Search results for: computer case simulation
Commenced in January 2007
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Edition: International
Paper Count: 17568

Search results for: computer case simulation

3438 The History of Chartered Certified Accountants: The Case of Tunisia

Authors: Mariam Dammak, Yosra Makni Fourati, Rania Mnejja

Abstract:

This paper aims to highlight the conditions and the context of the birth and the implementation of the Chartered Certified Accountants in Tunisian universities. For this purpose, we present an historical overview of the establishment of institutions that started the courses of Chartered accounting, including the Institute of Higher Commercial Studies (IHEC) of Carthage, the Higher Institute of Management (ISG) of Tunis, the Faculty of Economics and Management (FSEG) of Sfax and later the Higher Institute of Accounting and Administration of Enterprises (ISCAE) of Tunis. Then, it would be relevant to examine the changes, carried out by the Tunisian government, of the regulations in force relating to this academic path, from its birth during the 1970s until nowadays. We conducted a documentary study (archival documents, official documents, etc.) accompanied by semi-structured interviews with key actors (accountants, academics, officials of the Ministry of Higher Education) who marked the history of the studies of Tunisian charted accounting. Addressing this research question in Tunisia may contribute to the literature in three ways. First, previous researches dealing with the history of charted accounting-education are scared. Second, this paper allows us to understand the circumstances and context of the birth and teaching of accounting in Tunisia. Eventually, it helps to position the accounting curriculum in relation to international requirements. In fact, the training of accountants is closely related to the practice of the profession, regulated by the Order of Chartered Accountants in Tunisia (OECT). This Order is a member of the International Federation of Accountants (IFAC), since its creation in the 80s, has obligations to align with international requirements, particularly those relating to higher education, set up in 2005 and updated in 2015 (International Standard Education: IES).

Keywords: accounting history, chartered certified accountants, higher accounting education, Tunisian context

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3437 Assessing Economic Losses Of 2104 Flood Disaster: A Case Study on Dabong, Kelantan, Malaysia

Authors: Ahmad Hamidi Mohamed, Jamaluddin Othman, Mashitah Suid, Mohd Zaim Mohd Shukri

Abstract:

Floods are considered an annual natural disaster in Kelantan. However, the record-setting flood of 2014 was a 'tsunami-like disaster'. A study has been conducted with the objectives to assess the economic impact of the flood to the resident of Dabong area in Kelantan Darul Naim, Malaysia. This area was selected due to the severity during the flood. The impacts of flood on local people were done by conducting structured interviews with the use of questionnaires. The questionnaire was intended to acquire information on losses faced by Dabong residence. Questionnaires covered various areas of inconveniences suffered with respect to health effects, including illnesses suffered, their intensities, duration and their associated costs. Loss of productivity and quality of life was also assessed. Inquiries were made to Government agencies to obtain relevant statistical data regarding the loss due to the flood tragedy. The data collected by giving formal request to the governmental agencies and formal meetings were done. From the study a staggering amount of losses were calculated. This figure comes from losses of property, Farmers/Agriculture, Traders/Business, Health, Insurance and Governmental losses. Flood brings hardship to the people of Dabong and these losses of home will cause inconveniences to the society. The huge amount of economic loss extracted from this study shows that federal and state government of Kelantan need to find out the cause of the major flood in 2014. Fast and effective measures have to be planned and implemented in flood prone area to prevent same tragedy happens in the future.

Keywords: economic impact, flood tragedy, Malaysia, property losses

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3436 Effect of a Polyherbal Gut Therapy Protocol in Changes of Gut and Behavioral Symptoms of Antibiotic Induced Dysbiosis of Autistic Babies

Authors: Dinesh K. S., D. R. C. V. Jayadevan

Abstract:

Autism is the most prevalent of a subset of the disorders organized under the umbrella of pervasive developmental disorders. After the publication of Andrew Wakefield's paper in lancet, many critiques deny this connection even without looking in to the matter. The British Medical Journal even put an editorial regarding this issue. BMJ 2010; 340:c1807. But ayurveda has ample of evidences to believe this connectivity. Dysbiosis, yeast growth of the gut, nutritional deficiencies, enzyme deficiencies, essential fatty acid deficiencies, Gastro esophageal reflux disease, indigestion, inflammatory bowel, chronic constipation & its cascade are few of them to note. The purpose of this paper is to present the observed changes in the behavioural symptoms of autistic babies after a gut management protocol which is a usual programme of our autism treatment plan especially after dysbiotic changes after antibiotic administration. Is there any correlation between changes (if significant) in gut symptoms and behavioral problems of autistic babies especially after a dysbiosis induced by antibiotics. Retrospective analysis of the case sheets of autistic patients admitted in Vaidyaratnam P.S.Varier Ayurveda College hospital, kottakkal,kerala, india from September 2010 are taken for the data processing. Autistic patients are used to come to this hospital as a part of their usual course of treatment. We investigated 40 cases diagnosed as autistic by clinical psychologists from different institutions who had dysbiosis induced by antibiotics. Significant change in gut symptoms before and after treatment p<0.05 in most of its components Significant change in behavioral symptoms before and after treatments p<0.05 in most of the components Correlation between gut symptoms change and behavioral symptoms changes after treatment is + 0.86. Conclusion : Selected Polyherbal Ayurveda treatment has significant role to play to make changes abnormal behaviors in autistic babies and has a positive correlation with changes in gut symptoms induced by dysbiosis of antibiotic intake.

Keywords: ayurveda, autism, dysbiosis, antibiotic

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3435 Impact of Forced Displacement on Place Attachment and Home Perception of Internally Displaced Turkish Cypriots

Authors: Makbule Oktay

Abstract:

Home is a significant entity in people’s lives. It is a place that provides shelter to people and a place to which one feels a sense of attachment and belonging. It is an entity that people develop feelings and meaning to it. People – place bond, or in other words place attachment, and home perception might alter as a consequence of lifetime experiences. Thus, forced displacement appears as a dramatic experience for people who lose their homes, belongings and communities. It impacts people who involuntarily leave their homes and belongings behind, experience physical, social, cultural and economic disruption and are forced to settle in an unfamiliar environment. Place attachment and home perception of internally displaced people who involuntarily leave their homes might be different from those who haven’t experience forced displacement. Although place attachment, meaning of home and forced displacement are the subjects that have been broadly studied, there is a lack of studies which question the relation between the three subjects in general and on Turkish Cypriot case in particular. Considering this, it is the aim of this paper to investigate the impact of forced displacement to internally displaced people’s attachment to a particular place and home perception. To do so, the study focuses on internally displaced Turkish Cypriots who have been internally displaced as a result of conflict. Interview and questionnaire as two of the commonly used techniques in the place attachment and home perception studies have been used in this study too. The results of the study indicate that internal displacement has an apparent impact on place attachment of forcibly displaced people. As a consequence of longstanding displacement, forcibly displaced people developed multiple attachments. Compared to people who have not experienced displacement, forcibly displaced people have low attachments. Forced displacement does not strongly impact the home perception in terms of meaning of home in longstanding displacement situations even though displacement-related meanings of home exist.

