Search results for: characteristic numbers

Authors: Budur Almutairi

Abstract:

Introduction: There is an alarming increase in the number of diabetic patients in Saudi Arabia during the last twenty years. The World Health Organization (WHO) reports that the country ranks seventh in the world for the rate of diabetes. It is also estimated that around 7 million of the population are diabetic and almost around 3 million have pre-diabetes. The prevalence is more in urban area than in rural and more in women than in men and it is closely associated with the parallel rise in obesity rates. Diabetes is found to be contributing to the increasing mortality, morbidity and vascular complications and becoming a significant cause of medical complications and even death. The trends shown by the numbers are worrying as the prevalence is steadily doubling every two decades and particularly in Saudi Arabia, this could soon reach 50% in those over 50 years of age. The economic growth and prosperity have shown notable changes in the lifestyle of the people. Most importantly, along with an increased consumption of fast foods and sugar-rich carbonated soft drinks, eating habits became less healthy and the level of physical activity is decreased. The simultaneous technological advancement and the introduction of new mechanical devices like, elevators, escalators, remotes and vehicles pushed people to a situation of leading a more sedentary life. This study is attempting to evaluate the success of the campaign that introduced through popular social media in the country. Methodology: The Ministry of Health (MoH) has initiated a novel method of campaign activity to generate discussion among public about diabetes. There were mythical monsters introduced through popular social media with disguised messages about the condition of diabetes has generated widespread discussions about the disease among the general public. The characters that started appearing in social media About 600 retweets of the original post was testimonial for the success of the Twitter campaign. The second most successful form of campaign was a video that adopted a very popular approach of using Dark Comedy in which, the diabetes was represented through a twisted negative character that talks about his meticulous plans of how he is going to take the common people into his clutches. This fictional character gained more popularity when introduced into twitter and people started interacting with him raising various questions and challenging his anti-social activities. Major findings: The video generated more than 3,200,000 views ranking 9th in You Tube’s most popular video in Saudi Arabia and was shared 7000 times in a single week. Also, the hashtag got over 4,500,000impressions and over one million visits. Conclusion: Diabetes mellitus in Saudi Arabia is emerging as an epidemic of massive proportions, threatening to negate the benefits of modernization and economic revival. It is highly possible that healthy practices connected with the prevention and management of DM can easily be implemented in a manner that does not conflict with the cultural milieu of Saudi Arabia.

Keywords: campaign, diabetes, Saudi, social media

Procedia PDF Downloads 130

Authors: Md. Hafezur Rahaman, Mohd. Maniruzzaman, Md. Shadiqul Islam, Md. Masud Rana

Abstract:

With the growth of environmental awareness, enormous researches are running to develop the next generation materials based on sustainability, eco-competence, and green chemistry to preserve and protect the environment. Due to biodegradability and biocompatibility, poly (L-lactic acid) (PLLA) has a great interest in ecological and medical applications. Also, cellulose is one of the most abundant biodegradable, renewable polymers found in nature. It has several advantages such as low cost, high mechanical strength, biodegradability and so on. Recently, an immense deal of attention has been paid for the scientific and technological development of α-cellulose based composite material. PLLA could be used for grafting of cellulose to improve the compatibility prior to the composite preparation. Here it is quite difficult to form a bond between lower hydrophilic molecules like PLLA and α-cellulose. Dimmers and oligomers can easily be grafted onto the surface of the cellulose by ring opening or polycondensation method due to their low molecular weight. In this research, α-cellulose extracted from jute fiber is grafted with oligo(D-lactic acid) (ODLA) via graft polycondensation reaction in presence of para-toluene sulphonic acid and potassium persulphate in toluene at 130°C for 9 hours under 380 mmHg. Here ODLA is synthesized by ring opening polymerization of D-lactides in the presence of stannous octoate (0.03 wt% of lactide) and D-lactic acids at 140°C for 10 hours. Composites of PLLA with ODLA grafted α-cellulose are prepared by solution mixing and film casting method. Confirmation of grafting was carried out through FTIR spectroscopy and SEM analysis. A strongest carbonyl peak of FTIR spectroscopy at 1728 cm⁻¹ of ODLA grafted α-cellulose confirms the grafting of ODLA onto α-cellulose which is absent in α-cellulose. It is also observed from SEM photographs that there are some white areas (spot) on ODLA grafted α-cellulose as compared to α-cellulose may indicate the grafting of ODLA and consistent with FTIR results. Analysis of the composites is carried out by FTIR, SEM, WAXD and thermal gravimetric analyzer. Most of the FTIR characteristic absorption peak of the composites shifted to higher wave number with increasing peak area may provide a confirmation that PLLA and grafted cellulose have better compatibility in composites via intermolecular hydrogen bonding and this supports previously published results. Grafted α-cellulose distributions in composites are uniform which is observed by SEM analysis. WAXD studied show that only homo-crystalline structures of PLLA present in the composites. Thermal stability of the composites is enhanced with increasing the percentages of ODLA grafted α-cellulose in composites. As a consequence, the resultant composites have a resistance toward the thermal degradation. The effects of length of the grafted chain and biodegradability of the composites will be studied in further research.

Keywords: α-cellulose, composite, graft polycondensation, oligo(D-lactic acid), poly(L-lactic acid)

Procedia PDF Downloads 117

Authors: S. A. Abeykoon

Abstract:

This study explores the empowerment potential of the mobile phone, the widely penetrated and greatly affordable communication technology in Sri Lanka, for female heads of households in Trincomalee District, Sri Lanka-an area recovering from the effects of a 30-year civil war and the 2004 Boxing Day Tsunami. It also investigates how the use of mobile phones by these women is shaped and appropriated by the gendered power relations and inequalities in their respective communities and by their socio-economic factors and demographic characteristics. This qualitative study is based on the epistemology of constructionism; interpretivist, functionalist and critical theory approaches; and the process of action research. The data collection was conducted from September 2014 to November 2014 in two Divisional Secretaries of the Trincomalee District, Sri Lanka. A total of 30 semi-structured depth interviews and six focus groups with the female heads of households of Sinhalese, Tamil and Muslim ethnicities were conducted using purposive, representative and snowball sampling methods. The Grounded theory method was used to analyze transcribed interviews, focus group discussions and field notes that were coded and categorized in accordance with the research questions and the theoretical framework of the study. The findings of the study indicated that the mobile phone has mainly enabled the participants to balance their income earning activities and family responsibilities and has been useful in maintaining their family and social relationships, occupational duties and in making decisions. Thus, it provided them a higher level of security, safety, reassurance and self-confidence in carrying out their daily activities. They also practiced innovative strategies for the effective and efficient use of their mobile expenses. Although participants whose husbands or relatives have migrated were more tended to use smart phones, mobile literacy level of the majority of the participants was at a lower level limited to making and receiving calls and using SMS (Short Message Service) services. However, their interaction with the mobile phone was significantly shaped by the gendered power relations and their multiple identities based on their ethnicity, religion, class, education, profession and age. Almost all the participants were precautious of giving their mobile numbers to and have been harassed with ‘nuisance calls’ from men. For many, ownership and use of their mobile phone was shaped and influenced by their children and migrated husbands. Although these practices limit their use of the technology, there were many instances that they challenged these gendered harassments. While man-made and natural destructions have disempowered and victimized the women in the Sri Lankan society, they have also liberated women making them stronger and transforming their agency and traditional gender roles. Therefore, their present position in society is reflected in their mobile phone use as they assist such women to be more self-reliant and liberated, yet making them disempowered at some time.

Keywords: mobile phone, gender power relations, empowerment, female heads of households

Procedia PDF Downloads 336

Authors: Monika Trzaskowska, Dorota Zielinska, Anna Lepecka, Katarzyna Neffe-Skocinska, Beata Bilska, Marzena Tomaszewska, Danuta Kolozyn-Krajewska

Abstract:

Microbiological quality and food safety are important food characteristics. Regulation (EU) No 1169/2011 of the European Parliament and of the Council on the provision of food information to consumers introduces the obligation to provide information on the 'use-by' date or the date of minimum durability (DMD). The second term is the date until which the properly stored or transported foodstuff retains its physical, chemical, microbiological and organoleptic properties. The date should be preceded by 'best before'. It is used for durable products, e.g., pasta. In relation to reducing food losses, the question may be asked whether products with the date of minimum durability currently declared retain quality and safety beyond this. The aim of the study was to assess the sensory quality and microbiological safety of selected cereal products, i.e., pasta and millet after DMD. The scope of the study was to determine the markers of microbiological quality, i.e., the total viable count (TVC), the number of bacteria from the Enterobacteriaceae family and the number of yeast and mold (TYMC) on the last day of DMD and after 1 and 3 months of storage. In addition, the presence of Salmonella and Listeria monocytogenes was examined on the last day of DMD. The sensory quality of products was assessed by quantitative descriptive analysis (QDA), the intensity of 14 differentiators and overall quality were defined and determined. In the tested samples of millet and pasta, no pathogenic bacteria Salmonella and Listeria monocytogenes were found. The value of the distinguishing features of selected quality and microbiological safety indicators on the last DMD day was in the range of about 3-1 log cfu/g. This demonstrates the good microbiological quality of the tested food. Comparing the products, a higher number of microorganisms was found in the samples of millet. After 3 months of storage, TVC decreased in millet, while in pasta, it was found to increase in value. In both products, the number of bacteria from the Enterobacretiaceae family decreased. In contrast, the number of TYMCs increased in samples of millet, and in pasta decreased. The intensity of sensory characteristic in the studied period varied. It remained at a similar level or increased. Millet was found to increase the intensity and flavor of 'cooked porridge' 3 months after DMD. Similarly, in the pasta, the smell and taste of 'cooked pasta' was more intense. To sum up, the researched products on the last day of the minimum durability date were characterized by very good microbiological and sensory quality, which was maintained for 3 months after this date. Based on these results, the date of minimum durability of tested products could be extended. The publication was financed on the basis of an agreement with the National Center for Research and Development No. Gospostrateg 1/385753/1/NCBR/2018 for the implementation and financing of the project under the strategic research and development program 'social and economic development of Poland in the conditions of globalizing markets – GOSPOSTRATEG - acronym PROM'.

