Search results for: dynamic orthotropic behavior

Authors: Ledi Neçaj

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Objectives: The target of this paper is (1) to explain objectively physical activity model throughout three chronic cardiopulmonary conditions, and (2) to study the connection among physical activity dimensions with disease severity, self-reported physical and emotional functioning, and exercise performance. Material and Methods: This is a cross-sectional study of patients in their domestic environment. Patients with cardiopulmonary diseases were: chronic obstructive pulmonary disease (COPD), (n-63), coronary heart failure (n=60), and patients with implantable cardioverter defibrillator (n=60). Main results measures: Seven ambulatory physical activity dimensions (total steps, percentage time active, percentage time ambulating at low, medium, and hard intensity, maximum cadence for 30 non-stop minutes, and peak performance) have been measured with an accelerometer. Results: Subjects with COPD had the lowest amount of ambulatory physical activity compared with topics with coronary heart failure and cardiac dysrhythmias (all 7 interest dimensions, P<.05); total step counts have been: 5319 as opposed to 7464 as opposed to 9570, respectively. Six-minute walk distance becomes correlated (r=.44-.65, P<.01) with all physical activity dimensions inside the COPD pattern, the most powerful correlations being with total steps and peak performance. In topics with cardiac impairment, maximal oxygen intake had the most effective small to slight correlations with five of the physical activity dimensions (r=.22-.40, P<.05). In contrast, correlations among 6-minute walk test distance and physical activity have been higher (r=.48-.61, P<.01) albeit in a smaller pattern of most effective patients with coronary heart failure. For all three samples, self-reported physical and mental health functioning, age, frame mass index, airflow obstruction, and ejection fraction had both exceptionally small and no significant correlations with physical activity. Conclusions: Findings from this study present a profitable benchmark of physical activity patterns in individuals with cardiopulmonary diseases for comparison with future studies. All seven dimensions of ambulatory physical activity have disfavor between subjects with COPD, heart failure, and cardiac dysrhythmias. Depending on the research or clinical goal, the use of one dimension, such as total steps, may be sufficient. Although physical activity had high correlations with performance on a six-minute walk test relative to other variables, accelerometers-based physical activity monitoring provides unique, important information about real-world behavior in patients with cardiopulmonary not already captured with existing measures.

Keywords: ambulatory physical activity, walking, monitoring, COPD, heart failure, implantable defibrillator, exercise performance

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Authors: Khair Al-Deen Bsisu, Osama Mahmoud Abuzeid

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Significant technological advances have been achieved in the design and building construction of steel and glass in the last two decades. The metal glass support frame has been replaced by further sophisticated technological solutions, for example, the point fixed glazing systems. The minimization of the visual mass has reached extensive possibilities through the evolution of technology in glass production and the better understanding of the structural potential of glass itself, the technological development of bolted fixings, the introduction of the glazing support attachments of the glass suspension systems and the use for structural stabilization of cables that reduce to a minimum the amount of metal used. The variability of solutions of tension structures, allied to the difficulties related to geometric and material non-linear behavior, usually overrules the use of analytical solutions, letting numerical analysis as the only general approach to the design and analysis of tension structures. With the characteristics of low stiffness, lightweight, and small damping, tension structures are obviously geometrically nonlinear. In fact, analysis of cable truss is not only one of the most difficult nonlinear analyses because the analysis path may have rigid-body modes, but also a time consuming procedure. Non-linear theory allowing for large deflections is used. The flexibility of supporting members was observed to influence the stresses in the pane considerably in some cases. No other class of architectural structural systems is as dependent upon the use of digital computers as are tensile structures. Besides complexity, the process of design and analysis of tension structures presents a series of specificities, which usually lead to the use of special purpose programs, instead of general purpose programs (GPPs), such as ANSYS. In a special purpose program, part of the design know how is embedded in program routines. It is very probable that this type of program will be the option of the final user, in design offices. GPPs offer a range of types of analyses and modeling options. Besides, traditional GPPs are constantly being tested by a large number of users, and are updated according to their actual demands. This work discusses the use of ANSYS for the analysis and design of tension structures, such as cable truss structures under wind and gravity loadings. A model to describe the glass panels working in coordination with the cable truss was proposed. Under the proposed model, a FEM model of the glass panels working in coordination with the cable truss was established.

Keywords: Glass Construction material, Facades, Finite Element, Pre-Tensioned Cable Truss

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Authors: Cristina Lavilla, Andreas Heise

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The synthesis of sequence-controlled polymers has received increasing attention in the last years. Well-defined polyacrylates, polyacrylamides and styrene-maleimide copolymers have been synthesized by sequential or kinetic addition of comonomers. However this approach has not yet been introduced to the synthesis of polypeptides, which are in fact polymers developed by nature in a sequence-controlled way. Polypeptides are natural materials that possess the ability to self-assemble into complex and highly ordered structures. Their folding and properties arise from precisely controlled sequences and compositions in their constituent amino acid monomers. So far, solid-phase peptide synthesis is the only technique that allows preparing short peptide sequences with excellent sequence control, but also requires extensive protection/deprotection steps and it is a difficult technique to scale-up. A new strategy towards sequence control in the synthesis of polypeptides is introduced, based on the sequential addition of α-amino acid-N-carboxyanhydrides (NCAs). The living ring-opening process is conducted to full conversion and no purification or deprotection is needed before addition of a new amino acid. The length of every block is predefined by the NCA:initiator ratio in every step. This method yields polypeptides with a specific sequence and controlled molecular weights. A series of polypeptides with varying block sequences have been synthesized with the aim to identify structure-property relationships. All of them are able to adopt secondary structures similar to natural polypeptides, and display properties in the solid state and in solution that are characteristic of the primary structure. By design the prepared polypeptides allow selective modification of individual block sequences, which has been exploited to introduce functionalities in defined positions along the polypeptide chain. Poly(ethylene glycol)(PEG) was the functionality chosen, as it is known to favor hydrophilicity and also yield thermoresponsive materials. After PEGylation, hydrophilicity of the polypeptides is enhanced, and their thermal response in H2O has been studied. Noteworthy differences in the behavior of the polypeptides having different sequences have been found. Circular dichroism measurements confirmed that the α-helical conformation is stable over the examined temperature range (5-90 °C). It is concluded that PEG units are the main responsible of the changes in H-bonding interactions with H2O upon variation of temperature, and the position of these functional units along the backbone is a factor of utmost importance in the resulting properties of the α-helical polypeptides.

Keywords: α-amino acid N-carboxyanhydrides, multiblock copolymers, poly(ethylene glycol), polypeptides, ring-opening polymerization, sequence control

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Authors: Tae Young Jin, Jin Soo Kim

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Carbon emissions have emerged as global concerns. Intergovernmental Panel of Climate Change (IPCC) have published reports about Green House Gases (GHGs) emissions regularly. United Nations Framework Convention on Climate Change (UNFCCC) have held a conference yearly since 1995. Especially, COP21 held at December 2015 made the Paris agreement which have strong binding force differently from former COP. The Paris agreement was ratified as of 4 November 2016, they finally have legal binding. Participating countries set up their own Intended Nationally Determined Contributions (INDC), and will try to achieve this. Thus, carbon emissions must be reduced. The energy sector is one of most responsible for carbon emissions and fossil fuels particularly are. Thus, this paper attempted to examine the relationship between natural gas consumption and economic growth. To achieve this, we adopted the Cobb-Douglas production function that consists of natural gas consumption, economic growth, capital, and labor using dependent panel analysis. Data were preprocessed with Principal Component Analysis (PCA) to remove cross-sectional dependency which can disturb the panel results. After confirming the existence of time-trended component of each variable, we moved to cointegration test considering cross-sectional dependency and structural breaks to describe more realistic behavior of volatile international indicators. The cointegration test result indicates that there is long-run equilibrium relationship between selected variables. Long-run cointegrating vector and Granger causality test results show that while natural gas consumption can contribute economic growth in the short-run, adversely affect in the long-run. From these results, we made following policy implications. Since natural gas has positive economic effect in only short-run, the policy makers in developing countries must consider the gradual switching of major energy source, from natural gas to sustainable energy source. Second, the technology transfer and financing business suggested by COP must be accelerated. Acknowledgement—This work was supported by the Energy Efficiency & Resources Core Technology Program of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) granted financial resource from the Ministry of Trade, Industry & Energy, Republic of Korea (No. 20152510101880) and by the National Research Foundation of Korea Grant funded by the Korean Government (NRF-205S1A3A2046684).

