Search results for: “User acceptance of computer technology:A comparison of two theoretical models ”
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 23359

Search results for: “User acceptance of computer technology:A comparison of two theoretical models ”

3349 Developing Alternative Recovery Technology of Waste Heat in Automobile Factory

Authors: Kun-Ping Cheng, Dong-Shang Chang, Rou-Wen Wang

Abstract:

Pre-treatment of automobile paint-shop procedures are the preparation of warm water rinsing tank, hot water rinsing tank, degreasing tank, phosphate tank. The conventional boiler steam fuel is natural gas, producing steam to supply the heat exchange of each tank sink. In this study, the high-frequency soldering economizer is developed for recovering waste heat in the automotive paint-shop (RTO, Regenerative Thermal Oxidation). The heat recovery rate of the new economizer is 20% to 30% higher than the conventional embedded heat pipe. The adaptive control system responded to both RTO furnace exhaust gas and heat demands. In order to maintain the temperature range of the tanks, pre-treatment tanks are directly heated by waste heat recovery device (gas-to-water heat exchanger) through the hot water cycle of heat transfer. The performance of developed waste heat recovery system shows the annual recovery achieved to 1,226,411,483 Kcal of heat (137.8 thousand cubic meters of natural gas). Boiler can reduce fuel consumption by 20 to 30 percent compared to without waste heat recovery. In order to alleviate environmental impacts, the temperature at the end of the flue is further reduced from 160 to 110°C. The innovative waste heat recovery is helpful to energy savings and sustainable environment.

Keywords: waste heat recovery system, sustainability, RTO (Regenerative Thermal Oxidation), economizer, automotive industry

Procedia PDF Downloads 248
3348 The Impact of Artificial Intelligence on Torism Ouputs

Authors: Nancy Ayman Kamal Mohamed Mehrz

Abstract:

As the economies of other countries in the Mediterranean Basin, the tourism sector in our country has a high denominator in economics. Tourism businesses, which are building blocks of tourism, sector faces with a variety of problems during their activities. These problems faced make business efficiency and competition conditions of the businesses difficult. Most of the problems faced by the tourism businesses and the information of consumers about consumers’ rights were used in this study, which is conducted to determine the problems of tourism businesses in the Central Anatolia Region. It is aimed to contribute the awareness of staff and executives working at tourism sector and to attract attention of businesses active concurrently with tourism sector and legislators. E-tourism is among the issues that have recently been entered into the field of tourism. In order to achieve this type of tourism, Information and Communications Technology (or ICT) infrastructures as well as Co-governmental organizations and tourism resources are important. In this study, the opinions of managers and tourism officials about the e-tourism in Leman city were measured; it also surveyed the impact of level of digital literacy of managers and tourism officials on attracting tourists. This study was conducted. One of the environs of the Esfahan province. This study is a documentary – survey and the sources include library resources and also questionnaires. The results obtained indicate that if managers use ICT, it may help e-tourism to be developed in the region, and increasing managers’ beliefs on e-tourism and upgrading their level of digital literacy may affect e-tourism development.

Keywords: financial problems, the problems of tourism businesses, tourism businesses, internet, marketing, tourism, tourism management economic competitiveness, enhancing competitiveness

Procedia PDF Downloads 56
3347 Viewing Entrepreneurship Through a Goal Congruity Lens: The Roles of Dominance and Communal Goal Orientations in Women’s and Men’s Venture Interests

Authors: Xiaoming Yang, Abby Folberg, Carey Ryan, Lwetzel, Tgoering

Abstract:

We examined gender differences in entrepreneurial career interests drawing on goal congruity theory, which posits that people adopt gender-stereotypic goal orientations in response to social pressures to conform to traditional gender roles. Aspiring entrepreneurs (N = 351) first wrote three to five sentences about what they believed made an entrepreneur successful. They then completed measures of agentic and communal goal orientations (i.e., male and female stereotypic orientations, respectively) and indicated their interests in starting ventures in stereotypically feminine (e.g., salon), masculine (e.g., auto-repair) and science, technology, engineering, and mathematics (STEM; e.g., software developer) ventures. Qualitative analyses demonstrated that participants ascribed agentic and, more specifically, dominance, attributes to entrepreneurs; few participants ascribed communal attributes (e.g., warmth). Bifactor structural equation modeling indicated that, as expected, agentic goal orientations included dimensions of competence, self-direction, and dominance orientations and communal goal orientations were unidimensional. Further, as expected, dominance and communal orientations partially accounted for gender differences in all three career types. We discuss implications for entrepreneurial education and practice from a goal congruity perspective and the use of bifactor modeling to improve the measurement of goal orientations.

Keywords: gender, entrepreneurship, gender stereotypes, agentic and communal goal orientations, entrepreneurship education

Procedia PDF Downloads 79
3346 Defining a Reference Architecture for Predictive Maintenance Systems: A Case Study Using the Microsoft Azure IoT-Cloud Components

Authors: Walter Bernhofer, Peter Haber, Tobias Mayer, Manfred Mayr, Markus Ziegler

Abstract:

Current preventive maintenance measures are cost intensive and not efficient. With the available sensor data of state of the art internet of things devices new possibilities of automated data processing emerge. Current advances in data science and in machine learning enable new, so called predictive maintenance technologies, which empower data scientists to forecast possible system failures. The goal of this approach is to cut expenses in preventive maintenance by automating the detection of possible failures and to improve efficiency and quality of maintenance measures. Additionally, a centralization of the sensor data monitoring can be achieved by using this approach. This paper describes the approach of three students to define a reference architecture for a predictive maintenance solution in the internet of things domain with a connected smartphone app for service technicians. The reference architecture is validated by a case study. The case study is implemented with current Microsoft Azure cloud technologies. The results of the case study show that the reference architecture is valid and can be used to achieve a system for predictive maintenance execution with the cloud components of Microsoft Azure. The used concepts are technology platform agnostic and can be reused in many different cloud platforms. The reference architecture is valid and can be used in many use cases, like gas station maintenance, elevator maintenance and many more.