Keywords: date of minimum durability, food losses, food quality and safety, millet, pasta

Procedia PDF Downloads 161

Authors: G. Singer, M. Golan

Abstract:

Providing students with learning disabilities (LD) with extra time to grant them equal access to the exam is a necessary but insufficient condition to compensate for their LD; there should also be a clear indication that the additional time was actually used. For example, if students with LD use more time than students without LD and yet receive lower grades, this may indicate that a different accommodation is required. If they achieve higher grades but use the same amount of time, then the effectiveness of the accommodation has not been demonstrated. The main goal of this study is to evaluate the effect of including parameters related to LD and extended exam time, along with other commonly-used characteristics (e.g., student background and ability measures such as high-school grades), on the ability of ordinal decision-tree algorithms to predict exam performance. We use naturally-occurring data collected from hundreds of undergraduate engineering students. The sub-goals are i) to examine the improvement in prediction accuracy when the indicator of exam performance includes 'actual time used' in addition to the conventional indicator (exam grade) employed in most research; ii) to explore the effectiveness of extended exam time on exam performance for different courses and for LD students with different profiles (i.e., sets of characteristics). This is achieved by using the patterns (i.e., subgroups) generated by the algorithms to identify pairs of subgroups that differ in just one characteristic (e.g., course or type of LD) but have different outcomes in terms of exam performance (grade and time used). Since grade and time used to exhibit an ordering form, we propose a method based on ordinal decision-trees, which applies a weighted information-gain ratio (WIGR) measure for selecting the classifying attributes. Unlike other known ordinal algorithms, our method does not assume monotonicity in the data. The proposed WIGR is an extension of an information-theoretic measure, in the sense that it adjusts to the case of an ordinal target and takes into account the error severity between two different target classes. Specifically, we use ordinal C4.5, random-forest, and AdaBoost algorithms, as well as an ensemble technique composed of ordinal and non-ordinal classifiers. Firstly, we find that the inclusion of LD and extended exam-time parameters improves prediction of exam performance (compared to specifications of the algorithms that do not include these variables). Secondly, when the indicator of exam performance includes 'actual time used' together with grade (as opposed to grade only), the prediction accuracy improves. Thirdly, our subgroup analyses show clear differences in the effect of extended exam time on exam performance among different courses and different student profiles. From a methodological perspective, we find that the ordinal decision-tree based algorithms outperform their conventional, non-ordinal counterparts. Further, we demonstrate that the ensemble-based approach leverages the strengths of each type of classifier (ordinal and non-ordinal) and yields better performance than each classifier individually.

Keywords: actual exam time usage, ensemble learning, learning disabilities, ordinal classification, time extension

Procedia PDF Downloads 100

Authors: Mebruka Mohammed, Daniel Bisrat, Asfaw Debella, Tarekegn Birhanu

Abstract:

Lack of quality control standards for medicinal plants and their preparations is considered major barrier to their integration in to effective primary health care in Ethiopia. Poor quality herbal preparations led to countless adverse reactions extending to death. Denial of penetration for the Ethiopian medicinal plants in to the world’s booming herbal market is also another significant loss resulting from absence of herbal quality control system. Thus, in the present study, Gnidia stenophylla Gilg (popular antimalarial plant of south eastern Ethiopia), is standardized and a full monograph is produced that can serve as a guideline in quality control of the crude drug. Morphologically, the roots are found to be cylindrical and tapering towards the end. It has a hard, corky and friable touch with saddle brown color externally and it is relatively smooth and pale brown internally. It has got characteristic pungent odor and very bitter taste. Microscopically it has showed lignified xylem vessels, wider medullary rays with some calcium oxalate crystals, reddish brown secondary metabolite contents and slender shaped long fibres. Physicochemical standards quantified and resulted: foreign matter (5.25%), moisture content (6.69%), total ash (40.80%), acid insoluble ash (8.00%), water soluble ash (2.30%), alcohol soluble extractive (15.27%), water soluble extractive (10.98%), foaming index (100.01 ml/g), swelling index (7.60 ml/g). Phytochemically: Phenols, flavonoids, steroids, tannins and saponins were detected in the root extract; TLC and HPLC fingerprints were produced and an analytical marker was also tentatively characterized as 3-(3,4-dihydro-3,5-dihydroxy-2-(4-hydroxy-5-methylhex-1-en-2-yl)-7-methoxy-4-oxo-2H-chromen-8-yl)-5-hydroxy-2-(4-hydroxyphenyl)-7-methoxy-4H-chromen-4-one. Residue wise pesticides (i.e. DDT, DDE, g-BHC) and radiochemical levels fall below the WHO limit while Heavy metals (i.e. Co, Ni, Cr, Pb, and Cu), total aerobic count and fungal load lie way above the WHO limit. In conclusion, the result can be taken as signal that employing non standardized medicinal plants could cause many health risks of the Ethiopian people and Africans’ at large (as 80% of inhabitants in the continent depends on it for primary health care). Therefore, following a more universal approach to herbal quality by adopting the WHO guidelines and developing monographs using the various quality parameters is inevitable to minimize quality breach and promote effective herbal drug usage.

Keywords: Gnidia stenophylla Gilg, standardization/monograph, pharmacognostic, residue/impurity, quality

Procedia PDF Downloads 289

Authors: Shenlun Chen, Leonard Wee

Abstract:

Tumor grading is an essential reference for colorectal cancer (CRC) staging and survival prognostication. The widely used World Health Organization (WHO) grading system defines histological grade of CRC adenocarcinoma based on the density of glandular formation on whole slide images (WSI). Tumors are classified as well-, moderately-, poorly- or un-differentiated depending on the percentage of the tumor that is gland forming; >95%, 50-95%, 5-50% and <5%, respectively. However, manually grading WSIs is a time-consuming process and can cause observer error due to subjective judgment and unnoticed regions. Furthermore, pathologists’ grading is usually coarse while a finer and continuous differentiation grade may help to stratifying CRC patients better. In this study, a deep learning based automatic differentiation grading algorithm was developed and evaluated by survival analysis. Firstly, a gland segmentation model was developed for segmenting gland structures. Gland regions of WSIs were delineated and used for differentiation annotating. Tumor regions were annotated by experienced pathologists into high-, medium-, low-differentiation and normal tissue, which correspond to tumor with clear-, unclear-, no-gland structure and non-tumor, respectively. Then a differentiation prediction model was developed on these human annotations. Finally, all enrolled WSIs were processed by gland segmentation model and differentiation prediction model. The differentiation grade can be calculated by deep learning models’ prediction of tumor regions and tumor differentiation status according to WHO’s defines. If multiple WSIs were possessed by a patient, the highest differentiation grade was chosen. Additionally, the differentiation grade was normalized into scale between 0 to 1. The Cancer Genome Atlas, project COAD (TCGA-COAD) project was enrolled into this study. For the gland segmentation model, receiver operating characteristic (ROC) reached 0.981 and accuracy reached 0.932 in validation set. For the differentiation prediction model, ROC reached 0.983, 0.963, 0.963, 0.981 and accuracy reached 0.880, 0.923, 0.668, 0.881 for groups of low-, medium-, high-differentiation and normal tissue in validation set. Four hundred and one patients were selected after removing WSIs without gland regions and patients without follow up data. The concordance index reached to 0.609. Optimized cut off point of 51% was found by “Maxstat” method which was almost the same as WHO system’s cut off point of 50%. Both WHO system’s cut off point and optimized cut off point performed impressively in Kaplan-Meier curves and both p value of logrank test were below 0.005. In this study, gland structure of WSIs and differentiation status of tumor regions were proven to be predictable through deep leaning method. A finer and continuous differentiation grade can also be automatically calculated through above models. The differentiation grade was proven to stratify CAC patients well in survival analysis, whose optimized cut off point was almost the same as WHO tumor grading system. The tool of automatically calculating differentiation grade may show potential in field of therapy decision making and personalized treatment.