Keywords: developing countries, economic growth, natural gas consumption, panel data analysis

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Authors: Debasish Chowdhury, Sunil Mekale, Sarvanamurthy Sakthivel, Sukhvinder Kaur, Rambabu Khambampati, Ashok Agarwal

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Introduction: The migrant intervention in India was initiated during the National AIDS Control Program (NACP) Phase-2 (2002-2007). HIV Sentinel surveillance Studies (HSS) conducted in 2012-13 indicated higher HIV prevalence among migrants (0.99%) compared to general populations (0.35%). Migrants continue to bear a heightened risk of HIV infection which results from the condition and structure of the migration process. USAID PHFI-PIPPSE project in collaboration with the National AIDS Control Organization (NACO) developed a unique system called Migrant Service Delivery System (MSDS) to capture migrants profile with respect to their risk profile and to provide tailor made services to them. Description: MSDS is a web-based system, designed and implemented to increase service uptake among migrants through evidence based planning. 110 destination migrants Targeted Intervention (TI) from 11 states were selected for study with varied target populations in terms of occupations; to understand occupation related risk behaviors among the migrants. Occupation wise registration data of high risk vulnerable migrants were analyzed through MSDS for the period April 2014–June 2016. Analysis was made on specific indicators among these occupational groups to understand the risk behavior and their vulnerability to HIV and STIs. Findings: Out of total HIV positive migrant’s workers (N= 847) enrolled in MSDS HIV rate is found to be highest among Auto-Rickshaw (18.66%) followed by Daily wage laborers (14.46%), Loom workers (10.73%), Industrial workers (10.04%) and Construction worker 7.93%. With 45.14% positivity, industrial workers are found to be most vulnerable to Sexually Transmitted Infections (STIs) (N=10057) among all occupational categories followed by loom workers (16.28%), Skilled worker (Furniture, Jeweler)-7.14%, daily wage laborers (5.45%). Conclusion: MSDS is an effective tool to assess migrants’ risk and their vulnerability to HIV for designing evidence informed program. This system calls for a replication across all destination TIs by NACO for differential strategies for different occupation groups to ensure better yield through scientific planning of intervention among high risk and high vulnerable migrants.

Keywords: migrants, migrant service delivery system, risk, vulnerability

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Authors: Khadija Al-Hosni, Moon Fai Chan, Mohammed Al-Azri

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Background: Several studies suggest that most school-age adolescents are poorly informed on cancer warning signs and risk factors. Providing adolescents with sufficient knowledge would increase their awareness in adulthood and improve seeking behaviors later. Significant: The results will provide a clear vision in assisting key decision-makers in formulating policies on the students' awareness programs towards cancer. So, the likelihood of avoiding cancer in the future will be increased or even promote early diagnosis. Objectives: to evaluate the effectiveness of an education program designed to increase awareness of cancer signs and symptoms risk factors, improve the behavior of seeking help among school students in Oman, and address the barriers to obtaining medical help. Methods: A randomized controlled trial with two groups was conducted in Oman. A total of 1716 students (n=886/control, n= 830/education), aged 15-17 years, at 10th and 11th grade from 12 governmental schools 3 in governorates from 20-February-2022 to 12-May-2022. Basic demographic data were collected, and the Cancer Awareness Measure (CAM) was used as the primary outcome. Data were collected at baseline (T0) and 4 weeks after (T1). The intervention group received an education program about cancer's cause and its signs and symptoms. In contrast, the control group did not receive any education related to this issue during the study period. Non-parametric tests were used to compare the outcomes between groups. Results: At T0, the lamp was the most recognized cancer warning sign in control (55.0%) and intervention (55.2%) groups. However, there were no significant changes at T1 for all signs in the control group. In contrast, all sign outcomes were improved significantly (p<0.001) in the intervention group, the highest response was unexplained pain (93.3%). Smoking was the most recognized risk factor in both groups: (82.8% for control; 84.1% for intervention) at T0. However, there was no significant change in T1 for the control group, but there was for the intervention group (p<0.001), the highest identification was smoking cigarettes (96.5%). Too scared was the largest barrier to seeking medical help by students in the control group at T0 (63.0%) and T1 (62.8%). However, there were no significant changes in all barriers in this group. Otherwise, being too embarrassed (60.2%) was the largest barrier to seeking medical help for students in the intervention group at T0 and too scared (58.6%) at T1. Although there were reductions in all barriers, significant differences were found in six of ten only (p<0.001). Conclusion: The intervention was effective in improving students' awareness of cancer symptoms, warning signs (p<0.001), and risk factors (p<0.001 reduced the most addressed barriers to seeking medical help (p<0.001) in comparison to the control group. The Ministry of Education in Oman could integrate awareness of cancer within the curriculum, and more interventions are needed on the sociological part to overcome the barriers that interfere with seeking medical help.

Keywords: adolescents, awareness, cancer, education, intervention, student

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Authors: Catherine Alex Agbor

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The modern Nigerian society is dynamic, divided in zones based on economic, political and educational resources often shared across the zones. The Six Geopolitical Zones in Nigeria is a major division in modern Nigeria, created during the regime of president Ibrahim Badamasi Babangida. They are North Central, North East, North West, South East, South South and South West. However, the zone used in this study is known as former South-Eastern State of Akwa-Ibom State and Cross-River State; former Rivers State of Bayelsa State and Rivers State; and former Mid-Western Region, Nigeria of Delta State and Edo State. Many reforms have taken place overtime, particularly in the education sector. Education is constantly presenting new ideas and innovative approaches which act to facilitate the rapid exchange of knowledge and provide quality basic education for learners. The Federal Government of Nigeria in accordance with its National Council on Education directed the Nigerian Educational Research and Development Council to restructure its basic education curriculum with the hope to enable the nation meet national and global developmental goals. One of the goals of the 9-year Basic Education Programme is developing in the entire citizenry a strong consciousness for education and a strong commitment to its vigorous promotion. Another is ensuring the acquisition of appropriate levels of literacy, numeracy, manipulative, communicative and life-skills as well as the ethical, moral and civic values for laying a solid foundation for lifelong learning. Therefore, this article at the introductory stage is aimed to describe some key issues in Nigeria’s experience in the basic education curriculum. In this study, particular attention is paid to this very recent educational policy of the Nigerian government known as Universal Basic Education, its challenges and what can be done to make the policy achieve its desired objectives. It progresses to analyze modern requirements for second language teaching; and presents the challenges of second language teaching in Nigeria. Finally, it reports a study which investigated special efforts for appropriate achievement of quality education in language classroom in the south-south zone of Nigeria. One fundamental research question was posed on what educational practices can contribute to current understanding of the structure of language curriculum. More explicitly, the study was designed to analyze the extent to which quality content contributes to current understanding of the structure of school curriculum in the zone. Otherwise stated, it investigated how student-centred educational practices impact on their learning of French language. One hundred and eighty (180) participants (teachers) were purposefully sampled for the study. Qualitative technique was used to elicit information from participants. The qualitative method used was Focus Group Discussion (FGD). Participants were divided into six groups comprising of 30 teachers from each zone. Group discussions were based mainly on curriculum contents and practices. Information from participants revealed that the curriculum content, among others is inadequate and should be re-examined. Recommendations were proffered as a panacea to concrete implementation of the basic education in Nigeria.

Keywords: basic education, quality contents, second language, south-south states

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Authors: Yunhan Zhang, Xiaopeng Li, Zhongxiao Peng

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Additive manufacturing (AM) possesses several key characteristics, including high design freedom, energy-efficient manufacturing process, reduced material waste, high resolution of finished products, and excellent performance of finished products. These advantages have garnered widespread attention and fueled rapid development in recent decades. AM has significantly broadened the spectrum of available materials in the manufacturing industry and is gradually replacing some traditionally manufactured parts. Similar to components produced via traditional methods, products manufactured through AM are susceptible to degradation caused by wear during their service life. Given the prevalence of 316L stainless steel (SS) parts and the limited research on the tribological behavior of 316L SS samples or products fabricated using AM technology, this study aims to investigate the degradation process and wear mechanisms of 316L SS disks fabricated using AM technology. The wear mechanisms and tribological performance of these AM-manufactured samples are compared with commercial 316L SS samples made using conventional methods. Additionally, methods to enhance the tribological performance of additive-manufactured SS samples are explored. Four disk samples with a diameter of 75 mm and a thickness of 10 mm are prepared. Two of them (Group A) are prepared from a purchased SS bar using a milling method. The other two disks (Group B), with the same dimensions, are made of Gas Atomized 316L Stainless Steel (size range: 15-45 µm) purchased from Carpenter Additive and produced using Laser Powder Bed Fusion (LPBF). Pin-on-disk tests are conducted on these disks, which have similar surface roughness and hardness levels. Multiple tests are carried out under various operating conditions, including varying loads and/or speeds, and the friction coefficients are measured during these tests. In addition, the evolution of the surface degradation processes is monitored by creating moulds of the wear tracks and quantitatively analyzing the surface morphologies of the mould images. This analysis involves quantifying the depth and width of the wear tracks and analyzing the wear debris generated during the wear processes. The wear mechanisms and wear performance of these two groups of SS samples are compared. The effects of load and speed on the friction coefficient and wear rate are investigated. The ultimate goal is to gain a better understanding of the surface degradation of additive-manufactured SS samples. This knowledge is crucial for enhancing their anti-wear performance and extending their service life.

