Search results for: finite rate of innovation

Authors: Golson Mohamed, Yasmine Gamasy, Khaled EL-Khatib, Anas Al-Natour, Shady Fadel, Haytham Rashwan, Haytham Badawy, Nadia Farghaly

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Introduction: Wilm's tumor is the most common malignant renal tumor in children. Much progress has been made in the management of patients with this malignancy over the last 3 decades. Today treatments are based on several trials and studies conducted by the International Society of Pediatric Oncology (SIOP) in Europe and National Wilm's Tumor Study Group (NWTS) in the USA. It is necessary for us to understand why do we follow either of the protocols, NWTS which follows the upfront surgery principle or the SIOP which follows the upfront chemotherapy principle in all stages of the disease. Objective: The aim of is to assess outcome in patients treated with preoperative chemotherapy and patients treated with upfront surgery to compare their effect on overall survival. Study design: to decide which protocol to follow, study was carried out on records for patients aged 1 day to 18 years old suffering from Wilm's tumor who were admitted to Alexandria University Hospital, pediatric oncology, pediatric urology and pediatric surgery departments, with a retrospective survey records from 2010 to 2015, Design and editing of the transfer sheet with a (PRISMA flow study) Preferred Reporting Items for Systematic Reviews and Meta-Analyses. Data were fed to the computer and analyzed using IBM SPSS software package version 20.0. (11) Qualitative data were described using number and percent. Quantitative data were described using Range (minimum and maximum), mean, standard deviation and median. Comparison between different groups regarding categorical variables was tested using Chi-square test. When more than 20% of the cells have expected count less than 5, correction for chi-square was conducted using Fisher’s Exact test or Monte Carlo correction. The distributions of quantitative variables were tested for normality using Kolmogorov-Smirnov test, Shapiro-Wilk test, and D'Agstino test, if it reveals normal data distribution, parametric tests were applied. If the data were abnormally distributed, non-parametric tests were used. For normally distributed data, a comparison between two independent populations was done using independent t-test. For abnormally distributed data, comparison between two independent populations was done using Mann-Whitney test. Significance of the obtained results was judged at the 5% level. Results: A significantly statistical difference was observed for survival between the two studied groups favoring the upfront chemotherapy(86.4%)as compared to the upfront surgery group (59.3%) where P=0.009. As regard complication, 20 cases (74.1%) out of 27 were complicated in the group of patients treated with upfront surgery. Meanwhile, 30 cases (68.2%) out of 44 had complications in patients treated with upfront chemotherapy. Also, the incidence of intraoperative complication (rupture) was less in upfront chemotherapy group as compared to upfront surgery group. Conclusion: Upfront chemotherapy has superiority over upfront surgery.As the patient who started with upfront chemotherapy shown, higher survival rate, less percent in complication, less percent needed for radiotherapy, and less rate in recurrence.

Keywords: Wilm's tumor, renal tumor, chemotherapy, surgery

Procedia PDF Downloads 297

Authors: D. Mokatsanyane, J. Jansen Van Rensburg

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This paper analyses the influence and impact of COVID-19 on major agricultural commodity prices in South Africa. According to a World Bank report, the agricultural sector in South Africa has been unable to reduce the domestic food crisis that has been occurring over the past years, hence the increased rate of poverty, which is currently at 55.5 percent as of April 2020. Despite the significance of this sector, empirical findings concluded that the agricultural sector now accounts for 1.88 percent of South Africa's gross domestic product (GDP). Suggesting that the agricultural sector's contribution to the economy has diminished. Despite the low contribution to GDP, this primary sector continues to play an essential role in the economy. Over the past years, multiple factors have contributed to the soaring commodities prices, namely, climate shocks, biofuel demand, demand and supply shocks, the exchange rate, speculation in commodity derivative markets, trade restrictions, and economic growth. The COVID-19 outbursts have currently disturbed the supply and demand of staple crops. To address the disruption, the government has exempted the agricultural sector from closure and restrictions on movement. The spread of COVID-19 has caused turmoil all around the world, but mostly in developing countries. According to Statistic South Africa, South Africa's economy decreased by seven percent in 2020. Consequently, this has arguably made the agricultural sector the most affected sector since slumped economic growth negatively impacts food security, trade, farm livelihood, and greenhouse gas emissions. South Africa is sensitive to the fruitfulness of global food chains. Restrictions in trade, reinforced sanitary control systems, and border controls have influenced food availability and prices internationally. The main objective of this study is to evaluate the behavior of agricultural commodity prices pre-and during-COVID to determine the impact of volatility drivers on these crops. Historical secondary data of spot prices for the top five major commodities, namely white maize, yellow maize, wheat, soybeans, and sunflower seeds, are analysed from 01 January 2017 to 1 September 2021. The timeframe was chosen to capture price fluctuations between pre-COVID-19 (01 January 2017 to 23 March 2020) and during-COVID-19 (24 March 2020 to 01 September 2021). The Generalised Autoregressive Conditional Heteroscedasticity (GARCH) statistical model will be used to measure the influence of price fluctuations. The results reveal that the commodity market has been experiencing volatility at different points. Extremely high volatility is represented during the first quarter of 2020. During this period, there was high uncertainty, and grain prices were very volatile. Despite the influence of COVID-19 on agricultural prices, the demand for these commodities is still existing and decent. During COVID-19, analysis indicates that prices were low and less volatile during the pandemic. The prices and returns of these commodities were low during COVID-19 because of the government's actions to respond to the virus's spread, which collapsed the market demand for food commodities.

