Search results for: specific heat capacity

Authors: R. Loukil, M. Chtourou, T. Damak

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This paper investigates the training of multilayer neural network using the classic approach. Then, for estimation purposes, we suggest the use of a specific neural observer that we study its training algorithm which is the back-propagation one in the case of the disponibility of the state and in the case of an unmeasurable state. A MATLAB simulation example will be studied to highlight the usefulness of this kind of observer.

Keywords: training, estimation purposes, neural observer, back-propagation, unmeasurable state

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Authors: S. P. Sharma, Som Nath Saha

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This paper deals with the analytical investigation of thermal and thermohydraulic performance of double flow solar air heaters with corrugated and flat plate absorber. A mathematical model of double flow solar air heater has been presented, and a computer program in C⁺⁺ language is developed to estimate the outlet temperature of air for the evaluation of thermal and thermohydraulic efficiency by solving the governing equations numerically using relevant correlations for heat transfer coefficients. The results obtained from the mathematical model is compared with the available experimental results and it is found to be reasonably good. The results show that the double flow solar air heaters have higher efficiency than conventional solar air heater, although the double flow corrugated absorber is superior to that of flat plate double flow solar air heater. It is also observed that the thermal efficiency increases with increase in mass flow rate; however, thermohydraulic efficiency increases with increase in mass flow rate up to a certain limit, attains the maximum value, then thereafter decreases sharply.

Keywords: corrugated absorber, double flow, solar air heater, thermos-hydraulic efficiency

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Authors: Hong Lu, Xiong Xiao

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Shaft parts are widely used in machinery industry, however, bending deformation often occurred when this kind of parts is being heat treated. This parts needs to be straightened to meet the requirement of straightness. As for the pressure straightening process, a good straightening stroke algorithm is related to the precision and efficiency of straightening process. In this paper, the relationship between straightening load and deflection during the straightening process is analyzed, and the mathematical model of the straightening process has been established. By the mathematical model, the iterative method is used to solve the straightening stroke. Compared to the traditional straightening stroke algorithm, straightening stroke calculated by this method is much more precise; because it can adapt to the change of material performance parameters. Considering that the straightening method is widely used in the mass production of the shaft parts, knowledge base is used to store the data of the straightening process, and a straightening stroke algorithm based on empirical data is set up. In this paper, the straightening process control model which combine the straightening stroke method based on iteration and straightening stroke algorithm based on empirical data has been set up. Finally, an experiment has been designed to verify the straightening process control model.

Keywords: straightness, straightening stroke, deflection, shaft parts

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Authors: Ilhem Ouelhazi, Mouna Elakhdar, Lakdar Kairouani

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A computer simulation model for a combined ejector-vapor compression cycle that uses working fluid R134a. A refrigeration system was developed which combines a basic vapor compression refrigeration cycle with an ejector cooling cycle. A one-dimensional mathematical model was developed using the equations governing the flow and thermodynamics based on the constant area ejector flow model. The effects of the operating parameters on the cooling capacity, the performance coefficient, and the entrainment ratio are studied. The current model is based on the NIST-REFPROP database for refrigerants properties calculations. The simulated performance is compared with the available experimental data from the literature for validation.

Keywords: combined refrigeration cycle, constant area ejector, R134a, ejector-cooling cycle, performance, mathematical simulation, vapor compression cycle

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Authors: Lucille Alonso, Florent Renard

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The characterizations of urban heat island (UHI) and their interactions with climate change and urban climates are the main research and public health issue, due to the increasing urbanization of the population. These solutions require a better knowledge of the UHI and micro-climate in urban areas, by combining measurements and modelling. This study is part of this topic by evaluating microclimatic conditions in dense urban areas in the Lyon Metropolitan Area (France) using a combination of data traditionally used such as topography, but also from LiDAR (Light Detection And Ranging) data, Landsat 8 satellite observation and Sentinel and ground measurements by bike. These bicycle-dependent weather data collections are used to build the database of the variable to be modelled, the air temperature, over Lyon’s hyper-center. This study aims to model the air temperature, measured during 6 mobile campaigns in Lyon in clear weather, using multiple linear regressions based on 33 explanatory variables. They are of various categories such as meteorological parameters from remote sensing, topographic variables, vegetation indices, the presence of water, humidity, bare soil, buildings, radiation, urban morphology or proximity and density to various land uses (water surfaces, vegetation, bare soil, etc.). The acquisition sources are multiple and come from the Landsat 8 and Sentinel satellites, LiDAR points, and cartographic products downloaded from an open data platform in Greater Lyon. Regarding the presence of low, medium, and high vegetation, the presence of buildings and ground, several buffers close to these factors were tested (5, 10, 20, 25, 50, 100, 200 and 500m). The buffers with the best linear correlations with air temperature for ground are 5m around the measurement points, for low and medium vegetation, and for building 50m and for high vegetation is 100m. The explanatory model of the dependent variable is obtained by multiple linear regression of the remaining explanatory variables (Pearson correlation matrix with a |r| < 0.7 and VIF with < 5) by integrating a stepwise sorting algorithm. Moreover, holdout cross-validation is performed, due to its ability to detect over-fitting of multiple regression, although multiple regression provides internal validation and randomization (80% training, 20% testing). Multiple linear regression explained, on average, 72% of the variance for the study days, with an average RMSE of only 0.20°C. The impact on the model of surface temperature in the estimation of air temperature is the most important variable. Other variables are recurrent such as distance to subway stations, distance to water areas, NDVI, digital elevation model, sky view factor, average vegetation density, or building density. Changing urban morphology influences the city's thermal patterns. The thermal atmosphere in dense urban areas can only be analysed on a microscale to be able to consider the local impact of trees, streets, and buildings. There is currently no network of fixed weather stations sufficiently deployed in central Lyon and most major urban areas. Therefore, it is necessary to use mobile measurements, followed by modelling to characterize the city's multiple thermal environments.