Keywords: degradation process, additive manufacturing, stainless steel, surface features

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Authors: Kyohei Yoshino, Masahiko Matsumiya, Yuji Sasaki

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Recently, studies have been conducted on Au(III) extraction using ionic liquids (ILs) as extractants or diluents. ILs such as piperidinium, pyrrolidinium, and pyridinium have been studied as extractants for noble metal extractions. Furthermore, the polarity, hydrophobicity, and solvent miscibility of these ILs can be adjusted depending on their intended use. Therefore, the unique properties of ILs make them functional extraction media. The extraction mechanism of Au(III) using phosphonium-based ILs and relevant thermodynamic studies are yet to be reported. In the present work, we focused on the mechanism of Au(III) extraction and related thermodynamic analyses using phosphonium-based ILs. Triethyl-n-pentyl, triethyl-n-octyl, and triethyl-n-dodecyl phosphonium bis(trifluoromethyl-sulfonyl)amide, [P₂₂₂ₓ][NTf₂], (X = 5, 8, and 12) were investigated for Au(III) extraction. The IL–Au complex was identified as [P₂₂₂₅][AuCl₄] using UV–Vis–NIR and Raman spectroscopic analyses. The extraction behavior of Au(III) was investigated with a change in the [P₂₂₂ₓ][NTf₂]IL concentration from 1.0 × 10–4 to 1.0 × 10–1 mol dm−3. The results indicate that Au(III) can be easily extracted by the anion-exchange reaction in the [P₂₂₂ₓ][NTf₂]IL. The slope range 0.96–1.01 on the plot of log D vs log[P₂₂₂ₓ][NTf2]IL indicates the association of one mole of IL with one mole of [AuCl4−] during extraction. Consequently, [P₂₂₂ₓ][NTf₂] is an anion-exchange extractant for the extraction of Au(III) in the form of anions from chloride media. Thus, this type of phosphonium-based IL proceeds via an anion exchange reaction with Au(III). In order to evaluate the thermodynamic parameters on the Au(III) extraction, the equilibrium constant (logKₑₓ’) was determined from the temperature dependence. The plot of the natural logarithm of Kₑₓ’ vs the inverse of the absolute temperature (T–1) yields a slope proportional to the enthalpy (ΔH). By plotting T–1 vs lnKₑₓ’, a line with a slope range 1.129–1.421 was obtained. Thus, the result indicated that the extraction reaction of Au(III) using the [P₂₂₂ₓ][NTf₂]IL (X=5, 8, and 12) was exothermic (ΔH=-9.39〜-11.81 kJ mol-1). The negative value of TΔS (-4.20〜-5.27 kJ mol-1) indicates that microscopic randomness is preferred in the [P₂₂₂₅][NTf₂]IL extraction system over [P₂₂₂₁₂][NTf₂]IL. The total negative alternation in Gibbs energy (-5.19〜-6.55 kJ mol-1) for the extraction reaction would thus be relatively influenced by the TΔS value on the number of carbon atoms in the alkyl side length, even if the efficiency of ΔH is significantly influenced by the total negative alternations in Gibbs energy. Electrochemical analysis revealed that extracted Au(III) can be reduced in two steps: (i) Au(III)/Au(I) and (ii) Au(I)/Au(0). The diffusion coefficients of the extracted Au(III) species in [P₂₂₂ₓ][NTf₂] (X = 5, 8, and 12) were evaluated from 323 to 373 K using semi-integral and semi-differential analyses. Because of the viscosity of the IL medium, the diffusion coefficient of the extracted Au(III) increases with increasing alkyl chain length. The 4f7/2 spectrum based on X-ray photoelectron spectroscopy revealed that the Au electrodeposits obtained after 10 cycles of continuous extraction and electrodeposition were in the metallic state.

Keywords: au(III), electrodeposition, phosphonium-based ionic liquids, solvent extraction

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Authors: Ana Julia C. Kfouri

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A prerequisite of any building design is to provide security to the users, taking the climate and its physical and physical-geometrical variables into account. It is also important to highlight the relevance of the right material elements, which arise between the person and the agent, and must provide improved thermal comfort conditions and low environmental impact. Furthermore, technology is constantly advancing, as well as computational simulations for projects, and they should be used to develop sustainable building and to provide higher quality of life for its users. In relation to comfort, the more satisfied the building users are, the better their intellectual performance will be. Based on that, the study of thermal comfort in educational buildings is of relative relevance, since the thermal characteristics in these environments are of vital importance to all users. Moreover, educational buildings are large constructions and when they are poorly planned and executed they have negative impacts to the surrounding environment, as well as to the user satisfaction, throughout its whole life cycle. In this line of thought, to evaluate university classroom conditions, it was accomplished a detailed case study on the thermal comfort situation at Federal University of Parana (UFPR). The main goal of the study is to perform a thermal analysis in three classrooms at UFPR, in order to address the subjective and physical variables that influence thermal comfort inside the classroom. For the assessment of the subjective components, a questionnaire was applied in order to evaluate the reference for the local thermal conditions. Regarding the physical variables, it was carried out on-site measurements, which consist of performing measurements of air temperature and air humidity, both inside and outside the building, as well as meteorological variables, such as wind speed and direction, solar radiation and rainfall, collected from a weather station. Then, a computer simulation based on results from the EnergyPlus software to reproduce air temperature and air humidity values of the three classrooms studied was conducted. The EnergyPlus outputs were analyzed and compared with the on-site measurement results to be possible to come out with a conclusion related to the local thermal conditions. The methodological approach included in the study allowed a distinct perspective in an educational building to better understand the classroom thermal performance, as well as the reason of such behavior. Finally, the study induces a reflection about the importance of thermal comfort for educational buildings and propose thermal alternatives for future projects, as well as a discussion about the significant impact of using computer simulation on engineering solutions, in order to improve the thermal performance of UFPR’s buildings.

Keywords: computer simulation, educational buildings, EnergyPlus, humidity, temperature, thermal comfort

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Authors: Jerome Joshi

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

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

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Authors: Nivedhitha Venkatakrishnan

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Walking down busy temple streets in India is an experience in lifetime. Especially the temple streets are one of the most energetic places not only because of the divinity but also because of the streets itself which provides place for people to relax, meet, shop, linger, just walk around these activities create a set of experience which results in memories that lasts longer. Thinking of any temple street in India the image that comes to anyone’s mind are the elegantly sculpted Gopurams (Gateway) that depicts the craftsmanship and the history of the place, people taking a holy dip in the water, the aroma of the agarbathi’s, flowers with the divine Vedic chants and the sound of the temple bell flock of pigeons flying from the niches of the Gopuram with the sun in the backdrop. It gives a feeling of impulse energy that brings in life to these streets. Any temple street with even any one factor missing would look dead. This will be amiss in the essence in the scene of one’s experiences. These Temple Streets traditionally cater not only for religious purpose but to a wide range of activities. A vibrant street that facilitates such activities are preferred by the public any day. The research seeks to understand and find out the definition of Vibrancy in Indian Context. What is Vibrancy? What brings in the feeling of Vibrancy/Liveliness/Energy? Is it the Built structure and the city? Or is it the people? Or is it the Activity? Or is it Built structure – city – People – Activity put together brings the sense of Vibrancy to a place? How to define Vibrancy? Is it measurable? For which a case of Car Street Udupi, Karnataka is taken. The research is carried out in two stages. ‘Stage One’ makes use of ethnographic fieldwork as a basic method, complimented by structured field observations using a behavioral mapping procedure of the streets. Stage Two’ utilizes surveys that collected. This stage seeks to understand what design characteristics and furniture arrangements are associated with stationary, social and gathering activities of people by each cultural group and all groups collectively. The main conclusion from this research is that retail activities remain the main concern of people in cultural streets. Management and higher-level planning of retail activities on the streets could encourage and motivate possible Shops to enrich the trade variety of the street that provides a means for social and cultural diversity. In addition to business activities, spatial design characteristics are found to have an influence on people’s behavior and activity. The findings of this research suggest that retail and business activities, together with the design and skillful management of the public areas, could support a wider range of static and social activities among people of various ethnic backgrounds.