Keywords: colorectal cancer, differentiation, survival analysis, tumor grading

Procedia PDF Downloads 134

Authors: Koteswara Rao Pagolu, Raghava Rao Tamanam

Abstract:

The present study was aimed to find out the prevalence of DD's in Visakhapatnam, one of the north coastal districts of Andhra Pradesh, India during a span of five years. A cross-sectional investigation was held at District early intervention center (DEIC), Visakhapatnam from 2016 to 2020. To identify the pattern and trend of different DD's including seasonal variations, a retrospective analysis of the health center's inpatient database for the past 5 years was done. Male and female children aged 2 months-18 years are included in the study with the prior permission of the concerned medical officer. The screening tool developed by the Ministry of health and family welfare, India, was used for the study. Among 26,423 cases, children with birth defects are 962, 2229 with deficiencies, 7516 with diseases, and 15716 with disabilities were admitted during the study period. From birth defects, congenital deafness occurred in large numbers with 22.66%, and neural tube defect observed in a small number of cases with 0.83% during the period. From the side of deficiencies, severe acute malnutrition has mostly occurred (66.80 %) and a small number of children were affected with goiter (1.70%). Among the diseases, dental carriers (67.97%) are mostly found and these cases were at peak during the years 2016 and 2019. From disabilities, children with vision impairment (20.55%) have mostly approached the center. Over the past 5 years, the admission rate of down's syndrome and congenital deafness cases showed a rising trend up to 2019 and then declined. Hearing impairment, motor delay, and learning disorder showed a steep rise and gradual decline trend, whereas severe anemia, vitamin-D deficiency, otitis media, reactive airway disease, and attention deficit hyperactivity disorder showed a declining trend. However, congenital heart diseases, dental caries, and vision impairment admission rates showed a zigzag pattern over the past 5 years. This center had inadequate diagnostic facilities related to genetic disease management. For advanced confirmation, the cases are referred to a district government hospital or private diagnostic laboratories in the city for genetic tests. Information regarding the overall burden and pattern of admissions in the health center is obtained by the review of DEIC records. Through this study, it is observed that the incidence of birth defects, as well as genetic disease burden, is high in the Visakhapatnam district. Hence there is a need for strengthening of management services for these diseases in this region.

Keywords: child health screening, developmental delays, district early intervention center, genetic disease management, infrastructural facility, Visakhapatnam district

Procedia PDF Downloads 213

Authors: Olga Yu Kurapova, Alexander V. Shorokhov, Vladimir G. Konakov

Abstract:

Nowadays, due to their exceptional anion conductivity at high temperatures cubic zirconia solid solutions, stabilized by rare-earth and alkaline-earth metal oxides, are widely used as a solid electrolyte (SE) materials in different electrochemical devices such as gas sensors, oxygen pumps, solid oxide fuel cells (SOFC), etc. Nowadays the intensive studies are carried out in a field of novel fully stabilized zirconia based SE development. The use of precursor powders for SE manufacturing allows predetermining the microstructure, electrical and sensor characteristics of zirconia based ceramics used as SE. Thus the goal of the present work was the investigation of the effect of precursor powder size on the electrical and sensor characteristics of fully stabilized zirconia-based solid electrolytes with compositions of 0,08Y2O3∙0,92ZrO2 (YSZ), 0,06Ce2O3∙ 0,06Y2O3∙0,88ZrO2 and 0,09Ce2O3∙0,06Y2O3-0,85ZrO2. The synthesis of precursors powders with different mean particle size was performed by sol-gel synthesis in the form of reversed co-precipitation from aqueous solutions. The cakes were washed until the neutral pH and pan-dried at 110 °С. Also, YSZ ceramics was obtained by conventional solid state synthesis including milling into a planetary mill. Then the powder was cold pressed into the pellets with a diameter of 7.2 and ~4 mm thickness at P ~16 kg/cm2 and then hydrostatically pressed. The pellets were annealed at 1600 °С for 2 hours. The phase composition of as-synthesized SE was investigated by X-Ray photoelectron spectroscopy ESCA (spectrometer ESCA-5400, PHI) X-ray diffraction analysis - XRD (Shimadzu XRD-6000). Following galvanic cell О2 (РО2(1)), Pt | SE | Pt, (РО2(2) = 0.21 atm) was used for SE sensor properties investigation. The value of РО2(1) was set by mixing of O2 and N2 in the defined proportions with the accuracy of  5%. The temperature was measured by Pt/Pt-10% Rh thermocouple, The cell electromotive force (EMF) measurement was carried out with ± 0.1 mV accuracy. During the operation at the constant temperature, reproducibility was better than 5 mV. Asymmetric potential measured for all SE appeared to be negligible. It was shown that the resistivity of YSZ ceramics decreases in about two times upon the mean agglomerates decrease from 200-250 to 40 nm. It is likely due to the both surface and bulk resistivity decrease in grains. So the overall decrease of grain size in ceramic SE results in the significant decrease of the total ceramics resistivity allowing sensor operation at lower temperatures. For the SE manufactured the estimation of oxygen ion transfer number tion was carried out in the range 600-800 °С. YSZ ceramics manufactured from powders with the mean particle size 40-140 nm, shows the highest values i.e. 0.97-0.98. SE manufactured from precursors with the mean particle size 40-140 nm shows higher sensor characteristic i.e. temperature and oxygen concentration EMF dependencies, EMF (ENernst - Ereal), tion, response time, then ceramics, manufactured by conventional solid state synthesis.

Keywords: oxygen sensors, precursor powders, sol-gel synthesis, stabilized zirconia ceramics

Procedia PDF Downloads 282

Authors: Katarina Ott, Velibor Mačkić, Mihaela Bronić, Branko Stanić

Abstract:

The determinants of national budget transparency have been widely discussed in the literature, while research on determinants of local budget transparency are scarce and empirically inconclusive, particularly in the new, fiscally centralised, EU member states. To fill the gap, we combine two strands of the literature: that concerned with public administration and public finance, shedding light on the economic and financial determinants of local budget transparency, and that on the political economy of transparency (principal agent theory), covering the relationships among politicians and between politicians and voters. Our main hypothesis states that variables describing residents’ capacity have a greater impact on local budget transparency than variables indicating the institutional capacity of local government units (LGUs). Additional subhypotheses test the impact of each variable analysed on local budget transparency. We address the determinants of local budget transparency in Croatia, measured by the number of key local budget documents published on the LGUs’ websites. By using a data set of 128 cities and 428 municipalities over the 2015-2017 period and by applying panel data analysis based on Poisson and negative binomial distribution, we test our main hypothesis and sub-hypotheses empirically. We measure different characteristics of institutional and residents’ capacity for each LGU. Age, education and ideology of the mayor/municipality head, political competition indicators, number of employees, current budget revenues and direct debt per capita have been used as a measure of the institutional capacity of LGU. Residents’ capacity in each LGU has been measured through the numbers of citizens and their average age as well as by average income per capita. The most important determinant of local budget transparency is average residents' income per capita at both city and municipality level. The results are in line with most previous research results in fiscally decentralised countries. In the context of a fiscally centralised country with numerous small LGUs, most of whom have low administrative and fiscal capacity, this has a theoretical rationale in the legitimacy and principal-agent theory (opportunistic motives of the incumbent). The result is robust and significant, but because of the various other results that change between city and municipality levels (e.g. ideology and political competition), there is a need for further research (both on identifying other determinates and/or methods of analysis). Since in Croatia the fiscal capacity of a LGU depends heavily on the income of its residents, units with higher per capita incomes in many cases have also higher budget revenues allowing them to engage more employees and resources. In addition, residents’ incomes might be also positively associated with local budget transparency because of higher citizen demand for such transparency. Residents with higher incomes expect more public services and have more access to and experience in using the Internet, and will thus typically demand more budget information on the LGUs’ websites.