Keywords: air temperature, LIDAR, multiple linear regression, surface temperature, urban heat island

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Authors: Suresh Ramachandra

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Accounting values of firms are determined by strategies that firms pursue which are influenced by board characteristics specific to firms. Using two broad constructs of board characteristics, namely, board capital and board control, in the Malaysian context, this research attempts to infer their conjoint relevance to accounting values. The results of this research indicate that firms are able to increase their accounting values by deliberately selecting board characteristics which include director reputation and political affiliations.

Keywords: accounting values, board characteristics, board capital, board control

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Authors: Anna Martin, Raffael Osen

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The demand for fish from aquaculture is constantly growing. Concurrently, due to a shortage of fishmeal caused by extensive overfishing, fishmeal substitution by plant proteins is getting increasingly important for the production of sustainable aquafeed. Several research studies evaluated the impact of plant protein meals, concentrates or isolates on fish health and fish feed quality. However, these protein raw materials often require elaborate and expensive manufacturing and their availability is limited. Rapeseed press cake (RPC) – a side product of de-oiling processes – exhibits a high potential as a plant-based fishmeal alternative in fish feed for carnivorous species due to its availability, low costs and protein content. In order to produce aquafeed with RPC, it is important to systematically assess i) inclusion levels of RPC with similar pellet qualities compared to fishmeal containing formulations and ii) how extrusion parameters can be adjusted to achieve targeted pellet qualities. However, the effect of RPC on extrusion system parameters and pellet quality has only scarcely been investigated. Therefore, the aim of this study was to evaluate the impact of feed formulation, extruder barrel temperature (90, 100, 110 °C) and screw speed (200, 300, 400 rpm) on extrusion system parameters and the physical properties of fish feed pellets. A co-rotating pilot-scale twin screw extruder was used to produce five iso-nitrogenous feed formulations: a fish meal based reference formulation including 16 g/100g fishmeal and four formulations in which fishmeal was substituted by RPC to 25, 50, 75 or 100 %. Extrusion system parameters, being product temperature, pressure at the die, specific mechanical energy (SME) and torque, were monitored while samples were taken. After drying, pellets were analyzed regarding to optical appearance, sectional and longitudinal expansion, sinking velocity, bulk density, water stability, durability and specific hardness. In our study, the addition of minor amounts of RPC already had high impact on pellet quality parameters, especially on expansion but only marginally affected extrusion system parameters. Increasing amounts of RPC reduced sectional expansion, sinking velocity, bulk density and specific hardness and increased longitudinal expansion compared to a reference formulation without RPC. Water stability and durability were almost not affected by RPC addition. Moreover, pellets with rapeseed components showed a more coarse structure than pellets containing only fishmeal. When the adjustment of barrel temperature and screw speed was investigated, it could be seen that the increase of extruder barrel temperature led to a slight decrease of SME and die pressure and an increased sectional expansion of the reference pellets but did almost not affect rapeseed containing fish feed pellets. Also changes in screw speed had little effects on the physical properties of pellets however with raised screw speed the SME and the product temperature increased. In summary, a one-to-one substitution of fishmeal with RPC without the adjustment of extrusion process parameters does not result in fish feed of a designated quality. Therefore, a deeper knowledge of raw materials and their behavior under thermal and mechanical stresses as applied during extrusion is required.

Keywords: extrusion, fish feed, press cake, rapeseed

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Authors: Eunjung Lee

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This study aims to analyze the sentences generated by the beginners who learn ‘e,’ a postposition in Korean and to find out the regularity of learners’ interlanguage upon investigating the usages of ‘e’ that appears by meanings and functions in their interlanguage, and conditions that ‘e’ is used. This study was conducted with mainly two assumptions; first, the learner’s language has the specific type of interlanguage; and second, there is the regularity of interlanguage when students produce ‘e’ under the specific conditions. Learners’ output has various values and can be used as the useful data to understand interlanguage. Therefore, all the sentences containing a postposition ‘e’ by English speaking learners were searched in ‘Learners’ corpus sharing center in The National Institute of Korean Language’ in Korea, and the data were collected upon limiting the levels of learners with Level 1 and 2. 789 sentences that were used with ‘e’ were selected as the final subjects of the analysis. First, to understand the environmental characteristics to be used with a postposition, ‘e’ after summarizing 13 meaning and functions of ‘e’ appeared in three books of Korean dictionary that summarized the Korean grammar, 1) meaning function of ‘e’ that were used in each sentence was classified; 2) the nouns that were combined with ‘e,’ keywords of the sentences, and the characteristics of modifiers, linkers, and predicates appeared in front of ‘e’ were analyzed; 3) the regularity by the novice learners’ meaning and functions were reviewed; and 4) the differences of the regularity by level 1 and 2 learners’ meaning and functions were found. Upon the study results, the novice learners showed 1) they used the nouns related to ‘time(시간), before(전), after(후), next(다음), the next(그다음), then(때), day of the week(요일), and season(계절)’ mainly in front of ‘e’ when they used ‘e’ as the meaning function of time; 2) they used mainly the verbs of ‘go(가다),’ ‘come(오다),’ and ‘go round(다니다)’ as the predicate to match with ‘e’ that was the meaning function of direction and destination; and 3) they used mainly the nouns related to ‘locations or countries’ in front of ‘e,’ a meaning function postposition of ‘place,’ used mainly the verbs ‘be(있다), not be(없다), live(살다), be many(많다)’ after ‘e,’ and ‘i(이) or ka(가)’ was combined mainly in the subject words in case of ‘be(있다), not be(없다)’ or ‘be many(많다),’ and ‘eun(은) or nun(는)’ was combined mainly in the subject words in front of ‘live at’ In addition, 4) they used ‘e’ which indicates ‘cause or reason’ in the form of ‘because( 때문에),’ and 5) used ‘e’ of the subjects as the predicates to match with the predicates such as ‘treat(대하다), like(들다), and catch(걸리다).’ From these results, ‘e’ usage patterns of the Korean novice learners demonstrated very differently by the meaning functions and the learners’ interlanguage regularity could be deducted. However, little difference was found in interlanguage regularity between level 1 and 2. This study has the meaning to try to understand the interlanguage system and regularity in the learners’ acquisition process of postposition ‘e’ and this can be utilized to lessen their errors.