Keywords: forcibly displaced people, home perception, internal displacement, place attachment, Turkish Cypriots

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3434 The Implications of Population Dynamics on the Environmental Issues: A Case behind Global Change in Climate

Authors: Simiso Fisokuhle Nyandeni

Abstract:

The environment is one of the major components of intergenerational equity under sustainability; however, this component has been facing a lot of issues/crises, which include those that are caused by natural systems due to the actions of humans. Although some of those environmental issues may occur from natural causes, however, climate change effects have shown to increase rapidly due to human behavior, which led to the increase in greenhouse emissions and the over-exploitation of natural resources that maintain an ecological balance in our environment. Based on the recent projections, the growing population tends to outstrip the environmental resources, and as a result, the rapid depletion of natural resources that maintain ecological balance within the environment has resulted in such environmental issues. This paper has adopted desktop analysis to address the main objective, which seeks to address the effects of population dynamics on environmental issues and what needs to be done to maintain the ecological balance between the growing population and the limited resources that are available; thus, the collective data sources were used to justify the literature in order to get adequate results to influence the potential findings. The major findings postulate that there is an ecological imbalance between limited resources available and the growing population; as a result, the environment is taking action against humanity through climate change impacts. Hence findings further outline that in order to prevent such impacts, there should be drastic interventions by the governments (all stakeholders should be involved in decision-making; Governmental or non-governmental institutions, scientists, researchers, etc.) around the world to maintain this ecological balance and also to prioritize the adaptation measures. Therefore, this paper seeks to examine the implications of population dynamics on the environmental issues and what needs to be done in order to maintain this ecological balance between the growing population and environmental resources; hence, this review will be based on the climate change context.

Keywords: population dynamics, climate change, environment, sustainability

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3433 Heat-Induced Uncertainty of Industrial Computed Tomography Measuring a Stainless Steel Cylinder

Authors: Verena M. Moock, Darien E. Arce Chávez, Mariana M. Espejel González, Leopoldo Ruíz-Huerta, Crescencio García-Segundo

Abstract:

Uncertainty analysis in industrial computed tomography is commonly related to metrological trace tools, which offer precision measurements of external part features. Unfortunately, there is no such reference tool for internal measurements to profit from the unique imaging potential of X-rays. Uncertainty approximations for computed tomography are still based on general aspects of the industrial machine and do not adapt to acquisition parameters or part characteristics. The present study investigates the impact of the acquisition time on the dimensional uncertainty measuring a stainless steel cylinder with a circular tomography scan. The authors develop the figure difference method for X-ray radiography to evaluate the volumetric differences introduced within the projected absorption maps of the metal workpiece. The dimensional uncertainty is dominantly influenced by photon energy dissipated as heat causing the thermal expansion of the metal, as monitored by an infrared camera within the industrial tomograph. With the proposed methodology, we are able to show evolving temperature differences throughout the tomography acquisition. This is an early study showing that the number of projections in computer tomography induces dimensional error due to energy absorption. The error magnitude would depend on the thermal properties of the sample and the acquisition parameters by placing apparent non-uniform unwanted volumetric expansion. We introduce infrared imaging for the experimental display of metrological uncertainty in a particular metal part of symmetric geometry. We assess that the current results are of fundamental value to reach the balance between the number of projections and uncertainty tolerance when performing analysis with X-ray dimensional exploration in precision measurements with industrial tomography.

Keywords: computed tomography, digital metrology, infrared imaging, thermal expansion

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3432 Identify the Risks Factors and Problems of Waste Management in Developing Countries as Hurdles

Authors: Zubair Ahmad

Abstract:

The aim of this study is to analyze the risks factors and issues with waste management in developing nations as barriers. Depending on their content and categorization, wastes are managed differently. Waste management strategies differ for liquid, solid, and organic wastes. The final stage of trash disposal entails procedures like burning, interment, recycling, and treatment. Due to the rising creation of solid waste, the growing urban population has a magnified impact on the environment and public health. All regions, but especially informal urban neighborhoods, tribal villages, and official rural settlements have a protracted backlog in waste services. Another significant impediment seen in the developing world is a lack of education and awareness of effective waste-management practices. Unauthorized dumpsites pose a serious risk to the environment since they could contain dangerous elements like radioactive, infectious, and toxic waste. Wealthier individuals are more inclined to think that their actions will have an impact on environmental problems and to act to address them. Waste managers need to take action to make sure the public is given information that is consistent with what they currently know. The results of the data analysis conducted with the aid of the various methodologies discussed in the preceding chapter are presented in this chapter by the researcher. Descriptive analysis has been used in research to determine whether or not there are relationships between variables and to determine the importance of the variables. According to a survey, there are no efforts being made to lessen the odor that garbage dump sites emit (in terms of treating or recycling the material placed at dumpsite) This might be the case since respondents only commented on the waste management conditions in their immediate surroundings and may not have fully understood the steps taken to resolve this issue.

Keywords: risk factor of waste material, lack of awareness, developing countries struggles, waste management

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3431 Numerical Study of Fluid Flow and Heat Transfer in Microchannel with Thin Obstacles

Authors: Malorzata Kmiotek, Anna Kucaba-Pietal, Robert Smusz

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Due to the miniaturisation process, in many technical devices, microchannels are used in cooling systems. Because of the small size of microchannels, the flow inside is laminar, which caused a slow heat exchange. In order to intensify the heat exchange, the flow must be disturbed, for example, by introducing obstacles. We present results on the influence of a thin obstacle, placed on microchannel wall, on the fluid and heat flow in the aspect of their use by constructors of heat exchangers. The obstacle is called 'thin' when its geometrical parameter (o=w/h, w- width, h - height of the obstacle) satisfies inequality: o < 0.5. In this work, we report numerical results on heat and mass transfer in the microchannels of 400 micrometer height (H - height of the microchannel), where thin obstacles are immersed on the walls, to disturb the flow. The Reynolds number of the flow in microchannel varies between 20 and 200 and is typical for the flow in micro heat exchangers. The equations describing the fluid and heat flows in microchannels were solved numerically by using the finite element method with an application of CFD&FSI package of ADINA R&D, Inc. 9.4 solver. In the case of flows in the microchannels with sequences of thin rectangular obstacles placed on the bottom and the top wall of a microchannel, the influence of distances s (s is the distance between two thin obstacles) and heights of obstacles on the fluid and heat transfer was investigated. Thermal and flow conditions of the application area of microchannels in electronic cooling systems, i.e., wall temperature of 60 °C, the fluid temperature of 20°C were used to solve equations. Additionally, the distance s between the thin obstacles in microchannels as a multiple of the amount of the channel height was determined. Results show that placing thin obstacles on microchannel walls increase the length of recirculation zones of the flow and improves the heat transfer.