Keywords: budget transparency, count data, Croatia, local government, political economy

Procedia PDF Downloads 184

Authors: J. Martin Leal-Graciano, Juan J. Pérez-Gavilán, A. Reyes-Salazar, J. H. Castorena, J. L. Rivera-Salas

Abstract:

The experimental results about the global behavior of twelve 1:2 scaled reinforced concrete frame subject to in-plane lateral load are presented. The main objective was to generate experimental evidence about the use of steel bars within mortar bed-joints as shear reinforcement in infill walls. Similar to the Canadian and New Zealand standards, the Mexican code includes specifications for this type of reinforcement. However, these specifications were obtained through experimental studies of load-bearing walls, mainly confined walls. Little information is found in the existing literature about the effects of joint reinforcement on the seismic behavior of infill masonry walls. Consequently, the Mexican code establishes the same equations to estimate the contribution of joint reinforcement for both confined walls and infill walls. A confined masonry construction and a reinforced concrete frame infilled with masonry walls have similar appearances. However, substantial differences exist between these two construction systems, which are mainly related to the sequence of construction and to how these structures support vertical and lateral loads. To achieve the objective established, ten reinforced concrete frames with masonry infill walls were built and tested in pairs, having both specimens in the pair identical characteristics except that one of them included joint reinforcement. The variables between pairs were the type of units, the size of the columns of the frame and the aspect ratio of the wall. All cases included tie-columns and tie-beams on the perimeter of the wall to anchor the joint reinforcement. Also, two bare frame with identical characteristic to the infilled frames were tested. The purpose was to investigate the effects of the infill wall on the behavior of the system to in-plane lateral load. In addition, the experimental results were compared with the prediction of the Mexican code. All the specimens were tested in cantilever under reversible cyclic lateral load. To simulate gravity load, constant vertical load was applied on the top of the columns. The results indicate that the contribution of the joint reinforcement to lateral strength depends on the size of the columns of the frame. Larger size columns produce a failure mode that is predominantly a sliding mode. Sliding inhibits the production of new inclined cracks, which are necessary to activate (deform) the joint reinforcement. Regarding the effects of joint reinforcement in the performance of confined masonry walls, many facts were confirmed for infill walls: this type of reinforcement increases the lateral strength of the wall, produces a more distributed cracking and reduces the width of the cracks. Moreover, it reduces the ductility demand of the system at maximum strength. The prediction of the lateral strength provided by the Mexican code is property in some cases; however, the effect of the size of the columns on the contribution of joint reinforcement needs to be better understood.

Keywords: experimental study, Infill wall, Infilled frame, masonry wall

Procedia PDF Downloads 77

Authors: Waheed O. Majekodunmi

Abstract:

Climate change is a real global phenomenon and an unquestionable threat to our quest for a healthy and livable planet. It is now regarded as potentially the most monumental environmental challenge people and the planet will be confronted with over the next centuries. Expectedly, climate change mitigation was one of the central themes of COP 28. Despite contributing the least to climate change, Africa is and remains the hardest hit by the negative consequences of climate change including poor growth performance. Currently, it is being hypothesized that the high level of vulnerability and exposure to climate-related disasters, low adaptive capacity against global warming and high mitigation costs of climate change across the continent could be linked to the recent abysmal economic performance of African countries, especially in oil-producing countries where greenhouse gas emissions, is potentially more prevalent. This paper examines the impact of climate change on the economic performance of selected oil-producing countries in Africa using evidence from Nigeria, Algeria and Angola. The objective of the study is to determine whether or not climate change influences the economic performance of oil-producing countries in Africa by examining the nexus between economic growth and climate-related variables. The study seeks to investigate the effect of climate change on the pace of economic growth in African oil-producing countries. To achieve the research objectives, this study utilizes a quantitative approach by using historical and current secondary data sets to determine the relationship between climate-related variables and economic growth variables in the selected countries. The study employed numbers, percentages, tables and trend graphs to explain the trends or common patterns between climate change, economic growth and determinants of economic growth: governance effectiveness, infrastructure, macroeconomic stability and regulatory efficiency. Results from the empirical analysis of data show that the trends of economic growth and climate-related variables in the selected oil-producing countries are in the opposite directions as the increasing share of renewable energy sources in total energy consumption and the reduction in greenhouse gas emissions per capita in the oil-producing countries did not translate to higher economic growth. Further findings show that annual surface temperatures in the selected countries do not share similar trends with the food imports ratio and GDP per capita annual growth rate suggesting that climate change does not impact significantly agricultural productivity and economic growth in oil-producing countries in Africa. Annual surface temperature was also found to not share a similar pattern with governance effectiveness, macroeconomic stability and regulatory efficiency reinforcing the claim that some economic growth variables are independent of climate change. The policy implication of this research is that oil-producing African countries need to focus more on improving the macroeconomic environment and streamlining governance and institutional processes to boost their economic performance before considering the adoption of climate change adaptation and mitigation strategies.

Keywords: climate change, climate vulnerability, economic growth, greenhouse gas emissions per capita, oil-producing countries, share of renewable energy in total energy consumption

Procedia PDF Downloads 53

Authors: Chen Wang, Gerard Rowe

Abstract:

The number of undergraduate engineering students enrolled in university has been increasing rapidly recently, leading to challenges associated with increased student-instructor ratios and increased diversity in academic preparedness of the entrants. An increased student-instructor ratio makes the interaction between teachers and students more difficult, with the resulting student ‘anonymity’ known to be a risk to academic success. With increasing student numbers, there is also an increasing diversity in the academic preparedness of the students at entry to university. Conceptual understanding of the entrants has been quantified via diagnostic testing, with the results for the first-year course in electrical engineering showing significant conceptual misunderstandings amongst the entry cohort. The solution is clearly multi-faceted, but part of the solution likely involves greater demands being placed on students to be masters of their own learning. In consequence, it is highly desirable that instructors help students to develop better self-regulated learning skills. A self-regulated learner is one who is capable of setting up their own learning goals, monitoring their study processes, adopting and adjusting learning strategies, and reflecting on their own study achievements. The methods by which instructors might cultivate students’ self-regulated learning abilities is receiving increasing attention from instructors and researchers. The aim of this study was to help students understand fully their self-regulated learning skill levels and provide targeted instructions to help them improve particular learning abilities in order to meet the curriculum requirements. As a survey tool, this research applied the questionnaire ‘Motivated Strategies for Learning Questionnaire’ (MSLQ) to collect first year engineering student’s self-reported data of their cognitive abilities, motivational orientations and learning strategies. MSLQ is a widely-used questionnaire for assessment of university student’s self-regulated learning skills. The questionnaire was offered online as a part of the online-scaffolding-learning tools to develop student understanding of self-regulated learning theories and learning strategies. The online tools, which have been under development since 2015, are designed to help first-year students understand their self-regulated learning skill levels by providing prompt feedback after they complete the questionnaire. In addition, the online tool also supplies corresponding learning strategies to students if they want to improve specific learning skills. A total of 866 first year engineering students who enrolled in the first-year electrical engineering course were invited to participate in this research project. By the end of the course 857 students responded and 738 of their questionnaires were considered as valid questionnaires. Analysis of these surveys showed that 66% of the students thought the online-scaffolding-learning tools helped significantly to improve their self-regulated learning abilities. It was particularly pleasing that 16.4% of the respondents thought the online-scaffolding-learning tools were extremely effective. A current thrust of our research is to investigate the relationships between students’ self-regulated learning abilities and their academic performance. Our results are being used by the course instructors as they revise the curriculum and pedagogy for this fundamental first-year engineering course, but the general principles we have identified are applicable to most first-year STEM courses.

Keywords: academic preparedness, online-scaffolding-learning tool, self-regulated learning, STEM education

Procedia PDF Downloads 110

Authors: Shosh Shahrabani, Sharon Teitler-Regev, Helena Desivilya Syna, Fotini Voulgaris, Evangelos Tsoukatos, Vitor Ambrosio, Sandra M. Correia Loureiro

Abstract:

International crises that affect tourism, such as terror attacks, political unrest, and economic crises have become more frequent, and their influence has become broader. The influence of such extreme events depends on their salience in the tourists' awareness. Hence, it is important to understand the mechanisms underlying tourists' selection of travel destinations, especially their perceptions of crisis-related events and the impact of the sociopolitical and economic context in their countries of origin. The current study examined how the socio-political and economic context in the home countries of potential young tourists affected their selection of travel destinations. The objective was to elucidate how the salience of various crises (economic and political) in the tourists' perceptions, due to their experiences at home, color their construal of destinations affected by similar hazards and influence their travel intentions. The study focused on student tourists from Israel, Greece, and Portugal. Today about a fifth of international tourism is based on young people, especially students. These countries were chosen since Greece and Portugal are in the midst of economic crises. In addition, Greece and Portugal have experienced political instability, while Israel has security-related problems (including terrorist incidents). In 2013, a total of 648 students, responded to a questionnaire that included questions concerning attitudes and risk perceptions regarding travel to destinations with various risk hazards as well as socio-demographic details. The results indicate that over half of the Israelis intend to visit Greece or Portugal. The majority of the Portuguese intend to visit Greece, while less than a third of them intend to visit Israel. About half of the Greeks intend to visit Portugal, and most of them do not intend to visit Israel. The results indicate that greater perceived importance of economic crises mitigates the intention to travel to destinations with economic crises for tourists from origin countries that are also marked by economic crises, such as Greece and Portugal. However, for tourists from Israel, a country with a relatively stable economy, issues related to the economy barely affect their intention to travel to the other two countries. The findings also suggest that Greeks and Portuguese who are highly concerned about political unrest are unlikely to select Israel as a tourist destination. In addition, strong apprehension regarding terrorism impedes the intention to travel to destinations marked by terrorist incidents, such as Israel. The current research contributes to the existing literature by highlighting the impact of travelers' personal previous experience with crisis on their risk perceptions and in turn on their intentions to travel to countries with similar risks. Therefore, in a world where such incidents are on the rise, understanding tourists' risk perceptions and behavior and the factors influencing their destination-related decisions are crucial for countries that wish to increase the numbers of incoming tourists.