Keywords: interlanguage, interlagnage anaylsis, postposition ‘e’, Korean acquisition

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Authors: Ouassim Chemrouk, Naima Chabbi-Chemrouk

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Contemporary settlements and urban places are becoming increasingly complex involving technologically advanced building materials, and mechanical systems for controlling environmental quality such as thermal comfort, lighting, acoustics and other building performances. These systems, which rely exclusively on the utilization of nonrenewable energy are often expensive and environment pollutants. The proposed paper illustrates the important role of traditional knowledge and practice and what is sometimes called intangible cultural heritage assume in the design of the built environment. It shows that some traditional “ways of doing” that are transmitted at local scales from generation to generation could be built upon to become key resources for more livable urban places. Based on evidence from documentary sources and field surveys, it also shows how different attempts were made to translate some traditional practices and local know-how in the proposal of new urban schemes.

Keywords: key resource, know-how, local people, capacity building, liveable built environments

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Authors: Ajay Wadhwa

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A Laboratory course on computational physics is different from the conventional lab course on other topics of physics like Mechanics, Heat, Optics, etc. because it involves active participation of the teacher as well as one-to-one interaction between teacher and the student. The course content requires the teacher to teach programming language as well as numerical methods along with their applications in physics. The task becomes more daunting when about 90% of the students in the class have no previous experience of any programming language. In the presented work, we have described a methodology for conducting the computational physics course by using the Google Drive and Dropitto.me cloud storage services. We have evaluated the performance in a class of sixty students by dividing them equally into four groups. One of the groups was made the peer group on whom the presented methodology was tested. The other groups were taught by using conventional method of classroom lectures. In order to assess our methodology, we analyzed the performance of students in four class tests. A study of certain statistical parameters like the mean, standard deviation, and Z-test hypothesis revealed that the cyber methodology based on cloud storage is more efficient than the conventional method of teaching.

Keywords: computational Physics, Z-test hypothesis, cloud storage, Google drive

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Authors: Meet Patel, Darshan Patel, Nilay Shah

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Excess growth of wind-based renewable energy sources is required to identify the optimal location and damping capacity of doubly fed induction-generator-based (DFIG) wind farms while it penetrates into the transmission network. In this analysis, various ratings of DFIG wind farms are penetrated into the Single Machine Infinite Bus (SMIB ) at a different distance of the transmission line. On the basis of detailed examinations, a prime position is evaluated to maximize the stability of overall systems. A damping controller is designed at an optimum location to mitigate the small oscillations. The proposed model was validated using eigenvalue analysis, calculation of the participation factor, and time-domain simulation.

Keywords: DFIG, small signal stability, eigenvalues, time domain simulation

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Authors: Nouri Sabrina

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Numerical parametric study is conducted to study the effects of ampoule rotation on the flows and the dopant segregation in Vertical Bridgman (VB) crystal growth. Calculations were performed in unsteady state. The extended darcy model, whıch includes the time derivative and coriolis terms, has been employed in the momentum equation. It is found that the convection, and dopant segregation can be affected significantly by ampoule rotation, and the effect is similar to that by an axial magnetıc field. Ampoule rotation decreases the intensity of convection and stretches the flow cell axıally. When the convectıon is weak, the flow can be suppressed almost completely by moderate ampoule rotation and the dopant segregation becomes diffusion-controlled. For stronger convection, the elongated flow cell by ampoule rotation may bring dopant mixing into the bulk melt reducing axial segregation at the early stage of the growth. However, if the cellular flow cannot be suppressed completely, ampoule rotation may induce larger radial segregation due to poor mixing.

Keywords: rotating vertical solidification, Finite Volume Method, heat and mass transfer, porous medium, phase change

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Authors: Elena Ionescu, Elena Iacob, Marie-Louise Ionescu, Carmen Elena Tebrencu, Oana Teodora Ciuperca