Keywords: commodities market, commodity prices, generalised autoregressive conditional heteroscedasticity (GARCH), Price volatility, SAFEX

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Authors: Mateusz Wielopolski, Asia Guerreschi

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Circular Economy, as the counterargument to the ‘make-take-dispose’ linear model, is an approach that includes a variety of schools of thought looking at environmental, economic, and social sustainability. This, in turn, leads to a variety of strategies and often confusion when it comes to choosing the right one to make a circular transition as effective as possible. Due to the close interplay of circular product design, business model and social responsibility, companies often struggle to develop strategies that comply with all three triple-bottom-line criteria. Hence, to transition to circularity effectively, product design approaches must become more inclusive. In a case study conducted with the University of Bayreuth and the ISPO, we correlated aspects of material choice in product design, labeling and technological innovation with customer preferences and education about specific material and technology features. The study revealed those attributes of the consumers’ environmental awareness that directly translate into an increase of purchase power - primarily connected with individual preferences regarding sports activity and technical knowledge. Based on this outcome, we constituted a product development approach that incorporates the consumers’ individual preferences towards sustainable product features as well as their awareness about materials and technology. It allows deploying targeted customer education campaigns to raise the willingness to pay for sustainability. Next, we implemented the customer preference and education analysis into a circularity assessment tool that takes into account inherent company assets as well as subjective parameters like customer awareness. The outcome is a detailed but not cumbersome scoring system, which provides guidance for material and technology choices for circular product design while considering business model and communication strategy to the attentive customers. By including customer knowledge and complying with corresponding labels, companies develop more effective circular design strategies, while simultaneously increasing customers’ trust and loyalty.

Keywords: circularity, sustainability, product design, material choice, education, awareness, willingness to pay

Procedia PDF Downloads 166

Authors: Xiaochun Huang, Xuejun Zhao, Yun Zou, Feiyu Yang, Wenbin Liu, Nan Deng, Ming Zhang, Nengbin Cai

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A simple device termed infrared radiation (IR) was developed for rapid visualization of sweat fingerprints deposit on paper with blue light (450 nm, 11 W). In this approach, IR serves as the pretreatment device before the sweat fingerprints was illuminated by blue light. An annular blue light source was adopted for visualizing latent sweat fingerprints. Sample fingerprints were examined under various conditions after deposition, and experimental results indicate that the recovery rate of the latent sweat fingerprints is in the range of 50%-100% without chemical treatments. A mechanism for the observed visibility is proposed based on transportation and re-impregnation of fluorescer in paper at the region of water. And further exploratory experimental results gave the full support to the visible mechanism. Therefore, such a method as IR-pretreated in detecting latent fingerprints may be better for examination in the case where biological information of samples is needed for consequent testing.

Keywords: forensic science, visualization, infrared radiation, blue light, latent sweat fingerprints, detection

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Authors: Chung-Yang Chuang, Hui-Min Wang, Min-Yan Dong, Chang-Jung Chang

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PET fiber is the most widely used fiber worldwide. This man-made fiber is prepared from petroleum chemicals, which may cause environmental pollution and resource exhausting issues, such as the use of non-renewable sources, greenhouse gas emission and discharge of wastewater. Therefore, the textile made by recycle-PET is the trend in the future. Recycle-PET fiber, compared with petroleum-made PET, shows lower carbon emissions and resource exhaustion. However, “fabric decoloring” is the key barrier to textile recycling. The dyes existing in the fabrics may cause PET chain degradation and appearance drawbacks during the textile recycling process. In this research, the water-based decoloring agent was used to remove the dispersed dye in the PET fabrics in order to obtain the colorless PET fabrics after the decoloring process. The decoloring rate of PET fabrics after the decoloring process was up to 99.0%. This research provides a better solution to resolve the issues of appearance and physical properties degradation of fabrics-recycle PET materials due to the residual dye. It may be possible to convert waste PET textiles into new high-quality PET fiber and build up the loop of PET textile recycling.

Keywords: PET, decoloring, disperse dye, textile recycle

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Authors: Hassan Gharibi

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This research aims to comparing the emotion seeking and attachment styles between runaway and normal girls. The statistical population consisted of 80 (13-25 year-old) girls were selected among runaway girls and normal girls(40 runaway girls +40 normal girls). Normal girls were matched with the runaway girls in demographic features and selected by simple random method. Measuring tools in this research include the 1993 Shaver and Hazan attachment style scale and the Arent emotion seeking scale. Data analyzed by independent t test. Findings showed that there is no significant difference between two groups of girls in ambivalent and avoidant attachment styles. Secure attachment style rate in normal girls is more than runaway girls. Findings showed significant difference of insecure attachment style (avoidant and ambivalent styles together) between the two groups bout in variable of emotion seeking there is no significant difference.

Keywords: attachment styles, emotion seeking, runaway, girls

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Authors: Nguyen Quynh Trang, Nguyễn Thị Hông Nhung

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The study aimed to identify the effectiveness of using the mind map technique to enhance students’ medical vocabulary retention among a group of students at a higher education institution - Thai Nguyen University of Medicine and Pharmacy during the first semester of the school year 2022-2023. The research employed a quasi-experimental method, exploring primary sources such as questionnaires and the analyzed results of pre-and-post tests. Almost teachers and students showed high preferences for the implementation of the mind map technique in language teaching and learning. Furthermore, results from the pre-and-post tests between the experimental group and control one pointed out that this technique brought back positive academic performance in teaching and learning English. The research findings revealed that there should be more supportive policies to evoke the use of the mind map technique in a pedagogical context. Aim of the Study: The purpose of this research was to investigate whether using mind mapping can help students to enhance nursing students’ medical vocabulary retention and to assess the students’ attitudes toward using mind mapping as a tool to improve their vocabulary. The methodology of the study: The research employed a quasi-experimental method, exploring primary sources such as questionnaires and the analyzed results of pre-and-post tests. The contribution of the study: The research contributed to the innovation of teaching vocabulary methods for English teachers at a higher education institution. Moreover, the research helped the English teachers and the administrators at a university evoke and maintain the motivation of students not only in English classes but also in other subjects. The findings of this research were beneficial to teachers, students, and researchers interested in using mind mapping to teach and learn English vocabulary. The research explored and proved the effectiveness of applying mind mapping in teaching and learning English vocabulary. Therefore, teaching and learning activities were conducted more and more effectively and helped students overcome challenges in remembering vocabulary and creating motivation to learn English vocabulary.

