way for matching it to 50 Ω. The study is done on the important matching parameters such as like wire diameter and helix to the ground plane gap. It is intended that these parameters control the matching without detrimentally affecting the radiation pattern. Using transmission line theory, a simple broadband technique is proposed, which is applicable for perfect matching of antennas with similar design parameters. We provide design curves to help to choose the proper dimensions of the matching section based on the antenna’s unmatched input impedance. Finally, using the proposed technique, a 4-turn axial mode helix is designed at 2.5 GHz center frequency and the measurement results of the manufactured antenna will be included. This parametric study gives a good insight into the input impedance characteristics of axial mode helical antennas and the proposed impedance matching approach provides a simple, useful method for matching these types of antennas.

Keywords: antenna, helix, helical, axial mode, wireless power transfer, impedance matching

Procedia PDF Downloads 318
5650 Construction of a Supply Chain Model Using the PREVA Method: The Case of Innovative Sargasso Recovery Projects in Ther Lesser Antilles

Authors: Maurice Bilioniere, Katie Lanneau

Abstract:

Suddenly appeared in 2011, invasions of sargasso seaweeds Fluitans and Natans are a climatic hazard which causes many problems in the Caribbean. Faced with the growth and frequency of the phenomenon of massive sargasso stranding on their coasts, the French West Indies are moving towards the path of industrial recovery. In this context of innovative projects, we will analyze the necessary requirements for the management and performance of the supply chain, taking into account the observed volatility of the sargasso input. Our prospective approach will consist in studying the theoretical framework of modeling a hybrid supply chain by coupling the discreet event simulation (DES) with a valuation of the process costs according to the "activity-based costing" method (ABC). The PREVA approach (PRocess EVAluation) chosen for our modeling has the advantage of evaluating the financial flows of the logistic process using an analytical model chained with an action model for the evaluation or optimization of physical flows.

Keywords: sargasso, PREVA modeling, supply chain, ABC method, discreet event simulation (DES)

Procedia PDF Downloads 179
5649 Status of Vocational Education and Training in India: Policies and Practices

Authors: Vineeta Sirohi

Abstract:

The development of critical skills and competencies becomes imperative for young people to cope with the unpredicted challenges of the time and prepare for work and life. Recognizing that education has a critical role in reaching sustainability goals as emphasized by 2030 agenda for sustainability development, educating youth in global competence, meta-cognitive competencies, and skills from the initial stages of formal education are vital. Further, educating for global competence would help in developing work readiness and boost employability. Vocational education and training in India as envisaged in various policy documents remain marginalized in practice as compared to general education. The country is still far away from the national policy goal of tracking 25% of the secondary students at grade eleven and twelve under the vocational stream. In recent years, the importance of skill development has been recognized in the present context of globalization and change in the demographic structure of the Indian population. As a result, it has become a national policy priority and taken up with renewed focus by the government, which has set the target of skilling 500 million people by 2022. This paper provides an overview of the policies, practices, and current status of vocational education and training in India supported by statistics from the National Sample Survey, the official statistics of India. The national policy documents and annual reports of the organizations actively involved in vocational education and training have also been examined to capture relevant data and information. It has also highlighted major initiatives taken by the government to promote skill development. The data indicates that in the age group 15-59 years, only 2.2 percent reported having received formal vocational training, and 8.6 percent have received non-formal vocational training, whereas 88.3 percent did not receive any vocational training. At present, the coverage of vocational education is abysmal as less than 5 percent of the students are covered by the vocational education programme. Besides, launching various schemes to address the mismatch of skills supply and demand, the government through its National Policy on Skill Development and Entrepreneurship 2015 proposes to bring about inclusivity by bridging the gender, social and sectoral divide, ensuring that the skilling needs of socially disadvantaged and marginalized groups are appropriately addressed. It is fundamental that the curriculum is aligned with the demands of the labor market, incorporating more of the entrepreneur skills. Creating nonfarm employment opportunities for educated youth will be a challenge for the country in the near future. Hence, there is a need to formulate specific skill development programs for this sector and also programs for upgrading their skills to enhance their employability. There is a need to promote female participation in work and in non-traditional courses. Moreover, rigorous research and development of a robust information base for skills are required to inform policy decisions on vocational education and training.

Keywords: policy, skill, training, vocational education

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5648 Discrete Swarm with Passive Congregation for Cost Minimization of the Multiple Vehicle Routing Problem

Authors: Tarek Aboueldahab, Hanan Farag

Abstract:

Cost minimization of Multiple Vehicle Routing Problem becomes a critical issue in the field of transportation because it is NP-hard optimization problem and the search space is complex. Many researches use the hybridization of artificial intelligence (AI) models to solve this problem; however, it can not guarantee to reach the best solution due to the difficulty of searching the whole search space. To overcome this problem, we introduce the hybrid model of Discrete Particle Swarm Optimization (DPSO) with a passive congregation which enable searching the whole search space to compromise between both local and global search. The practical experiment shows that our model obviously outperforms other hybrid models in cost minimization.

Keywords: cost minimization, multi-vehicle routing problem, passive congregation, discrete swarm, passive congregation

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5647 Economic Environment and Entrepreneurial Development in Lagos and Ogun States, Nigeria

Authors: Jayeola Olabisi, T. Olawale Oladunjoye, Ademola A. Adewumi

Abstract:

The study empirically examines the relationship that exists between the economic environment and entrepreneurial development in Nigeria. A structured questionnaire is administered on the study and data collected are analysed using Analysis of Variance and Regression. The following variables are indices of determination; Interest Rate (IR); Income Tax (IT). The results of the study show that there is a significant relationship between IR and ED in Nigeria (p < 0.5) with a positive correlation (r=0.526, r2=0.276). Also, there is a significant relationship between IT and ED in Nigeria (p < 0.05), with a positive association (r=0.546; r2=0.299). The study concludes that the emergence of the higher level of the stable economic environment is critical to entrepreneurial development in Nigeria. Therefore, government involvement in public private partnership for infrastructural development, enlargement of productive, judicious and transparent use of funds collected from income tax and affordable interest rate will galvanise the inward sourcing of raw materials that boost entrepreneurial development in Nigeria.