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Echinacea species (Asteraceae) has received a global attention because it is widely used for treatment of cold, flu and upper respiratory tract infections. Echinacea species contain a great variety of chemical components that contribute to their activity. The most important components responsible for the biological activity are those with high molecular-weight such as polysaccharides, polyacetylenes, highly unsaturated alkamides and caffeic acid derivatives. The principal factors that may influence the chemical composition of Echinacea include the species and the part of plant used (aerial parts or roots ). In recent years the market for Echinacea has grown rapidly and also the cases of adultery/replacement especially for Echinacea root. The identification of presence or absence of same biomarkers provide information for safe use of Echinacea species in food supplements industry. The aim of the study was the preliminary evaluation and fingerprinting by UV-VISIBLE spectroscopy of biomarkers in terms of content in phenolic derivatives of some Echinacea species (E. purpurea, E. angustifolia and E. pallida) for identification and authentication of the species. The steps of the study were: (1) samples (extracts) preparation from Echinacea species (non-hydrolyzed and hydrolyzed ethanol extracts); (2) samples preparation of reference substances (polyphenol acids: caftaric acid, caffeic acid, chlorogenic acid, ferulic acid; flavonoids: rutoside, hyperoside, isoquercitrin and their aglycones: quercitri, quercetol, luteolin, kaempferol and apigenin); (3) identification of specific absorption at wavelengths between 700-200 nm; (4) identify the phenolic compounds from Echinacea species based on spectral characteristics and the specific absorption; each class of compounds corresponds to a maximum absorption in the UV spectrum. The phytochemical compounds were identified at specific wavelengths between 700-200 nm. The absorption intensities were measured. The obtained results proved that ethanolic extract showed absorption peaks attributed to: phenolic compounds (free phenolic acids and phenolic acids derivatives) registrated between 220-280 nm, unsymmetrical chemical structure compounds (caffeic acid, chlorogenic acid, ferulic acid) with maximum absorption peak and absorption "shoulder" that may be due to substitution of hydroxyl or methoxy group, flavonoid compounds (in free form or glycosides) between 330-360 nm, due to the double bond in position 2,3 and carbonyl group in position 4 flavonols. UV spectra showed two major peaks of absorption (quercetin glycoside, rutin, etc.). The results obtained by UV-VIS spectroscopy has revealed the presence of phenolic derivatives such as cicoric acid (240 nm), caftaric acid (329 nm), caffeic acid (240 nm), rutoside (205 nm), quercetin (255 nm), luteolin (235 nm) in all three species of Echinacea. The echinacoside is absent. This profile mentioned above and the absence of phenolic compound echinacoside leads to the conclusion that species harvested as Echinacea angustifolia and Echinacea pallida are Echinacea purpurea also; It can be said that preliminary fingerprinting of Echinacea species through correspondence with the phenolic derivatives profile can be achieved by UV-VIS spectroscopic investigation, which is an adequate technique for preliminary identification and authentication of Echinacea in medicinal herbs.

Keywords: Echinacea species, Fingerprinting, Phenolic compounds, UV-VIS spectroscopy

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Authors: Mozhdeh Shirinzadeh, Richard Stroetmann

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Orthotropic steel deck bridge consists of a deck plate, longitudinal stiffeners under the deck plate, cross beams and the main longitudinal girders. Due to the several advantages, Orthotropic Steel Deck (OSD) systems have been utilized in many bridges worldwide. The significant feature of this structural system is its high load-bearing capacity while having relatively low dead weight. In addition, cost efficiency and the ability of rapid field erection have made the orthotropic steel deck a popular type of bridge worldwide. However, OSD bridges are highly susceptible to fatigue damage. A large number of welded joints can be regarded as the main weakness of this system. This problem is, in particular, evident in the bridges which were built before 1994 when the fatigue design criteria had not been introduced in the bridge design codes. Recently, an Orthotropic-composite slab (OCS) for road bridges has been experimentally and numerically evaluated and developed at Technische Universität Dresden as a part of AIF-FOSTA research project P1265. The results of the project have provided a solid foundation for the design and analysis of Orthotropic-composite decks with dowel strips as a durable alternative to conventional steel or reinforced concrete decks. In continuation, while using the achievements of that project, the application of a modified Ortho-composite deck for an existing typical OSD bridge is investigated. Composite action is obtained by using rows of dowel strips in a clothoid (CL) shape. Regarding Eurocode criteria for different fatigue detail categories of an OSD bridge, the effect of the proposed modification approach is assessed. Moreover, a numerical parametric study is carried out utilizing finite element software to determine the impact of different variables, such as the size and arrangement of dowel strips, the application of transverse or longitudinal rows of dowel strips, and local wheel loads. For the verification of the simulation technique, experimental results of a segment of an OCS deck are used conducted in project P1265. Fatigue assessment is performed based on the last draft of Eurocode 1993-2 (2024) for the most probable detail categories (Hot-Spots) that have been reported in the previous statistical studies. Then, an analytical comparison is provided between the typical orthotropic steel deck and the modified Ortho-composite deck bridge in terms of fatigue issues and durability. The load-bearing capacity of the bridge, the critical deflections, and the composite behavior are also evaluated and compared. Results give a comprehensive overview of the efficiency of the rehabilitation method considering the required design service life of the bridge. Moreover, the proposed approach is assessed with regard to the construction method, details and practical aspects, as well as the economic point of view.

Keywords: composite action, fatigue, finite element method, steel deck, bridge

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Authors: Ali Raza

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The dynamic landscape of communication has brought about significant advancements that intersect with the realms of public health and journalism. This abstract explores the evolving synergy between these fields, highlighting how their intersection has contributed to informed societies and improved public health outcomes. In the digital age, communication plays a pivotal role in shaping public perception, policy formulation, and collective action. Public health, concerned with safeguarding and improving community well-being, relies on effective communication to disseminate information, encourage healthy behaviors, and mitigate health risks. Simultaneously, journalism, with its commitment to accurate and timely reporting, serves as the conduit through which health information reaches the masses. Advancements in communication technologies have revolutionized the ways in which public health information is both generated and shared. The advent of social media platforms, mobile applications, and online forums has democratized the dissemination of health-related news and insights. This democratization, however, brings challenges, such as the rapid spread of misinformation and the need for nuanced strategies to engage diverse audiences. Effective collaboration between public health professionals and journalists is pivotal in countering these challenges, ensuring that accurate information prevails. The synergy between public health and journalism is most evident during public health crises. The COVID-19 pandemic underscored the pivotal role of journalism in providing accurate and up-to-date information to the public. However, it also highlighted the importance of responsible reporting, as sensationalism and misinformation could exacerbate the crisis. Collaborative efforts between public health experts and journalists led to the amplification of preventive measures, the debunking of myths, and the promotion of evidence-based interventions. Moreover, the accessibility of information in the digital era necessitates a strategic approach to health communication. Behavioral economics and data analytics offer insights into human decision-making and allow tailored health messages to resonate more effectively with specific audiences. This approach, when integrated into journalism, enables the crafting of narratives that not only inform but also influence positive health behaviors. Ethical considerations emerge prominently in this alliance. The responsibility to balance the public's right to know with the potential consequences of sensational reporting underscores the significance of ethical journalism. Health journalists must meticulously source information from reputable experts and institutions to maintain credibility, thus fortifying the bridge between public health and the public. As both public health and journalism undergo transformative shifts, fostering collaboration between these domains becomes essential. Training programs that familiarize journalists with public health concepts and practices can enhance their capacity to report accurately and comprehensively on health issues. Likewise, public health professionals can gain insights into effective communication strategies from seasoned journalists, ensuring that health information reaches a wider audience. In conclusion, the convergence of public health and journalism, facilitated by communication advancements, is a cornerstone of informed societies. Effective communication strategies, driven by collaboration, ensure the accurate dissemination of health information and foster positive behavior change. As the world navigates complex health challenges, the continued evolution of this synergy holds the promise of healthier communities and a more engaged and educated public.