Keywords: medical vocabulary retention, mind map technique, nursing students, medical vocabulary

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Authors: Prasad Pokkunuri

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Visco-elastic materials combine the stress response properties of both solids and fluids and have found use in a variety of damping applications – both vibrational and acoustic. Defense and automotive applications, in particular, are subject to high impact and shock loading – for example: aircraft landing gear, firearms, and shock absorbers. Field responsive fluids – a class of smart materials – are the preferred choice of energy absorbents because of their controllability. These fluids’ stress response can be controlled by the application of a magnetic or electric field, in a closed loop. Their rheological properties – elasticity, plasticity, and viscosity – can be varied all the way from that of a liquid such as water to a hard solid. This work presents a simplified model to study the impulse response behavior of such fluids for use in recoil damping systems. The well-known Burger’s equation, in conjunction with various visco-elastic constitutive models, is used to represent fluid behavior. The Kelvin-Voigt, Upper Convected Maxwell (UCM), and Oldroyd-B constitutive models are implemented in this study. Using these models in a one-dimensional framework eliminates additional complexities due to geometry, pressure, body forces, and other source terms. Using a finite difference formulation to numerically solve the governing equation(s), the response to an initial impulse is studied. The disturbance is confined within the problem domain with no-inflow, no-outflow boundary conditions, and its decay characteristics studied. Visco-elastic fluids typically involve a time-dependent stress relaxation which gives rise to interesting behavior when subjected to an impulsive load. For particular values of viscous damping and elastic modulus, the fluid settles into a stable oscillatory state, absorbing and releasing energy without much decay. The simplified formulation enables a comprehensive study of different modes of system response, by varying relevant parameters. Using the insights gained from this study, extension to a more detailed multi-dimensional model is considered.

Keywords: Burgers Equation, Impulse Response, Recoil Damping Systems, Visco-elastic Fluids

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Authors: Rashid Ahmed , John N. Avaritsiotis

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Many signal subspace-based approaches have already been proposed for determining the fixed Direction of Arrival (DOA) of plane waves impinging on an array of sensors. Two procedures for DOA estimation based neural networks are presented. First, Principal Component Analysis (PCA) is employed to extract the maximum eigenvalue and eigenvector from signal subspace to estimate DOA. Second, minor component analysis (MCA) is a statistical method of extracting the eigenvector associated with the smallest eigenvalue of the covariance matrix. In this paper, we will modify a Minor Component Analysis (MCA(R)) learning algorithm to enhance the convergence, where a convergence is essential for MCA algorithm towards practical applications. The learning rate parameter is also presented, which ensures fast convergence of the algorithm, because it has direct effect on the convergence of the weight vector and the error level is affected by this value. MCA is performed to determine the estimated DOA. Preliminary results will be furnished to illustrate the convergences results achieved.

Keywords: Direction of Arrival, neural networks, Principle Component Analysis, Minor Component Analysis

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Authors: Muhammad Luqman, Mujahid Karim

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Agricultural journalism considered an effective tool in the diffusion of agricultural technologies among the members of farming communities. Various agricultural journalism forms are used by the different organization in order to address the community problems and provide solutions to them. The present study was conducted for analyzing the role of agricultural journalism in the dissemination of agricultural information. The universe of the study was district Sargodha from which a sample of 100 was collected through a validating and pre-tested questionnaire. Statistical analysis of collected data was done with the help of SPSS. It was concluded that majority (64.6%) of the respondent were middle-aged (31-50) years, also indicates a high (73.23%) literacy rate above middle-level education, most (78.3%) of the respondents were connected with the occupation of farming. In various forms of agricultural journalism “Radio/T.V./F.M) is used by 99.4% of the respondent, Mobile phones (96%), Magazine/ Newspaper/ periodical (66.4%) and social media (60.9%). Regarding majors areas focused on agriculture journalism “Help farmers to enhance their productivity is on the highest level with a mean of ( =3.98/5.00). The regression model of farmer's education and various forms of agricultural journalism facilities used was found to be significant.

Keywords: agricultural information, journalism, farming community, technology diffusion and adoption

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Authors: L. Q. Yuan, J. Yang, A. Siddiqui

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A new regression uncertainty analysis methodology was applied to determine the uncertainties of the critical heat flux (CHF) power correlation for an advanced 43-element bundle design, which was developed by Canadian Nuclear Laboratories (CNL) to achieve improved economics, resource utilization and energy sustainability. The new methodology is considered more appropriate than the traditional methodology in the assessment of the experimental uncertainty associated with regressions. The methodology was first assessed using both the Monte Carlo Method (MCM) and the Taylor Series Method (TSM) for a simple linear regression model, and then extended successfully to a non-linear CHF power regression model (CHF power as a function of inlet temperature, outlet pressure and mass flow rate). The regression uncertainty assessed by MCM agrees well with that by TSM. An equation to evaluate the CHF power regression uncertainty was developed and expressed as a function of independent variables that determine the CHF power.