Keywords: interest rate, income tax, business environment and entrepreneurial development

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5646 Service-Oriented Enterprise Architecture (SoEA) Adoption and Maturity Measurement Model: A Systematic Review

Authors: Nur Azaliah Abu Bakar, Harihodin Selamat, Mohd Nazri Kama

Abstract:

This article provides a systematic review of existing research related to the Service-oriented Enterprise Architecture (SoEA) adoption and maturity measurement model. The review’s main goals are to support research, to facilitate other researcher’s search for relevant studies and to propose areas for future studies within this area. In addition, this article provides useful information on SoEA adoption issues and its related maturity model, based on research-based knowledge. The review results suggest that motives, critical success factors (CSFs), implementation status and benefits are the most frequently studied areas and that each of these areas would benefit from further exposure.

Keywords: systematic literature review, service-oriented architecture, adoption, maturity model

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5645 Assessing Role of Newspapers in Creating Awareness of HIV/AIDS in Pakistan

Authors: Fatima Kiran

Abstract:

This study investigates the HIV/AIDS coverage in the selected newspapers. The premises of the study depend upon the fact that informing public about any social issue that effects people’s life is among one of the fundamental functions of media, such as HIV/AIDS is one of prime importance. In this study two most prime newspapers of Pakistan Daily Jang and Daily Dawn were analyzed. This paper adopted two approaches for investigation one is content analysis and another is discourse analysis. The content analysis was used to determine the frequency of HIV/AIDS content coverage. Discourse analysis was used to determine consciousness of these newspapers on covering HIV/AIDS stories with correct language and terminologies according to the given media guideline of UNICEF. Total 368 editions from 1st July 2017 to 31st December 2017 were sampled for the study. The result of the study indicates that newspapers have severely underestimated the severity of HIV/AIDS. The coverage given by newspapers is dissatisfactory. Selected newspapers used inappropriate terminologies and language in the stories which shows negligence of newspapers regarding HIV/AIDS issue.

Keywords: Pakistani newspapers, HIV/AIDS, coverage, public awareness, content analysis, discourse analysis, press consciousness

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5644 Proposing Problem-Based Learning as an Effective Pedagogical Technique for Social Work Education

Authors: Christine K. Fulmer

Abstract:

Social work education is competency based in nature. There is an expectation that graduates of social work programs throughout the world are to be prepared to practice at a level of competence, which is beneficial to both the well-being of individuals and community. Experiential learning is one way to prepare students for competent practice. The use of Problem-Based Learning (PBL) is a form experiential education that has been successful in a number of disciplines to bridge the gap between the theoretical concepts in the classroom to the real world. PBL aligns with the constructivist theoretical approach to learning, which emphasizes the integration of new knowledge with the beliefs students already hold. In addition, the basic tenants of PBL correspond well with the practice behaviors associated with social work practice including multi-disciplinary collaboration and critical thinking. This paper makes an argument for utilizing PBL in social work education.

Keywords: social work education, problem-based learning, pedagogy, experiential learning, constructivist theoretical approach

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5643 Vibration Analysis of Power Lines with Moving Dampers

Authors: Mohammad Bukhari, Oumar Barry

Abstract:

In order to reduce the Aeolian vibration of overhead transmission lines, the Stockbridge damper is usually attached. The efficiency of Stockbridge damper depends on its location on the conductor and its resonant frequencies. When the Stockbridge damper is located on a vibration node, it becomes inefficient. Hence, the static damper should be subrogated by a dynamic one. In the present study, a proposed dynamic absorber for transmission lines is studied. Hamilton’s principle is used to derive the governing equations, then the system of ordinary differential equations is solved numerically. Parametric studies are conducted to determine how certain parameters affect the performance of the absorber. The results demonstrate that replacing the static absorber by a dynamic one enhance the absorber performance for wider range of frequencies. The results also indicate that the maximum displacement decreases as the absorber speed and the forcing frequency increase. However, this reduction in maximum displacement is accompanying with increasing in the steady state vibration displacement. It is also indicated that the energy dissipation in moving absorber covers higher range of frequencies.

Keywords: absorber performance, Aeolian vibration, Hamilton’s principle, stockbridge damper

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5642 Pharmacokinetics of Oral Controlled-Release Formulation of Doxycycline Hyclate with Polymethacrylate and Acrylic Acid for Dogs

Authors: S. M. Arciniegas, D. Vargas, L. Gutierrez

Abstract:

The aim of this study was to develop oral drug presentation of doxycycline hyclate that maintains longer therapeutic levels than conventional forms. A polymethacrylate and acrylic acid based matrix were used in different proportions to obtain controlled-release formulations; DOX1 (1:0.25:0.0035), DOX2 (1:2:0.0225) and DOX-C (without excipients). All were tested in vivo in healthy dogs and their serum concentrations vs. time profile was investigated after its oral administration in this species. DOX1 and DOX2 show therapeutic concentrations for 60 hours, while DOX-C only for 24 hours. The pharmacokinetics values tested were K½el, Cmax, Tmax, AUC, AUC∞, AUCt, AUMC, RT, Kel, Vdss, Clb and Frel. DOX1 does not differ significantly from DOX-C, but shows significant differences in all variables with DOX2 (p<0.05). In conclusion, DOX1 presents best pharmacokinetics for time-dependent drug and longer release time of 60 hours, thereby reducing the frequency of administration, the patient's stress, the occurrence of adverse effects and the cost of treatment.