Keywords: public awareness, journalism ethics, health promotion, media influence, health literacy

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Authors: Oloruntegbe Kunle Oke, Alake Ese Monica, Odutuyi Olubu Musili

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This research explores the differing effectiveness of cascade and cluster models in professional development programs for educators in Ondo State, Nigeria. The cascade model emphasizes a top-down approach, where training is cascaded from expert trainers to lower levels of teachers. In contrast, the cluster model, a bottom-up approach, fosters collaborative learning among teachers within specific clusters. Through a review of the literature and empirical studies of the implementations of the former in two academic sessions followed by the cluster model in another two, the study examined their effectiveness on teacher development, productivity and students’ achievements. The study also drew a comparative analysis of the strengths and weaknesses associated with each model, considering factors such as scalability, cost-effectiveness, adaptability in various contexts, and sustainability. 2500 teachers from Ondo State Primary Schools participated in the cascade with intensive training in five zones for a week each in two academic sessions. On the other hand, 1,980 and 1,663 teachers in 52 and 34 clusters, respectively, were in the first and the following session. The programs were designed for one week of rigorous training of teachers by facilitators in the former while the latter was made up of four components: sit-in-observation, need-based assessment workshop, pre-cluster and the actual cluster meetings in addition to sensitization, and took place one day a week for ten weeks. Validated Cluster Impact Survey Instruments, CISI and Teacher’s Assessment Questionnaire (TAQ) were administered to ascertain the effectiveness of the models during and after implementation. The findings from the literature detailed specific effectiveness, strengths and limitations of each approach, especially the potential for inconsistencies and resistance to change. Findings from the data collected revealed the superiority of the cluster model. Response to TAQ equally showed content knowledge and skill update in both but were more sustained in the cluster model. Overall, the study contributes to the ongoing discourse on effective strategies for improving teacher training and enhancing student outcomes, offering practical recommendations for the development and implementation of future professional development projects.

Keywords: cascade model, cluster model, teachers’ development, productivity, students’ achievement

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Authors: C. Shalini Devi

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This work describes the stress concentration in a rectangular specimen with a circular hole made up of hybrid composite material with the combination of glass/carbon with epoxy. The arrangements of cross ply lamina in the sequence of alternative carbon and glass, using carbon fiber in panel, gives more strength to the structure as the carbon properties are higher when compared to glass. Typical aircraft and automobile components are with cut-outs, and such cut-outs reduce the weight of the aircraft according to the weight reduction law and also they reduce the bulking load carrying capacity. Experimental investigations were carried out using three specimens as per ASTM D5766 and three specimens as per ASTM D3039 in the Universal Testing Machine. Stress concentration in the rectangular specimen with a hole is also analysed using FEA and comparing the results.

Keywords: composite, stress concentration, finite element analysis, tensile strength

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Authors: Daisy B. Badilla, Peter A. Gostomski

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Abstract: Biofiltration may be used to control indoor air pollution. In biofiltration, microorganisms break down harmful contaminants in air or water, transforming them into non-toxic substances like carbon dioxide, water, and biomass. In this study, the CO₂ production and the elimination capacity (EC) of toluene at inlet concentrations between 20 and 80 ppm were investigated using three biofilters operated separately with soil as bed material. Results showed soil, with its rich microflora taken to full advantage without inoculants and additional nutrients, biodegraded toluene at removal rates comparable to those in other studies at higher concentrations. The amount of CO₂ generated corresponds to the amount of toluene removed, indicating efficient biodegradation and suggesting stable long-term performance at these low concentrations. Although the concentrations in this study differ from typical indoor toluene levels (ppb), the findings suggest that biofiltration could be effective for indoor air pollution control with appropriate design, taking into account biomass growth or biofilm structure, concentration, and gas flow rate.