Keywords: activity, liveliness, temple street, vibrancy

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Authors: Amelia Frickey, Timothy (TJ) Sheridan, Angelica Rossi, Bahar Aliakbarian

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The growth of large food supply chains demanded improved end-to-end traceability of food products, which has led to companies being increasingly interested in using smart technologies such as Radio Frequency Identification (RFID)-enabled packaging to track items. As technology is being widely used, there are several technological or economic issues that should be overcome to facilitate the adoption of this track-and-trace technology. One of the technological challenges of RFID technology is its sensitivity to different environmental form factors, including packaging materials and the content of the packaging. Although researchers have assessed the performance loss due to the proximity of water and aqueous solutions, there is still the need to further investigate the impacts of food products on the reading range of RFID tags. However, to the best of our knowledge, there are not enough studies to determine the correlation between RFID tag performance and food beverages properties. The goal of this project was to investigate the effect of the solution properties (pH and conductivity) and different packaging materials filled with food-like water-based solutions on the performance of an RFID tag. Three commercially available ultra high-frequency RFID tags were placed on three different bottles and filled with different concentrations of water-based solutions, including sodium chloride, citric acid, sucrose, and ethanol. Transparent glass, Polyethylneterephtalate (PET), and Tetrapak® were used as the packaging materials commonly used in the beverage industries. Tag readability (Theoretical Read Range, TRR) and sensitivity (Power on Tag Forward, PoF) were determined using an anechoic chamber. First, the best place to attach the tag for each packaging material was investigated using empty and water-filled bottles. Then, the bottles were filled with the food-like solutions and tested with the three different tags and the PoF and TRR at the fixed frequency of 915MHz. In parallel, the pH and conductivity of solutions were measured. The best-performing tag was then selected to test the bottles filled with wine, orange, and apple juice. Despite various solutions altering the performance of each tag, the change in tag performance had no correlation with the pH or conductivity of the solution. Additionally, packaging material played a significant role in tag performance. Each tag tested performed optimally under different conditions. This study is the first part of comprehensive research to determine the regression model for the prediction of tag performance behavior based on the packaging material and the content. More investigations, including more tags and food products, are needed to be able to develop a robust regression model. The results of this study can be used by RFID tag manufacturers to design suitable tags for specific products with similar properties.

Keywords: smart food packaging, supply chain management, food waste, radio frequency identification

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Authors: Sara R. Knigge, Sugat R. Tuladhar, Hans-Klaus HöFfler, Tobias Schilling, Tim Kaufeld, Axel Haverich

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Tissue engineered (TE) heart valves based on degradable electrospun fiber scaffold represent a promising approach to overcome the known limitations of mechanical or biological prostheses. But the mechanical stress in the high-pressure system of the human circulation is a severe challenge for the delicate materials. Hence, the prediction of the scaffolds` in vivo degradation kinetics must be as accurate as possible to prevent fatal events in future animal or even clinical trials. Therefore, this study investigates whether long-term testing in full blood provides more meaningful results regarding the degradation behavior than conventional tests in simulated body fluids (SBF) or Phosphate Buffered Saline (PBS). Fiber mats were produced from a polycaprolactone (PCL)/tetrafluoroethylene solution by electrospinning. The morphology of the fiber mats was characterized via scanning electron microscopy (SEM). A maximum physiological degradation environment utilizing a test set-up with porcine full blood was established. The set-up consists of a reaction vessel, an oxygenator unit, and a roller pump. The blood parameters (pO2, pCO2, temperature, and pH) were monitored with an online test system. All tests were also carried out in the test circuit with SBF and PBS to compare conventional degradation media with the novel full blood setting. The polymer's degradation is quantified by SEM picture analysis, differential scanning calorimetry (DSC), and Raman spectroscopy. Tensile and cyclic loading tests were performed to evaluate the mechanical integrity of the scaffold. Preliminary results indicate that PCL degraded slower in full blood than in SBF and PBS. The uptake of water is more pronounced in the full blood group. Also, PCL preserved its mechanical integrity longer when degraded in full blood. Protein absorption increased during the degradation process. Red blood cells, platelets, and their aggregates adhered on the PCL. Presumably, the degradation led to a more hydrophilic polymeric surface which promoted the protein adsorption and the blood cell adhesion. Testing degradable implants in full blood allows for developing more reliable scaffold materials in the future. Material tests in small and large animal trials thereby can be focused on testing candidates that have proven to function well in an in-vivo-like setting.

Keywords: Electrospun scaffold, full blood degradation test, long-term polymer degradation, tissue engineered aortic heart valve

Procedia PDF Downloads 128

Authors: D. Y. Fong, C. Y. Kuo, Y. T. Chiang, W. C. Lin

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Objectives: Qigong is an ancient Chinese practice in pursuit of a healthier body and a more peaceful mindset. It emphasizes on the restoration of vital energy (Qi) in body, mind, and spirit. The practice is the combination of gentle movements and mild breathing which help the doers reach the condition of tranquility. On account of the features of Qigong, first, we use cross-sectional methodology to compare the differences among the varied levels of Qigong practitioners on cognitive function with event-related potential (ERP) and electroencephalography (EEG). Second, we use the longitudinal methodology to explore the effects on the Qigong trainees for pretest and posttest on ERP and EEG. Current study adopts Attentional Network Test (ANT) task to examine the participants’ cognitive function, and aging-related researches demonstrated a declined tread on the cognition in older adults and exercise might ameliorate the deterioration. Qigong exercise integrates physical posture (muscle strength), breathing technique (aerobic ability) and focused intention (attention) that researchers hypothesize it might improve the cognitive function in aging adults. Method: Sixty participants were involved in this study, including 20 young adults (21.65±2.41 y) with normal physical activity (YA), 20 Qigong experts (60.69 ± 12.42 y) with over 7 years Qigong practice experience (QE), and 20 normal and healthy adults (52.90±12.37 y) with no Qigong practice experience as experimental group (EG). The EG participants took Qigong classes 2 times a week and 2 hours per time for 24 weeks with the purpose of examining the effect of Qigong intervention on cognitive function. ANT tasks (alert network, orient network, and executive control) were adopted to evaluate participants’ cognitive function via ERP’s P300 components and P300 amplitude topography. Results: Behavioral data: 1.The reaction time (RT) of YA is faster than the other two groups, and EG was faster than QE in the cue and flanker conditions of ANT task. 2. The RT of posttest was faster than pretest in EG in the cue and flanker conditions. 3. No difference among the three groups on orient, alert, and execute control networks. ERP data: 1. P300 amplitude detection in QE was larger than EG at Fz electrode in orient, alert, and execute control networks. 2. P300 amplitude in EG was larger at pretest than posttest on the orient network. 3. P300 Latency revealed no difference among the three groups in the three networks. Conclusion: Taken together these findings, they provide neuro-electrical evidence that older adults involved in Qigong practice may develop a more overall compensatory mechanism and also benefit the performance of behavior.

Keywords: Qigong, cognitive function, aging, event-related potential (ERP)

Procedia PDF Downloads 378

Authors: Evrim Colak, Andriy E. Serebryannikov, Pavel V. Usik, Ekmel Ozbay

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Working with a dielectric photonic crystal (PC) structure which does not include surface corrugations, unidirectional transmission and dual-beam splitting are observed under normal incidence as a result of the strong diffractions caused by the embedded defect layer. The defect layer has twice the period of the regular PC segments which sandwich the defect layer. Although the PC has even number of rows, the structural symmetry is broken due to the asymmetric placement of the defect layer with respect to the symmetry axis of the regular PC. The simulations verify that efficient splitting and occurrence of strong diffractions are related to the dispersion properties of the Floquet-Bloch modes of the photonic crystal. Unidirectional and bi-directional splitting, which are associated with asymmetric transmission, arise due to the dominant contribution of the first positive and first negative diffraction orders. The effect of the depth of the defect layer is examined by placing single defect layer in varying rows, preserving the asymmetry of PC. Even for deeply buried defect layer, asymmetric transmission is still valid even if the zeroth order is not coupled. This transmission is due to evanescent waves which reach to the deeply embedded defect layer and couple to higher order modes. In an additional selected performance, whichever surface is illuminated, i.e., in both upper and lower surface illumination cases, incident beam is split into two beams of equal intensity at the output surface where the intensity of the out-going beams are equal for both illumination cases. That is, although the structure is asymmetric, symmetric bidirectional transmission with equal transmission values is demonstrated and the structure mimics the behavior of symmetric structures. Finally, simulation studies including the examination of a coupled-cavity defect for two different permittivity values (close to the permittivity values of GaAs or Si and alumina) reveal unidirectional splitting for a wider band of operation in comparison to the bandwidth obtained in the case of a single embedded defect layer. Since the dielectric materials that are utilized are low-loss and weakly dispersive in a wide frequency range including microwave and optical frequencies, the studied structures should be scalable to the mentioned ranges.