Keywords: case study, internet of things, predictive maintenance, reference architecture

Procedia PDF Downloads 230
3345 Bridging Healthcare Information Systems and Customer Relationship Management for Effective Pandemic Response

Authors: Sharda Kumari

Abstract:

As the Covid-19 pandemic continues to leave its mark on the global business landscape, companies have had to adapt to new realities and find ways to sustain their operations amid social distancing measures, government restrictions, and heightened public health concerns. This unprecedented situation has placed considerable stress on both employees and employers, underscoring the need for innovative approaches to manage the risks associated with Covid-19 transmission in the workplace. In response to these challenges, the pandemic has accelerated the adoption of digital technologies, with an increasing preference for remote interactions and virtual collaboration. Customer relationship management (CRM) systems have risen to prominence as a vital resource for organizations navigating the post-pandemic world, providing a range of benefits that include acquiring new customers, generating insightful consumer data, enhancing customer relationships, and growing market share. In the context of pandemic management, CRM systems offer three primary advantages: (1) integration features that streamline operations and reduce the need for multiple, costly software systems; (2) worldwide accessibility from any internet-enabled device, facilitating efficient remote workforce management during a pandemic; and (3) the capacity for rapid adaptation to changing business conditions, given that most CRM platforms boast a wide array of remotely deployable business growth solutions, a critical attribute when dealing with a dispersed workforce in a pandemic-impacted environment. These advantages highlight the pivotal role of CRM systems in helping organizations remain resilient and adaptive in the face of ongoing global challenges.

Keywords: healthcare, CRM, customer relationship management, customer experience, digital transformation, pandemic response, patient monitoring, patient management, healthcare automation, electronic health record, patient billing, healthcare information systems, remote workforce, virtual collaboration, resilience, adaptable business models, integration features, CRM in healthcare, telehealth, pandemic management

Procedia PDF Downloads 89
3344 Legal Feminism, Modernity and Their Impact on Some African Countries

Authors: Umulisa Linda, Andy Cons Matata

Abstract:

The origin of legal feminism can be attributed to an attempt to provide a safe space for women such as voting, parental, and inheritance rights, among others. It was also a rebellion against male supremacy. However, with the development of technology and especially in the era of the internet, it appears that both legal feminism and the modernism are losing their luster. While these movements had their origin either in the United States of America or western Europe, their impacts have been felt as far as Africa, Asia, and Latin America. In Africa, different countries have different levels of penetration of these movements. This study, therefore, had its focus on how legal feminism and modernism have influenced legal developments in Kenya and Rwanda. The study adopted a qualitative approach with the respondents being asked about their feelings and perceptions on how the two movements had affected legal developments in their countries. In order to gauge the opinion of different categories of people such as the youth, middle-aged and the elderly people as well as being gender-sensitive, the study adopted a purpose method of sampling. The questionnaires and the focus group discussions were employed as the main tools for data gathering. From the questionnaires, the focus group discussions, and the data analysis that followed, the study concluded that both legal feminism and modernity had penetrated the legal systems of both Kenya and Rwanda so deeply. The study further found that the proponents of the two movements were mostly urban based and educated women. The men were generally opposed to the movements.

Keywords: legal development, legal feminsim, modernism, voting, parental and inheritance rights

Procedia PDF Downloads 125
3343 Omani Community in Digital Age: A Study of Omani Women Using Back Channel Media to Empower Themselves for Frontline Entrepreneurship

Authors: Sangeeta Tripathi, Muna Al Shahri

Abstract:

This research article presents the changing role and status of women in Oman. Transformation of women’s status started with the regime of His Majesty Sultan Qaboos Bin Said in 1970. It is always desired by the Sultan to enable women in all the ways for the balance growth of the country. Forbidding full face veil for women in public offices is one of the best efforts for their empowerment. Women education is also increasing rapidly. They are getting friendly with new information communication technology and using different social media applications such as WhatsApp, Instagram and Facebook for interaction and economic growth. Though there are some traditional and tribal boundaries, women are infused with courage and enjoying fair treatment and equal opportunities in different career positions. The study will try to explore changing mindset of young Omani women towards these traditional tribal boundaries, cultural heritage, business and career: ‘How are young Omani women making balance between work and social prestige?’, ‘How are they preserving their cultural values, embracing new technologies and approaching social network to enhance their economic power.’ This paper will discover their hurdles while using internet for their new entrepreneur. It will also examine the prospects of online business in Oman. The mixed research methodology is applied to find out the result.

Keywords: advertising, business, entrepreneurship, tribal barrier

Procedia PDF Downloads 289
3342 Integration from Laboratory to Industrialization for Hybrid Printed Electronics

Authors: Ahmed Moulay, Mariia Zhuldybina, Mirko Torres, Mike Rozel, Ngoc Duc Trinh, Chloé Bois

Abstract:

Hybrid printed electronics technology (HPE) provides innovative opportunities to enhance conventional electronics applications, which are often based on printed circuit boards (PCB). By combining the best of both performance from conventional electronic components and the flexibility from printed circuits makes it possible to manufacture HPE at high volumes using roll-to-roll printing processes. However, several challenges must be overcome in order to accurately integrate an electronic component on a printed circuit. In this presentation, we will demonstrate the integration process of electronic components from the lab scale to the industrialization. Both the printing quality and the integration technique must be studied to define the optimal conditions. To cover the parameters that influence the print quality of the printed circuit, different printing processes, flexible substrates, and conductive inks will be used to determine the optimized printing process/ink/substrate system. After the systems is selected, an electronic component of 2.5 mm2 chip size will be integrated to validate the functionality of the printed, electronic circuit. Critical information such as the conductive adhesive, the curing conditions, and the chip encapsulation will be determined. Thanks to these preliminary results, we are able to demonstrate the chip integration on a printed circuit using industrial equipment, showing the potential of industrialization, compatible using roll-to-roll printing and integrating processes.

Keywords: flat bed screen-printing, hybrid printed electronics, integration, large-scale production, roll-to-roll printing, rotary screen printing

Procedia PDF Downloads 161
3341 Compositional Assessment of Fermented Rice Bran and Rice Bran Oil and Their Effect on High Fat Diet Induced Animal Model

Authors: Muhammad Ali Siddiquee, Md. Alauddin, Md. Omar Faruque, Zakir Hossain Howlader, Mohammad Asaduzzaman

Abstract:

Rice bran (RB) and rice bran oil (RBO) are explored as prominent food components worldwide. In this study, fermented rice bran (FRB) was produced by employing edible gram-positive bacteria (Lactobacillus acidophilus, Lactobacillus bulgaricus, and Bifidobacterium bifidum) at 125 x 10⁵ spore g⁻¹ of rice bran, and investigated to evaluate nutritional quality. The crude rice bran oil (CRBO) was extracted from RB, and its quality was also investigated compared to market-available rice bran oil (MRBO) in Bangladesh. We found that fermentation of rice bran with lactic acid bacteria increased total proteins (29.52%), fat (5.38%), ash (48.47%), crude fiber (38.96%), and moisture (61.04%) and reduced the carbohydrate content (36.61%). We also found that essential amino acids (methionine, tryptophan, threonine, valine, leucine, lysine, histidine, and phenylalanine) and non-essential amino acids (alanine, aspartate, glycine, glutamine, proline, serine, and tyrosine) were increased in FRB except methionine and proline. Moreover, total phenolic content, tannin content, flavonoid content, and antioxidant activity were increased in FRB. The RBO analysis showed that γ-oryzanol content (10.00mg/g) was found in CRBO compared to MRBO (ranging from 7.40 to 12.70 mg/g) and Vitamin-E content 0.20% was found higher in CRBO compared to MRBO (ranging 0.097 to 0.12%). The total saturated (25.16%) and total unsaturated fatty acids (74.44%) were found in CRBO, whereas MRBO contained total saturated (22.08 to 24.13%) and total unsaturated fatty acids (71.91 to 83.29%), respectively. The physiochemical parameters were found satisfactory in all samples except acid value and peroxide value higher in CRBO. Finally, animal experiments showed that FRB and CRBO reduce the body weight, glucose, and lipid profile in high-fat diet-induced animal models. Thus, FRB and RBO could be value-added food supplements for human health.

Keywords: fermented rice bran, crude rice bran oil, amino acids, proximate composition, gamma-oryzanol, fatty acids, heavy metals, physiochemical parameters

Procedia PDF Downloads 49
3340 The Contribution of a Workshop Aimed at Providing Social Work Students with Practical Tools for Managing Household Finances

Authors: Ahuva Even-Zohar

Abstract:

Context: Families living in poverty often struggle with poor financial management and accumulating debts. Social workers play a crucial role in assisting these families, but they typically receive no formal training in financial management. Research Aim: The aim of this study was to assess the impact of a voluntary organization called Paamonim on social work students' attitudes toward providing material support and assistance in financial management to families living in poverty. Additionally, the study aimed to evaluate the students' perception of the workshop's contribution and their actual use of the tools acquired during the training. Methodology: The study involved 134 social work students, with 55 in a regular program and 79 in a retraining program. The first stage of the study involved the students receiving an explanation of the research, ensuring confidentiality, and signing informed consent. The students completed two questionnaires: The Student Attitudes Questionnaire and a sociodemographic questionnaire. In the second stage, three months after the workshop, the students completed the questionnaires again, along with a feedback questionnaire. Findings: The study found that there were no significant differences in the students' attitudes toward providing material support and proper financial management to families living in poverty before and after the workshop. However, their attitudes remained positive, at a medium level or higher. The students reported that the workshop provided them with tools to assist families in poverty, and they used these tools to some extent in their practical training. They found the workshop interesting and acknowledged its importance in raising awareness about budget management and enriching their knowledge of money management. The students acknowledged the workshop's effectiveness but mentioned that it was too short. Theoretical Importance: This study highlights the importance of developing programs to help families living in poverty manage their household finances. The workshop enriched the students' knowledge and skills, which are vital for their role as social workers working with families in poverty to rehabilitate their financial situations. Data Collection and Analysis Procedures: The students completed self-report questionnaires before and after the workshop, providing insights into their attitudes and perception about the role of social workers in providing material support for families living in poverty and helping them manage their household finances. Statistical analysis was conducted to compare the students' attitudes pre and post-workshop, and a feedback questionnaire assessed the students' perception of the contribution of the workshop. Question Addressed: This study addressed the question of whether a workshop on financial management can positively impact social work students' attitudes and skills in assisting families living in poverty with their household finances. Conclusion: Despite being short and consisting of only one session, the workshop proved to be valuable in enriching the students' knowledge and providing them with important tools for their role as social workers. The students reported positive attitudes toward providing material support and financial assistance to families in need. The practical recommendation is to continue offering such workshops as part of the social work curriculum to further enhance students' abilities to help families manage their finances effectively.

Keywords: financial literacy, poverty, social work students, workshop

Procedia PDF Downloads 52
3339 A Comparative Study of Innovative Regions in the World Based on the Theory of Innovation Ecosystem: Cases of the Silicon Valley, Cambridge, Tsukuba and Zhongguancun

Authors: Xinlan Zhang, Dandong Ge, Bingying Liu, Haoyang Liang

Abstract:

With the rapid development of technology and urbanization, innovation has become an important driving force for urban development. Since the late 20th Century, a number of cities and regions have emerged in the world with innovation as the main driving force, and many of them are still the most important innovation centers in the world. Based on the perspective of innovation ecosystem theory, this paper compares Silicon Valley in the United States, Cambridge in the United Kingdom, Tsukuba in Japan and Zhongguancun in China to explore the reasons for the success of innovative regions and their respective characteristics, hoping to provide a reference for the development of other innovative cities. The main conclusions of this study are the following; firstly, different countries have different social backgrounds. The development model of innovative regions is closely related to the regional backgrounds. Secondly, the market force and the government power have important significance for the development of the innovation regions. The influence of the government power in the early stage of development is great, and in the latter stage, development is dominated by the market force. In addition, the self-organizing ability of the region has a great impact on the innovation ability of the region. Strong self-organizing ability is conducive to the development of innovation economy.

Keywords: contrastive study, development model, innovation ecosystem, innovative regions

Procedia PDF Downloads 142
3338 Fault Analysis of Ship Power System Comprising of Parallel Generators and Variable Frequency Drive

Authors: Umair Ashraf, Kjetil Uhlen, Sverre Eriksen, Nadeem Jelani

Abstract:

Although advancement in technology has increased the reliability and ease of work in ship power system, but these advancements are also adding complexities. Ever increasing non linear loads, like power electronics (PE) devices effect the stability of the system. Frequent load variations and complex load dynamics are due to the frequency converters and motor drives, these problem are more prominent when system is connected with the weak grid. In the ship power system major consumers are thruster motors for the propulsion. For the control operation of these motors variable frequency drives (VFD) are used, mostly VFDs operate on nominal voltage of the system. Some of the consumers in ship operate on lower voltage than nominal, these consumers got supply through step down transformers. In this paper the vector control scheme is used for the control of both rectifier and inverter, parallel operation of the synchronous generators is also demonstrated. The simulation have been performed with induction motor as load on VFD and parallel RLC load. Fault analysis has been performed first for the system which do not have VFD and then for the system with VFD. Three phase to the ground, single phase to the ground fault were implemented and behavior of the system in both the cases was observed.