Keywords: tetracyclines, long-acting, sustained-release, carbopol, eudragit, canine

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5641 A Hybrid Digital Watermarking Scheme

Authors: Nazish Saleem Abbas, Muhammad Haris Jamil, Hamid Sharif

Abstract:

Digital watermarking is a technique that allows an individual to add and hide secret information, copyright notice, or other verification message inside a digital audio, video, or image. Today, with the advancement of technology, modern healthcare systems manage patients’ diagnostic information in a digital way in many countries. When transmitted between hospitals through the internet, the medical data becomes vulnerable to attacks and requires security and confidentiality. Digital watermarking techniques are used in order to ensure the authenticity, security and management of medical images and related information. This paper proposes a watermarking technique that embeds a watermark in medical images imperceptibly and securely. In this work, digital watermarking on medical images is carried out using the Least Significant Bit (LSB) with the Discrete Cosine Transform (DCT). The proposed methods of embedding and extraction of a watermark in a watermarked image are performed in the frequency domain using LSB by XOR operation. The quality of the watermarked medical image is measured by the Peak signal-to-noise ratio (PSNR). It was observed that the watermarked medical image obtained performing XOR operation between DCT and LSB survived compression attack having a PSNR up to 38.98.

Keywords: watermarking, image processing, DCT, LSB, PSNR

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5640 Damage Cost for Private Property by Extreme Wind over the past 10 Years in Korea

Authors: Gou-Moon Choi, Woo-Young Jung, Chan-Young Yune

Abstract:

Recently, the natural disaster has increased worldwide. In Korea, the damage to life and property caused by a typhoon, heavy rain, heavy snow, and an extreme wind also increases every year. Among natural disasters, the frequency and the strength of wind have increased because sea surface temperature has risen due to the increase of the average temperature of the Earth. In the case of extreme wind disaster, it is impossible to control or reduce the occurrence, and the recovery cost always exceeds the damage cost. Therefore, quantitative estimation of the damage cost for extreme wind needs to be established beforehand to install proactive countermeasures. In this study, the damage cost for private properties was analyzed based on the data for the past 10 years in Korea. The damage cost curve was also suggested for the metropolitan cities and provinces. The result shows the possibility for the regional application of the damage cost curve because the damage cost of the regional area is estimated based on the cost of cities and provinces.

Keywords: damage cost, extreme wind, natural disaster, private property

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5639 Life Cycle Assessment: Drinking Glass Systems

Authors: Devina Jain

Abstract:

The choice between single-use drinking glasses and reusable glasses is of major concern to our lifestyles, and hence, the environment. This study is aimed at comparing three systems - a disposable paper cup, a disposable cup and a reusable stainless steel cup or glass - with respect to their effect on the environment to find out which one is more advantageous for reducing the impact on the environment. Life Cycle Assessment was conducted using modeling software, Umberto NXT Universal (Version 7.1). For the purpose of this study, the cradle to grave approach was considered. Results showed that cleaning is of a very strong influence on the environmental burden by these drinking systems, with a contribution of up to 90 to 100%. Thus, the burden is determined by the way in which the utensils are washed, and how much water is consumed. It maybe seems like a small, insignificant daily practice. In the short term, it would seem that paper and plastic cups are a better idea, since they are easy to acquire and do not need to be stored, but in the long run, we can say that steel cups will have less of an environmental impact. However, if the frequency of use and the number of glasses employed per use are of significance to decide the appropriateness of the usage, it is better to use disposable cups and glasses.

Keywords: disposable glass, life cycle assessment, paper, plastic, reusable glass, stainless steel

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5638 Dynamic Analysis of Double Deck Tunnel

Authors: C. W. Kwak, I. J. Park, D. I. Jang

Abstract:

The importance of cost-wise effective application and construction is getting increase due to the surge of traffic volume in the metropolitan cities. Accordingly, the necessity of the tunnel has large section becomes more critical. Double deck tunnel can be one of the most appropriate solutions to the necessity. The dynamic stability of double deck tunnel is essential against seismic load since it has large section and connection between perimeter lining and interim slab. In this study, 3-dimensional dynamic numerical analysis was conducted based on the Finite Difference Method to investigate the seismic behavior of double deck tunnel. Seismic joint for dynamic stability and the mitigation of seismic impact on the lining was considered in the modeling and analysis. Consequently, the mitigation of acceleration, lining displacement and stress were verified successfully.

Keywords: double deck tunnel, interim slab, 3-dimensional dynamic numerical analysis, seismic joint

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5637 Women, Science and Engineering Doctorate Recipients from U.S. Universities

Authors: Cheryl Leggon

Abstract:

Although women in the aggregate are earning more doctorates in science and engineering from U.S. institutions, they continue to concentrate in some fields--e.g., biology--and underrepresented in others--e.g., engineering. Traditionally, most studies of women doctorate recipients in the sciences (including the social, behavioral and economic sciences) or engineering do not report their findings by demographic subgroups. This study extends the literature on these topics by using an intersectional approach to examine decadal trends. Intersectionality suggests that race, gender, and nation are not separate mutually exclusive entities whose impacts are summative, but rather as a confluence of synergistic factors that shape complex social inequities. Drawing on critical aspects of the intersectionality approach is particularly well suited for a more fine-grained analysis of the representation of women doctorate recipients in science and engineering. The implications of the findings are discussed in terms of policies and evidence-based programmatic strategies for enhancing women’s participation in fields in which they are especially underrepresented.