Keywords: asymmetric transmission, beam deflection, blazing, bi-directional splitting, defect layer, dual beam splitting, Floquet-Bloch modes, isofrequency contours, line defect, oblique incidence, photonic crystal, unidirectionality

Procedia PDF Downloads 167

Authors: Sevdenur Onger, Ali Asram Sagiroglu

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Hyperpigmentation is a cosmetically unappealing skin problem caused by an overabundance of melanin in the skin. Its pathophysiology is caused by melanocytes being exposed to paracrine melanogenic stimuli, which can upregulate melanogenesis-related enzymes (such as tyrosinase) and cause melanosome formation. Tyrosinase is linked to the development of melanosomes biochemically, and it is the main target of hyperpigmentation treatment. therefore, decreasing tyrosinase activity to reduce melanosomes has become the main target of hyperpigmentation treatment. Niacinamide (NA) is a natural chemical found in a variety of plants that is used as a skin-whitening ingredient in cosmetic formulations. NA decreases melanogenesis in the skin by inhibiting melanosome transfer from melanocytes to covering keratinocytes. Furthermore, NA protects the skin from reactive oxygen species and acts as a main barrier with the skin, reducing moisture loss by increasing ceramide and fatty acid synthesis. However, it is very difficult for hydrophilic compounds such as NA to penetrate deep into the skin. Furthermore, because of the nicotinic acid in NA, it is an irritant. As a result, we've concentrated on strategies to increase NA skin permeability while avoiding its irritating impacts. Since nanotechnology can affect drug penetration behavior by controlling the release and increasing the period of permanence on the skin, it can be a useful technique in the development of whitening formulations. Liposomes have become increasingly popular in the cosmetics industry in recent years due to benefits such as their lack of toxicity, high penetration ability in living skin layers, ability to increase skin moisture by forming a thin layer on the skin surface, and suitability for large-scale production. Therefore, liposomes containing NA were developed for this study. Different formulations were prepared by varying the amount of phospholipid and cholesterol and examined in terms of particle sizes, polydispersity index (PDI) and pH values. The pH values of the produced formulations were determined to be suitable with the pH value of the skin. Particle sizes were determined to be smaller than 250 nm and the particles were found to be of homogeneous size in the formulation (pdi<0.30). Despite the important advantages of liposomal systems, they have low viscosity and stability for topical use. For these reasons, in this study, liposomal cream formulations have been prepared for easy topical application of liposomal systems. As a result, liposomal cream formulations containing NA have been successfully prepared and characterized. Following the in-vitro release and ex-vivo diffusion studies to be conducted in the continuation of the study, it is planned to test the formulation that gives the most appropriate result on the volunteers after obtaining the approval of the ethics committee.

Keywords: delivery systems, hyperpigmentation, liposome, niacinamide

Procedia PDF Downloads 97

Authors: Naghmeh M. Bandari, Javad Dargahi, Muthukumaran Packirisamy

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Robot-assisted minimally invasive surgery (RMIS) has been widely performed around the world during the last two decades. RMIS demonstrates significant advantages over conventional surgery, e.g., improving the accuracy and dexterity of a surgeon, providing 3D vision, motion scaling, hand-eye coordination, decreasing tremor, and reducing x-ray exposure for surgeons. Despite benefits, surgeons cannot touch the surgical site and perceive tactile information. This happens due to the remote control of robots. The literature survey identified the lack of force feedback as the riskiest limitation in the existing technology. Without the perception of tool-tissue contact force, the surgeon might apply an excessive force causing tissue laceration or insufficient force causing tissue slippage. The primary use of force sensors has been to measure the tool-tissue interaction force in real-time in-situ. Design of a tactile sensor is subjected to a set of design requirements, e.g., biocompatibility, electrical-passivity, MRI-compatibility, miniaturization, ability to measure static and dynamic force. In this study, a planar optical fiber-based sensor was proposed to mount at the surgical grasper. It was developed based on the light intensity modulation principle. The deflectable part of the sensor was a beam modeled as a cantilever Euler-Bernoulli beam on rigid substrates. A semi-cylindrical indenter was attached to the bottom surface the beam at the mid-span. An optical fiber was secured at both ends on the same rigid substrates. The indenter was in contact with the fiber. External force on the sensor caused deflection in the beam and optical fiber simultaneously. The micro-bending of the optical fiber would consequently result in light power loss. The sensor was simulated and studied using finite element methods. A laser light beam with 800nm wavelength and 5mW power was used as the input to the optical fiber. The output power was measured using a photodetector. The voltage from photodetector was calibrated to the external force for a chirp input (0.1-5Hz). The range, resolution, and hysteresis of the sensor were studied under monotonic and harmonic external forces of 0-2.0N with 0 and 5Hz, respectively. The results confirmed the validity of proposed sensing principle. Also, the sensor demonstrated an acceptable linearity (R2 > 0.9). A minimum external force was observed below which no power loss was detectable. It is postulated that this phenomenon is attributed to the critical angle of the optical fiber to observe total internal reflection. The experimental results were of negligible hysteresis (R2 > 0.9) and in fair agreement with the simulations. In conclusion, the suggested planar sensor is assessed to be a cost-effective solution, feasible, and easy to use the sensor for being miniaturized and integrated at the tip of robotic graspers. Geometrical and optical factors affecting the minimum sensible force and the working range of the sensor should be studied and optimized. This design is intrinsically scalable and meets all the design requirements. Therefore, it has a significant potential of industrialization and mass production.

Keywords: force sensor, minimally invasive surgery, optical sensor, robotic surgery, tactile sensor

Procedia PDF Downloads 198

Authors: Zi Y. Kang, Tracy D. Cassidy, Tom Cassidy

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3D apparel CAD is one of the remarkable products in advanced technology which enables intuitive design, visualisation and evaluation of garments through stereoscopic drape simulation. The progressive improvements of 3D apparel CAD have led to the creation of more realistic clothing simulation which is used not only in design development but also in presentation, promotion and communication for fashion as well as other industries such as film, game and social network services. As a result, 3D clothing technology is becoming more ubiquitous in human culture and lives today. This study considers that such phenomenon implies that the technology has reached maturity and it is time to inspect the status of current technology and to explore its potential uses in ways to create cultural values to further move forward. For this reason, this study aims to generate virtual costumes as culturally significant objects using 3D apparel CAD and to assess its capability, applicability and attitudes of the audience towards clothing simulation through comparison with physical counterparts. Since the access to costume collection is often limited due to the conservative issues, the technology may make valuable contribution by democratization of culture and knowledge for museums and its audience. This study is expected to provide foundation knowledge for development of clothing technology and for expanding its boundary of practical uses. To prevent any potential damage, two replicas of the costumes in the 1860s and 1920s at the Museum of London were chosen as samples. Their structural, visual and physical characteristics were measured and collected using patterns, scanned images of fabrics and objective fabric measurements with scale, KES-F (Kawabata Evaluation System of Fabrics) and Titan. Commercial software, DC Suite 5.0 was utilised to create virtual costumes applying collected data and the following outcomes were produced for the evaluation: Images of virtual costumes and video clips showing static and dynamic simulation. Focus groups were arranged with fashion design students and the public for evaluation which exposed the outcomes together with physical samples, fabrics swatches and photographs. The similarities, application and acceptance of virtual costumes were estimated through discussion and a questionnaire. The findings show that the technology has the capability to produce realistic or plausible simulation but expression of some factors such as details and capability of light material requires improvements. While the use of virtual costumes was viewed as more interesting and futuristic replacements to physical objects by the public group, the fashion student group noted more differences in detail and preferred physical garments highlighting the absence of tangibility. However, the advantages and potential of virtual costumes as effective and useful visual references for educational and exhibitory purposes were underlined by both groups. Although 3D apparel CAD has sufficient capacity to assist garment design process, it has limits in identical replication and more study on accurate reproduction of details and drape is needed for its technical improvements. Nevertheless, the virtual costumes in this study demonstrated the possibility of the technology to contribute to cultural and knowledgeable value creation through its applicability and as an interesting way to offer 3D visual information.