Keywords: CHF experiment, CHF correlation, regression uncertainty, Monte Carlo Method, Taylor Series Method

Procedia PDF Downloads 392

Authors: F. Heyecan Giritli, Gizem Akgül

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Because of the raising population of world; the need for houses, buildings and infrastructures are increasing rapidly. Energy and water consumption, waste production continues to increase. If this situation of resources continues, there will be a significant loss for next generations. Therefore, there are a lot of researches and solutions developed in the world. Also sustainability criteria are collected together by some countries to serve construction industry with certification systems. Sustainable building production process’s scope requires different path from traditional building production process. Moreover, the key objective of sustainable buildings is that the process includes whole life cycle duration. The process approaches from the decision of the project to the end of it; so the project team is needed from the beginning of the integrated project delivery model. Further more, by defining project team at the beginning of the project provides communication among the team members and defined problem solving and decision making methods. In this research includes the certification systems among the world to comprehend the head lines and assessment criteria. Therefore, it is understand that usually all green building criteria have the same contents. The aim of this research is to assess the sustainable project stakeholder’ perceptions in Turkish construction industry from the point of occupation, job title and years of experience. Therefore, a survey is made to assess the perceptions of each attendant. In Turkey, sustainability criteria are not clearly defined; on the other hand some regulations like waste management, energy efficiency are made by legal agencies. LEED certification system is the most popular system in Turkey that has attended and certificated. From the LEED official data, it’s understood that 308 project registered in Turkey. Therefore, LEED sustainability criteria are used in the survey. Head lines of LEED certification criteria; sustainable sites, water efficiency, energy and atmosphere, material and resources, indoor environmental quality, innovation and regional priority are indicated to assess the perceptions of survey participants. Moreover, only surveying of criteria are not enough; so the equipment, methods, risks and benefits also considered.

Keywords: LEED, sustainability, perceptions, stakeholders, construction, Turkey, risk, benefit

Procedia PDF Downloads 281

Authors: Mohammed Abdullah Alrajhi

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The rapid growth in the number of mobile phone subscribers has resulted in an increased number of mobile base stations all over the world. Generally, mobile base stations are existing in huge numbers in populated areas than in non-populated ones to serve the largest number of users. The total number of mobile subscriptions in the Kingdom of Saudi Arabia reached around 50 million at the end of 2014, with a penetration rate of 165.1% according to the quarterly electronic newsletter issued by the Communications and Information Technology Commission. The current investigation was conducted primarily to measure the level of electromagnetic fields emitted from 400 mobile base stations for the purpose of environmental safety and radiation protection in light of national guidelines for public exposure as well as the International Commission on Non-Ionizing Radiation Protection (ICNIRP). The outcomes of this investigation provide valuable comments and recommendation for safety and protection of electromagnetic fields emitted from mobile base stations.

Keywords: electromagnetic fields, mobile, safety, protection, ICNIRP

Procedia PDF Downloads 384

Authors: K. Caban-Piaskowska

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The aim of the article is to show how the role of a designer has changed, from the point of view of human resources management and thanks to the increased importance of design management, and is to present how a rehabilitation product, through technology approach to designing, becomes a universal product. Designing for the disabled is a very undiscovered area on the pattern-designing market, most often because it is associated with devices which support rehabilitation. In consequence, it means that the realizations have a limited group of receivers and are not that attractive for designers. The relation between using modern design in building rehabilitation devices and increasing the efficiency of treatment and physiotherapy. Using modern technology can have marketing significance. Rehabilitation products designed and produced in a modern way makes an impression that experts and professionals are involved in the lives of the user – patient. In order to illustrate the problem presented above i.e. Creating a rehabilitation product as an example of design management, the case study method was used in the research. The analysis of the case was created on the basis of an interview conducted by the author with a designer who took part in meetings with people who use rehabilitation and their physiotherapists, and created universal products in Poland in the years of 2012 to 2017. Usually, engineers and constructors deal with creating products which remind us of old torture devices, however, they are indestructible in construction. Such image of those products for the disabled clearly indicates that it is a wonderful niche for designers and emphasizes the need to make those products more attractive and innovative. Products for the disabled cannot be limited to rehabilitation equipment only e.g. wheelchairs or standing frames. Introducing the idea of universal designing can significantly broaden the circle of pattern-designing receivers – everyday-use items – with the disabled people. Fulfilling these criteria will decide about the advantage on the competitive market. It is possible due to the usage of the design management concept in the functioning of an organization. Using modern technology and materials in the production of equipment, and changing the role of a designer broadening the circle of receivers by designing a wide use process which makes it possible to use the product by people with various needs. What is more, introducing rehabilitation functions in everyday-use items can also become an innovative accent in designing. In the reality of the market, each group of users can and should be treated as a problem and a realization task.

Keywords: design management, innovation, rehabilitation product, universal product

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Authors: Chia-Yung Chou, Che-Chuan Cheng, Chin Chi Hsu, Chun-Hui Wu

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This study investigates the fluid of boundary layer flow as it flows through the superhydrophobic surface. The superhydrophobic surface will be assembled into an observation channel for fluid experiments. The fluid in the channel will be doped with visual flow field particles, which will then be pumped by the syringe pump and introduced into the experimentally observed channel through the pipeline. Through the polarized light irradiation, the movement of the particles in the channel is captured by a high-speed camera, and the velocity of the particles is analyzed by MATLAB to find out the particle velocity field changes caused on the fluid boundary layer. This study found that the superhydrophobic surface can effectively increase the velocity near the wall surface, and the faster with the flow rate increases. The superhydrophobic surface also had longer the slip length compared with the plan surface. In the calculation of the drag coefficient, the superhydrophobic surface produces a lower drag coefficient, and there is a more significant difference when the Re reduced in the flow field.