Keywords: doctorates, engineering, science, women

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5636 Evaluation of the Effectiveness of a Sewage Treatment Plant in Oman: Samail Case Study

Authors: Azza Mohsin Al-Hashami, Reginald Victor

Abstract:

Treatment of wastewater involves physical, chemical, and biological processes to remove the pollutants from wastewater. This study evaluates of the effectiveness of sewage treatment plants (STP) in Samail, Oman. Samail STP has tertiary treatment using conventional activated sludge with surface aeration. The collection of wastewater is through a network with a total length of about 60 km and also by tankers for the areas outside the network. Treated wastewater from this STP is used for the irrigation of vegetation in the STP premises and as a backwash for sand filters. Some treated water is supplied to the Samail municipality, which uses it for the landscaping, road construction, and 'the Million Date Palms' project. In this study, homogenous samples were taken from eight different treatment stages along the treatment continuum for one year, at a frequency of once a month, to evaluate the physical, chemical, and biological parameters. All samples were analyzed using the standard methods for the examination of water and wastewater. The spatial variations in water quality along the continuum are discussed. Despite these variations, the treated wastewater from Samail STP was of good quality, and most of the parameters are within class A category in Oman Standards for wastewater reuse and discharge.

Keywords: wastewater, STP, treatment, processes

Procedia PDF Downloads 186
5635 A Critical Analysis of the Current Concept of Healthy Eating and Its Impact on Food Traditions

Authors: Carolina Gheller Miguens

Abstract:

Feeding is, and should be, pleasurable for living beings so they desire to nourish themselves while preserving the continuity of the species. Social rites usually revolve around the table and are closely linked to the cultural traditions of each region and social group. Since the beginning, food has been closely linked with the products each region provides, and, also, related to the respective seasons of production. With the globalization and facilities of modern life we are able to find an ever increasing variety of products at any time of the year on supermarket shelves. These lifestyle changes end up directly influencing food traditions. With the era of uncontrolled obesity caused by the dazzle with the large and varied supply of low-priced to ultra-processed industrial products now in the past, today we are living a time when people are putting aside the pleasure of eating to exclusively eat food dictated by the media as healthy. Recently the medicalization of food in our society has become so present in daily life that almost without realizing we make food choices conditioned to the studies of the properties of these foods. The fact that people are more attentive to their health is interesting. However, when this care becomes an obsessive disorder, which imposes itself on the pleasure of eating and extinguishes traditional customs, it becomes dangerous for our recognition as citizens belonging to a culture and society. This new way of living generates a rupture with the social environment of origin, possibly exposing old traditions to oblivion after two or three generations. Based on these facts, the presented study analyzes these social transformations that occur in our society that triggered the current medicalization of food. In order to clarify what is actually a healthy diet, this research proposes a critical analysis on the subject aiming to understand nutritional rationality and relate how it acts in the medicalization of food. A wide bibliographic review on the subject was carried out followed by an exploratory research in online (especially social) media, a relevant source in this context due to the perceived influence of such media in contemporary eating habits. Finally, this data was crossed, critically analyzing the current situation of the concept of healthy eating and medicalization of food. Throughout this research, it was noticed that people are increasingly seeking information about the nutritional properties of food, but instead of seeking the benefits of products that traditionally eat in their social environment, they incorporate external elements that often bring benefits similar to the food already consumed. This is because the access to information is directed by the media and exalts the exotic, since this arouses more interest of the population in general. Efforts must be made to clarify that traditional products are also healthy foods, rich in history, memory and tradition and cannot be replaced by a standardized diet little concerned with the construction of taste and pleasure, having a relationship with food as if it were a Medicinal product.

Keywords: food traditions, food transformations, healthy eating, medicalization of food

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5634 Geoecological Problems of Karst Waters in Chiatura Municipality, Georgia

Authors: Liana Khandolishvili, Giorgi Dvalashvili

Abstract:

Karst waters in the world play an important role in the water supply. Among them, the Vaucluse in Chiatura municipality (Georgia) is used as drinking water and is irreplaceable for the local population. Accordingly, it is important to assess their geo-ecological conditions and take care to maintain sustainability. The aim of the paper is to identify the hazards of pollution of underground waters in the karst environment and to develop a scheme for their protection, which will take into consideration both the hydrogeological characteristics and the role of humans. To achieve this goal, the EPIK method was selected using which an epikarst zone of the study area was studied in detail, as well as the protective cover, infiltration conditions and frequency of karst network development, after which the conditions of karst waters in Chiatura municipality was assessed, their main pollutants were identified and the recommendations were prepared for their protection. The results of the study showed that the karst water pollution rate in Chiatura municipality is highest, where karst-fissured layers are represented and intensive extraction works are underway. The EPIK method is innovative in Georgia and was first introduced on the example of karst waters of Chiatura municipality.