Keywords: non-linear load, power electronics, parallel operating generators, pulse width modulation, variable frequency drives, voltage source converters, weak grid

Procedia PDF Downloads 561
3337 Airborne Particulate Matter Passive Samplers for Indoor and Outdoor Exposure Monitoring: Development and Evaluation

Authors: Kholoud Abdulaziz, Kholoud Al-Najdi, Abdullah Kadri, Konstantinos E. Kakosimos

Abstract:

The Middle East area is highly affected by air pollution induced by anthropogenic and natural phenomena. There is evidence that air pollution, especially particulates, greatly affects the population health. Many studies have raised a warning of the high concentration of particulates and their affect not just around industrial and construction areas but also in the immediate working and living environment. One of the methods to study air quality is continuous and periodic monitoring using active or passive samplers. Active monitoring and sampling are the default procedures per the European and US standards. However, in many cases they have been inefficient to accurately capture the spatial variability of air pollution due to the small number of installations; which eventually is attributed to the high cost of the equipment and the limited availability of users with expertise and scientific background. Another alternative has been found to account for the limitations of the active methods that is the passive sampling. It is inexpensive, requires no continuous power supply, and easy to assemble which makes it a more flexible option, though less accurate. This study aims to investigate and evaluate the use of passive sampling for particulate matter pollution monitoring in dry tropical climates, like in the Middle East. More specifically, a number of field measurements have be conducted, both indoors and outdoors, at Qatar and the results have been compared with active sampling equipment and the reference methods. The samples have been analyzed, that is to obtain particle size distribution, by applying existing laboratory techniques (optical microscopy) and by exploring new approaches like the white light interferometry to. Then the new parameters of the well-established model have been calculated in order to estimate the atmospheric concentration of particulates. Additionally, an extended literature review will investigate for new and better models. The outcome of this project is expected to have an impact on the public, as well, as it will raise awareness among people about the quality of life and about the importance of implementing research culture in the community.

Keywords: air pollution, passive samplers, interferometry, indoor, outdoor

Procedia PDF Downloads 387
3336 Accuracy Analysis of the American Society of Anesthesiologists Classification Using ChatGPT

Authors: Jae Ni Jang, Young Uk Kim

Abstract:

Background: Chat Generative Pre-training Transformer-3 (ChatGPT; San Francisco, California, Open Artificial Intelligence) is an artificial intelligence chatbot based on a large language model designed to generate human-like text. As the usage of ChatGPT is increasing among less knowledgeable patients, medical students, and anesthesia and pain medicine residents or trainees, we aimed to evaluate the accuracy of ChatGPT-3 responses to questions about the American Society of Anesthesiologists (ASA) classification based on patients’ underlying diseases and assess the quality of the generated responses. Methods: A total of 47 questions were submitted to ChatGPT using textual prompts. The questions were designed for ChatGPT-3 to provide answers regarding ASA classification in response to common underlying diseases frequently observed in adult patients. In addition, we created 18 questions regarding the ASA classification for pediatric patients and pregnant women. The accuracy of ChatGPT’s responses was evaluated by cross-referencing with Miller’s Anesthesia, Morgan & Mikhail’s Clinical Anesthesiology, and the American Society of Anesthesiologists’ ASA Physical Status Classification System (2020). Results: Out of the 47 questions pertaining to adults, ChatGPT -3 provided correct answers for only 23, resulting in an accuracy rate of 48.9%. Furthermore, the responses provided by ChatGPT-3 regarding children and pregnant women were mostly inaccurate, as indicated by a 28% accuracy rate (5 out of 18). Conclusions: ChatGPT provided correct responses to questions relevant to the daily clinical routine of anesthesiologists in approximately half of the cases, while the remaining responses contained errors. Therefore, caution is advised when using ChatGPT to retrieve anesthesia-related information. Although ChatGPT may not yet be suitable for clinical settings, we anticipate significant improvements in ChatGPT and other large language models in the near future. Regular assessments of ChatGPT's ASA classification accuracy are essential due to the evolving nature of ChatGPT as an artificial intelligence entity. This is especially important because ChatGPT has a clinically unacceptable rate of error and hallucination, particularly in pediatric patients and pregnant women. The methodology established in this study may be used to continue evaluating ChatGPT.

Keywords: American Society of Anesthesiologists, artificial intelligence, Chat Generative Pre-training Transformer-3, ChatGPT

Procedia PDF Downloads 24
3335 Production of Camel Nanobodies against of Anti-Morphine-3-Glucuronide for the Development of a Biosensor for Detecting Illicit Drug

Authors: Shirin Jalili, Sadegh Hasannia, Hadi Shirzad, Afshin Khara

Abstract:

Morphine is one of the most medicinally important analgesics and narcotics. Structurally, it is classified as an alkaloid because of the presence of nitrogen. Its structure is similar to that of codeine, thebaine, and heroin. An immunoassay to accurately discriminate between these analogous alkaloids would be highly beneficial. A key factor for such an assay is specificity with high sensitivity, which is totally dependent on the antibody employed. However, most antibodies against haptens are polyclonal serum antibodies that exhibit significant cross-reactivities with closely related compounds. The camel-derived single-chain antibody fragments (VHH) are the smallest molecules with antigen-binding capacity, possessing unique properties compared to other conventional antibodies. In this study, a library containing the VHH genes of a camel immunized with with morphine conjugated BSA following phage display technology was generated. By screening the camel-derived variable region of the heavy chain cDNA phage display library with the ability to bind the desired hapten, we obtained some nanobodies that recognize this hapten. Phage display expression of the Nbs from this library and pannings against this hapten resulted in a clear enrichment of four distinct Nb-displaying phages with specificity for morphine that could be a potential target site for the development of new strategies for the development of a biosensor for detecting illicit drug.