Keywords: Finite Element Method, heat transfer, mechanical engineering, microchannel

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3430 A Tomb Structure in Pursuit of Tradition in 2oth Century Turkey and Its Story; the Tomb of Haci Hâkim Kemal Onsun and His Wife

Authors: Yavuz Arat, Ugur Tuztasi, Mehmet Uysal

Abstract:

Anatolia has been the host of many civilizations and a site where architectural structures of many cultural layers were interpreted. Most significantly the Turks who settled in Central Asia brought their architectural dynamics and cultural accumulation to Anatolia after the 12th century. The tomb structures first observed in Central Asia under the influence of Islamic faith and Turkish cultural heritage has blossomed under Great Seljuk Empire and with the Anatolian Seljuk Empire these tombs changed both in size and form with rich and beautiful samples from Ahlat to Sivas to Kayseri and Konya. This tomb tradition which started during 13th century has continued during the Ottoman Empire period with some alterations of form and evolved into the rarely observed mausoleum type tombs. The Ottoman tradition of building tombs inside mosque gardens and their forms present the clues of an important burial tradition. However this understanding was abandoned in 20th century Turkey. This tradition was abandoned with regard to legal regulations and health conditions. This study investigates the vestiges of this tradition and its spatial reflections over a sample. The present sample is representative of a tradition that started in 1970s and the case of building tombs inside mosque gardens will be illustrated over the tomb of Hacı Kemal Onsun and his wife which is located in Konya, the capital of the Anatolian Seljuks. The building process of this tomb will be evaluated with regard to burial traditions and architectural stylization.

Keywords: tomb, language of architectural form, Anatolian Seljuk tombs, Ottoman tombs

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3429 Application of Remote Sensing and In-Situ Measurements for Discharge Monitoring in Large Rivers: Case of Pool Malebo in the Congo River Basin

Authors: Kechnit Djamel, Ammarri Abdelhadi, Raphael Tshimang, Mark Trrig

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One of the most important aspects of monitoring rivers is navigation. The variation of discharge in the river generally produces a change in available draft for a vessel, particularly in the low flow season, which can impact the navigable water path, especially when the water depth is less than the normal one, which allows safe navigation for boats. The water depth is related to the bathymetry of the channel as well as the discharge. For a seasonal update of the navigation maps, a daily discharge value is required. Many novel approaches based on earth observation and remote sensing have been investigated for large rivers. However, it should be noted that most of these approaches are not currently able to directly estimate river discharge. This paper discusses the application of remote sensing tools using the analysis of the reflectance value of MODIS imagery and is combined with field measurements for the estimation of discharge. This approach is applied in the lower reach of the Congo River (Pool Malebo) for the period between 2019 and 2021. The correlation obtained between the observed discharge observed in the gauging station and the reflectance ratio time series is 0.81. In this context, a Discharge Reflectance Model (DRM) was developed to express discharge as a function of reflectance. This model introduces a non-contact method that allows discharge monitoring using earth observation. DRM was validated by field measurements using ADCP, in different sections on the Pool Malebo, over two different periods (dry and wet seasons), as well as by the observed discharge in the gauging station. The observed error between the estimated and measured discharge values ranges from 1 to 8% for the ADCP and from (1% to 11%) for the gauging station. The study of the uncertainties will give us the possibility to judge the robustness of the DRM.

Keywords: discharge monitoring, navigation, MODIS, empiric, ADCP, Congo River

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3428 Wellness Tourism in Baluwarti Tourism Village, Surakarta City

Authors: Deria Adi Wijaya, Amad Saeroji, Jimmi Sandi P., Nanang Wijayanto

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Tourism and the creative economy are combinations that can become a sustainable source of welfare that can boost the economy so as to increase the country's foreign exchange. Therefore the development of the tourism sector is one of the priorities in President Joko Widodo's leadership framework for the 2019-2024 period. Entering the current pandemic, each party is required to be able to implement strict health protocols to slow the rate of SARS-Cov2 infection, or what is known as the coronavirus, but on the other hand, the need to turn the wheels of the economy must continue. Therefore, an effort is needed to develop tourism activities that are full of experiences that add health benefits. Anticipating this, the Ministry of Tourism and Creative Economy collaborated with the Ministry of Health to offer an innovative development model, namely wellness tourism. The development of wellness tourism is an alternative that can make a positive contribution to the development of Indonesian tourism during the pandemic. This research seeks to synergize efforts to develop national tourism into the regional sphere; in this case, Baluwarti Tourism Village, which is located within the walls of the Surakarta Sunanate Palace, has the potential to be developed into a wellness tourism destination in Surakarta City. Considering that a village that is in the immediate vicinity of a palace certainly has a variety of potential attractions for royal wellness tourism. The main objectives of this study are 1) to identify the potential for palace-style wellness tourism in Baluwarti Tourism Village; 2) to formulate development in the form of tour packages in Baluwarti Tourism Village. Of course, the development of the wellness tour package is still based on local wisdom, namely a tour package that raises local potential as a palace-style wellness tourism attraction that can improve the economy of the local people through the tourism sector in the post-pandemic era.

Keywords: potential, wellness tourism, Baluwarti Tourism Village, Surakarta Sunanate Palace, Surakarta City

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3427 Agro-Insurance and Farming Development Opportunities in Georgia

Authors: Tamar Lazariashvili

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Introduction: The agro-insurance has great importance for agricultural development in the country. In the article, the insurance market of the Georgian agricultural sector has been studied, the level of interest of farmers with insurance products and the trend of demand for those products are revealed; also, the importance of insurance is substantiated. Methodology: The following research methods are applied in the presented paper: statistical (selection, grouping, observation, trend) and qualitative research (in-depth interview with farmers). They claim that the main reason for aggravation is the low level of trust, less awareness about the conditions of the insurance contract. In order to eradicate distrust towards agro-insurance, it is recommended to increase awareness of insured farmers in terms of an insurance agreement. In the case of disputable issues between insurance companies and the customers (farmers), it is advisable to enact the Mediation Service, which will be able to protect the rights of insured farmers. Main Findings: Insurance companies prefer to deal with large farmers, the number of them is very small in Georgia as the credit market. The government interference in this sector is also a very cautious topic. However, the government can strengthen the awareness of farmers about the characteristics and advantages of the insurance system in order to increase the number of insured and reduce insurance premiums for farmers. Conclusion: Enactment of agro-insurance will increase the interest and confidence of financial institutions in the farming sector, financial resources will be accessible to the farmers that will facilitate the stable development of the sector in the country. The size of the agro-insurance market in the country should be increased, and the new territories should be covered. The State must have an obligation to ensure the risk of farmers and subsidize insurance companies. Based on the analysis of the insurance market, the conclusions on agro-insurance issues and the relevant recommendations are proposed.