Keywords: biofiltration, air pollution control, soil, toluene

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Authors: A. Raj Kumar, S. Bilaloglu

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Stroke is a leading cause of adult disability worldwide. We depend on our hands for our activities of daily living(ADL). Although many patients regain the ability to walk, they continue to experience long-term hand motor impairments. As the number of individuals with young stroke is increasing, there is a critical need for effective approaches for rehabilitation of hand function post-stroke. Motor relearning for dexterity requires task-specific kinesthetic, tactile and visual feedback. However, when a stroke results in both sensory and motor impairment, it becomes difficult to ascertain when and what type of sensory substitutions can facilitate motor relearning. In an ideal situation, real-time task-specific data on the ability to learn and data-driven feedback to assist such learning will greatly assist rehabilitation for dexterity. We have found that kinesthetic and tactile information from the unaffected hand can assist patients re-learn the use of optimal fingertip forces during a grasp and lift task. Measurement of fingertip grip force (GF), load forces (LF), their corresponding rates (GFR and LFR), and other metrics can be used to gauge the impairment level and progress during learning. Currently ATI mini force-torque sensors are used in research settings to measure and compute the LF, GF, and their rates while grasping objects of different weights and textures. Use of the ATI sensor is cost prohibitive for deployment in clinical or at-home rehabilitation. A cost effective mechatronic device is developed to quantify GF, LF, and their rates for stroke rehabilitation purposes using off-the-shelf components such as load cells, flexi-force sensors, and an Arduino UNO microcontroller. A salient feature of the device is its integration with an interactive gaming environment to render a highly engaging user experience. This paper elaborates the integration of kinesthetic and tactile sensing through computation of LF, GF and their corresponding rates in real time, information processing, and interactive interfacing through augmented reality for visual feedback.

Keywords: feedback, gaming, kinesthetic, rehabilitation, tactile

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Authors: Watcharet Kongwarakom, Tosaphol Ratniyomchai, Thanatchai Kulworawanichpong

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This paper presents a design and analysis of wireless charging lane system (WCLS) for light rail transit (LRT) by considering the performance of wireless charging, traffic conditions and energy consumption drawn by the LRT system. The dynamic of the vehicle movement in terms of the vehicle speed profile during running on the WCLS, a dwell time during stopping at the station for taking the WCLS and the capacity of the WCLS in each section are taken into account to alignment design of the WCLS. This paper proposes a case study of the design of the WCLS into 2 sub-cases including continuous and discontinuous WCLS with the same distance of WCLS in total. The energy consumption by the LRT through the WCLS with the different designs of the WCLS is compared to find out the better configuration of those two cases by considering the best performance of the power transfer between the LRT and the WCLS.

Keywords: Light rail transit, Wireless charging lane, Energy consumption, Power transfer

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Authors: Feixiong Chen, Naoufel Haddour, Marie Frenea-Robin, Yves MéRieux, Yann Chevolot, Virginie Monnier

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Neonatal thrombopenia occurs when the mother generates antibodies against her baby’s platelet antigens. It is particularly critical for newborns because it can cause coagulation troubles leading to intracranial hemorrhage. In this case, diagnosis must be done quickly to make platelets transfusion immediately after birth. Before transfusion, platelet antigens must be tested carefully to avoid rejection. The majority of thrombopenia (95 %) are caused by antibodies directed against Human Platelet Antigen 1a (HPA-1a) or 5b (HPA-5b). The common method for antigen platelets detection is polymerase chain reaction allowing for identification of gene sequence. However, it is expensive, time-consuming and requires significant blood volume which is not suitable for newborns. We propose to develop a point-of-care device based on double functionalized magnetic colloids with 1) antibodies specific to antigen platelets and 2) highly sensitive electroactive molecules in order to be detected by an electrochemical microsensor. These magnetic colloids will be used first to isolate platelets from other blood components, then to capture specifically platelets bearing HPA-1a and HPA-5b antigens and finally to attract them close to sensor working electrode for improved electrochemical signal. The expected advantages are an assay time lower than 20 min starting from blood volume smaller than 100 µL. Our functionalization procedure based on amine dendrimers and NHS-ester modification of initial carboxyl colloids will be presented. Functionalization efficiency was evaluated by colorimetric titration of surface chemical groups, zeta potential measurements, infrared spectroscopy, fluorescence scanning and cyclic voltammetry. Our results showed that electroactive molecules and antibodies can be immobilized successfully onto magnetic colloids. Application of a magnetic field onto working electrode increased the detected electrochemical signal. Magnetic colloids were able to capture specific purified antigens extracted from platelets.

Keywords: Magnetic Nanoparticles , Electroactive Molecules, Antibody, Platelet

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Authors: José Luis Gallizo, Pilar Gargallo, Ramon Saladrigues, Manuel Salvador

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This study offers an exploratory statistical analysis of the persistence of annual profits across a sample of firms from different European Union (EU) countries. To this end, a hierarchical Bayesian dynamic model has been used which enables the annual behaviour of those profits to be broken down into a permanent structural and a transitory component, while also distinguishing between general effects affecting the industry as a whole to which each firm belongs and specific effects affecting each firm in particular. This breakdown enables the relative importance of those fundamental components to be more accurately evaluated by country and sector. Furthermore, Bayesian approach allows for testing different hypotheses about the homogeneity of the behaviour of the above components with respect to the sector and the country where the firm develops its activity. The data analysed come from a sample of 23,293 firms in EU countries selected from the AMADEUS data-base. The period analysed ran from 1999 to 2007 and 21 sectors were analysed, chosen in such a way that there was a sufficiently large number of firms in each country sector combination for the industry effects to be estimated accurately enough for meaningful comparisons to be made by sector and country. The analysis has been conducted by sector and by country from a Bayesian perspective, thus making the study more flexible and realistic since the estimates obtained do not depend on asymptotic results. In general terms, the study finds that, although the industry effects are significant, more important are the firm specific effects. That importance varies depending on the sector or the country in which the firm carries out its activity. The influence of firm effects accounts for around 81% of total variation and display a significantly lower degree of persistence, with adjustment speeds oscillating around 34%. However, this pattern is not homogeneous but depends on the sector and country analysed. Industry effects depends also on sector and country analysed have a more marginal importance, being significantly more persistent, with adjustment speeds oscillating around 7-8% with this degree of persistence being very similar for most of sectors and countries analysed.