Keywords: hydrophobic, boundary layer, slip length, friction

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Authors: Mohammad Shakir, Reshma Jolly, Mohammad Shoeb Khan, Noor-E-Iram

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A nanocomposite system incorporating dextrin into nano-hydroxyapatite/chitin matrix (n-HA/DX/CT) has been successfully synthesized via co-precipitation route at room temperature for the application in bone tissue engineering by investigating biocompatibility, cytotoxicity and mechanical properties. The FTIR spectra of n-HA/DX/CT nanocomposite indicated a considerable intermolecular interaction between the various components of the system. The results of XRD, TEM and TGA/DTA revealed that the crystallinity, size and thermal stability of the n-HA/DX/CT scaffold has decreased and increased respectively. The result of SEM image of the n-HA/DX/CT scaffold indicated that the incorporation of dextrin affected the surface morphology while considerable in-vitro bioactivity has been observed in n-HA/DX/CT based on SBF study, referring a step towards possibility of making direct bond to living bone if implanted. Moreover, MTT assay suggested the non-toxic nature of n-HA/DX/CT to murine fibroblast L929 cells. The swelling study of n-HA/DX/CT scaffold indicated the low swelling rate for n-HADX/CT. All these results have paved the way for n-HA/DX/CT to be used as a competent material for bone tissue engineering.

Keywords: autograft, chitin, dextrin, nanocomposite

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Authors: Mahasa Zahirnia

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The purpose of this paper is to explore new and effective ways of optimizing satellite images using artificial intelligence, and the process of implementing reinforcement learning to enhance the quality of data captured within the image. In our implementation of Bellman's Reinforcement Learning equations, associated state diagrams, and multi-stage image processing, we were able to enhance image quality, detect and define objects. Reinforcement learning is the differentiator in the area of artificial intelligence, and Q-Learning relies on trial and error to achieve its goals. The reward system that is embedded in Q-Learning allows the agent to self-evaluate its performance and decide on the best possible course of action based on the current and future environment. Results show that within a simulated environment, built on the images that are commercially available, the rate of detection was 40-90%. Reinforcement learning through Q-Learning algorithm is not just desired but required design criteria for image optimization and enhancements. The proposed methods presented are a cost effective method of resolving uncertainty of the data because reinforcement learning finds ideal policies to manage the process using a smaller sample of images.

Keywords: Q-learning, image optimization, reinforcement learning, Markov decision process

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Authors: Isadora Bugarin, Taygoara F. de Oliveira

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Multiphase flows have currently been placed as a key solution for technological advances in energy and thermal sciences. The comprehension of droplet motion and behavior on non-isothermal flows is, however, rather limited. The present work consists of an investigation of a 2D droplet migration on natural convection inside a square enclosure with differentially heated walls. The investigation in question concerns the effects on drop motion of imposing different combinations of Prandtl and Rayleigh numbers while defining the drop on distinct initial positions. The finite differences method was used to compute the Navier-Stokes and energy equations for a laminar flow, considering the Boussinesq approximation. Also, a high order level set method was applied to simulate the two-phase flow. A previous analysis developed by the authors had shown that for fixed values of Rayleigh and Prandtl, the variation of the droplet initial position at the beginning of the simulation delivered different patterns of motion, in which for Ra≥10⁴ the droplet presents two very specific behaviors: it can travel through a helical path towards the center or define cyclic circular paths resulting in closed paths when reaching the stationary regime. Now, when varying the Prandtl number for different Rayleigh regimes, it was observed that this particular parameter also affects the migration of the droplet, altering the motion patterns as its value is increased. On higher Prandtl values, the drop performs wider paths with larger amplitudes, traveling closer to the walls and taking longer time periods to finally reach the stationary regime. It is important to highlight that drastic drop behavior changes on the stationary regime were not yet observed, but the path traveled from the begging of the simulation until the stationary regime was significantly altered, resulting in distinct turning over frequencies. The flow’s unsteady Nusselt number is also registered for each case studied, enabling a discussion on the overall effects on heat transfer variations.

Keywords: droplet migration, level set method, multiphase flow, natural convection in enclosure, Prandtl number

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Authors: Khaled Alshammari

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A facile approach to synthesizing highly active and stable Au/NiO catalysts for the hydrogenation of nitro-aromatics is reported. Preformed gold nanoparticles have been immobilized onto NiO using a colloidal method. In this article, the reduction of 4-nitrophenol with NaBH4 has been used as a model reaction to investigate the catalytic activity of synthesized Au/NiO catalysts. In addition, we report a systematic study of the reduction kinetics and the influence of specific reaction parameters such as (i) temperature, (ii) stirring rate, (iii) sodium borohydride concentration and (iv) substrate/metal molar ratio. The reaction has been performed at a substrate/metal molar ratio of 7.4, a ratio significantly higher than previously reported. The reusability of the catalyst has been examined, with little to no decrease in activity observed over 5 catalytic cycles. Systematic variation of Au loading reveals the successful synthesis of low-cost and efficient Au/NiO catalysts at very low Au content and using high substrate/metal molar ratios.