Keywords: Agro-insurance, agricultural product, Agro-market, farming

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3426 Comparative Study of Flood Plain Protection Zone Determination Methodologies in Colombia, Spain and Canada

Authors: P. Chang, C. Lopez, C. Burbano

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Flood protection zones are riparian buffers that are formed to manage and mitigate the impact of flooding, and in turn, protect local populations. The purpose of this study was to evaluate the Guía Técnica de Criterios para el Acotamiento de las Rondas Hídricas in Colombia against international regulations in Canada and Spain, in order to determine its limitations and contribute to its improvement. The need to establish a specific corridor that allows for the dynamic development of a river is clear; however, limitations present in the Colombian Technical Guide are identified. The study shows that international regulations provide similar concepts as used in Colombia, but additionally integrate aspects such as regionalization that allows for a better characterization of the channel way, and incorporate the frequency of flooding and its probability of occurrence in the concept of risk when determining the protection zone. The case study analyzed in Dosquebradas - Risaralda aimed at comparing the application of the different standards through hydraulic modeling. It highlights that the current Colombian standard does not offer sufficient details in its implementation phase, which leads to a false sense of security related to inaccuracy and lack of data. Furthermore, the study demonstrates how the Colombian norm is ill-adapted to the conditions of Dosquebradas typical of the Andes region, both in the social and hydraulic aspects, and does not reduce the risk, nor does it improve the protection of the population. Our study considers it pertinent to include risk estimation as an integral part of the methodology when establishing protect flood zone, considering the particularity of water systems, as they are characterized by an heterogeneous natural dynamic behavior.

Keywords: environmental corridor, flood zone determination, hydraulic domain, legislation flood protection zone

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3425 Search for APN Permutations in Rings ℤ_2×ℤ_2^k

Authors: Daniel Panario, Daniel Santana de Freitas, Brett Stevens

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Almost Perfect Nonlinear (APN) permutations with optimal resistance against differential cryptanalysis can be found in several domains. The permutation used in the standard for symmetric cryptography (the AES), for example, is based on a special kind of inversion in GF(28). Although very close to APN (2-uniform), this permutation still contains one number 4 in its differential spectrum, which means that, rigorously, it must be classified as 4-uniform. This fact motivates the search for fully APN permutations in other domains of definition. The extremely high complexity associated to this kind of problem precludes an exhaustive search for an APN permutation with 256 elements to be performed without the support of a suitable mathematical structure. On the other hand, in principle, there is nothing to indicate which mathematically structured domains can effectively help the search, and it is necessary to test several domains. In this work, the search for APN permutations in rings ℤ2×ℤ2k is investigated. After a full, exhaustive search with k=2 and k=3, all possible APN permutations in those rings were recorded, together with their differential profiles. Some very promising heuristics in these cases were collected so that, when used as a basis to prune backtracking for the same search in ℤ2×ℤ8 (search space with size 16! ≅244), just a few tenths of a second were enough to produce an APN permutation in a single CPU. Those heuristics were empirically extrapolated so that they could be applied to a backtracking search for APNs over ℤ2×ℤ16 (search space with size 32! ≅2117). The best permutations found in this search were further refined through Simulated Annealing, with a definition of neighbors suitable to this domain. The best result produced with this scheme was a 3-uniform permutation over ℤ2×ℤ16 with only 24 values equal to 3 in the differential spectrum (all the other 968 values were less than or equal 2, as it should be the case for an APN permutation). Although far from being fully APN, this result is technically better than a 4-uniform permutation and demanded only a few seconds in a single CPU. This is a strong indication that the use of mathematically structured domains, like the rings described in this work, together with heuristics based on smaller cases, can lead to dramatic cuts in the computational resources involved in the complexity of the search for APN permutations in extremely large domains.

Keywords: APN permutations, heuristic searches, symmetric cryptography, S-box design

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3424 Controlling Deforestation in the Densely Populated Region of Central Java Province, Banjarnegara District, Indonesia

Authors: Guntur Bagus Pamungkas

Abstract:

As part of a tropical country that is normally rich in forest land areas, Indonesia has always been in the world's spotlight due to its significantly increasing process of deforestation. In one hand, it is related to the mainstay for maintaining the sustainability of the earth's ecosystem functions. On the other hand, they also cover the various potential sources of the global economy. Therefore, it can always be the target of different scale of investors to excessively exploit them. No wonder the emergence of disasters in various characteristics always comes up. In fact, the deforestation phenomenon does not only occur in various forest land areas in the main islands of Indonesia but also includes Java Island, the most densely populated areas in the world. This island only remains the forest land of about 9.8% of the total forest land in Indonesia due to its long history of it, especially in Central Java Province, the most densely populated area in Java. Again, not surprisingly, this province belongs to the area with the highest frequency of disasters because of it, landslides in particular. One of the areas that often experience it is Banjarnegara District, especially in mountainous areas that lies in the range from 1000 to 3000 meters above sea level, where the remains of land forest area can easyly still be found. Even among them still leaves less untouchable tropical rain forest whose area also covers part of a neighboring district, Pekalongan, which is considered to be the rest of the world's little paradise on Earth. The district's landscape is indeed beautiful, especially in the Dieng area, a major tourist destination in Central Java Province after Borobudur Temple. However, annually hazardous always threatens this district due to this landslide disaster. Even, there was a tragic event that was buried with its inhabitants a few decades ago. This research aims to find part of the concept of effective forest management through monitoring the presence of remaining forest areas in this area. The research implemented monitoring of deforestation rates using the Stochastic Cellular Automata-Markov Chain (SCA-MC) method, which serves to provide a spatial simulation of land use and cover changes (LULCC). This geospatial process uses the Landsat-8 OLI image product with Thermal Infra-Red Sensors (TIRS) Band 10 in 2020 and Landsat 5 TM with TIRS Band 6 in 2010. Then it is also integrated with physical and social geography issues using the QGIS 2.18.11 application with the Mollusce Plugin, which serves to clarify and calculate the area of land use and cover, especially in forest areas—using the LULCC method, which calculates the rate of forest area reduction in 2010-2020 in Banjarnegara District. Since the dependence of this area on the use of forest land is quite high, concepts and preventive actions are needed, such as rehabilitation and reforestation of critical lands through providing proper monitoring and targeted forest management to restore its ecosystem in the future.