Keywords: economic crises, political instability, risk perception, young tourists

Procedia PDF Downloads 459

Authors: S. Jimenez, R.Duarte, J.Sanchez-Choliz, I. Villanua

Abstract:

There is a certain consensus in economic literature about the factors that have influenced in historical differences in growth rates observed between developed and developing countries. However, it is less clear what elements have marked different paths of growth in developed economies in recent decades. R&D has always been seen as one of the major sources of technological progress, and productivity growth, which is directly influenced by technological developments. Following recent literature, we can say that ‘innovation pushes the technological frontier forward’ as well as encourage future innovation through the creation of externalities. In other words, productivity benefits from innovation are not fully appropriated by innovators, but it also spread through the rest of the economies encouraging absorptive capacities, what have become especially important in a context of increasing fragmentation of production This paper aims to contribute to this literature in two ways, first, exploring alternative indexes of R&D flows embodied in inter-country, inter-sectorial flows of good and services (as approximation to technology spillovers) capturing structural and technological characteristic of countries and, second, analyzing the impact of direct and embodied R&D on the evolution of labor productivity at the country/sector level in recent decades. The traditional way of calculation through a multiregional input-output framework assumes that all countries have the same capabilities to absorb technology, but it is not, each one has different structural features and, this implies, different capabilities as part of literature, claim. In order to capture these differences, we propose to use a weight based on specialization structure indexes; one related with the specialization of countries in high-tech sectors and the other one based on a dispersion index. We propose these two measures because, as far as we understood, country capabilities can be captured through different ways; countries specialization in knowledge-intensive sectors, such as Chemicals or Electrical Equipment, or an intermediate technology effort across different sectors. Results suggest the increasing importance of country capabilities while increasing the trade openness. Besides, if we focus in the country rankings, we can observe that with high-tech weighted R&D embodied countries as China, Taiwan and Germany arose the top five despite not having the highest intensities of R&D expenditure, showing the importance of country capabilities. Additionally, through a fixed effects panel data model we show that, in fact, R&D embodied is important to explain labor productivity increases, in fact, even more that direct R&D investments. This is reflecting that globalization is more important than has been said until now. However, it is true that almost all analysis done in relation with that consider the effect of t-1 direct R&D intensity over economic growth. Nevertheless, from our point of view R&D evolve as a delayed flow and it is necessary some time to be able to see its effects on the economy, as some authors have already claimed. Our estimations tend to corroborate this hypothesis obtaining a gap between 4-5 years.

Keywords: economic growth, embodied, input-output, technology

Procedia PDF Downloads 124

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 253

Authors: Jane E. Hill

Abstract:

Sexual, physical, or emotional abuses are behaviors used by one person in a relationship or within a family unit to control the other person. Physical abuse can consist of, but not limited to hitting, pushing, and shoving. Sexual abuse is unwanted or forced sexual activity on a person without their consent. Abusive behaviors include intimidation, manipulation, humiliation, isolation, frightening, terrorizing, coercing, threatening, blaming, hurting, injuring, or wounding another individual. Although emotional, psychological and financial abuses are not criminal behaviors, they are forms of abuse and can leave emotional scars on their victim. The purpose of this literature review research was to examine characteristics of female offenders, past abuse, and pathways to offending. The question that guided this research: does past abuse influence recidivism? The theoretical foundation used was relational theory by Jean Baker Miller. One common feature of female offenders is abuse (sexual, physical, or verbal). Abuse can cause mental illnesses and substance abuse. The abuse does not directly affect the women's recidivism. However, results indicated the psychological and maladaptive behaviors as a result of the abuse did contribute to indirect pathways to continue offending. The female offenders’ symptoms of ongoing depression, anxiety, and engaging in substance abuse (self medicating) did lead to the women's incarceration. Using the childhood victimization model as the treatment approach for women's mental illness and substance abuse disorders that were a result from history of child abuse have shown success. With that in mind, if issues surrounding early victimization are not addressed, then the women offenders may not recover from their mental illness or addiction and are at a higher risk of reoffending. However, if the women are not emotionally ready to engage in the treatment process, then it should not be forced onto them because it may cause harm (targeting prior traumatic experiences). Social capital is family support and sources that assist in helping the individual with education, employment opportunities that can lead to success. Human capital refers to internal knowledge, skills, and capacities that help the individual act in new and appropriate ways. The lack of human and social capital is common among female offenders, which leads to extreme poverty and economic marginalization, more often in frequent numbers than men. In addition, the changes in welfare reform have exacerbated women’s difficulties in gaining adequate-paying jobs to support themselves and their children that have contributed to female offenders reoffending. With that in mind, one way to lower the risk factor of female offenders from reoffending is to provide them with educational and vocational training, enhance their self-efficacy, and teach them appropriate coping skills and life skills. Furthermore, it is important to strengthen family bonds and support. Having a supportive family relationship was a statistically significant protective factor for women offenders.

Keywords: characteristics, childhood victimization model, female offenders, treatment

Procedia PDF Downloads 111

Authors: Carlos Minguez, Christian F. Sagbay, Erika E. Ordoñez

Abstract:

Guinea pigs (Cavia porcellus) play prominent roles as experimental models for medical research and as pets. However, in developing countries like South America, the Philippines, and sub-Saharan Africa, the meat of guinea pigs is an economic source of animal protein for the poor and malnourished humans because guinea pigs are mainly fed with forage and do not compete directly with human beings for food resources, such as corn or wheat. To achieve efficient production of guinea pigs, it is essential to provide insurance against vitamin C deficiency. The objective of this research was to investigate the effect of the partial replacement of alfalfa with fresh citrus pulp (Citrus sinensis) in a diet of guinea pigs on the growth performance, slaughter traits and mortality during the fattening period (between 20 and 74 days of age). A total of 300 guinea pigs were housed in collective cages of about ten animals (2 x 1 x 0.4 m) and were distributed into two completely randomized groups. Guinea pigs in both groups were fed ad libitum, with a standard commercial pellet diet (10 MJ of digestible energy/kg, 17% crude protein, 11% crude fiber, and 4.5% crude fat). Control group was supplied with fresh alfalfa as forage. In the treatment group, 30% of alfalfa was replaced by fresh citrus pulp. Growth traits, including body weight (BW), average daily gain (ADG), feed intake (FI), and feed conversion ratio (FCR), were measured weekly. On day 74, the animals were slaughtered, and slaughter traits, including live weight at slaughter (LWS), full gastrointestinal tract weight (FGTW), hot carcass weight (with head; HCW), cold carcass weight (with head; CCW), drip loss percentage (DLP) and dressing out carcass yield percentage (DCY), were evaluated. Contrasts between groups were obtained by calculated generalized least squares values. Mortality was evaluated by Fisher's exact test due to low numbers in some cells. In the first week, there were significant differences in the growth traits BW, ADG, FI, and FCR, which were superior in control group. These differences may have been due to the origin of the young guinea pigs, which, before weaning, were all raised without fresh citrus pulp, and they were not familiarized with the new supplement. In the second week, treatment group had significantly increased ADG compared with control group, which may have been the result of a process of compensatory growth. During subsequent weeks, no significant differences were observed between animals raised in the two groups. Neither were any significant differences observed across the total fattening period. No significant differences in slaughter traits or mortality rate were observed between animals from the two groups. In conclusion, although there were no significant differences in growth performance, slaughter traits, or mortality, the use of fresh citrus pulp is recommended. Fresh citrus pulp is a by-product of orange juice industry and it is cheap or free. Forage made with fresh citrus pulp could reduce about of 30 % the quantity of alfalfa in guinea pig for meat and as consequence, reduce the production costs.