Keywords: cave, EPIK method, pollution, Karst waters, geology, geography, ecology

Procedia PDF Downloads 98
5633 Teachers' and Learners' Experiences of Learners' Writing in English First Additional Language

Authors: Jane-Francis A. Abongdia, Thandiswa Mpiti

Abstract:

There is an international concern to develop children’s literacy skills. In many parts of the world, the need to become fluent in a second language is essential for gaining meaningful access to education, the labour market and broader social functioning. In spite of these efforts, the problem still continues. The level of English language proficiency is far from satisfactory and these goals are unattainable by others. The issue is more complex in South Africa as learners are immersed in a second language (L2) curriculum. South Africa is a prime example of a country facing the dilemma of how to effectively equip a majority of its population with English as a second language or first additional language (FAL). Given the multilingual nature of South Africa with eleven official languages, and the position and power of English, the study investigates teachers’ and learners’ experiences on isiXhosa and Afrikaans background learners’ writing in English First Additional Language (EFAL). Moreover, possible causes of writing difficulties and teacher’s practices for writing are explored. The theoretical and conceptual framework for the study is provided by studies on constructivist theories and sociocultural theories. In exploring these issues, a qualitative approach through semi-structured interviews, classroom observations, and document analysis were adopted. This data is analysed by critical discourse analysis (CDA). The study identified a weak correlation between teachers’ beliefs and their actual teaching practices. Although the teachers believe that writing is as important as listening, speaking, reading, grammar and vocabulary, and that it needs regular practice, the data reveal that they fail to put their beliefs into practice. Moreover, the data revealed that learners were disturbed by their home language because when they do not know a word they would write either the isiXhosa or the Afrikaans equivalent. Code-switching seems to have instilled a sense of “dependence on translations” where some learners would not even try to answer English questions but would wait for the teacher to translate the questions into isiXhosa or Afrikaans before they could attempt to give answers. The findings of the study show a marked improvement in the writing performance of learners who used the process approach in writing. These findings demonstrate the need for assisting teachers to shift away from focusing only on learners’ performance (testing and grading) towards a stronger emphasis on the process of writing. The study concludes that the process approach to writing could enable teachers to focus on the various parts of the writing process which can give more freedom to learners to experiment their language proficiency. It would require that teachers develop a deeper understanding of the process/genre approaches to teaching writing advocated by CAPS. All in all, the study shows that both learners and teachers face numerous challenges relating to writing. This means that more work still needs to be done in this area. The present study argues that teachers teaching EFAL learners should approach writing as a critical and core aspect of learners’ education. Learners should be exposed to intensive writing activities throughout their school years.

Keywords: constructivism, English second language, language of learning and teaching, writing

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5632 Distribution System Modelling: A Holistic Approach for Harmonic Studies

Authors: Stanislav Babaev, Vladimir Cuk, Sjef Cobben, Jan Desmet

Abstract:

The procedures for performing harmonic studies for medium-voltage distribution feeders have become relatively mature topics since the early 1980s. The efforts of various electric power engineers and researchers were mainly focused on handling large harmonic non-linear loads connected scarcely at several buses of medium-voltage feeders. In order to assess the impact of these loads on the voltage quality of the distribution system, specific modeling and simulation strategies were proposed. These methodologies could deliver a reasonable estimation accuracy given the requirements of least computational efforts and reduced complexity. To uphold these requirements, certain analysis assumptions have been made, which became de facto standards for establishing guidelines for harmonic analysis. Among others, typical assumptions include balanced conditions of the study and the negligible impact of impedance frequency characteristics of various power system components. In latter, skin and proximity effects are usually omitted, and resistance and reactance values are modeled based on the theoretical equations. Further, the simplifications of the modelling routine have led to the commonly accepted practice of neglecting phase angle diversity effects. This is mainly associated with developed load models, which only in a handful of cases are representing the complete harmonic behavior of a certain device as well as accounting on the harmonic interaction between grid harmonic voltages and harmonic currents. While these modelling practices were proven to be reasonably effective for medium-voltage levels, similar approaches have been adopted for low-voltage distribution systems. Given modern conditions and massive increase in usage of residential electronic devices, recent and ongoing boom of electric vehicles, and large-scale installing of distributed solar power, the harmonics in current low-voltage grids are characterized by high degree of variability and demonstrate sufficient diversity leading to a certain level of cancellation effects. It is obvious, that new modelling algorithms overcoming previously made assumptions have to be accepted. In this work, a simulation approach aimed to deal with some of the typical assumptions is proposed. A practical low-voltage feeder is modeled in PowerFactory. In order to demonstrate the importance of diversity effect and harmonic interaction, previously developed measurement-based models of photovoltaic inverter and battery charger are used as loads. The Python-based script aiming to supply varying voltage background distortion profile and the associated current harmonic response of loads is used as the core of unbalanced simulation. Furthermore, the impact of uncertainty of feeder frequency-impedance characteristics on total harmonic distortion levels is shown along with scenarios involving linear resistive loads, which further alter the impedance of the system. The comparative analysis demonstrates sufficient differences with cases when all the assumptions are in place, and results indicate that new modelling and simulation procedures need to be adopted for low-voltage distribution systems with high penetration of non-linear loads and renewable generation.

Keywords: electric power system, harmonic distortion, power quality, public low-voltage network, harmonic modelling

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5631 Physical and Mechanical Phenomena Associated with Rock Failure in Brazilian Disc Specimens

Authors: Hamid Reza Nejati, Amin Nazerigivi, Ahmad Reza Sayadi

Abstract:

Failure mechanism of rocks is one of the fundamental aspects to study rock engineering stability. Rock is a material that contains flaws, initial damage, micro-cracks, etc. Failure of rock structure is largely due to tensile stress and was influenced by various parameters. In the present study, the effect of brittleness and loading rate on the physical and mechanical phenomena produced in rock during loading sequences is considered. For this purpose, Acoustic Emission (AE) technique is used to monitor fracturing process of three rock types (onyx marble, sandstone and soft limestone) with different brittleness and sandstone samples under different loading rate. The results of experimental tests revealed that brittleness and loading rate have a significant effect on the mode and number of induced fracture in rocks. An increase in rock brittleness increases the frequency of induced cracks, and the number of tensile fracture decreases when loading rate increases.