Keywords: deforestation, populous area, LULCC method, proper control and effective forest management

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3423 Rescaled Range Analysis of Seismic Time-Series: Example of the Recent Seismic Crisis of Alhoceima

Authors: Marina Benito-Parejo, Raul Perez-Lopez, Miguel Herraiz, Carolina Guardiola-Albert, Cesar Martinez

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Persistency, long-term memory and randomness are intrinsic properties of time-series of earthquakes. The Rescaled Range Analysis (RS-Analysis) was introduced by Hurst in 1956 and modified by Mandelbrot and Wallis in 1964. This method represents a simple and elegant analysis which determines the range of variation of one natural property (the seismic energy released in this case) in a time interval. Despite the simplicity, there is complexity inherent in the property measured. The cumulative curve of the energy released in time is the well-known fractal geometry of a devil’s staircase. This geometry is used for determining the maximum and minimum value of the range, which is normalized by the standard deviation. The rescaled range obtained obeys a power-law with the time, and the exponent is the Hurst value. Depending on this value, time-series can be classified in long-term or short-term memory. Hence, an algorithm has been developed for compiling the RS-Analysis for time series of earthquakes by days. Completeness time distribution and locally stationarity of the time series are required. The interest of this analysis is their application for a complex seismic crisis where different earthquakes take place in clusters in a short period. Therefore, the Hurst exponent has been obtained for the seismic crisis of Alhoceima (Mediterranean Sea) of January-March, 2016, where at least five medium-sized earthquakes were triggered. According to the values obtained from the Hurst exponent for each cluster, a different mechanical origin can be detected, corroborated by the focal mechanisms calculated by the official institutions. Therefore, this type of analysis not only allows an approach to a greater understanding of a seismic series but also makes possible to discern different types of seismic origins.

Keywords: Alhoceima crisis, earthquake time series, Hurst exponent, rescaled range analysis

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3422 Application of an Analytical Model to Obtain Daily Flow Duration Curves for Different Hydrological Regimes in Switzerland

Authors: Ana Clara Santos, Maria Manuela Portela, Bettina Schaefli

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This work assesses the performance of an analytical model framework to generate daily flow duration curves, FDCs, based on climatic characteristics of the catchments and on their streamflow recession coefficients. According to the analytical model framework, precipitation is considered to be a stochastic process, modeled as a marked Poisson process, and recession is considered to be deterministic, with parameters that can be computed based on different models. The analytical model framework was tested for three case studies with different hydrological regimes located in Switzerland: pluvial, snow-dominated and glacier. For that purpose, five time intervals were analyzed (the four meteorological seasons and the civil year) and two developments of the model were tested: one considering a linear recession model and the other adopting a nonlinear recession model. Those developments were combined with recession coefficients obtained from two different approaches: forward and inverse estimation. The performance of the analytical framework when considering forward parameter estimation is poor in comparison with the inverse estimation for both, linear and nonlinear models. For the pluvial catchment, the inverse estimation shows exceptional good results, especially for the nonlinear model, clearing suggesting that the model has the ability to describe FDCs. For the snow-dominated and glacier catchments the seasonal results are better than the annual ones suggesting that the model can describe streamflows in those conditions and that future efforts should focus on improving and combining seasonal curves instead of considering single annual ones.

Keywords: analytical streamflow distribution, stochastic process, linear and non-linear recession, hydrological modelling, daily discharges

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3421 Comparative Parametric Analysis on the Dynamic Response of Fibre Composite Beams with Debonding

Authors: Indunil Jayatilake, Warna Karunasena

Abstract:

Fiber Reinforced Polymer (FRP) composites enjoy an array of applications ranging from aerospace, marine and military to automobile, recreational and civil industry due to their outstanding properties. A structural glass fiber reinforced polymer (GFRP) composite sandwich panel made from E-glass fiber skin and a modified phenolic core has been manufactured in Australia for civil engineering applications. One of the major mechanisms of damage in FRP composites is skin-core debonding. The presence of debonding is of great concern not only because it severely affects the strength but also it modifies the dynamic characteristics of the structure, including natural frequency and vibration modes. This paper deals with the investigation of the dynamic characteristics of a GFRP beam with single and multiple debonding by finite element based numerical simulations and analyses using the STRAND7 finite element (FE) software package. Three-dimensional computer models have been developed and numerical simulations were done to assess the dynamic behavior. The FE model developed has been validated with published experimental, analytical and numerical results for fully bonded as well as debonded beams. A comparative analysis is carried out based on a comprehensive parametric investigation. It is observed that the reduction in natural frequency is more affected by single debonding than the equally sized multiple debonding regions located symmetrically to the single debonding position. Thus it is revealed that a large single debonding area leads to more damage in terms of natural frequency reduction than isolated small debonding zones of equivalent area, appearing in the GFRP beam. Furthermore, the extents of natural frequency shifts seem mode-dependent and do not seem to have a monotonous trend of increasing with the mode numbers.

Keywords: debonding, dynamic response, finite element modelling, novel FRP beams

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3420 Numerical Modeling of Film Cooling of the Surface at Non-Uniform Heat Flux Distributions on the Wall

Authors: M. V. Bartashevich

Abstract:

The problem of heat transfer at thin laminar liquid film is solved numerically. A thin film of liquid flows down an inclined surface under conditions of variable heat flux on the wall. The use of thin films of liquid allows to create the effective technologies for cooling surfaces. However, it is important to investigate the most suitable cooling regimes from a safety point of view, in order, for example, to avoid overheating caused by the ruptures of the liquid film, and also to study the most effective cooling regimes depending on the character of the distribution of the heat flux on the wall, as well as the character of the blowing of the film surface, i.e., the external shear stress on its surface. In the statement of the problem on the film surface, the heat transfer coefficient between the liquid and gas is set, as well as a variable external shear stress - the intensity of blowing. It is shown that the combination of these factors - the degree of uniformity of the distribution of heat flux on the wall and the intensity of blowing, affects the efficiency of heat transfer. In this case, with an increase in the intensity of blowing, the cooling efficiency increases, reaching a maximum, and then decreases. It is also shown that the more uniform the heating of the wall, the more efficient the heat sink. A separate study was made for the flow regime along the horizontal surface when the liquid film moves solely due to external stress influence. For this mode, the analytical solution is used for the temperature at the entrance region for further numerical calculations downstream. Also the influence of the degree of uniformity of the heat flux distribution on the wall and the intensity of blowing of the film surface on the heat transfer efficiency was also studied. This work was carried out at the Kutateladze Institute of Thermophysics SB RAS (Russia) and supported by FASO Russia.