Keywords: fresh citrus, growth, Guinea pig, mortality

Procedia PDF Downloads 192

Authors: Antonina Semakova, Karim Mynbaev, Nikolai Bazhenov, Anton Chernyaev, Sergei Kizhaev, Nikolai Stoyanov

Abstract:

At present, heterostructures are used for fabrication of almost all types of optoelectronic devices. Our research focuses on the optoelectronic properties of InAs(Sb) solid solutions that are widely used in fabrication of light emitting diodes (LEDs) operating in middle wavelength infrared range (MWIR). This spectral range (2-6 μm) is relevant for laser diode spectroscopy of gases and molecules, for systems for the detection of explosive substances, medical applications, and for environmental monitoring. The fabrication of MWIR LEDs that operate efficiently at room temperature is mainly hindered by the predominance of non-radiative Auger recombination of charge carriers over the process of radiative recombination, which makes practical application of LEDs difficult. However, non-radiative recombination can be partly suppressed in quantum-well structures. In this regard, studies of such structures are quite topical. In this work, electroluminescence (EL) of LED heterostructures based on InAs(Sb) epitaxial films with the molar fraction of InSb ranging from 0 to 0.09 and multi quantum-well (MQW) structures was studied in the temperature range 4.2-300 K. The growth of the heterostructures was performed by metal-organic chemical vapour deposition on InAs substrates. On top of the active layer, a wide-bandgap InAsSb(Ga,P) barrier was formed. At low temperatures (4.2-100 K) stimulated emission was observed. As the temperature increased, the emission became spontaneous. The transition from stimulated emission to spontaneous one occurred at different temperatures for structures with different InSb contents in the active region. The temperature-dependent carrier lifetime, limited by radiative recombination and the most probable Auger processes (for the materials under consideration, CHHS and CHCC), were calculated within the framework of the Kane model. The effect of various recombination processes on the carrier lifetime was studied, and the dominant role of Auger processes was established. For MQW structures quantization energies for electrons, light and heavy holes were calculated. A characteristic feature of the experimental EL spectra of these structures was the presence of peaks with energy different from that of calculated optical transitions between the first quantization levels for electrons and heavy holes. The obtained results showed strong effect of the specific electronic structure of InAsSb on the energy and intensity of optical transitions in nanostructures based on this material. For the structure with MQWs in the active layer, a very weak temperature dependence of EL peak was observed at high temperatures (>150 K), which makes it attractive for fabricating temperature-resistant gas sensors operating in the middle-infrared range.

Keywords: Electroluminescence, InAsSb, light emitting diode, quantum wells

Procedia PDF Downloads 212

Authors: Akbar Gharbali, Ali Abbasian Ardekani, Afshin Mohammadi

Abstract:

Introduction: Thyroid nodules have an incidence of 33-68% in the general population. More than 5-15% of these nodules are malignant. Early detection and treatment of thyroid nodules increase the cure rate and provide optimal treatment. Between the medical imaging methods, Ultrasound is the chosen imaging technique for assessment of thyroid nodules. The confirming of the diagnosis usually demands repeated fine-needle aspiration biopsy (FNAB). So, current management has morbidity and non-zero mortality. Objective: To explore diagnostic potential of automatic texture analysis (TA) methods in differentiation benign and malignant thyroid nodules by ultrasound imaging in order to help for reliable diagnosis and monitoring of the thyroid nodules in their early stages with no need biopsy. Material and Methods: The thyroid US image database consists of 70 patients (26 benign and 44 malignant) which were reported by Radiologist and proven by the biopsy. Two slices per patient were loaded in Mazda Software version 4.6 for automatic texture analysis. Regions of interests (ROIs) were defined within the abnormal part of the thyroid nodules ultrasound images. Gray levels within an ROI normalized according to three normalization schemes: N1: default or original gray levels, N2: +/- 3 Sigma or dynamic intensity limited to µ+/- 3σ, and N3: present intensity limited to 1% - 99%. Up to 270 multiscale texture features parameters per ROIs per each normalization schemes were computed from well-known statistical methods employed in Mazda software. From the statistical point of view, all calculated texture features parameters are not useful for texture analysis. So, the features based on maximum Fisher coefficient and the minimum probability of classification error and average correlation coefficients (POE+ACC) eliminated to 10 best and most effective features per normalization schemes. We analyze this feature under two standardization states (standard (S) and non-standard (NS)) with Principle Component Analysis (PCA), Linear Discriminant Analysis (LDA) and Non-Linear Discriminant Analysis (NDA). The 1NN classifier was performed to distinguish between benign and malignant tumors. The confusion matrix and Receiver operating characteristic (ROC) curve analysis were used for the formulation of more reliable criteria of the performance of employed texture analysis methods. Results: The results demonstrated the influence of the normalization schemes and reduction methods on the effectiveness of the obtained features as a descriptor on discrimination power and classification results. The selected subset features under 1%-99% normalization, POE+ACC reduction and NDA texture analysis yielded a high discrimination performance with the area under the ROC curve (Az) of 0.9722, in distinguishing Benign from Malignant Thyroid Nodules which correspond to sensitivity of 94.45%, specificity of 100%, and accuracy of 97.14%. Conclusions: Our results indicate computer-aided diagnosis is a reliable method, and can provide useful information to help radiologists in the detection and classification of benign and malignant thyroid nodules.

Keywords: ultrasound imaging, thyroid nodules, computer aided diagnosis, texture analysis, PCA, LDA, NDA

Procedia PDF Downloads 279

Authors: Alicia Ettlin

Abstract:

Amid the rise of neoliberalism to the leading economic policy model in Western societies in the 1980s, people have started to internalise a neoliberal way of thinking, whereby the human body has become an entity that can and needs to be precisely managed through free yet rational decision-making processes. The neoliberal citizen has consequently become an entrepreneur of the self who is free, independent, rational, productive and responsible for themselves, their health and wellbeing as well as their appearance. The focus on individuals as entrepreneurs who manage their bodies through the rationally thinking mind has, however, become increasingly criticised for viewing the social actor as ‘disembodied’, as a detached, social actor whose powerful mind governs over the passive body. On the other hand, the discourse around embodiment seeks to connect rational decision-making processes to the dominant neoliberal discourse which creates an embodied understanding that the body, just as other areas of people’s lives, can and should be shaped, monitored and managed through cognitive and rational thinking. This perspective offers an understanding of the body regarding its connections with the social environment that reaches beyond the debates around mind-body binary thinking. Hence, following this argument, body management should not be thought of as either solely guided by embodied discourses nor as merely falling into a mind-body dualism, but rather, simultaneously and inseparably as both at once. The descriptive, qualitative analysis of semi-structured in-depth interviews conducted with young Australian amateur athletes between the age of 18 and 24 has shown that most participants are interested in measuring and managing their body to create self-knowledge and self-improvement. The participants thereby connected self-improvement to weight loss, muscle gain or simply staying fit and healthy. Self-knowledge refers to body measurements including weight, BMI or body fat percentage. Self-management and self-knowledge that are reliant on one another to take rational and well-thought-out decisions, are both characteristic values of the neoliberal doctrine. A neoliberal way of thinking and looking after the body has also by many been connected to rewarding themselves for their discipline, hard work or achievement of specific body management goals (e.g. eating chocolate for reaching the daily step count goal). A few participants, however, have shown resistance against these neoliberal values, and in particular, against the precise monitoring and management of the body with the help of self-tracking devices. Ultimately, however, it seems that most participants have internalised the dominant discourses around self-responsibility, and by association, a sense of duty to discipline their body in normative ways. Even those who have indicated their resistance against body work and body management practices that follow neoliberal thinking and measurement systems, are aware and have internalised the concept of the rational operating mind that needs or should decide how to look after the body in terms of health but also appearance ideals. The discussion around the collected data thereby shows that embodiment and the mind/body dualism constitute two connected, rather than two separate or opposing concepts.

Keywords: dualism, embodiment, mind, neoliberalism

Procedia PDF Downloads 163

Authors: Xiaochen Mu

Abstract:

Data rights confirmation, as a key legal issue in the development of the digital economy, is undergoing a transition from a traditional rights paradigm to a more complex private-economic paradigm. In this process, data rights confirmation has evolved from a simple claim of rights to a complex structure encompassing multiple dimensions of personality rights and property rights. Current data rights confirmation practices are primarily reflected in two models: holistic rights confirmation and process rights confirmation. The holistic rights confirmation model continues the traditional "one object, one right" theory, while the process rights confirmation model, through contractual relationships in the data processing process, recognizes rights that are more adaptable to the needs of data circulation and value release. In the design of the data property rights system, there is a hierarchical characteristic aimed at decoupling from raw data to data applications through horizontal stratification and vertical staging. This design not only respects the ownership rights of data originators but also, based on the usufructuary rights of enterprises, constructs a corresponding rights system for different stages of data processing activities. The subjects of data property rights include both data originators, such as users, and data producers, such as enterprises, who enjoy different rights at different stages of data processing. The intellectual property rights system, with the mission of incentivizing innovation and promoting the advancement of science, culture, and the arts, provides a complete set of mechanisms for protecting innovative results. However, unlike traditional private property rights, the granting of intellectual property rights is not an end in itself; the purpose of the intellectual property system is to balance the exclusive rights of the rights holders with the prosperity and long-term development of society's public learning and the entire field of science, culture, and the arts. Therefore, the intellectual property granting mechanism provides both protection and limitations for the rights holder. This perfectly aligns with the dual attributes of data. In terms of achieving the protection of data property rights, the granting of intellectual property rights is an important institutional choice that can enhance the effectiveness of the data property exchange mechanism. Although this is not the only path, the granting of data property rights within the framework of the intellectual property rights system helps to establish fundamental legal relationships and rights confirmation mechanisms and is more compatible with the classification and grading system of data. The modernity of the intellectual property rights system allows it to adapt to the needs of big data technology development through special clauses or industry guidelines, thus promoting the comprehensive advancement of data intellectual property rights legislation. This paper analyzes data protection under the virtual property layer theory and two-fold virtual property rights system. Based on the “bundle of right” theory, this paper establishes specific three-level data rights. This paper analyzes the cases: Google v. Vidal-Hall, Halliday v Creation Consumer Finance, Douglas v Hello Limited, Campbell v MGN and Imerman v Tchenquiz. This paper concluded that recognizing property rights over personal data and protecting data under the framework of intellectual property will be beneficial to establish the tort of misuse of personal information.