Keywords: digital clothing technology, garment simulation, 3D Apparel CAD, virtual costume

Procedia PDF Downloads 195

Authors: Jorge Ferro-Diaz, Lazaro Marquez-Llauger, Jose Alberto Camejo-Lamas, Lazaro Marquez-Govea

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The invasion of Scaevola sericea Vahl (Goodeniaceae) in Cuba is a recent process, this exotic invasive species was reported for the first time, in the national territory, by 2008. S. sericea is native to the coasts around the Indian Ocean and western Pacific, common on sandy beaches; it has expanded rapidly around the planet by either natural or anthropic causes, mainly due to its use in hotel gardening. Cuba is highly vulnerable to the colonization of these species, mainly due to tropical hurricanes which have increased in the last decades; it also affects other native species such as Tournefortia gnaphalodes (L.) R. Br. (Boraginaceae) that show invasive manifestations because of the unbalanced state of demographic processes of littoral vegetation, which has been studied by authors during the last 10 years. The fast development of Cuban tourism has encouraged the use of exotic species in gardening that invade large sectors of sandy coasts. Taking into account the importance of assessing the impacts dimensions and adopting effective control measures, a monitoring program for the invasion of S. sericea in Cuba was undertaken. The program has been implemented since 2013 and the main objective was to identify invasive patterns and interactions with other native species of coastal vegetation. This experience also aimed to validate the design and propose a standardized monitoring protocol to be applied throughout the country. In the Cuban territory, 12 sites were chosen, where there were established 24 permanent plots of 100 m2; measurements were taken twice a year taking into consideration variables such as abundance, plant height, soil cover, flora and companion vegetation, density and frequency; other physical variables of the beaches were also measured. Similarly, for associated individuals of T. gnaphalodes, the same variables were measured. The results of these first four years allowed us to document patterns of S. sericea invasion, highlighting the use of adventitious roots to enhance their colonization, and to characterize demographic indicators, ecosystem affections, and interactions with native plants. A density-dependent relationship with T. gnaphalodes was documented, finding a controlling effect on S. sericea, so that a manipulation experiment was applied to evaluate possible management actions to be incorporated in the Plans of the protected areas involved. With these results, it was concluded, for the evaluated sites, that S. sericea has had an invasion dynamics ruled by effects of coastal dynamics, more intense in beaches with affectations to the native vegetation, and more controlled in beaches with more preserved vegetation. It was found that when S. sericea is established, the mechanism that most reinforces its invasion is the use of adventitious roots, used to expand the patches and colonize beach sectors. It was also found that when the density of T. gnaphalodes increases, it detains the expansion of S. sericea and reduces its colonization possibilities, behaving as a natural controller of its biological invasion. The results include a proposal of a new Monitoring Protocol for Scaevola sericea in Cuba, with the possibility of extending its implementation to other countries in the region.

Keywords: biological invasion, exotic invasive species, plant interactions, Scaevola sericea

Procedia PDF Downloads 200

Authors: Kaushik Vaideeswaran, Jean Gobet, Patrick Margraf, Olha Sereda

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Nitrocarburisation is a surface hardening technique often applied to improve the wear resistance of steel surfaces. It is considered to be a promising solution in comparison with other processes such as flame spraying, owing to the formation of a diffusion layer which provides mechanical integrity, as well as its cost-effectiveness. To improve other tribological properties of the surface such as the coefficient of friction (COF), dry lubricants are utilized. Currently, the lifetime of steel components in many applications using either of these techniques individually are faced with the limitations of the two: high COF for nitrocarburized surfaces and low wear resistance of dry lubricant coatings. To this end, the current study involves the creation of a hybrid surface using the impregnation of a dry lubricant on to a nitrocarburized surface. The mechanical strength and hardness of Gerster SA’s nitrocarburized surfaces accompanied by the impregnation of the porous outermost layer with a solid lubricant will create a hybrid surface possessing both outstanding wear resistance and a low friction coefficient and with high adherence to the substrate. Gerster SA has the state-of-the-art technology for the surface hardening of various steels. Through their expertise in the field, the nitrocarburizing process parameters (atmosphere, temperature, dwelling time) were optimized to obtain samples that have a distinct porous structure (in terms of size, shape, and density) as observed by metallographic and microscopic analyses. The porosity thus obtained is suitable for the impregnation of a dry lubricant. A commercially available dry lubricant with a thermoplastic matrix was employed for the impregnation process, which was optimized to obtain a void-free interface with the surface of the nitrocarburized layer (henceforth called hybrid surface). In parallel, metallic samples without nitrocarburisation were also impregnated with the same dry lubricant as a reference (henceforth called reference surface). The reference and the nitrocarburized surfaces, with and without the dry lubricant were tested for their tribological behavior by sliding against a quenched steel ball using a nanotribometer. Without any lubricant, the nitrocarburized surface showed a wear rate 5x lower than the reference metal. In the presence of a thin film of dry lubricant ( < 2 micrometers) and under the application of high loads (500 mN or ~800 MPa), while the COF for the reference surface increased from ~0.1 to > 0.3 within 120 m, the hybrid surface retained a COF < 0.2 for over 400m of sliding. In addition, while the steel ball sliding against the reference surface showed heavy wear, the corresponding ball sliding against the hybrid surface showed very limited wear. Observations of the sliding tracks in the hybrid surface using Electron Microscopy show the presence of the nitrocarburized nodules as well as the lubricant, whereas no traces of the lubricant were found in the sliding track on the reference surface. In this manner, the clear advantage of combining nitrocarburisation with the impregnation of a dry lubricant towards forming a hybrid surface has been demonstrated.

Keywords: dry lubrication, hybrid surfaces, improved wear resistance, nitrocarburisation, steels

Procedia PDF Downloads 104

Authors: Mahtab Abdollahi Sarvi, Siamak Epackachi, Ali Imanpour

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Reinforced concrete shear walls are commonly used as the lateral load-resisting system of mid- to high-rise office or residential buildings around the world. Design of such systems is often governed by wind rather than seismic effects, in particular in low-to-moderate seismic regions. The current design philosophy as per the majority of building codes under wind loads require elastic response of lateral load-resisting systems including reinforced concrete shear walls when subjected to the rare design wind load, resulting in significantly large wall sections needed to meet strength requirements and drift limits. The latter can highly influence the design in upper stories due to stringent drift limits specified by building codes, leading to substantial added costs to the construction of the wall. However, such walls may offer limited to moderate over-strength and ductility due to their large reserve capacity provided that they are designed and detailed to appropriately develop such over-strength and ductility under extreme wind loads. This would significantly contribute to reducing construction time and costs, while maintaining structural integrity under gravity and frequently-occurring and less frequent wind events. This paper aims to investigate the over-strength and ductility capacity of several imaginary office buildings located in Edmonton, Canada with a glance at earthquake design philosophy. Selected models are 10- to 25-story buildings with three types of reinforced concrete shear wall configurations including rectangular, barbell, and flanged. The buildings are designed according to National Building Code of Canada. Then fiber-based numerical models of the walls are developed in Perform 3D and by conducting nonlinear static (pushover) analysis, lateral nonlinear behavior of the walls are evaluated. Ductility and over-strength of the structures are obtained based on the results of the pushover analyses. The results confirmed moderate nonlinear capacity of reinforced concrete shear walls under extreme wind loads. This is while lateral displacements of the walls pass the serviceability limit states defined in Pre standard for Performance-Based Wind Design (ASCE). The results indicate that we can benefit the limited nonlinear response observed in the reinforced concrete shear walls to economize the design of such systems under wind loads.

Keywords: concrete shear wall, high-rise buildings, nonlinear static analysis, response modification factor, wind load

Procedia PDF Downloads 81

Authors: A. T. Perez Fontenla, S. Sgobba, A. Bartkowska, Y. Askar, M. Dalemir Celuch, A. Newborough, M. Karppinen, H. Haalien, S. Deleval, S. Larcher, C. Charvet, L. Bruno, R. Trant

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The present study investigates the corrosion behavior of copper (Cu) based conducts predominantly brazed with Sil-Fos (self-fluxing copper-based filler with silver and phosphorus) within various cooling circuits of demineralized water across different particle accelerator components at CERN. The study covers a range of sample service time, from a few months to fifty years, and includes various accelerator components such as quadrupoles, dipoles, and bending magnets. The investigation comprises the established sample extraction procedure, examination methodology including non-destructive testing, evaluation of the corrosion phenomena, and identification of commonalities across the studied components as well as analysis of the environmental influence. The systematic analysis included computed microtomography (CT) of the joints that revealed distributed defects across all brazing interfaces. Some defects appeared to result from areas not wetted by the filler during the brazing operation, displaying round shapes, while others exhibited irregular contours and radial alignment, indicative of a network or interconnection. The subsequent dry cutting performed facilitated access to the conduct's inner surface and the brazed joints for further inspection through light and electron microscopy (SEM) and chemical analysis via Energy Dispersive X-ray spectroscopy (EDS). Brazing analysis away from affected areas identified the expected phases for a Sil-Fos alloy. In contrast, the affected locations displayed micrometric cavities propagating into the material, along with selective corrosion of the bulk Cu initiated at the conductor-braze interface. Corrosion product analysis highlighted the consistent presence of sulfur (up to 6 % in weight), whose origin and role in the corrosion initiation and extension is being further investigated. The importance of this study is paramount as it plays a crucial role in comprehending the underlying factors contributing to recently identified water leaks and evaluating the extent of the issue. Its primary objective is to provide essential insights for the repair of impacted brazed joints when accessibility permits. Moreover, the study seeks to contribute to the improvement of design and manufacturing practices for future components, ultimately enhancing the overall reliability and performance of magnet systems within CERN accelerator facilities.