Keywords: Heat Flux, Heat Transfer Enhancement, External Blowing, Thin Liquid Film

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3419 Periodontal Soft Tissue Sculpturing and Use of Interim Appliance for Rehabilitation of Anterior Edentulousness: Case Report

Authors: Hande Yesil, Seda Aycan Altan, M. Vehbi Bal, Alper Uyar, O. Cumhur Sipahi

Abstract:

Purpose: Fixed partial dentures (FPDs) must fulfill functional requirements such as phonetics, chewing efficiency and esthetics especially in the anterior region. A convex type tissue surface is usually recommended for pontics of FPDs. That pontic design also provides suitable oral hygiene and ease of cleaning. However, high esthetic requirements and correct emergence profile are not always achievable because of the convex shape of adjacent soft tissues. Therefore, the ovate type pontic which fulfills the high esthetic demands of the patients may be a good alternative to the modified ridge lap pontic design. Clinical Report: A female patient referred with the complaint of anterior upper edentulousness. In the oral examination it was determined that teeth 11, 12, 21, 22 were deficient. A thick and convex gingival tissue that may cause aesthetic problems was also observed.. Periodontal augmentation surgery was performed to ensure proper papillary configuration and gingival contour. An interim removable partial denture (IRPD) which applied pressure to operated gingival tissues was fabricated postoperatively. The IRPD was used for 4 weeks and after completion of tissue sculpting, the permanent FPD with an ovate pontic was fabricated and cemented. After a follow-up period of 6 months, not any esthetical and hygienic problem was detected and the patient was satisfied with her prosthesis. Conclusion: It was concluded that shaping of gingival contours with IRPD and use of a FPD with ovate pontic fulfills all esthetic and hygienic requirements.

Keywords: interim appliance, ovate pontic, tissue sculpturing, fixed partial denture

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3418 Enhancing the Interpretation of Group-Level Diagnostic Results from Cognitive Diagnostic Assessment: Application of Quantile Regression and Cluster Analysis

Authors: Wenbo Du, Xiaomei Ma

Abstract:

With the empowerment of Cognitive Diagnostic Assessment (CDA), various domains of language testing and assessment have been investigated to dig out more diagnostic information. What is noticeable is that most of the extant empirical CDA-based research puts much emphasis on individual-level diagnostic purpose with very few concerned about learners’ group-level performance. Even though the personalized diagnostic feedback is the unique feature that differentiates CDA from other assessment tools, group-level diagnostic information cannot be overlooked in that it might be more practical in classroom setting. Additionally, the group-level diagnostic information obtained via current CDA always results in a “flat pattern”, that is, the mastery/non-mastery of all tested skills accounts for the two highest proportion. In that case, the outcome does not bring too much benefits than the original total score. To address these issues, the present study attempts to apply cluster analysis for group classification and quantile regression analysis to pinpoint learners’ performance at different proficiency levels (beginner, intermediate and advanced) thus to enhance the interpretation of the CDA results extracted from a group of EFL learners’ reading performance on a diagnostic reading test designed by PELDiaG research team from a key university in China. The results show that EM method in cluster analysis yield more appropriate classification results than that of CDA, and quantile regression analysis does picture more insightful characteristics of learners with different reading proficiencies. The findings are helpful and practical for instructors to refine EFL reading curriculum and instructional plan tailored based on the group classification results and quantile regression analysis. Meanwhile, these innovative statistical methods could also make up the deficiencies of CDA and push forward the development of language testing and assessment in the future.

Keywords: cognitive diagnostic assessment, diagnostic feedback, EFL reading, quantile regression

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3417 Evaluating the Management of Febrile Infants (Less than 90 Days) Presenting to Tallaght Ed- Completed Audit Cycle

Authors: Amel Osman, Stewart McKenna

Abstract:

Aim: Fever may present as the sole sign of a serious underlying infection in young infants. Febrile Infants aged less than 90 days are at an elevated susceptibility to invasive bacterial infections, thus presenting a challenge in ensuring the appropriate management of these cases. This study aims to ensure strict adherence to NICE guidelines for the management of fever in infants between 0 and 90 days presenting to Tallaght Hospital ED. A comprehensive audit, followed by a re-audit, was conducted to enhance the quality of care delivered to these patients. In accordance with NICE guidelines, all febrile infants should undergo blood tests. Additionally, LP should be performed in all neonates under 28 days, infants displaying signs of illness, and those with WCC below 5 or above 15. Method: A retrospective case review was performed, encompassing all patients aged between 0 to 90 days who presented with fever at Tallaght ED. Data retrieval was conducted from electronic records on two separate occasions, six months apart. The evaluation encompassed the assessment of body temperature as well as both partial and full septic workups. Results: Over the study period, 150 infants presented to the ED with fever in the initial audit, and 120 in the re-audit. In the first study, 81 patients warranted a full septic workup as per NICE, but only 48 received it. Conversely, 40 patients met criteria for a partial septic workup, with 12 undergoing blood tests. In the second study, 73 patients qualified for a full septic workup, of which 52 were completed. Additionally, 27 patients were indicated for a partial workup, with 20 undergoing blood tests. Conclusion: Managing febrile infants under three months of age presenting to Tallaght ED remains a persistent challenge, underscoring the need for continuous educational initiatives to guarantee that these patients receive the requisite assessments and treatments.

Keywords: infants, fever, septic workup, tallaght

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3416 Photoluminescence in Cerium Doped Fluorides Prepared by Slow Precipitation Method

Authors: Aarti Muley, S. J. Dhoblae

Abstract:

CaF₂ and BaF₂ doped with cerium were prepared by slow precipitation method with different molar concentration and different cerium concentration. Both the samples were also prepared by direct method for comparison. The XRD of BaF₂:Ce shows that it crystallizes to BCC structure. The peak matches with JCPDS file no. 4-0452. Also, The XRD pattern of CaF₂:Ce matches well with the JCPDS file number 75- 0363 and crystallized to BCC phase. In CaF₂, the double-humped photoluminescence spectra were observed at 320nm and 340nm when the sample was prepared by the direct precipitation method, and the ratio between these peaks is unity. However when the sample prepared by slow precipitation method the double-humped emission spectra of CaF₂:Ce was observed at 323nm and 340nm. The ratio between these peaks is 0.58, and the optimum concentration is obtained for 0.1 molar CaF₂ with Ce concentration 1.5%. When the cerium concentration is increased by 2% the peak at 323nm vanishes, and the emission was observed at 342nm with the shoulder at 360nm. In this case, the intensity reduces drastically. The excitation is observed at 305nm with a small peak at 254nm. One molar BaF₂ doped with 0.1% of cerium was synthesized by direct precipitation method gives double humped spectra at 308nm and 320nm, when it is prepared with slow precipitation method with the cerium concentration 0.05m%, 0.1m%, 0.15m%, 0.2m% the broad emission is observed around 325nm with the shoulder at 350nm. The excitation spectra are narrow and observed at 290nm. As the percentage of cerium is increased further again shift is observed. The emission spectra were observed at 360nm with a small peak at 330nm. The phenomenon of shifting of emission spectra at low concentration of cerium can directly relate with the particle size and reported for nanomaterials also.