Keywords: phage display, nanobody, Morphine-3, glucuronide, ELISA, biosensor

Procedia PDF Downloads 411
3334 Evaluation the Influence of Trunk Bracing in Joint Contact Forces in Subjects with Scoliosis

Authors: Azadeh Jafari, Mohammad Taghi Karimi, Azadeh Nadi

Abstract:

Background: Scoliosis is the lateral curvature of the spine which may influence the abilities of the subjects during standing and walking. Most of the scoliotic subjects use orthosis to reduce the curve and to decrease the risk of curve progression. There was lack of information regarding the effects of orthosis on kinematic and joint contact force. Therefore, this research was done to highlight the effects of orthosis on the aforementioned parameters. Method: 5 scoliotic subjects were recruited in this study, with single curve less than 40 (females with age 13.2 ± 1.7). They were asked to walk with and without orthosis. The kinematic of the joints, force applied on the legs, moments transmitted through the joints and joint contact forces were evaluated in this study. Moreover, the lengths of muscles were determined by use of computer muscle control approach in OpenSim. Results: There was a significant difference between the second peak of vertical ground reaction force while walking with and without orthosis (p-value < 0.05). There was no difference between spatiotemporal gait parameters while walking with and without orthosis (P-value > 0.05). The mean values of joint contact forces (vertical component) increased by the use of orthosis, but the difference was not significant (p-value > 0.05). Conclusion: Although the kinematic of most of the body joints was not influenced by the use of orthosis, the joint contact force may be increased by orthosis. The increase in joint contact force may be due to the performance of orthosis which restricts the motions of pelvic and increases compensatory mechanism used by the subjects to decrease the side effects of the orthosis.

Keywords: scoliosis, joint contact force, kinetic, kinematic

Procedia PDF Downloads 192
3333 Comprehensive Study of Data Science

Authors: Asifa Amara, Prachi Singh, Kanishka, Debargho Pathak, Akshat Kumar, Jayakumar Eravelly

Abstract:

Today's generation is totally dependent on technology that uses data as its fuel. The present study is all about innovations and developments in data science and gives an idea about how efficiently to use the data provided. This study will help to understand the core concepts of data science. The concept of artificial intelligence was introduced by Alan Turing in which the main principle was to create an artificial system that can run independently of human-given programs and can function with the help of analyzing data to understand the requirements of the users. Data science comprises business understanding, analyzing data, ethical concerns, understanding programming languages, various fields and sources of data, skills, etc. The usage of data science has evolved over the years. In this review article, we have covered a part of data science, i.e., machine learning. Machine learning uses data science for its work. Machines learn through their experience, which helps them to do any work more efficiently. This article includes a comparative study image between human understanding and machine understanding, advantages, applications, and real-time examples of machine learning. Data science is an important game changer in the life of human beings. Since the advent of data science, we have found its benefits and how it leads to a better understanding of people, and how it cherishes individual needs. It has improved business strategies, services provided by them, forecasting, the ability to attend sustainable developments, etc. This study also focuses on a better understanding of data science which will help us to create a better world.

Keywords: data science, machine learning, data analytics, artificial intelligence

Procedia PDF Downloads 63
3332 Hybrid Approach for Software Defect Prediction Using Machine Learning with Optimization Technique

Authors: C. Manjula, Lilly Florence

Abstract:

Software technology is developing rapidly which leads to the growth of various industries. Now-a-days, software-based applications have been adopted widely for business purposes. For any software industry, development of reliable software is becoming a challenging task because a faulty software module may be harmful for the growth of industry and business. Hence there is a need to develop techniques which can be used for early prediction of software defects. Due to complexities in manual prediction, automated software defect prediction techniques have been introduced. These techniques are based on the pattern learning from the previous software versions and finding the defects in the current version. These techniques have attracted researchers due to their significant impact on industrial growth by identifying the bugs in software. Based on this, several researches have been carried out but achieving desirable defect prediction performance is still a challenging task. To address this issue, here we present a machine learning based hybrid technique for software defect prediction. First of all, Genetic Algorithm (GA) is presented where an improved fitness function is used for better optimization of features in data sets. Later, these features are processed through Decision Tree (DT) classification model. Finally, an experimental study is presented where results from the proposed GA-DT based hybrid approach is compared with those from the DT classification technique. The results show that the proposed hybrid approach achieves better classification accuracy.

Keywords: decision tree, genetic algorithm, machine learning, software defect prediction

Procedia PDF Downloads 317
3331 The Qualification and Quality of Space Sciences and Space Engineering Education in Turkey

Authors: Hatice Canan Gungor, Ahmet Akdemir

Abstract:

The fields of engineering and technological sciences are increasing in quality and quantity day by day all over the world. Countries have to follow, implement and adapt these developments in order to economical empowerments. In our era, it's possible to follow the rapidly developing technology and to produce new technologies by inquisitive, curious, numerical thinking individuals who can show several approaches to problem solving. In this case, countries should develop te result oriented and need-focused curriculums in university education. As in the whole world, there are more space studies in our country as well. Universities should undertake the task of supply the need for staff of this technological race. In this context, questions about the purpose, content and learning outcomes of the space sciences and space engineering departments in our country will be researched answers to reveal the characteristic of this section. In this study, it was determined in which universities the space engineering and the departments of basic sciences educate with formal education and the contents of this education, and the universities were compared with each other as of 2017. In our country three universities provide Aeronautical and Aerospace Engineering, two universities provide Space Sciences and Technologies, two universities provide Aerospace Engineering, two universities provide Aeronautics and Astronautics Engineering education. In all universities, specialized courses are taught after basic engineering education. But the question that needs to be answered is, do the lessons benefit in practice? The answer of this question will reveal the quality of the education. This paper suggests that surveys be conducted to search for the answer to this question. It's thought to be the base for the next works.

Keywords: education, space engineering, space science, quality of systems

Procedia PDF Downloads 268
3330 Different Goals and Strategies of Smart Cities: Comparative Study between European and Asian Countries

Authors: Yountaik Leem, Sang Ho Lee

Abstract:

In this paper, different goals and the ways to reach smart cities shown in many countries during planning and implementation processes will be discussed. Each country dealt with technologies which have been embedded into space as development of ICTs (information and communication technologies) for their own purposes and by their own ways. For example, European countries tried to adapt technologies to reduce greenhouse gas emission to overcome global warming while US-based global companies focused on the way of life using ICTs such as EasyLiving of Microsoft™ and CoolTown of Hewlett-Packard™ during last decade of 20th century. In the North-East Asian countries, urban space with ICTs were developed in large scale on the viewpoint of capitalism. Ubiquitous city, first introduced in Korea which named after Marc Weiser’s concept of ubiquitous computing pursued new urban development with advanced technologies and high-tech infrastructure including wired and wireless network. Japan has developed smart cities as comprehensive and technology intensive cities which will lead other industries of the nation in the future. Not only the goals and strategies but also new directions to which smart cities are oriented also suggested at the end of the paper. Like a Finnish smart community whose slogan is ‘one more hour a day for citizens,’ recent trend is forwarding everyday lives and cultures of human beings, not capital gains nor physical urban spaces.