Keywords: nonochemistry, catalyst, nanoparticles supported, characterization of materials, colloidal nanoparticles

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Authors: Yemane Hailu Fissuh, Zhongzhan Zhang

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In biomedical researches and randomized clinical trials, the most commonly interested outcomes are time-to-event so-called survival data. The importance of robust models in this context is to compare the effect of randomly controlled experimental groups that have a sense of causality. Causal estimation is the scientific concept of comparing the pragmatic effect of treatments conditional to the given covariates rather than assessing the simple association of response and predictors. Hence, the causal effect based semiparametric transformation model was proposed to estimate the effect of treatment with the presence of possibly time-varying covariates. Due to its high flexibility and robustness, the semiparametric transformation model which shall be applied in this paper has been given much more attention for estimation of a causal effect in modeling left-truncated and right censored survival data. Despite its wide applications and popularity in estimating unknown parameters, the maximum likelihood estimation technique is quite complex and burdensome in estimating unknown parameters and unspecified transformation function in the presence of possibly time-varying covariates. Thus, to ease the complexity we proposed the modified estimating equations. After intuitive estimation procedures, the consistency and asymptotic properties of the estimators were derived and the characteristics of the estimators in the finite sample performance of the proposed model were illustrated via simulation studies and Stanford heart transplant real data example. To sum up the study, the bias of covariates was adjusted via estimating the density function for truncation variable which was also incorporated in the model as a covariate in order to relax the independence assumption of failure time and truncation time. Moreover, the expectation-maximization (EM) algorithm was described for the estimation of iterative unknown parameters and unspecified transformation function. In addition, the causal effect was derived by the ratio of the cumulative hazard function of active and passive experiments after adjusting for bias raised in the model due to the truncation variable.

Keywords: causal estimation, EM algorithm, semiparametric transformation models, time-to-event outcomes, time-varying covariate

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Authors: Jarek Krajewski, Andre Wittenborn, Martin Sauerland

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This abstract describes a promising approach for estimating post-traumatic stress disorder (PTSD) based on prosodic speech characteristics. It illustrates the validity of this method by briefly discussing results from an Arabic refugee sample (N= 47, 32 m, 15 f). A well-established standardized self-report scale “Reaction of Adolescents to Traumatic Stress” (RATS) was used to determine the ground truth level of PTSD. The speech material was prompted by telling about autobiographical related sadness inducing experiences (sampling rate 16 kHz, 8 bit resolution). In order to investigate PTSD-induced speech changes, a self-developed set of 136 prosodic speech features was extracted from the .wav files. This set was adapted to capture traumatization related speech phenomena. An artificial neural network (ANN) machine learning model was applied to determine the PTSD level and reached a correlation of r = .37. These results indicate that our classifiers can achieve similar results to those seen in speech-based stress research.

Keywords: speech prosody, PTSD, machine learning, feature extraction

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Authors: K. Yang, Y. Wei, M. Zhang, S. Yong, R. Torah, J. Tudor, S. Beeby

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E-textiles are traditional textiles with integrated electronic functionality. It is an emerging innovation with numerous applications in fashion, wearable computing, health and safety monitoring, and the military and medical sectors. The piezoelectric effect is a widespread and versatile transduction mechanism used in sensor and actuator applications. Piezoelectric materials produce electric charge when stressed. Conversely, mechanical deformation occurs when an electric field is applied across the material. Lead Zirconate Titanate (PZT) is a widely used piezoceramic material which has been used to fabricate e-textiles through screen printing, electro spinning and hydrothermal synthesis. This paper explores an alternative fabrication process: Spray coating. Spray coating is a straightforward and cost effective fabrication method applicable on both flat and curved surfaces. It can also be applied selectively by spraying through a stencil which enables the required design to be realised on the substrate. This work developed a sprayable PZT based piezoelectric ink consisting of a binder (Fabink-Binder-01), PZT powder (80 % 2 µm and 20 % 0.8 µm) and acetone as a thinner. The optimised weight ratio of PZT/binder is 10:1. The components were mixed using a SpeedMixer DAC 150. The fabrication processes is as follows: 1) Screen print a UV-curable polyurethane interface layer on the textile to create a smooth textile surface. 2) Spray one layer of a conductive silver polymer ink through a pre-designed stencil and dry at 90 °C for 10 minutes to form the bottom electrode. 3) Spray three layers of the PZT ink through a pre-designed stencil and dry at 90 °C for 10 minutes for each layer to form a total thickness of ~250µm PZT layer. 4) Spray one layer of the silver ink through a pre-designed stencil on top of the PZT layer and dry at 90 °C for 10 minutes to form the top electrode. The domains of the PZT elements were aligned by polarising the material at an elevated temperature under a strong electric field. A d33 of 37 pC/N has been achieved after polarising at 90 °C for 6 minutes with an electric field of 3 MV/m. The application of the piezoelectric textile was demonstrated by fabricating a pressure sensor to switch an LED on/off. Other potential applications on e-textiles include motion sensing, energy harvesting, force sensing and a buzzer.

Keywords: piezoelectric, PZT, spray coating, pressure sensor, e-textile

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Authors: Trang Huyen Nguyen, Thien Tri Huynh

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The objectives of this paper were to determine demographics of readers at Hochiminh city (HCMC), study reading motivation which affected citizens to read sports newspapers and measure readers’ satisfaction on issues related sports newspapers. Subjects of this survey were HCMC’s citizens. After collecting data, there were 568 useful feedbacks (the rate of response was 94.7%). The data analysis in the study included descriptive statistics and inferred statistics by SPSS 16.0 program for the research questions. The majority of respondents were male, from 24 to 32 years old, got the first degree and earned monthly from $US 150 to 300. Moreover, they were government officials and read newspaper from 11 to 20 times per month, bought newspapers by themselves. Finding information to predict results of sports matches was the highest motive affected readers; and the diversity information was the most pleasure that readers felt about sports newspapers. According to research findings, the board of editors could use the worthy information to make a strategic plan for newspaper on contents as well as design to meet the increasing demands of readers.