Keywords: dynamic models, Bayesian inference, MCMC, abnormal returns, persistence of profits, return on assets

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Authors: Moshe Wasserblat, Jonathan Mamou, Oren Pereg

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Natural Language Processing (NLP) has made a major leap in the last few years, in practical integration into medical solutions; for example, extracting clinical concepts from medical texts such as medical condition, medication, treatment, and symptoms. However, training and deploying those models in real environments still demands a large amount of annotated data and NLP/Machine Learning (ML) expertise, which makes this process costly and time-consuming. We present a practical and efficient method for clinical concept extraction that does not require costly labeled data nor ML expertise. The method includes three steps: Step 1- the user injects a large in-domain text corpus (e.g., PubMed). Then, the system builds a contextual model containing vector representations of concepts in the corpus, in an unsupervised manner (e.g., Phrase2Vec). Step 2- the user provides a seed set of terms representing a specific medical concept (e.g., for the concept of the symptoms, the user may provide: ‘dry mouth,’ ‘itchy skin,’ and ‘blurred vision’). Then, the system matches the seed set against the contextual model and extracts the most semantically similar terms (e.g., additional symptoms). The result is a complete set of terms related to the medical concept. Step 3 –in production, there is a need to extract medical concepts from the unseen medical text. The system extracts key-phrases from the new text, then matches them against the complete set of terms from step 2, and the most semantically similar will be annotated with the same medical concept category. As an example, the seed symptom concepts would result in the following annotation: “The patient complaints on fatigue [symptom], dry skin [symptom], and Weight loss [symptom], which can be an early sign for Diabetes.” Our evaluations show promising results for extracting concepts from medical corpora. The method allows medical analysts to easily and efficiently build taxonomies (in step 2) representing their domain-specific concepts, and automatically annotate a large number of texts (in step 3) for classification/summarization of medical reports.

Keywords: clinical concepts, concept expansion, medical records annotation, medical records summarization

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Authors: Hong Kai, Zhong Jun Jie, Chen Lin Qi, Wang Chen Guang

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There are inefficient global scheduling parallelism and local scheduling parallelism prone to processor starvation in current scheduling algorithms. Regarding this issue, this paper proposed a load-aware queue partitioning scheduling strategy by first allocating the queues according to the number of processor cores, calculating the load factor to specify the load queue capacity, and it assigned the awaiting nodes to the appropriate perceptual queues through the precursor nodes and the communication computation overhead. At the same time, real-time computation of the load factor could effectively prevent the processor from being starved for a long time. Experimental comparison with two classical algorithms shows that there is a certain improvement in both performance metrics of scheduling length and task speedup ratio.

Keywords: load-aware, scheduling algorithm, perceptual queue, heterogeneous multi-core

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Authors: Israt Jahan Eshita

Abstract:

Flows developed between two parallel disks have many engineering applications. Two types of non-swirling flows can be generated in such a domain. One is purely source flow in disc type domain (outward flow). Other is purely sink flow in disc type domain (inward flow). This situation often appears in some turbo machinery components such as air bearings, heat exchanger, radial diffuser, vortex gyroscope, disc valves, and viscosity meters. The main goal of this paper is to show the mesh convergence, because mesh convergence saves time, and economical to run and increase the efficiency of modeling for both sink and source flow. Then flow field is resolved using a very fine mesh near-wall, using enhanced wall treatment. After that we are going to compare this flow using standard k-epsilon, RNG k-epsilon turbulence models. Lastly compare some experimental data with numerical solution for sink flow. The good agreement of numerical solution with the experimental works validates the current modeling.

Keywords: hydraulic diameter, k-epsilon model, meshes convergence, Reynolds number, RNG model, sink flow, source flow, wall y+

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Authors: Ashleigh Dawn Moeller

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This is a comparative case study which examines the language attitudes and behaviors of descendants of Volga German immigrants in North America and how these attitudes combined with surrounding social conditions have caused their heritage language to develop differently within each community. Of particular interest for this study are the accounts of second- and third-generation descendants in Oregon, Kansas, and North Dakota regarding their parents’ and grandparents’ attitudes toward their language and how this correlates with the current sentiment as well as visibility of their heritage language and culture. This study discusses the point at which cultural identity could diverge from language identity and what elements play a role in this development, establishing the potential for environments (linguistic landscapes) which uphold their heritage yet have detached from the language itself. Emigrating from Germany in the 1700s, these families settled for over a hundred years along the Volga Region of Imperial Russia. Subsequently, many descendants of these settlers immigrated to the Americas in the 1800-1900s. Identifying neither as German nor Russian, they called themselves Wolgadeutche (Volga Germans). During their time in Russia, the German language was maintained relatively homogenously, yet the use and status of their heritage language diverged considerably upon settlement across the Americas. Data shows that specific conditions, such as community isolation, size, religion, location as well as language policy established prior to and following the Volga German immigration to North America have had a substantial impact on the maintenance of their heritage language—causing complete loss in some areas and peripheral use or even full rebirth in others. These past conditions combined with the family accounts correlate directly with the general attitudes and ideologies of the descendants toward their heritage language. Data also shows that in many locations, despite a strong presence of German within the linguistic landscape, minimal to no German is spoken nor understood; the attitude toward the language is indifferent while a staunch holding to the heritage is maintained and boasted. Data for this study was gathered from historical accounts, archived records and newspapers, and published biographies as well as from formal interviews with second- and third-generation descendants of Volga German immigrants conducted in Oregon and Kansas. Through the interviews, members of the community have shared and provided their family genealogies as well as biographies published by family members. These have helped to trace their relatives back to specific locations, thus allowing for comparisons within the same families residing in distinctly different areas of North America. This study is part of a larger ongoing project which researches the immigration of Volga and Black Sea Germans to North America and diachronically examines the over-arching sociological factors which have directly impacted the maintenance, loss, or rebirth of their heritage language. This project follows specific families who settled in areas of Colorado, Kansas, Nebraska, Illinois, Minnesota, North and South Dakota, Saskatchewan, and Manitoba, and who later had relatives move west to areas of Oregon and Washington State. Interviews for the larger project will continue into the following year.