Keywords: smart cities, urban strategy, future direction, comparative study

Procedia PDF Downloads 249
3329 The Use of Social Media Sarcasm as a Response to Media-Coverage of Iran’s Unprecedented Attack on Israel

Authors: Afif J Arabi

Abstract:

On April 15, 2024, Iran announced its unprecedented military attack by sending waves of more than 300 drones and ballistic missiles toward Israel. The Attack lasted approximately five hours and was a widely covered, distributed, and followed media event. Iran’s military action against Israel was a long-awaited action across the Middle East since the early days of the October 7th war on Gaza and after a long history of verbal threats. While people in many Arab countries stayed up past midnight in anticipation of watching the disastrous results of this unprecedented attack, voices on traditional and social media alike started to question the timed public announcement of the attack, which gave Israel at least a two-hour notice to prepare its defenses. When live news coverage started showing that nearly all the drones and missiles were intercepted by Israel – with help from the U.S. and other countries – and no deaths were reported, the social media response to this media event turned toward sarcasm, mockery, irony, and humor. Social media users posted sarcastic pictures, jokes, and comments mocking the Iranian offensive. This research examines this unique media event and the sarcastic response it generated on social media. The study aims to investigate the causes leading to media sarcasm in militarized political conflict, the social function of such generated sarcasm, and the role of social media as a platform for consuming frustration, dissatisfaction, and outrage passively through various media products. The study compares the serious traditional media coverage of the event with the humorous social media response among Arab countries. The research uses an eclectic theoretical approach using framing theory as a paradigm for understanding and investigating communication social functionalism theory in media studies to examine sarcasm. Social functionalism theory is a sociological perspective that views society as a complex system whose parts work together to promote solidarity and stability. In the context of media and sarcasm, this theory would suggest that sarcasm serves specific functions within society, such as reinforcing social norms, providing a means for social critique, or functioning as a safety valve for expressing social tension.; and a qualitative analysis of specific examples including responses of SM commentators to such manifestations of political criticism. The preliminary findings of this study point to a heightened dramatization of the televised event and a widespread belief that this attack was a staged show incongruent with Iran’s official enmity and death threats toward Israel. The social media sarcasm reinforces Arab’s view of Iran and Israel as mutual threats. This belief stems from the complex dynamics, historical context, and regional conflict surrounding these three nations: Iran, Israel, and Arabs.

Keywords: social functionalism, social media sarcasm, Television news framing, live militarized conflict coverage, iran, israel, communication theory

Procedia PDF Downloads 19
3328 Mixed Matrix Membranes Based on [M₂(DOBDC)] (M = Mg, Co, Ni) and Polydimethylsiloxane for CO₂/N₂ Separation

Authors: Hyunuk Kim, Yang No Yun, Muhammad Sohail, Jong-Ho Moon, Young Cheol Park

Abstract:

Metal-organic frameworks (MOFs), which are emerging absorbents assembled from metal ions and organic ligands, have attracted attention for their permanent porosity and design of tunable pore size. These microporous materials showed interesting properties for CO₂ storage and separation. In particular, MOFs with high surface area and open metal sites showed the remarkable adsorption capacity and selectivity for CO₂. [Mg₂ (DOBDC)] (DOBDC = 2,5-dioxidobenzene-1,4-dicarboxylate) (MOF-74 or CPO-27) is a well-known absorbent showing an exceptionally high CO₂ sorption capacity at low partial pressure and room temperature. In this work, we synthesized [M₂(DOBDC)(DMF)₂] (M = Mg, Co, Ni) and determined their single-crystal structures by X-ray crystallography. The removal of coordinated guest molecules generates Lewis acidic sites and showed high CO₂ adsorption affinity. Both CO₂ adsorption capacity and surface area are much higher than reported values in literature. To fabricate MMMs, microcrystalline [M₂ (DOBDC)(DMF)₂] was synthesized by microwave reaction and dispersed in PDMS solution. The MMMs with a various amount of [M₂ (DOBDC)(DMF) ₂] in PDMS were fabricated by a solution casting method. [M₂ (DOBDC)(DMF)₂]@PDMS membrane showed higher CO2 permeability and CO₂/N₂ selectivity than those of PDMS. Therefore, we believe that MMMs combining polymer and MOFs provide new materials for CO₂ separation technology.

Keywords: metal-organic frameworks, mixed matrix membrane, CO2/N2 separation, polydimethylsiloxane (PDMS)

Procedia PDF Downloads 192
3327 Development and Power Characterization of an IoT Network for Agricultural Imaging Applications

Authors: Jacob Wahl, Jane Zhang

Abstract:

This paper describes the development and characterization of a prototype IoT network for use with agricultural imaging and monitoring applications. The sensor and gateway nodes are designed using the ESP32 SoC with integrated Bluetooth Low Energy 4.2 and Wi-Fi. A development board, the Arducam IoTai ESP32, is used for prototyping, testing, and power measurements. Google’s Firebase is used as the cloud storage site for image data collected by the sensor. The sensor node captures images using the OV2640 2MP camera module and transmits the image data to the gateway via Bluetooth Low Energy. The gateway then uploads the collected images to Firebase via a known nearby Wi-Fi network connection. This image data can then be processed and analyzed by computer vision and machine learning pipelines to assess crop growth or other needs. The sensor node achieves a wireless transmission data throughput of 220kbps while consuming 150mA of current; the sensor sleeps at 162µA. The sensor node device lifetime is estimated to be 682 days on a 6600mAh LiPo battery while acquiring five images per day based on the development board power measurements. This network can be utilized by any application that requires high data rates, low power consumption, short-range communication, and large amounts of data to be transmitted at low-frequency intervals.

Keywords: Bluetooth low energy, ESP32, firebase cloud, IoT, smart farming

Procedia PDF Downloads 128
3326 Adolescent-Parent Relationship as the Most Important Factor in Preventing Mood Disorders in Adolescents: An Application of Artificial Intelligence to Social Studies

Authors: Elżbieta Turska

Abstract:

Introduction: One of the most difficult times in a person’s life is adolescence. The experiences in this period may shape the future life of this person to a large extent. This is the reason why many young people experience sadness, dejection, hopelessness, sense of worthlessness, as well as losing interest in various activities and social relationships, all of which are often classified as mood disorders. As many as 15-40% adolescents experience depressed moods and for most of them they resolve and are not carried into adulthood. However, (5-6%) of those affected by mood disorders develop the depressive syndrome and as many as (1-3%) develop full-blown clinical depression. Materials: A large questionnaire was given to 2508 students, aged 13–16 years old, and one of its parts was the Burns checklist, i.e. the standard test for identifying depressed mood. The questionnaire asked about many aspects of the student’s life, it included a total of 53 questions, most of which had subquestions. It is important to note that the data suffered from many problems, the most important of which were missing data and collinearity. Aim: In order to identify the correlates of mood disorders we built predictive models which were then trained and validated. Our aim was not to be able to predict which students suffer from mood disorders but rather to explore the factors influencing mood disorders. Methods: The problems with data described above practically excluded using all classical statistical methods. For this reason, we attempted to use the following Artificial Intelligence (AI) methods: classification trees with surrogate variables, random forests and xgboost. All analyses were carried out with the use of the mlr package for the R programming language. Resuts: The predictive model built by classification trees algorithm outperformed the other algorithms by a large margin. As a result, we were able to rank the variables (questions and subquestions from the questionnaire) from the most to least influential as far as protection against mood disorder is concerned. Thirteen out of twenty most important variables reflect the relationships with parents. This seems to be a really significant result both from the cognitive point of view and also from the practical point of view, i.e. as far as interventions to correct mood disorders are concerned.