Keywords: brittleness, loading rate, acoustic emission, tensile fracture, shear fracture

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5630 A Case Study on Improving Language Skills of Preschoolers by Parent-Child Reading

Authors: Hoi Yan Lau

Abstract:

In Hong Kong, most families have working parents, and the primary caregivers of young children are helpers. This leads to a lack of interaction and language expression in children’s home environment, which affects their language development. This study aims to explore the effectiveness of parent-child reading in improving young children’s language skills. A 4-year-old girl and her mother are recruited to a 3 months’ parent-child reading program. There is a total of 26 reading sessions which target to enhance the parent’s skill of parent-child reading and to assess the child’s language ability. At the same time, the child’s use of language in normal classroom settings is analyzed by anecdotal records. It is shown that the parent is able to use more and better guiding questions during parent-child reading after this program, which in turn leads to more and longer response of the child during the reading sessions. The child also has an increase in Mean Length of Utterance and has a higher frequency of using complete sentences when interacting with other classmates in the classroom. It is worthwhile to further investigate the inclusion of promoting parent-child reading to enhance children’s language development in preschool curriculum planning.

Keywords: Hong Kong, language skills, parent-child reading, preschoolers

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5629 Devulcanization of Waste Rubber Using Thermomechanical Method Combined with Supercritical CO₂

Authors: L. Asaro, M. Gratton, S. Seghar, N. Poirot, N. Ait Hocine

Abstract:

Rubber waste disposal is an environmental problem. Particularly, many researches are centered in the management of discarded tires. In spite of all different ways of handling used tires, the most common is to deposit them in a landfill, creating a stock of tires. These stocks can cause fire danger and provide ambient for rodents, mosquitoes and other pests, causing health hazards and environmental problems. Because of the three-dimensional structure of the rubbers and their specific composition that include several additives, their recycling is a current technological challenge. The technique which can break down the crosslink bonds in the rubber is called devulcanization. Strictly, devulcanization can be defined as a process where poly-, di-, and mono-sulfidic bonds, formed during vulcanization, are totally or partially broken. In the recent years, super critical carbon dioxide (scCO₂) was proposed as a green devulcanization atmosphere. This is because it is chemically inactive, nontoxic, nonflammable and inexpensive. Its critical point can be easily reached (31.1 °C and 7.38 MPa), and residual scCO₂ in the devulcanized rubber can be easily and rapidly removed by releasing pressure. In this study thermomechanical devulcanization of ground tire rubber (GTR) was performed in a twin screw extruder under diverse operation conditions. Supercritical CO₂ was added in different quantities to promote the devulcanization. Temperature, screw speed and quantity of CO₂ were the parameters that were varied during the process. The devulcanized rubber was characterized by its devulcanization percent and crosslink density by swelling in toluene. Infrared spectroscopy (FTIR) and Gel permeation chromatography (GPC) were also done, and the results were related with the Mooney viscosity. The results showed that the crosslink density decreases as the extruder temperature and speed increases, and, as expected, the soluble fraction increase with both parameters. The Mooney viscosity of the devulcanized rubber decreases as the extruder temperature increases. The reached values were in good correlation (R= 0.96) with de the soluble fraction. In order to analyze if the devulcanization was caused by main chains or crosslink scission, the Horikx's theory was used. Results showed that all tests fall in the curve that corresponds to the sulfur bond scission, which indicates that the devulcanization has successfully happened without degradation of the rubber. In the spectra obtained by FTIR, it was observed that none of the characteristic peaks of the GTR were modified by the different devulcanization conditions. This was expected, because due to the low sulfur content (~1.4 phr) and the multiphasic composition of the GTR, it is very difficult to evaluate the devulcanization by this technique. The lowest crosslink density was reached with 1 cm³/min of CO₂, and the power consumed in that process was also near to the minimum. These results encourage us to do further analyses to better understand the effect of the different conditions on the devulcanization process. The analysis is currently extended to monophasic rubbers as ethylene propylene diene monomer rubber (EPDM) and natural rubber (NR).

Keywords: devulcanization, recycling, rubber, waste

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5628 Collaborative Procurement in the Pursuit of Net- Zero: A Converging Journey

Authors: Bagireanu Astrid, Bros-Williamson Julio, Duncheva Mila, Currie John

Abstract:

The Architecture, Engineering, and Construction (AEC) sector plays a critical role in the global transition toward sustainable and net-zero built environments. However, the industry faces unique challenges in planning for net-zero while struggling with low productivity, cost overruns and overall resistance to change. Traditional practices fall short due to their inability to meet the requirements for systemic change, especially as governments increasingly demand transformative approaches. Working in silos and rigid hierarchies and a short-term, client-centric approach prioritising immediate gains over long-term benefit stands in stark contrast to the fundamental requirements for the realisation of net-zero objectives. These practices have limited capacity to effectively integrate AEC stakeholders and promote the essential knowledge sharing required to address the multifaceted challenges of achieving net-zero. In the context of built environment, procurement may be described as the method by which a project proceeds from inception to completion. Collaborative procurement methods under the Integrated Practices (IP) umbrella have the potential to align more closely with net-zero objectives. This paper explores the synergies between collaborative procurement principles and the pursuit of net zero in the AEC sector, drawing upon the shared values of cross-disciplinary collaboration, Early Supply Chain involvement (ESI), use of standards and frameworks, digital information management, strategic performance measurement, integrated decision-making principles and contractual alliancing. To investigate the role of collaborative procurement in advancing net-zero objectives, a structured research methodology was employed. First, the study focuses on a systematic review on the application of collaborative procurement principles in the AEC sphere. Next, a comprehensive analysis is conducted to identify common clusters of these principles across multiple procurement methods. An evaluative comparison between traditional procurement methods and collaborative procurement for achieving net-zero objectives is presented. Then, the study identifies the intersection between collaborative procurement principles and the net-zero requirements. Lastly, an exploration of key insights for AEC stakeholders focusing on the implications and practical applications of these findings is made. Directions for future development of this research are recommended. Adopting collaborative procurement principles can serve as a strategic framework for guiding the AEC sector towards realising net-zero. Synergising these approaches overcomes fragmentation, fosters knowledge sharing, and establishes a net-zero-centered ecosystem. In the context of the ongoing efforts to amplify project efficiency within the built environment, a critical realisation of their central role becomes imperative for AEC stakeholders. When effectively leveraged, collaborative procurement emerges as a powerful tool to surmount existing challenges in attaining net-zero objectives.