Keywords: calcium fluoride, barium fluoride, photoluminescence, slow precipitation method

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3415 Attraction and Retention of Newly Graduated Medical Doctors to Deprived Regions in Ghana: A Qualitative Case Study

Authors: Lily Yarney, Emmanuel M. Y. Seidu, Thomas Chireh Kuusaanu, Belinda Adzimah-Yeboah

Abstract:

Healthcare delivery is labor-intensive; the role of the health worker is, therefore, indispensable in maintaining and improving individual and population health. In Ghana, doctor-patient ratio is 1:10,450, with a disproportionate tilt in favor of the relatively resource rich southern part of the country. The Upper West Region located in Northern Ghana, is among the poorest regions in the country. The study was aimed at finding out the reasons why medical doctors are unwilling to accept postings to the Upper West Region where their services are needed most despite some efforts to attract, motivate and retain them. Current initiatives by the Ministry of Health and its partners to attract and retain doctors in the region were also examined. Qualitative methodology was employed with an in-depth interview guide to collect data. Sixteen respondents comprising medical doctors, health managers, and other health-related partners purposively selected took part in the study. Data were recorded, transcribed, coded, and categorized into themes in tandem with the objectives of the study. The study found that medical doctors are unwilling to take up appointments in the Upper West Region because of limited opportunities for career and continuing professional development, poor financial inducement, and weak leadership, among other important contextual social and cultural factors. Critical success factors to surmount these challenges include concessions and sponsorship for medical specialization training for doctors and clear implementable national and local policies on postings.

Keywords: attraction, retention, medical doctors, deprived regions, Ghana

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3414 Prevalence of Diabetes Mellitus Among Human Immune Deficiency Virus-Positive Patients Under Anti-retroviral Attending in Rwanda, a Case Study of University Teaching Hospital of Butare

Authors: Venuste Kayinamura, V. Iyamuremye, A. Ngirabakunzi

Abstract:

Anti-retroviral therapy (ART) for HIV patient can cause a deficiency in glucose metabolism by promoting insulin resistance, glucose intolerance, and diabetes, diabetes mellitus keep increasing among HIV-infected patients worldwide but there is limited data on levels of blood glucose and its relationship with antiretroviral drugs (ARVs) and HIV-infection worldwide, particularly in Rwanda. A convenient sampling strategy was used in this study and it involved 323 HIV patients (n=323). Patients who are HIV positive under ARVs were involved in this study. The patient’s blood glucose was analyzed using an automated machine or glucometer (COBAS C 311). Data were analyzed using Microsoft Excel and SPSS V. 20.0 and presented in percentages. The highest diabetes mellitus prevalence was 93.33 % in people aged >40 years while the lowest diabetes mellitus prevalence was 6.67% in people aged between 21-and 40 years. The P-value was (0.021). Thus, there is a significant association between age and diabetes occurrence. The highest diabetes mellitus prevalence was 28.2% in patients under ART treatment for more than 10 years, 16.7% were <5years while 20% of patients were on ART treatment between 5-10 years. The P-value here is (0.03), thus the incidence of diabetes is associated with long-term ART use in HIV-infected patients. This study assessed the prevalence of diabetes among HIV-infected patients under ARVs attending the University Teaching Hospital of Butare (CHUB), it shows that the prevalence of diabetes is high in HIV-infected patients under ARTs. This study found no significant relationship between gender and diabetes mellitus growth. Therefore, regular assessment of diabetes mellitus especially among HIV-infected patients under ARVs is highly recommended to control other health issues caused by diabetes mellitus.

Keywords: anti-retroviral, diabetes mellitus, antiretroviral therapy, human immune deficiency virus

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3413 Causes of Jaundice and Skin Rashes Amongst Children in Selected Rural Communities in the Gambia

Authors: Alhage Drammeh

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The research is on the occurrence of certain diseases among children in rural and far-flung parts of the Gambia and the extent to which they are caused by lack of access to clean water. A baseline survey was used to discover, describe, and explain the actual processes. The paper explains the purpose of the research, which is majorly to improve the health condition of children, especially those living in rural communities. The paper also gives a brief overview of the socio-economic situation of The Gambia, emphasizing its status as a Least Developed Country (LDC) and the majority of its population living below the poverty line, with women and children hardest hit. The research used as case studies of two rural communities in the Gambia -Basse Dampha Kunda Village and Foni Besse. Data was collected through oral interviews and medical tests conducted among people in both villages, with an emphasis on children. The demographic detail of those tested is tabulated for a clearer understanding. The results were compared, revealing that skin rashes, hepatitis, and certain other diseases are more prevalent in communities lacking access to safe drinking water. These results were also presented in a tabular form. The study established how some policy failures and neglect on the part of the Government of The Gambia are imperiling the health of many rural dwellers in the country, the most glaring being that the research team was unable to test water samples collected from the two communities, as there are no laboratory reagents for testing water anywhere in The Gambia. Many rural communities lack basic amenities, especially clean and potable water, as well as health facilities. The study findings also highlighted the need for healthcare providers and medical NGOs to voice the plight of rural dwellers and collaborate with the government to set up health facilities in rural areas of The Gambia.

Keywords: jaundice, skin rashes, children, rural communities, the Gambia, causes

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3412 Industrial Rock Characterization using Nuclear Magnetic Resonance (NMR): A Case Study of Ewekoro Quarry

Authors: Olawale Babatunde Olatinsu, Deborah Oluwaseun Olorode

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Industrial rocks were collected from a quarry site at Ewekoro in south-western Nigeria and analysed using Nuclear Magnetic Resonance (NMR) technique. NMR measurement was conducted on the samples in partial water-saturated and full brine-saturated conditions. Raw NMR data were analysed with the aid of T2 curves and T2 spectra generated by inversion of raw NMR data using conventional regularized least-squares inversion routine. Results show that NMR transverse relaxation (T2) signatures fairly adequately distinguish between the rock types. Similar T2 curve trend and rates at partial saturation suggests that the relaxation is mainly due to adsorption of water on micropores of similar sizes while T2 curves at full saturation depict relaxation decay rate as: 1/T2(shale)>1/ T2(glauconite)>1/ T2(limestone) and 1/T2(sandstone). NMR T2 distributions at full brine-saturation show: unimodal distribution in shale; bimodal distribution in sandstone and glauconite; and trimodal distribution in limestone. Full saturation T2 distributions revealed the presence of well-developed and more abundant micropores in all the samples with T2 in the range, 402-504 μs. Mesopores with amplitudes much lower than those of micropores are present in limestone, sandstone and glauconite with T2 range: 8.45-26.10 ms, 6.02-10.55 ms, and 9.45-13.26 ms respectively. Very low amplitude macropores of T2 values, 90.26-312.16 ms, are only recognizable in limestone samples. Samples with multiple peaks showed well-connected pore systems with sandstone having the highest degree of connectivity. The difference in T2 curves and distributions for the rocks at full saturation can be utilised as a potent diagnostic tool for discrimination of these rock types found at Ewekoro.