Keywords: heritage language, immigrant language, language change, language contact, linguistic landscape, Volga Germans, Wolgadeutsche

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Authors: Afsaneh Ghorbanzadeh, Afshin Farahbakhsh, Zakieh Bayat

Abstract:

The drug capsulation was used for release and targeted delivery in determined time, place and temperature or pH. The DOX nanocapsules were used to reduce and to minimize the unwanted side effects of drug. In this paper, the encapsulation methods of doxorubicin (DOX) and the labeling it by the magnetic core of iron (Fe3O4) has been studied. The Fe3O4 was conjugated with DOX via hydrazine bond. The solution was capsuled by the sensitive polymer of heat or pH such as chitosan-g-poly (N-isopropylacrylamide-co-N,N-dimethylacrylamide), dextran-g-poly(N-isopropylacrylamide-co-N,N-dimethylacrylamide) and mPEG-G2.5 PAMAM by hydrazine bond. The drug release was very slow at temperatures lower than 380°C. There was a rapid and controlled drug release at temperatures higher than 380°C. According to experiments, the use mPEG-G2.5PAMAM is the best method of DOX nanocapsules synthesis, because in this method, the drug delivery time to certain place is lower than other methods and the percentage of released drug is higher. The synthesized magnetic carrier system has potential applications in magnetic drug-targeting delivery and magnetic resonance imaging.

Keywords: drug carrier, drug release, doxorubicin, iron oxide NPs

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Authors: Cormac Reale, Luke J. Prendergast, Kenneth Gavin

Abstract:

While significant improvements have been made in axial pile design methods over recent years, the influence of soils natural variability has not been adequately accounted for within them. Soil variability is a crucial parameter to consider as it can account for large variations in pile capacity across the same site. This paper seeks to address this knowledge deficit, by demonstrating how soil spatial variability can be accommodated into existing cone penetration test (CPT) based pile design methods, in the form of layered non-homogeneous random fields. These random fields model the scope of a given property’s variance and define how it varies spatially. A Monte Carlo analysis of the pile will be performed taking into account parameter uncertainty and spatial variability, described using the measured scales of fluctuation. The results will be discussed in light of Eurocode 7 and the effect of spatial averaging on design capacities will be analysed.

Keywords: pile axial design, reliability, spatial variability, CPT

Procedia PDF Downloads 249

Authors: Hanbey Hazar, Hakan Gul

Abstract:

In this study, Thermal Barrier Coating (TBC) application is performed in order to reduce the engine emissions. Piston, exhaust, and intake valves of a single-cylinder four-cycle gasoline engine were coated with chromium carbide (Cr3C2) at a thickness of 300 µm by using the Plasma Spray coating method which is a TBC method. Gasoline engine was converted into an LPG system. The study was conducted in 4 stages. In the first stage, the piston, exhaust, and intake valves of the gasoline engine were coated with Cr3C2. In the second stage, gasoline engine was converted into the LPG system and the emission values in this engine were recorded. In the third stage, the experiments were repeated under the same conditions with a standard (uncoated) engine and the results were recorded. In the fourth stage, data obtained from both engines were loaded on Artificial Neural Networks (ANN) and estimated values were produced for every revolution. Thus, mathematical modeling of coated and uncoated engines was performed by using ANN. While there was a slight increase in exhaust gas temperature (EGT) of LPG engine due to TBC, carbon monoxide (CO) values decreased.

Keywords: LPG fuel, thermal barrier coating, artificial neural network, mathematical modelling

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Authors: Merzak Laribi, Abdelmadjid Kasser

Abstract:

Thermal spraying processes are widely used to produce coatings on original constructions as well as in repair and maintenance of long standing structures. A lot of efforts forwarding to develop thermal spray coatings technology have been focused on improving mechanical characteristics, minimizing residual stress level and reducing porosity of the coatings. The specific aim of this paper is to determine either residual stresses distribution or wear resistance of stainless steel coating thermally sprayed on a carbon steel substrate. Internal stresses determination was performed using an extensometric method in combination with a simultaneous progressive electrolytic polishing. The procedure consists of measuring micro-deformations using a bi-directional extensometric gauges glued on the substrate side of the materials. Very thin layers of the deposits are removed by electrochemical polishing across the sample surface. Micro-deformations are instantaneously measured, leading to residual stresses calculation after each removal. Wear resistance of the coating has been determined using a ball-on-plate tribometer. Friction coefficient is instantaneously measured during the tribological test. Attention was particularly focused on the influence of a post-annealing at 850 °C for one hour in vacuum either on the residual stresses distribution or on the wear resistance behavior under specific wear and lubrication conditions. The obtained results showed that the microstructure of the obtained arc sprayed stainless steel coating is classical. It is homogeneous and contains un-melted particles, metallic oxides and also pores and micro-cracks. The internal stresses are in compression in the coating. They are more or less scattered between -50 and -270 MPa on the surface and decreased more at the interface. The value at the surface of the substrate is about –700 MPa, partially due to the molten particles impact with the substrate. The post annealing has reduced the residual stresses in both coating and surface of the steel substrate so that the hole material becomes more relaxed. Friction coefficient has an average value of 0.3 and 0.4 respectively for non annealed and annealed specimen. It is rather oil lubrication which is really benefit so that friction coefficient is decreased to about 0.06.

Keywords: residual stresses, wear resistance, stainless steel, coating, thermal spraying, annealing, lubrication

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