Keywords: collaborative procurement, net-zero, knowledge sharing, architecture, built environment

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5627 Nursing Experience in the Intensive Care of a Lung Cancer Patient with Pulmonary Embolism on Extracorporeal Membrane Oxygenation

Authors: Huang Wei-Yi

Abstract:

Objective: This article explores the intensive care nursing experience of a lung cancer patient with pulmonary embolism who was placed on ECMO. Following a sudden change in the patient’s condition and a consensus reached during a family meeting, the decision was made to withdraw life-sustaining equipment and collaborate with the palliative care team. Methods: The nursing period was from October 20 to October 27, 2023. The author monitored physiological data, observed, provided direct care, conducted interviews, performed physical assessments, and reviewed medical records. Together with the critical care team and bypass personnel, a comprehensive assessment was conducted using Gordon's Eleven Functional Health Patterns to identify the patient’s health issues, which included pain related to lung cancer and invasive devices, fear of death due to sudden deterioration, and altered tissue perfusion related to hemodynamic instability. Results: The patient was admitted with fever, back pain, and painful urination. During hospitalization, the patient experienced sudden discomfort followed by cardiac arrest, requiring multiple CPR attempts and ECMO placement. A subsequent CT angiogram revealed a pulmonary embolism. The patient's condition was further complicated by severe pain due to compression fractures, and a diagnosis of terminal lung cancer was unexpectedly confirmed, leading to emotional distress and uncertainty about future treatment. Throughout the critical care process, ECMO was removed on October 24, stabilizing the patient’s body temperature between 36.5-37°C and maintaining a mean arterial pressure of 60-80 mmHg. Pain management, including Morphine 8mg in 0.9% N/S 100ml IV drip q6h PRN and Ultracet 37.5 mg/325 mg 1# PO q6h, kept the pain level below 3. The patient was transferred to the ward on October 27 and discharged home on October 30. Conclusion: During the care period, collaboration with the medical team and palliative care professionals was crucial. Adjustments to pain medication, symptom management, and lung cancer-targeted therapy improved the patient’s physical discomfort and pain levels. By applying the unique functions of nursing and the four principles of palliative care, positive encouragement was provided. Family members, along with social workers, clergy, psychologists, and nutritionists, participated in cross-disciplinary care, alleviating anxiety and fear. The consensus to withdraw ECMO and life-sustaining equipment enabled the patient and family to receive high-quality care and maintain autonomy in decision-making. A follow-up call on November 1 confirmed that the patient was emotionally stable, pain-free, and continuing with targeted lung cancer therapy.

Keywords: intensive care, lung cancer, pulmonary embolism, ECMO

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5626 Collapse Surface Definition of Clayey Sands

Authors: Omid Naeemifar, Ibrahim Naeimifar, Roza Rahbari

Abstract:

It has been shown that a certain collapse surface may be defined for loose sands in the three dimensional space in which the sample sand experiences collapse and instability leading to an unsteady and strain-softening behaviour. The unsteady state due to collapse surface may lead to such phenomena in the sand as liquefaction and flow behaviour during undrained loading. Investigating the existence of the collapse surface in Firoozkooh 161 sand and its different clay mixtures with various plasticities, the present study aims to carry out an in-depth investigation of the effects of clay percent and its plasticity on the clayey sand behaviours. The results obtained indicate that collapse surface characteristics largely depend on fine percent and its plasticity. Interesting findings are also reported in this paper on the effects of fine sand percent and its plasticity on the behavioural characteristics and liquefaction potential of clayey sands.

Keywords: critical state, collapse surface, liquefaction, clayey sand

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5625 Kinematic Optimization of Energy Extraction Performances for Flapping Airfoil by Using Radial Basis Function Method and Genetic Algorithm

Authors: M. Maatar, M. Mekadem, M. Medale, B. Hadjed, B. Imine

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In this paper, numerical simulations have been carried out to study the performances of a flapping wing used as an energy collector. Metamodeling and genetic algorithms are used to detect the optimal configuration, improving power coefficient and/or efficiency. Radial basis functions and genetic algorithms have been applied to solve this problem. Three optimization factors are controlled, namely dimensionless heave amplitude h₀, pitch amplitude θ₀ and flapping frequency f. ANSYS FLUENT software has been used to solve the principal equations at a Reynolds number of 1100, while the heave and pitch motion of a NACA0015 airfoil has been realized using a developed function (UDF). The results reveal an average power coefficient and efficiency of 0.78 and 0.338 with an inexpensive low-fidelity model and a total relative error of 4.1% versus the simulation. The performances of the simulated optimum RBF-NSGA-II have been improved by 1.2% compared with the validated model.