Keywords: accelerator facilities, brazed copper conducts, demineralized water, magnets

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Authors: Ahmad Ali, Muhammad Imran Ghani, Haiyan Ding, Zhihui Cheng, Muhammad Iqbal

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Background and Aims: In recent years, protected cultivation trend, especially in the northern parts of China, spread dynamically where production area, structure, and crops diversity have expanded gradually under plastic greenhouse vegetable cropping (PGVC) system. Under this growing system, continuous monoculture with excessive synthetic fertilizers inputs are common cultivation practices frequently adopted by commercial producers. Such long-term cumulative wild exercise year after year sponsor the continuous cropping obstacles in PGVC soil, which have greatly threatened the regional soil eco-sustainability and further impose the continuous assault on soil ecological diversity leading to the exhaustion of agriculture productivity. The aim of this study was to develop new allelopathic insights by exploiting available biological resources in the favor of sustainable PGVC to illuminate the continuous obstacle factors in plastic greenhouse. Method: A greenhouse study was executed under plastic tunnel located at the Horticulture Experimental Station of the College of Horticulture, Northwest A&F University, Yangling, Shaanxi Province, one of the prominent regions for intensive commercial PGVC in China. Post-harvest garlic residues (stalk, leaves) mechanically smashed, homogenized into powder size and incorporated at the ratio of 1:100; 3:100; 5:100 as a soil amendment in a replanted soil that have been used for continuous cucumber monoculture for 7 years (annually double cropping system in a greenhouse). Results: Incorporated C-rich garlic stalk significantly influenced the soil condition through various ways; organic matter decomposition and mineralization, moderately adjusted the soil pH, enhanced the soil nutrient availability, increased enzymatic activities, and promoted 20% more cucumber yield in short-time. Using Illumina MiSeq sequencing analysis of bacterial 16S rRNA and fungal 18S rDNA genes, the current study revealed that addition of garlic stalk/residue could also improve the microbial abundance and community composition in extensively exploited soil, and contributed in soil functionality, caused prosper changes in soil characteristics, reinforced to good crop yield. Conclusion: Our study provided evidence that addition of garlic stalk as soil fertility amendment is a feasible, cost-effective and efficient resource utilization way for renovation of degraded soil health, ameliorate soil quality components and improve ecological environment in short duration. Our study may provide a better scientific understanding for efficient crop residue management typically from allelopathic source.

Keywords: garlic stalk, microbial community dynamics, plant growth, soil amendment, soil-plant system

Procedia PDF Downloads 107

Authors: Nynke de Jong, Inge G. P. Duimel-Peeters

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The flipped classroom as an instructional strategy and a type of blended learning that reverses the traditional learning environment by delivering instructional content, off- and online, in- and outside the classroom, has been implemented in a 4-weeks module focusing on ageing in Europe at the Maastricht University. The main aim regarding the organization of this module was implementing flipped classroom-principles in order to create meaningful learning opportunities, while educational technologies are used to deliver content outside of the classroom. Technologies used in this module were an online interactive real time lecture from England, two interactive face-to-face lectures with visual supports, one group session including role plays and team-based learning meetings. The cohort of 2015-2016, using educational technologies, was compared with the cohort of 2014-2015 on module evaluation such as organization and instructiveness of the module, who studied the same content, although conforming the problem-based educational strategy, i.e. educational base of the Maastricht University. The cohort of 2015-2016 with its specific organization, was also more profound evaluated on outcomes as (1) experienced duration of the lecture by students, (2) experienced content of the lecture, (3) experienced the extent of the interaction and (4) format of lecturing. It was important to know how students reflected on duration and content taken into account their background knowledge so far, in order to distinguish between sufficient enough regarding prior knowledge and therefore challenging or not fitting into the course. For the evaluation, a structured online questionnaire was used, whereby above mentioned topics were asked for to evaluate by scoring them on a 4-point Likert scale. At the end, there was room for narrative feedback so that interviewees could express more in detail, if they wanted, what they experienced as good or not regarding the content of the module and its organization parts. Eventually, the response rate of the evaluation was lower than expected (54%), however, due to written feedback and exam scores, we dare to state that it gives a good and reliable overview that encourages to work further on it. Probably, the response rate may be explained by the fact that resit students were included as well, and that there maybe is too much evaluation as some time points in the program. However, overall students were excited about the organization and content of the module, but the level of self-directed behavior, necessary for this kind of educational strategy, was too low. They need to be more trained in self-directness, therefore the module will be simplified in 2016-2017 with more clear and fewer topics and extra guidance (step by step procedure). More specific information regarding the used technologies will be explained at the congress, as well as the outcomes (min and max rankings, mean and standard deviation).

Keywords: blended learning, flipped classroom, public health, self-directness

Procedia PDF Downloads 199

Authors: Mounir Baccar, Imen Jmal

Abstract:

Because of the rise in energy costs, thermal storage systems designed for the heating and cooling of buildings are becoming increasingly important. Energy storage can not only reduce the time or rate mismatch between energy supply and demand but also plays an important role in energy conservation. One of the most preferable storage techniques is the Latent Heat Thermal Energy Storage (LHTES) by Phase Change Materials (PCM) due to its important energy storage density and isothermal storage process. This paper presents a numerical study of the solidification of a PCM (paraffin RT27) in a rectangular thermal storage exchanger for air conditioning systems taking into account the presence of natural convection. Resolution of continuity, momentum and thermal energy equations are treated by the finite volume method. The main objective of this numerical approach is to study the effect of natural convection on the PCM solidification time and the impact of fins number on heat transfer enhancement. It also aims at investigating the temporal evolution of PCM solidification, as well as the longitudinal profiles of the HTF circling in the duct. The present research undertakes the study of two cases: the first one treats the solidification of PCM in a PCM-air heat exchanger without fins, while the second focuses on the solidification of PCM in a heat exchanger of the same type with the addition of fins (3 fins, 5 fins, and 9 fins). Without fins, the stratification of the PCM from colder to hotter during the heat transfer process has been noted. This behavior prevents the formation of thermo-convective cells in PCM area and then makes transferring almost conductive. In the presence of fins, energy extraction from PCM to airflow occurs at a faster rate, which contributes to the reduction of the discharging time and the increase of the outlet air temperature (HTF). However, for a great number of fins (9 fins), the enhancement of the solidification process is not significant because of the effect of confinement of PCM liquid spaces for the development of thermo-convective flow. Hence, it can be concluded that the effect of natural convection is not very significant for a high number of fins. In the optimum case, using 3 fins, the increasing temperature of the HTF exceeds approximately 10°C during the first 30 minutes. When solidification progresses from the surfaces of the PCM-container and propagates to the central liquid phase, an insulating layer will be created in the vicinity of the container surfaces and the fins, causing a low heat exchange rate between PCM and air. As the solid PCM layer gets thicker, a progressive regression of the field of movements is induced in the liquid phase, thus leading to the inhibition of heat extraction process. After about 2 hours, 68% of the PCM became solid, and heat transfer was almost dominated by conduction mechanism.