Keywords: Ewekoro, NMR techniques, industrial rocks, characterization, relaxation

Procedia PDF Downloads 297
3411 Physical Modeling of Woodwind Ancient Greek Musical Instruments: The Case of Plagiaulos

Authors: Dimitra Marini, Konstantinos Bakogiannis, Spyros Polychronopoulos, Georgios Kouroupetroglou

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Archaemusicology cannot entirely depend on the study of the excavated ancient musical instruments as most of the time their condition is not ideal (i.e., missing/eroded parts) and moreover, because of the concern damaging the originals during the experiments. Researchers, in order to overcome the above obstacles, build replicas. This technique is still the most popular one, although it is rather expensive and time-consuming. Throughout the last decades, the development of physical modeling techniques has provided tools that enable the study of musical instruments through their digitally simulated models. This is not only a more cost and time-efficient technique but also provides additional flexibility as the user can easily modify parameters such as their geometrical features and materials. This paper thoroughly describes the steps to create a physical model of a woodwind ancient Greek instrument, Plagiaulos. This instrument could be considered as the ancestor of the modern flute due to the common geometry and air-jet excitation mechanism. Plagiaulos is comprised of a single resonator with an open end and a number of tone holes. The combination of closed and open tone holes produces the pitch variations. In this work, the effects of all the instrument’s components are described by means of physics and then simulated based on digital waveguides. The synthesized sound of the proposed model complies with the theory, highlighting its validity. Further, the synthesized sound of the model simulating the Plagiaulos of Koile (2nd century BCE) was compared with its replica build in our laboratory by following the scientific methodologies of archeomusicology. The aforementioned results verify that robust dynamic digital tools can be introduced in the field of computational, experimental archaemusicology.

Keywords: archaeomusicology, digital waveguides, musical acoustics, physical modeling

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3410 Analytical Method for Seismic Analysis of Shaft-Tunnel Junction under Longitudinal Excitations

Authors: Jinghua Zhang

Abstract:

Shaft-tunnel junction is a typical case of the structural nonuniformity in underground structures. The shaft and the tunnel possess greatly different structural features. Even under uniform excitations, they tend to behave discrepantly. Studies on shaft-tunnel junctions are mainly performed numerically. Shaking table tests are also conducted. Although many numerical and experimental data are obtained, an analytical solution still has great merits of gaining more insights into the shaft-tunnel problem. This paper will try to remedy the situation. Since the seismic responses of shaft-tunnel junctions are very related to directions of the excitations, they are studied in two scenarios: the longitudinal-excitation scenario and the transverse-excitation scenario. The former scenario will be addressed in this paper. Given that responses of the tunnel are highly dependent on the shaft, the analytical solutions would be developed firstly for the vertical shaft. Then, the seismic responses of the tunnel would be discussed. Since vertical shafts bear a resemblance to rigid caissons, the solution proposed in this paper is derived by introducing terms of shaft-tunnel and soil-tunnel interactions into equations originally developed for rigid caissons. The validity of the solution is examined by a validation model computed by finite element method. The mutual influence between the shaft and the tunnel is introduced. The soil-structure interactions are discussed parametrically based on the proposed equations. The shaft-tunnel relative displacement and the soil-tunnel relative stiffness are found to be the most important parameters affecting the magnitudes and distributions of the internal forces of the tunnel. A hinge-joint at the shaft-tunnel junction could significantly reduce the degree of stress concentration compared with a rigid joint.

Keywords: analytical solution, longitudinal excitation, numerical validation , shaft-tunnel junction

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3409 Improving the Biomechanical Resistance of a Treated Tooth via Composite Restorations Using Optimised Cavity Geometries

Authors: Behzad Babaei, B. Gangadhara Prusty

Abstract:

The objective of this study is to assess the hypotheses that a restored tooth with a class II occlusal-distal (OD) cavity can be strengthened by designing an optimized cavity geometry, as well as selecting the composite restoration with optimized elastic moduli when there is a sharp de-bonded edge at the interface of the tooth and restoration. Methods: A scanned human maxillary molar tooth was segmented into dentine and enamel parts. The dentine and enamel profiles were extracted and imported into a finite element (FE) software. The enamel rod orientations were estimated virtually. Fifteen models for the restored tooth with different cavity occlusal depths (1.5, 2, and 2.5 mm) and internal cavity angles were generated. By using a semi-circular stone part, a 400 N load was applied to two contact points of the restored tooth model. The junctions between the enamel, dentine, and restoration were considered perfectly bonded. All parts in the model were considered homogeneous, isotropic, and elastic. The quadrilateral and triangular elements were employed in the models. A mesh convergence analysis was conducted to verify that the element numbers did not influence the simulation results. According to the criteria of a 5% error in the stress, we found that a total element number of over 14,000 elements resulted in the convergence of the stress. A Python script was employed to automatically assign 2-22 GPa moduli (with increments of 4 GPa) for the composite restorations, 18.6 GPa to the dentine, and two different elastic moduli to the enamel (72 GPa in the enamel rods’ direction and 63 GPa in perpendicular one). The linear, homogeneous, and elastic material models were considered for the dentine, enamel, and composite restorations. 108 FEA simulations were successively conducted. Results: The internal cavity angles (α) significantly altered the peak maximum principal stress at the interface of the enamel and restoration. The strongest structures against the contact loads were observed in the models with α = 100° and 105. Even when the enamel rods’ directional mechanical properties were disregarded, interestingly, the models with α = 100° and 105° exhibited the highest resistance against the mechanical loads. Regarding the effect of occlusal cavity depth, the models with 1.5 mm depth showed higher resistance to contact loads than the model with thicker cavities (2.0 and 2.5 mm). Moreover, the composite moduli in the range of 10-18 GPa alleviated the stress levels in the enamel. Significance: For the class II OD cavity models in this study, the optimal geometries, composite properties, and occlusal cavity depths were determined. Designing the cavities with α ≥100 ̊ was significantly effective in minimizing peak stress levels. The composite restoration with optimized properties reduced the stress concentrations on critical points of the models. Additionally, when more enamel was preserved, the sturdier enamel-restoration interface against the mechanical loads was observed.

Keywords: dental composite restoration, cavity geometry, finite element approach, maximum principal stress

Procedia PDF Downloads 102