Keywords: numerical simulation, flapping wing, energy extraction, power coefficient, efficiency, RBF, NSGA-II

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5624 Achievable Average Secrecy Rates over Bank of Parallel Independent Fading Channels with Friendly Jamming

Authors: Munnujahan Ara

Abstract:

In this paper, we investigate the effect of friendly jamming power allocation strategies on the achievable average secrecy rate over a bank of parallel fading wiretap channels. We investigate the achievable average secrecy rate in parallel fading wiretap channels subject to Rayleigh and Rician fading. The achievable average secrecy rate, due to the presence of a line-of-sight component in the jammer channel is also evaluated. Moreover, we study the detrimental effect of correlation across the parallel sub-channels, and evaluate the corresponding decrease in the achievable average secrecy rate for the various fading configurations. We also investigate the tradeoff between the transmission power and the jamming power for a fixed total power budget. Our results, which are applicable to current orthogonal frequency division multiplexing (OFDM) communications systems, shed further light on the achievable average secrecy rates over a bank of parallel fading channels in the presence of friendly jammers.

Keywords: fading parallel channels, wire-tap channel, OFDM, secrecy capacity, power allocation

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5623 Cost-Effective Indoor-Air Quality (IAQ) Monitoring via Cavity Enhanced Photoacoustic Technology

Authors: Jifang Tao, Fei Gao, Hong Cai, Yuan Jin Zheng, Yuan Dong Gu

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Photoacoustic technology is used to measure effect absorption of a light by means of acoustic detection, which provides a high sensitive, low-cross response, cost-effective solution for gas molecular detection. In this paper, we proposed an integrated photoacoustic sensor for Indoor-air quality (IAQ) monitoring. The sensor consists of an acoustically resonant cavity, a high silicon acoustic transducer chip, and a low-cost light source. The light is modulated at the resonant frequency of the cavity to create an enhanced periodic heating and result in an amplified acoustic pressure wave. The pressure is readout by a novel acoustic transducer with low noise. Based on this photoacoustic sensor, typical indoor gases, including CO2, CO, O2, and H2O have been successfully detected, and their concentration are also evaluated with very high accuracy. It has wide potential applications in IAQ monitoring for agriculture, food industry, and ventilation control systems used in public places, such as schools, hospitals and airports.

Keywords: indoor-air quality (IAQ) monitoring, photoacoustic gas sensor, cavity enhancement, integrated gas sensor

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5622 Exploitation Pattern of Atlantic Bonito in West African Waters: Case Study of the Bonito Stock in Senegalese Waters

Authors: Ousmane Sarr

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The Senegalese coasts have high productivity of fishery resources due to the frequency of intense up-welling system that occurs along its coast, caused by the maritime trade winds making its waters nutrients rich. Fishing plays a primordial role in Senegal's socioeconomic plans and food security. However, a global diagnosis of the Senegalese maritime fishing sector has highlighted the challenges this sector encounters. Among these concerns, some significant stocks, a priority target for artisanal fishing, need further assessment. If no efforts are made in this direction, most stock will be overexploited or even in decline. It is in this context that this research was initiated. This investigation aimed to apply a multi-modal approach (LBB, Catch-only-based CMSY model and its most recent version (CMSY++); JABBA, and JABBA-Select) to assess the stock of Atlantic bonito, Sarda sarda (Bloch, 1793) in the Senegalese Exclusive Economic Zone (SEEZ). Available catch, effort, and size data from Atlantic bonito over 15 years (2004-2018) were used to calculate the nominal and standardized CPUE, size-frequency distribution, and length at retentions (50 % and 95 % selectivity) of the species. These relevant results were employed as input parameters for stock assessment models mentioned above to define the stock status of this species in this region of the Atlantic Ocean. The LBB model indicated an Atlantic bonito healthy stock status with B/BMSY values ranging from 1.3 to 1.6 and B/B0 values varying from 0.47 to 0.61 of the main scenarios performed (BON_AFG_CL, BON_GN_Length, and BON_PS_Length). The results estimated by LBB are consistent with those obtained by CMSY. The CMSY model results demonstrate that the SEEZ Atlantic bonito stock is in a sound condition in the final year of the main scenarios analyzed (BON, BON-bt, BON-GN-bt, and BON-PS-bt) with sustainable relative stock biomass (B2018/BMSY = 1.13 to 1.3) and fishing pressure levels (F2018/FMSY= 0.52 to 1.43). The B/BMSY and F/FMSY results for the JABBA model ranged between 2.01 to 2.14 and 0.47 to 0.33, respectively. In contrast, The estimated B/BMSY and F/FMSY for JABBA-Select ranged from 1.91 to 1.92 and 0.52 to 0.54. The Kobe plots results of the base case scenarios ranged from 75% to 89% probability in the green area, indicating sustainable fishing pressure and an Atlantic bonito healthy stock size capable of producing high yields close to the MSY. Based on the stock assessment results, this study highlighted scientific advice for temporary management measures. This study suggests an improvement of the selectivity parameters of longlines and purse seines and a temporary prohibition of the use of sleeping nets in the fishery for the Atlantic bonito stock in the SEEZ based on the results of the length-base models. Although these actions are temporary, they can be essential to reduce or avoid intense pressure on the Atlantic bonito stock in the SEEZ. However, it is necessary to establish harvest control rules to provide coherent and solid scientific information that leads to appropriate decision-making for rational and sustainable exploitation of Atlantic bonito in the SEEZ and the Eastern Atlantic Ocean.

Keywords: multi-model approach, stock assessment, atlantic bonito, SEEZ

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