Keywords: mood disorders, adolescents, family, artificial intelligence

Procedia PDF Downloads 87
3325 Attitudes to Thinking and Learning in Sustainability Education: Case Basics of Natural Stone Industry in Circular Economy

Authors: Anne-Marie Tuomala

Abstract:

Education for sustainable development (ESD) aims to provide students with the attitudes, values, and behaviors necessary for the contribution to sustainability. The research was implemented as a part of the Horizons Europe research project, where each partner organization had at least one pilot project locally. The pilot in question was an online course about the basics of the natural stone industry in Finland and its sustainability and circular economy aspects. The course was open to all students of applied universities in Finland, and it was implemented twice during the research. The Stone from Finland association participated in the course design, and it was also an expert in the local context and real-life provider. The multiple case-study method was chosen, as it enables purposeful sampling of cases that are tailored to the specific study. It was also assumed that it predicts quite comparable results of two different course implementations of the course with the same topic and content. The Curtin University of Technology’s Attitudes Towards Thinking and Learning Survey was adapted. The results show the importance of the trans-disciplinary nature of sustainability education. In addition, the new industry areas with the general - but also industry-specific sustainability issues - must be introduced to students and encourage them to do critically reflective learning. Surveys that guide them to analyze their own attitudes to thinking and learning may expose students to their weaknesses but also result in forms of more active sustainability interaction.

Keywords: education for sustainable development, learning attitudes, learning of circular economy, virtual learning

Procedia PDF Downloads 17
3324 Outdoor Performances of Micro Scale Wind Turbine Stand Alone System

Authors: Ahmed. A. Hossam Eldin, Karim H. Youssef, Kareem M. AboRas

Abstract:

Recent current rapid industrial development and energy shortage are essential problems, which face most of the developing countries. Moreover, increased prices of fossil fuel and advanced energy conversion technology lead to the need for renewable energy resources. A study, modelling and simulation of an outdoor micro scale stand alone wind turbine was carried out. For model validation an experimental study was applied. In this research the aim was to clarify effects of real outdoor operating conditions and the instantaneous fluctuations of both wind direction and wind speed on the actual produced power. The results were compared with manufacturer’s data. The experiments were carried out in Borg Al-Arab, Alexandria. This location is on the north Western Coast of Alexandria. The results showed a real max output power for outdoor micro scale wind turbine, which is different from manufacturer’s value. This is due to the fact that the direction of wind speed is not the same as that of the manufacturer’s data. The measured wind speed and direction by the portable metrological weather station anemometer varied with time. The blade tail response could not change the blade direction at the same instant of the wind direction variation. Therefore, designers and users of micro scale wind turbine stand alone system cannot rely on the maker’s name plate data to reach the required power.

Keywords: micro-turbine, wind turbine, inverters, renewable energy, hybrid system

Procedia PDF Downloads 463
3323 Structural Strength Evaluation and Wear Prediction of Double Helix Steel Wire Ropes for Heavy Machinery

Authors: Krunal Thakar

Abstract:

Wire ropes combine high tensile strength and flexibility as compared to other general steel products. They are used in various application areas such as cranes, mining, elevators, bridges, cable cars, etc. The earliest reported use of wire ropes was for mining hoist application in 1830s. Over the period, there have been substantial advancement in the design of wire ropes for various application areas. Under operational conditions, wire ropes are subjected to varying tensile loads and bending loads resulting in material wear and eventual structural failure due to fretting fatigue. The conventional inspection methods to determine wire failure is only limited to outer wires of rope. However, till date, there is no effective mathematical model to examine the inter wire contact forces and wear characteristics. The scope of this paper is to present a computational simulation technique to evaluate inter wire contact forces and wear, which are in many cases responsible for rope failure. Two different type of ropes, IWRC-6xFi(29) and U3xSeS(48) were taken for structural strength evaluation and wear prediction. Both ropes have a double helix twisted wire profile as per JIS standards and are mainly used in cranes. CAD models of both ropes were developed in general purpose design software using in house developed formulation to generate double helix profile. Numerical simulation was done under two different load cases (a) Axial Tension and (b) Bending over Sheave. Different parameters such as stresses, contact forces, wear depth, load-elongation, etc., were investigated and compared between both ropes. Numerical simulation method facilitates the detailed investigation of inter wire contact and wear characteristics. In addition, various selection parameters like sheave diameter, rope diameter, helix angle, swaging, maximum load carrying capacity, etc., can be quickly analyzed.

Keywords: steel wire ropes, numerical simulation, material wear, structural strength, axial tension, bending over sheave

Procedia PDF Downloads 140
3322 Improved Computational Efficiency of Machine Learning Algorithm Based on Evaluation Metrics to Control the Spread of Coronavirus in the UK

Authors: Swathi Ganesan, Nalinda Somasiri, Rebecca Jeyavadhanam, Gayathri Karthick

Abstract:

The COVID-19 crisis presents a substantial and critical hazard to worldwide health. Since the occurrence of the disease in late January 2020 in the UK, the number of infected people confirmed to acquire the illness has increased tremendously across the country, and the number of individuals affected is undoubtedly considerably high. The purpose of this research is to figure out a predictive machine learning archetypal that could forecast COVID-19 cases within the UK. This study concentrates on the statistical data collected from 31st January 2020 to 31st March 2021 in the United Kingdom. Information on total COVID cases registered, new cases encountered on a daily basis, total death registered, and patients’ death per day due to Coronavirus is collected from World Health Organisation (WHO). Data preprocessing is carried out to identify any missing values, outliers, or anomalies in the dataset. The data is split into 8:2 ratio for training and testing purposes to forecast future new COVID cases. Support Vector Machines (SVM), Random Forests, and linear regression algorithms are chosen to study the model performance in the prediction of new COVID-19 cases. From the evaluation metrics such as r-squared value and mean squared error, the statistical performance of the model in predicting the new COVID cases is evaluated. Random Forest outperformed the other two Machine Learning algorithms with a training accuracy of 99.47% and testing accuracy of 98.26% when n=30. The mean square error obtained for Random Forest is 4.05e11, which is lesser compared to the other predictive models used for this study. From the experimental analysis Random Forest algorithm can perform more effectively and efficiently in predicting the new COVID cases, which could help the health sector to take relevant control measures for the spread of the virus.