Keywords: motivation, satisfaction, readers, sports newspapers

Procedia PDF Downloads 281

Authors: C. Yin, B. Zhang, Y. Liu, J. Cai

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Airborne EM (AEM) is an effective geophysical exploration tool, especially suitable for ridged mountain areas. In these areas, topography will have serious effects on AEM system responses. However, until now little study has been reported on topographic effect on airborne EM systems. In this paper, an edge-based unstructured finite-element (FE) method is developed for 3D topographic modeling for both frequency and time-domain airborne EM systems. Starting from the frequency-domain Maxwell equations, a vector Helmholtz equation is derived to obtain a stable and accurate solution. Considering that the AEM transmitter and receiver are both located in the air, the scattered field method is used in our modeling. The Galerkin method is applied to discretize the Helmholtz equation for the final FE equations. Solving the FE equations, the frequency-domain AEM responses are obtained. To accelerate the calculation speed, the response of source in free-space is used as the primary field and the PARDISO direct solver is used to deal with the problem with multiple transmitting sources. After calculating the frequency-domain AEM responses, a Hankel’s transform is applied to obtain the time-domain AEM responses. To check the accuracy of present algorithm and to analyze the characteristic of topographic effect on airborne EM systems, both the frequency- and time-domain AEM responses for 3 model groups are simulated: 1) a flat half-space model that has a semi-analytical solution of EM response; 2) a valley or hill earth model; 3) a valley or hill earth with an abnormal body embedded. Numerical experiments show that close to the node points of the topography, AEM responses demonstrate sharp changes. Special attentions need to be paid to the topographic effects when interpreting AEM survey data over rugged topographic areas. Besides, the profile of the AEM responses presents a mirror relation with the topographic earth surface. In comparison to the topographic effect that mainly occurs at the high-frequency end and early time channels, the EM responses of underground conductors mainly occur at low frequencies and later time channels. For the signal of the same time channel, the dB/dt field reflects the change of conductivity better than the B-field. The research of this paper will serve airborne EM in the identification and correction of the topographic effects.

Keywords: 3D, Airborne EM, forward modeling, topographic effect

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Authors: Nicola Menga, Giuseppe Carbone

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Although contact mechanics has been widely focused on the study of contacts between half-space, it has been recently pointed out that in presence of finite thickness elastic layers the results of the contact problem show significant difference in terms of the main contact quantities (e.g. contact area, penetration, mean pressure, etc.). Actually, there exist a wide range of industrial application demanding for this kind of studies, such as seals leakage prediction or pressure-sensitive coatings for electrical applications. In this work, we focus on the contact between a rigid profile and an elastic layer of thickness h confined under two different configurations: rigid constrain and applied uniform pressure. The elastic problem at hand has been formalized following Green’s function method and then numerically solved by means of a matrix inversion. We study different contact conditions, both considering and neglecting adhesive interactions at the interface. This leads to different solution techniques: Adhesive contacts equilibrium solution is found, in term of contact area for given penetration, making stationary the total free energy of the system; whereas, adhesiveless contacts are addressed defining an equilibrium criterion, again on the contact area, relying on the fracture mechanics stress intensity factor KI. In particular, we make the KI vanish at the edges of the contact area, as peculiar for adhesiveless elastic contacts. The results are obtained in terms of contact area, penetration, and mean pressure for both adhesive and adhesiveless contact conditions. As expected, in the case of a uniform applied pressure the slab turns out much more compliant than the rigidly constrained one. Indeed, we have observed that the peak value of the contact pressure, for both the adhesive and adhesiveless condition, is much higher for the rigidly constrained configuration than in the case of applied uniform pressure. Furthermore, we observed that, for little contact area, both systems behave the same and the pull-off occurs at approximately the same contact area and mean contact pressure. This is an expected result since in this condition the ratio between the layers thickness and the contact area is very high and both layer configurations recover the half-space behavior where the pull-off occurrence is mainly controlled by the adhesive interactions, which are kept constant among the cases.

Keywords: contact mechanics, adhesion, friction, thick layer

Procedia PDF Downloads 485

Authors: Sahar Nasr, Lin Li, Edwin Wang

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Bladder cancer (BLCA) is known as the 13th cause of death among cancer patients worldwide, and ~575,000 new BLCA cases are diagnosed each year. Urothelial carcinoma (UC) is the most prevalent subtype among BLCA patients, which can be categorized into muscle-invasive bladder cancer (MIBC) and non-muscle-invasive bladder cancer (NMIBC). Currently, various therapeutic options are available for UC patients, including (1) transurethral resection followed by intravesical instillation of chemotherapeutics or Bacillus Calmette-Guérin for NMIBC patients, (2) neoadjuvant platinum-based chemotherapy (NAC) plus radical cystectomy is the standard of care for localized MIBC patients, and (3) systematic chemotherapy for metastatic UC. However, conventional treatments may lead to several challenges for treating patients. As an illustration, some patients may suffer from recurrence of the disease after the first line of treatment. Recently, immune checkpoint therapy (ICT) has been introduced as an alternative treatment strategy for the first or second line of treatment in advanced or metastatic BLCA patients. Although ICT showed lucrative results for a fraction of BLCA patients, ~80% of patients were not responsive to it. Therefore, novel treatment methods are required to augment the ICI response rate within BLCA patients. It has been shown that the infiltration of T-cells into the tumor microenvironment (TME) is positively correlated with the response to ICT within cancerous patients. Therefore, the goal of this study is to enhance the infiltration of cytotoxic T-cells into TME through the identification of target genes within the tumor that are responsible for the non-T-cell inflamed TME and their inhibition. BLCA bulk RNA-sequencing data from The Cancer Genome Atlas (TCGA) and immune score for TCGA samples were used to determine the Pearson correlation score between the expression of different genes and immune score for each sample. The genes with strong negative correlations were selected (r < -0.2). Thereafter, the correlation between the expression of each gene and survival in BLCA patients was calculated using the TCGA data and Cox regression method. The genes that are common in both selected gene lists were chosen for further analysis. Afterward, BLCA bulk and single-cell RNA-sequencing data were ranked based on the expression of each selected gene and the top and bottom 25% samples were used for pathway enrichment analysis. If the pathways related to the T-cell infiltration (e.g., antigen presentation, interferon, or chemokine pathways) were enriched within the low-expression group, the gene was included for downstream analysis. Finally, the selected genes will be used to calculate the correlation between their expression and the infiltration rate of the activated CD+8 T-cells, natural killer cells and the activated dendric cells. A list of potential target genes has been identified and ranked based on the above-mentioned analysis and criteria. SUN-1 got the highest score within the gene list and other identified genes in the literature as benchmarks. In conclusion, inhibition of SUN1 may increase the tumor-infiltrating lymphocytes and the efficacy of ICI in BLCA patients. BLCA tumor cells with and without SUN-1 CRISPR/Cas9 knockout will be injected into the syngeneic mouse model to validate the predicted SUN-1 effect on increasing tumor-infiltrating lymphocytes.