Keywords: heat transfer enhancement, front solidification, PCM, natural convection

Procedia PDF Downloads 169

Authors: Solanki Ravirajsinh, Kudo Kuniaki, Sharma Ankit, Devi Sherine, Kuboshima Misaki, Tachi Shuntaro

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In software development life cycles, the absence of scalable CI/CD significantly impacts organizations, leading to increased overall maintenance costs, prolonged release delivery times, heightened manual efforts, and difficulties in meeting tight deadlines. Implementing CI/CD with standard serverless technologies using cloud services overcomes all the above-mentioned issues and helps organizations improve efficiency and faster delivery without the need to manage server maintenance and capacity. By integrating scalable CI/CD with scalable automation testing, productivity, quality, and agility are enhanced while reducing the need for repetitive work and manual efforts. Implementing scalable CI/CD for development using cloud services like ECS (Container Management Service), AWS Fargate, ECR (to store Docker images with all dependencies), Serverless Computing (serverless virtual machines), Cloud Log (for monitoring errors and logs), Security Groups (for inside/outside access to the application), Docker Containerization (Docker-based images and container techniques), Jenkins (CI/CD build management tool), and code management tools (GitHub, Bitbucket, AWS CodeCommit) can efficiently handle the demands of diverse development environments and are capable of accommodating dynamic workloads, increasing efficiency for faster delivery with good quality. CI/CD pipelines encourage collaboration among development, operations, and quality assurance teams by providing a centralized platform for automated testing, deployment, and monitoring. Scalable CI/CD streamlines the development process by automatically fetching the latest code from the repository every time the process starts, building the application based on the branches, testing the application using a scalable automation testing framework, and deploying the builds. Developers can focus more on writing code and less on managing infrastructure as it scales based on the need. Serverless CI/CD eliminates the need to manage and maintain traditional CI/CD infrastructure, such as servers and build agents, reducing operational overhead and allowing teams to allocate resources more efficiently. Scalable CI/CD adjusts the application's scale according to usage, thereby alleviating concerns about scalability, maintenance costs, and resource needs. Creating scalable automation testing using cloud services (ECR, ECS Fargate, Docker, EFS, Serverless Computing) helps organizations run more than 500 test cases in parallel, aiding in the detection of race conditions, performance issues, and reducing execution time. Scalable CI/CD offers flexibility, dynamically adjusting to varying workloads and demands, allowing teams to scale resources up or down as needed. It optimizes costs by only paying for the resources as they are used and increases reliability. Scalable CI/CD pipelines employ automated testing and validation processes to detect and prevent errors early in the development cycle.

Keywords: achieve parallel execution, cloud services, scalable automation testing, scalable continuous integration and deployment

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Authors: Anas Hallak, Latifa Seblini, Juergen Wilde

Abstract:

In mechatronics or sensor technology, plastic housings are used to protect sensitive components from harmful environmental influences, such as moisture, media, or reactive substances. Connections, preferably in the form of metallic lead-frame structures, through the housing wall are required for their electrical supply or control. In this system, an insufficient connection between the plastic component, e.g., Polyamide66, and the metal surface, e.g., copper, due to the incompatibility is dominating. As a result, leakage paths can occur along with the plastic-metal interface. Since adhesive bonding has been established as one of the most important joining processes and its use has expanded significantly, driven by the development of improved high-performance adhesives and bonding techniques, this technology has been involved in metal-plastic hybrid structures. In this study, an epoxy bonding agent from DELO (DUALBOND LT2266) has been used to improve the mechanical and chemical binding between the metal and the polymer. It is an adhesion promoter with two reaction stages. In these, the first stage provides fixation to the lead frame directly after the coating step, which can be done by UV-Exposure for a few seconds. In the second stage, the material will be thermally hardened during injection molding. To analyze the two reaction stages of the primer, dynamic DSC experiments were carried out and correlated with Fourier-transform infrared spectroscopy measurements. Furthermore, the number of crosslinking bonds formed in the system in each reaction stage has also been estimated by a rheological characterization. Those investigations have been performed with different times of UV exposure: 12, 96 s and in an industrial preferred temperature range from -20 to 175°C. The shear viscosity values of primer have been measured as a function of temperature and exposure times. For further interpretation, the storage modulus values have been calculated, and the so-called Booij–Palmen plot has been sketched. The next approach in this study is the self-healing mechanisms in the hydride system in which the primer should flow into micro-damage such as interface, cracks, inhibit them from growing, and close them. The ability of the primer to flow in and penetrate defined capillaries made in Ultramid was investigated. Holes with a diameter of 0.3 mm were produced in injection-molded A3EG7 plates with 4 mm thickness. A copper substrate coated with the DUALBOND was placed on the A3EG7 plate and pressed with a certain force. Metallographic analyses were carried out to verify the filling grade, which showed an almost 95% filling ratio of the capillaries. Finally, to estimate the self-healing mechanism in metal-plastic hybrid systems, characterizations have been done on a simple geometry with a metal inlay developed by the Institute of Polymer Technology in Friedrich-Alexander-University. The specimens have been modified with tungsten wire which was to be pulled out after the injection molding to create a micro-hole in the specimen at the interface between the primer and the polymer. The capability of the primer to heal those micro-cracks upon heating, pressing, and thermal aging has been characterized through metallographic analyses.

Keywords: hybrid structures, self-healing, thermoplastic housing, adhesive

Procedia PDF Downloads 171

Authors: Bin Shi, Mouhab Meshreki, Grégoire Bazin, Helmi Attia

Abstract:

Large monolithic components are widely used in the aerospace industry in order to reduce airplane weight. Milling is an important operation in manufacturing of the monolithic parts. More than 90% of the material could be removed in the milling operation to obtain the final shape. This results in low rigidity and post-machining distortion. The post-machining distortion is the deviation of the final shape from the original design after releasing the clamps. It is a major challenge in machining of the monolithic parts, which costs billions of economic losses every year. Three sources are directly related to the part distortion, including initial residual stresses (RS) generated from previous manufacturing processes, machining-induced RS and thermal load generated during machining. A finite element model was developed to simulate a milling process and predicate the post-machining distortion. In this study, a rolled-aluminum plate AA7175 with a thickness of 60 mm was used for the raw block. The initial residual stress distribution in the block was measured using a layer-removal method. A stress-mapping technique was developed to implement the initial stress distribution into the part. It is demonstrated that this technique significantly accelerates the simulation time. Machining-induced residual stresses on the machined surface were measured using MTS3000 hole-drilling strain-gauge system. The measured RS was applied on the machined surface of a plate to predict the distortion. The predicted distortion was compared with experimental results. It is found that the effect of the machining-induced residual stress on the distortion of a thick plate is very limited. The distortion can be ignored if the wall thickness is larger than a certain value. The RS generated from the thermal load during machining is another important factor causing part distortion. Very limited number of research on this topic was reported in literature. A coupled thermo-mechanical FE model was developed to evaluate the thermal effect on the plastic deformation of a plate. A moving heat source with a feed rate was used to simulate the dynamic cutting heat in a milling process. When the heat source passed the part surface, a small layer was removed to simulate the cutting operation. The results show that for different feed rates and plate thicknesses, the plastic deformation/distortion occurs only if the temperature exceeds a critical level. It was found that the initial residual stress has a major contribution to the part distortion. The machining-induced stress has limited influence on the distortion for thin-wall structure when the wall thickness is larger than a certain value. The thermal load can also generate part distortion when the cutting temperature is above a critical level. The developed numerical model was employed to predict the distortion of a frame part with complex structures. The predictions were compared with the experimental measurements, showing both are in good agreement. Through optimization of the position of the part inside the raw plate using the developed numerical models, the part distortion can be significantly reduced by 50%.

Keywords: modelling, monolithic parts, optimization, post-machining distortion, residual stresses

Procedia PDF Downloads 33

Authors: Mehrnaz Mostafavi

Abstract:

Recent advances in single-molecule protein identification (ID) and quantification techniques are poised to revolutionize proteomics, enabling researchers to delve into single-cell proteomics and identify low-abundance proteins crucial for biomedical and clinical research. This paper introduces a different approach to single-molecule protein ID and quantification using tri-color amino acid tags and a plasmonic nanopore device. A comprehensive simulator incorporating various physical phenomena was designed to predict and model the device's behavior under diverse experimental conditions, providing insights into its feasibility and limitations. The study employs a whole-proteome single-molecule identification algorithm based on convolutional neural networks, achieving high accuracies (>90%), particularly in challenging conditions (95–97%). To address potential challenges in clinical samples, where post-translational modifications affecting labeling efficiency, the paper evaluates protein identification accuracy under partial labeling conditions. Solid-state nanopores, capable of processing tens of individual proteins per second, are explored as a platform for this method. Unlike techniques relying solely on ion-current measurements, this approach enables parallel readout using high-density nanopore arrays and multi-pixel single-photon sensors. Convolutional neural networks contribute to the method's versatility and robustness, simplifying calibration procedures and potentially allowing protein ID based on partial reads. The study also discusses the efficacy of the approach in real experimental conditions, resolving functionally similar proteins. The theoretical analysis, protein labeler program, finite difference time domain calculation of plasmonic fields, and simulation of nanopore-based optical sensing are detailed in the methods section. The study anticipates further exploration of temporal distributions of protein translocation dwell-times and the impact on convolutional neural network identification accuracy. Overall, the research presents a promising avenue for advancing single-molecule protein identification and quantification with broad applications in proteomics research. The contributions made in methodology, accuracy, robustness, and technological exploration collectively position this work at the forefront of transformative developments in the field.

Keywords: nano proteomics, nanopore-based optical sensing, deep learning, artificial intelligence

Procedia PDF Downloads 48