Keywords: COVID-19, machine learning, supervised learning, unsupervised learning, linear regression, support vector machine, random forest

Procedia PDF Downloads 105
3321 Cardiothoracic Ratio in Postmortem Computed Tomography: A Tool for the Diagnosis of Cardiomegaly

Authors: Alex Eldo Simon, Abhishek Yadav

Abstract:

This study aimed to evaluate the utility of postmortem computed tomography (CT) and heart weight measurements in the assessment of cardiomegaly in cases of sudden death due to cardiac origin by comparing the results of these two diagnostic methods. The study retrospectively analyzed postmortem computed tomography (PMCT) data from 54 cases of sudden natural death and compared the findings with those of the autopsy. The study involved measuring the cardiothoracic ratio (CTR) from coronal computed tomography (CT) images and determining the actual cardiac weight by weighing the heart during the autopsy. The inclusion criteria for the study were cases of sudden death suspected to be caused by cardiac pathology, while exclusion criteria included death due to unnatural causes such as trauma or poisoning, diagnosed natural causes of death related to organs other than the heart, and cases of decomposition. Sensitivity, specificity, and diagnostic accuracy were calculated, and to evaluate the accuracy of using the cardiothoracic ratio (CTR) to detect an enlarged heart, the study generated receiver operating characteristic (ROC) curves. The cardiothoracic ratio (CTR) is a radiological tool used to assess cardiomegaly by measuring the maximum cardiac diameter in relation to the maximum transverse diameter of the chest wall. The clinically used criteria for CTR have been modified from 0.50 to 0.57 for use in postmortem settings, where abnormalities can be detected by comparing CTR values to this threshold. A CTR value of 0.57 or higher is suggestive of hypertrophy but not conclusive. Similarly, heart weight is measured during the traditional autopsy, and a cardiac weight greater than 450 grams is defined as hypertrophy. Of the 54 cases evaluated, 22 (40.7%) had a cardiothoracic ratio (CTR) ranging from > 0.50 to equal 0.57, and 12 cases (22.2%) had a CTR greater than 0.57, which was defined as hypertrophy. The mean CTR was calculated as 0.52 ± 0.06. Among the 54 cases evaluated, the weight of the heart was measured, and the mean was calculated as 369.4 ± 99.9 grams. Out of the 54 cases evaluated, 12 were found to have hypertrophy as defined by PMCT, while only 9 cases were identified with hypertrophy in traditional autopsy. The sensitivity and specificity of the test were calculated as 55.56% and 84.44%, respectively. The sensitivity of the hypertrophy test was found to be 55.56% (95% CI: 26.66, 81.12¹), the specificity was 84.44% (95% CI: 71.22, 92.25¹), and the diagnostic accuracy was 79.63% (95% CI: 67.1, 88.23¹). The limitation of the study was a low sample size of only 54 cases, which may limit the generalizability of the findings. The comparison of the cardiothoracic ratio with heart weight in this study suggests that PMCT may serve as a screening tool for medico-legal autopsies when performed by forensic pathologists. However, it should be noted that the low sensitivity of the test (55.5%) may limit its diagnostic accuracy, and therefore, further studies with larger sample sizes and more diverse populations are needed to validate these findings.

Keywords: PMCT, virtopsy, CTR, cardiothoracic ratio

Procedia PDF Downloads 70
3320 Linear Evolution of Compressible Görtler Vortices Subject to Free-Stream Vortical Disturbances

Authors: Samuele Viaro, Pierre Ricco

Abstract:

Görtler instabilities generate in boundary layers from an unbalance between pressure and centrifugal forces caused by concave surfaces. Their spatial streamwise evolution influences transition to turbulence. It is therefore important to understand even the early stages where perturbations, still small, grow linearly and could be controlled more easily. This work presents a rigorous theoretical framework for compressible flows using the linearized unsteady boundary region equations, where only the streamwise pressure gradient and streamwise diffusion terms are neglected from the full governing equations of fluid motion. Boundary and initial conditions are imposed through an asymptotic analysis in order to account for the interaction of the boundary layer with free-stream turbulence. The resulting parabolic system is discretize with a second-order finite difference scheme. Realistic flow parameters are chosen from wind tunnel studies performed at supersonic and subsonic conditions. The Mach number ranges from 0.5 to 8, with two different radii of curvature, 5 m and 10 m, frequencies up to 2000 Hz, and vortex spanwise wavelengths from 5 mm to 20 mm. The evolution of the perturbation flow is shown through velocity, temperature, pressure profiles relatively close to the leading edge, where non-linear effects can still be neglected, and growth rate. Results show that a global stabilizing effect exists with the increase of Mach number, frequency, spanwise wavenumber and radius of curvature. In particular, at high Mach numbers curvature effects are less pronounced and thermal streaks become stronger than velocity streaks. This increase of temperature perturbations saturates at approximately Mach 4 flows, and is limited in the early stage of growth, near the leading edge. In general, Görtler vortices evolve closer to the surface with respect to a flat plate scenario but their location shifts toward the edge of the boundary layer as the Mach number increases. In fact, a jet-like behavior appears for steady vortices having small spanwise wavelengths (less than 10 mm) at Mach 8, creating a region of unperturbed flow close to the wall. A similar response is also found at the highest frequency considered for a Mach 3 flow. Larger vortices are found to have a higher growth rate but are less influenced by the Mach number. An eigenvalue approach is also employed to study the amplification of the perturbations sufficiently downstream from the leading edge. These eigenvalue results are compared with the ones obtained through the initial value approach with inhomogeneous free-stream boundary conditions. All of the parameters here studied have a significant influence on the evolution of the instabilities for the Görtler problem which is indeed highly dependent on initial conditions.

Keywords: compressible boundary layers, Görtler instabilities, receptivity, turbulence transition

Procedia PDF Downloads 239