Keywords: data analysis, gene expression analysis, gene identification, immunoinformatic, functional genomics, transcriptomics

Procedia PDF Downloads 135

Authors: Abdallah Q. Bataineh

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The electronics market in Jordan is facing extraordinary expectations from consumers, whose opinions are progressively more essential and have effective power on the overall marketing strategy preparation and execution by electronics agents. This research aimed to explore the effect of price volatile, follow-up, maintenance and warranty policy on distributor’s retention. Focus group, in-depth interviews, and self-administered questionnaire were held with a total sample of 50 electronics distribution stores who have a direct contact and purchase frequently from electronic agencies. By using descriptive statistics and multiple regression tests, the main findings of this research is that there is an impact of price volatile, follow-up, maintenance and warranty policy on distributor’s retention, and the key predictor variable was price volatile. Thus, the researcher recommended flat rate pricing strategy to ensure that all distributors will sell the product on the same pricing base, regardless of the generated margin by each one of them. Moreover, conclusion and future research were also discussed.

Keywords: distributors retention, follow-up, maintenance, price volatile, warranty policy

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Authors: Saeedeh Ahmadi Basir, Mohammad Mahdavi Mazdeh, Mohammad Namakshenas

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Manufacturers often dispatch jobs in batches to reduce delivery costs. However, sending several jobs in batches can have a negative effect on other scheduling-related objective functions such as minimizing the number of tardy jobs which is often used to rate managers’ performance in many manufacturing environments. This paper aims to minimize the number of weighted tardy jobs and the sum of delivery costs of a two-stage assembly flow-shop problem in a batch delivery system. We present a mixed-integer linear programming (MILP) model to solve the problem. As this is an MILP model, the commercial solver (the CPLEX solver) is not guaranteed to find the optimal solution for large-size problems at a reasonable amount of time. We present several numerical examples to confirm the accuracy of the model.

Keywords: scheduling, two-stage assembly flow-shop, tardy jobs, batched delivery system

Procedia PDF Downloads 436

Authors: Minjung Park, Jimin Park, Youngwoon Kim, Hyungseop Han, Myoungryul Ok, Hojeong Jeon, Hyunkwang Seok, Yuchan Kim

Abstract:

Magnesium is an essential element in human body and has unique characteristics such as bioabsorbable and biodegradable properties. Therefore, there has been much attention on studies on the implants based on magnesium to avoid subsequent surgery. However, high amount of hydrogen gas is generated by relatively severe corrosion of magnesium especially in aqueous condition with chloride ions. And it contributes to the causes of swelling of skin and causes consequent inflammation of soft tissue where is directly in contact with implants. Therefore, there is still concern about the safety of the using biodegradable magnesium alloys, which is limited to various applications. In this study, we analyzed the influence of coenzyme on corrosion behavior of magnesium. The analysis of corrosion rate was held by using Hanks’ balanced salt solution (HBSS) as a body stimulated fluid and in condition of 37°C. Thus, with deferring the concentration of the coenzyme used in this study, corrosion rates from 0.0654ml/ cm² to 0.0438ml/cm² were observed in immersion tests. Also, comparable results were obtained in electrochemical tests. Results showed that hydrogen gas produced from corrosion of magnesium can be controlled.

Keywords: biodegradable magnesium, biomaterials, coenzyme, corrosion

Procedia PDF Downloads 391

Authors: Lydia Chan, Islam Shyha, Dale Dreyer, John Hamilton, Phil Hackney

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Nickel-based superalloys are generally known to be difficult to cut due to their strength, low thermal conductivity, and high work hardening tendency. Superalloy such as alloy 625 is often used in the oil and gas industry as a surfacing material to provide wear and corrosion resistance to components. The material is typically applied onto a metallic substrate through weld overlay cladding, an arc welding technique. Cladded surfaces are always rugged and carry a tough skin; this creates further difficulties to the machining process. The present work utilised design of experiment to optimise the internal cylindrical rough turning for weld overlay surfaces. An L27 orthogonal array was used to assess effects of the four selected key process variables: cutting insert, depth of cut, feed rate, and cutting speed. The optimal cutting conditions were determined based on productivity and the level of tool wear.

Keywords: cylindrical turning, nickel superalloy, turning of overlay, weld overlay

Procedia PDF Downloads 347