Keywords: data protection, property rights, intellectual property, Big data

Procedia PDF Downloads 39

Authors: L. Chiriatti, H. Hafid, H. R. Mercado-Mendoza, K. L. Apedo, C. Fond, F. Feugeas

Abstract:

Substituting natural aggregate with recycled aggregate coming from concrete demolition represents a promising alternative to face the issues of both the depletion of natural resources and the congestion of waste storage facilities. However, the crushing process of concrete demolition waste, currently in use to produce recycled concrete aggregate, does not allow the complete separation of natural aggregate from a variable amount of adhered mortar. Given the physicochemical characteristics of the latter, the introduction of recycled concrete aggregate into a concrete mix modifies, to a certain extent, both fresh and hardened concrete properties. As a consequence, the behavior of recycled reinforced concrete members could likely be influenced by the specificities of recycled concrete aggregates. Beyond the mechanical properties of concrete, and as a result of the composite character of reinforced concrete, the bond characteristics at the rebar/concrete interface have to be taken into account in an attempt to describe accurately the mechanical response of recycled reinforced concrete members. Hence, a comparative experimental campaign, including 16 pull-out tests, was carried out. Four concrete mixes with different recycled concrete aggregate content were tested. The main mechanical properties (compressive strength, tensile strength, Young’s modulus) of each concrete mix were measured through standard procedures. A single 14-mm-diameter ribbed rebar, representative of the diameters commonly used in the domain of civil engineering, was embedded into a 200-mm-side concrete cube. The resulting concrete cover is intended to ensure a pull-out type failure (i.e. exceedance of the rebar/concrete interface shear strength). A pull-out test carried out on the 100% recycled concrete specimen was enriched with exploratory acoustic emission measurements. Acoustic event location was performed by means of eight piezoelectric transducers distributed over the whole surface of the specimen. The resulting map was compared to existing data related to natural aggregate concrete. Damage distribution around the reinforcement and main features of the characteristic bond stress/free-end slip curve appeared to be similar to previous results obtained through comparable studies carried out on natural aggregate concrete. This seems to show that the usual bond mechanism sequence (‘chemical adhesion’, mechanical interlocking and friction) remains unchanged despite the addition of recycled concrete aggregate. However, the results also suggest that bond efficiency seems somewhat improved through the use of recycled concrete aggregate. This observation appears to be counter-intuitive with regard to the diminution of the main concrete mechanical properties with the recycled concrete aggregate content. As a consequence, the impact of recycled concrete aggregate content on bond characteristics seemingly represents an important factor which should be taken into account and likely to be further explored in order to determine flexural parameters such as deflection or crack distribution.

Keywords: acoustic emission monitoring, high-bond steel rebar, pull-out test, recycled aggregate concrete

Procedia PDF Downloads 171

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

Abstract:

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

Keywords: devulcanization, recycling, rubber, waste

Procedia PDF Downloads 385

Authors: Keping Zuo, Jia Yin Chia, Gideon Praveen Kumar Vijayakumar, Foad Kabinejadian, Fangsen Cui, Pei Ho, Hwa Liang Leo

Abstract:

Carotid artery is the major vessel supplying blood to the brain. Carotid artery stenosis is one of the three major causes of stroke and the stroke is the fourth leading cause of death and the first leading cause of disability in most developed countries. Although there is an increasing interest in carotid artery stenting for treatment of cervical carotid artery bifurcation therosclerotic disease, currently available bare metal stents cannot provide an adequate protection against the detachment of the plaque fragments over diseased carotid artery, which could result in the formation of micro-emboli and subsequent stroke. Our research group has recently developed a novel preferential covered-stent for carotid artery aims to prevent friable fragments of atherosclerotic plaques from flowing into the cerebral circulation, and yet retaining the ability to preserve the flow of the external carotid artery. The preliminary animal studies have demonstrated the potential of this novel covered-stent design for the treatment of carotid therosclerotic stenosis. The purpose of this study is to evaluate the biomechanical property of PU membrane of different concentration configurations in order to refine the stent coating technique and enhance the clinical performance of our novel carotid covered stent. Results from this study also provide necessary material property information crucial for accurate simulation analysis for our stents. Method: Medical grade Polyurethane (ChronoFlex AR) was used to prepare PU membrane specimens. Different PU membrane configurations were subjected to uniaxial test: 22%, 16%, and 11% PU solution were made by mixing the original solution with proper amount of the Dimethylacetamide (DMAC). The specimens were then immersed in physiological saline solution for 24 hours before test. All specimens were moistened with saline solution before mounting and subsequent uniaxial testing. The specimens were preconditioned by loading the PU membrane sample to a peak stress of 5.5 Mpa for 10 consecutive cycles at a rate of 50 mm/min. The specimens were then stretched to failure at the same loading rate. Result: The results showed that the stress-strain response curves of all PU membrane samples exhibited nonlinear characteristic. For the ultimate failure stress, 22% PU membrane was significantly higher than 16% (p<0.05). In general, our preliminary results showed that lower concentration PU membrane is stiffer than the higher concentration one. From the perspective of mechanical properties, 22% PU membrane is a better choice for the covered stent. Interestingly, the hyperelastic Ogden model is able to accurately capture the nonlinear, isotropic stress-strain behavior of PU membrane with R2 of 0.9977 ± 0.00172. This result will be useful for future biomechanical analysis of our stent designs and will play an important role for computational modeling of our covered stent fatigue study.

Keywords: carotid artery, covered stent, nonlinear, hyperelastic, stress, strain

Procedia PDF Downloads 310

Authors: Cherng-Jye Jeng, Ming-Feng Hou, Hsing-Yuan Liu, Chuan-Feng Chang, Lih-Rong Wang, Yen-Chin Lin

Abstract:

Introduction: The incidence of breast cancer has gradually increased in Taiwan, and the characteristic of younger ages impact these women in their middle age, and may also cause challenges in terms of family, work, and illness. Breasts are symbols of femininity, as well as of sex. For women, breasts are important organs for the female identity and sexual expression. Losing breasts not only affects the female role, but would also affect sexual attraction and sexual desire. Thus, women with breast cancer who have need for mastectomies experience physical incompletion, which affects women’s self-confidence, physical image, and self-orientation. Purposes: 1. To understand the physical experience of women with breast cancer. 2. To explore the issue of sexual issues on the health effects of women with breast cancer. 3. To construct a domestic sex life issue group model for domestic women with breast cancer. 4. To explore the accompaniment experiences and sexual relationship adjustments of spouses when women have breast cancer. Method: After the research plan passes IRB review, participants will be recruited at breast surgery clinic in the affiliated hospital, to screen suitable subjects for entry into the group. Between March and May 2015, two sexual health and sex life consultation groups were conducted, which were (1) 10 in postoperative groups for women with cancer; (2) 4 married couples group for postoperative women with cancer. After sharing experiences and dialogue, women can achieve mutual support and growth. Data organization and analysis underwent descriptive analysis in qualitative research, and the group process was transcribed into transcripts for overall-content and category-content analysis. Results: Ten women with breast cancer believed that participating in group can help them exchange experiences, and elevate sexual health. The main issues include: (1) after breast cancer surgery, patients generally received chemotherapy or estrogen suppressants, causing early menopause; in particular, vaginal dryness can cause pain or bleeding in intercourse, reducing their desire for sexual activity; (2) breast cancer accentuates original spousal or family and friend relationships; some people have support and care from their family, and spouses emphasize health over the appearance of breasts; however, some people do not have acceptance and support from their family, and some even hear spousal sarcasm about loss of breasts; (3) women with breast cancer have polarized expressions of optimism and pessimism in regards to their emotions, beliefs, and body image regarding cancer; this is related to the women’s original personalities, attribution of causes of cancer, and extent of worry about relapse. Conclusion: The research results can be provided as a reference to medical institutions or breast cancer volunteer teams, to pay attention to maintaining the health of women with breast cancer.

Keywords: women with breast cancer, experiences of objectifying the body, quality of sex life, sexual health

Procedia PDF Downloads 319

Authors: Daniel Sava, Dragos Gudovan, Iulia Alexandra Gudovan, Ioana Ardelean, Maria Sonmez, Denisa Ficai, Laurentia Alexandrescu, Ecaterina Andronescu

Abstract:

Graphene and graphene oxide have been intensively studied due to the very good properties, which are intrinsic to the material or come from the easy doping of those with other functional groups. Graphene and graphene oxide have known a broad band of useful applications, in electronic devices, drug delivery systems, medical devices, sensors and opto-electronics, coating materials, sorbents of different agents for environmental applications, etc. The board range of applications does not come only from the use of graphene or graphene oxide alone, or by its prior functionalization with different moieties, but also it is a building block and an important component in many composite devices, its addition coming with new functionalities on the final composite or strengthening the ones that are already existent on the parent product. An attempt to improve the mechanical properties of polyamide elastomers by compounding with graphene oxide in the parent polymer composition was attempted. The addition of the graphene oxide contributes to the properties of the final product, improving the hardness and aging resistance. Graphene oxide has a lower hardness and textile strength, and if the amount of graphene oxide in the final product is not correctly estimated, it can lead to mechanical properties which are comparable to the starting material or even worse, the graphene oxide agglomerates becoming a tearing point in the final material if the amount added is too high (in a value greater than 3% towards the parent material measured in mass percentages). Two different types of tests were done on the obtained materials, the hardness standard test and the tensile strength standard test, and they were made on the obtained materials before and after the aging process. For the aging process, an accelerated aging was used in order to simulate the effect of natural aging over a long period of time. The accelerated aging was made in extreme heat. For all materials, FT-IR spectra were recorded using FT-IR spectroscopy. From the FT-IR spectra only the bands corresponding to the polyamide were intense, while the characteristic bands for graphene oxide were very small in comparison due to the very small amounts introduced in the final composite along with the low absorptivity of the graphene backbone and limited number of functional groups. In conclusion, some compositions showed very promising results, both in tensile strength test and in hardness tests. The best ratio of graphene to elastomer was between 0.6 and 0.8%, this addition extending the life of the product. Acknowledgements: The present work was possible due to the EU-funding grant POSCCE-A2O2.2.1-2013-1, Project No. 638/12.03.2014, code SMIS-CSNR 48652. The financial contribution received from the national project ‘New nanostructured polymeric composites for centre pivot liners, centre plate and other components for the railway industry (RONERANANOSTRUCT)’, No: 18 PTE (PN-III-P2-2.1-PTE-2016-0146) is also acknowledged.

Keywords: graphene, graphene oxide, mechanical properties, dopping effect

Procedia PDF Downloads 314

Authors: Muhammad Ahnaf Zahin, Yaw Adu-Gyamfi

Abstract:

Bus transit is a crucial component of transportation networks, especially in urban areas. Any intelligent transportation system must have accurate real-time information on bus travel times since it minimizes waiting times for passengers at different stations along a route, improves service reliability, and significantly optimizes travel patterns. Bus agencies must enhance the quality of their information service to serve their passengers better and draw in more travelers since people waiting at bus stops are frequently anxious about when the bus will arrive at their starting point and when it will reach their destination. For solving this issue, different models have been developed for predicting bus travel times recently, but most of them are focused on smaller road networks due to their relatively subpar performance in high-density urban areas on a vast network. This paper develops a deep learning-based architecture using a single-step multi-station forecasting approach to predict average bus travel times for numerous routes, stops, and trips on a large-scale network using heterogeneous bus transit data collected from the GTFS database. Over one week, data was gathered from multiple bus routes in Saint Louis, Missouri. In this study, Gated Recurrent Unit (GRU) neural network was followed to predict the mean vehicle travel times for different hours of the day for multiple stations along multiple routes. Historical time steps and prediction horizon were set up to 5 and 1, respectively, which means that five hours of historical average travel time data were used to predict average travel time for the following hour. The spatial and temporal information and the historical average travel times were captured from the dataset for model input parameters. As adjacency matrices for the spatial input parameters, the station distances and sequence numbers were used, and the time of day (hour) was considered for the temporal inputs. Other inputs, including volatility information such as standard deviation and variance of journey durations, were also included in the model to make it more robust. The model's performance was evaluated based on a metric called mean absolute percentage error (MAPE). The observed prediction errors for various routes, trips, and stations remained consistent throughout the day. The results showed that the developed model could predict travel times more accurately during peak traffic hours, having a MAPE of around 14%, and performed less accurately during the latter part of the day. In the context of a complicated transportation network in high-density urban areas, the model showed its applicability for real-time travel time prediction of public transportation and ensured the high quality of the predictions generated by the model.

Keywords: gated recurrent unit, mean absolute percentage error, single-step forecasting, travel time prediction.

Procedia PDF Downloads 72

Authors: Tobias Schramm, Günther Prokop

Abstract:

In Germany, the number of road fatalities has been falling since 2010 at a more moderate rate than before. At the same time, the average age of all registered passenger cars in Germany is rising continuously. Studies show that there is a correlation between the age and mileage of passenger cars and the degradation of their chassis components. Various studies show that degraded shock absorbers increase the braking distance of passenger cars and have a negative impact on driving stability. The exact effect of degraded vehicle shock absorbers on road safety is still the subject of research. A shock absorber examination as part of the periodic technical inspection is only mandatory in very few countries. In Germany, there is as yet no requirement for such a shock absorber examination. More comprehensive findings on the effect of degraded shock absorbers on the safety-critical driving dynamics of passenger cars can provide further arguments for the introduction of mandatory shock absorber testing as part of the periodic technical inspection. The specific effect chains of untripped rollover accidents are also still the subject of research. However, current research results show that the high proportion of sport utility vehicles in the vehicle field significantly increases the probability of untripped rollover accidents. The aim of this work is to estimate the effect of degraded twin-tube shock absorbers on the safety-critical tipping and rolling behaviour of passenger cars, which can lead to untripped rollover accidents. A characteristic curve-based five-mass full vehicle model and a semi-physical phenomenological shock absorber model were set up, parameterized and validated. The shock absorber model is able to reproduce the damping characteristics of vehicle twin-tube shock absorbers with oil and gas loss for various excitations. The full vehicle model was validated with steering wheel angle sinus sweep driving maneuvers. The model was then used to simulate steering wheel angle sine and fishhook maneuvers, which investigate the safety-critical tipping and rolling behavior of passenger cars. The simulations were carried out in a realistic parameter space in order to demonstrate the effect of various vehicle characteristics on the effect of degraded shock absorbers. As a result, it was shown that degraded shock absorbers have a negative effect on the tipping and rolling behavior of all passenger cars. Shock absorber degradation leads to a significant increase in the observed roll angles, particularly in the range of the roll natural frequency. This superelevation has a negative effect on the wheel load distribution during the driving maneuvers investigated. In particular, the height of the vehicle's center of gravity and the stabilizer stiffness of the vehicles has a major influence on the effect of degraded shock absorbers on the overturning and rolling behaviour of passenger cars.

Keywords: numerical simulation, safety-critical driving dynamics, suspension degradation, tipping and rolling behavior of passenger cars, vehicle shock absorber

Procedia PDF Downloads 11

Authors: Xiaoyong He

Abstract:

The manipulation of THz waves is still a challenging task due to lack of natural materials interacted with it strongly. Designed by tailoring the characters of unit cells (meta-molecules), the advance of metamaterials (MMs) may solve this problem. However, because of Ohmic and radiation losses, the performance of MMs devices is subjected to the dissipation and low quality factor (Q-factor). This dilemma may be circumvented by Fano resonance, which arises from the destructive interference between a bright continuum mode and dark discrete mode (or a narrow resonance). Different from symmetric Lorentz spectral curve, Fano resonance indicates a distinct asymmetric line-shape, ultrahigh quality factor, steep variations in spectrum curves. Fano resonance is usually realized through symmetry breaking. However, if concentric double rings (DR) are placed closely to each other, the near-field coupling between them gives rise to two hybridized modes (bright and narrowband dark modes) because of the local asymmetry, resulting into the characteristic Fano line shape. Furthermore, from the practical viewpoint, it is highly desirable requirement that to achieve the modulation of Fano spectral curves conveniently, which is an important and interesting research topics. For current Fano systems, the tunable spectral curves can be realized by adjusting the geometrical structural parameters or magnetic fields biased the ferrite-based structure. But due to limited dispersion properties of active materials, it is still a tough work to tailor Fano resonance conveniently with the fixed structural parameters. With the favorable properties of extreme confinement and high tunability, graphene is a strong candidate to achieve this goal. The DR-structure possesses the excitation of so-called “trapped modes,” with the merits of simple structure and high quality of resonances in thin structures. By depositing graphene circular DR on the SiO2/Si/ polymer substrate, the tunable Fano resonance has been theoretically investigated in the terahertz regime, including the effects of graphene Fermi level, structural parameters and operation frequency. The results manifest that the obvious Fano peak can be efficiently modulated because of the strong coupling between incident waves and graphene ribbons. As Fermi level increases, the peak amplitude of Fano curve increases, and the resonant peak position shifts to high frequency. The amplitude modulation depth of Fano curves is about 30% if Fermi level changes in the scope of 0.1-1.0 eV. The optimum gap distance between DR is about 8-12 μm, where the value of figure of merit shows a peak. As the graphene ribbon width increases, the Fano spectral curves become broad, and the resonant peak denotes blue shift. The results are very helpful to develop novel graphene plasmonic devices, e.g. sensors and modulators.

Keywords: graphene, metamaterials, terahertz, tunable

Procedia PDF Downloads 344