Search results for: experimental work

Authors: Tesfay Gebremichael Reda

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Nanoparticle technology is fast progressing and is being employed in innumerable medical applications. At this time, the public's health is seriously threatened by the rise of bacterial strains resistant to several medications. Metal nanoparticles are a potential alternate approach for tackling this global concern, and this is the main focus of this study. The citrate precursor sol-gel synthesis method was used to synthesize the, Niₓ Co(₁-ₓ) Fe₂ O₄, (where x = 0.0:0.2:1.0) nanoparticle. XRD identified the development of the cubic crystal structure to have a preferential orientation along (311), and the average particle size was found to be 29-38 nm. The average crystallizes assessed with ImageJ software and origin 22 of the SEM are nearly identical to the XRD results. In the created NCF NPs, the FT-IR spectroscopy reveals structural examinations and the redistribution of cations between octahedral (505-428 cm-1) and tetrahedral (653-603 cm-1) locales. Finally, the decrease of coercive fields HC, 2384 Oe to 241.93 Oe replacement of Co²+ cation with Ni²+. Band gap energy rises as Ni concentration increases, which may be attributed to the fact that the ionic radii of Ni²+ ions are smaller than that of Co²+ ions, which results in a strong electrostatic interaction. On the contrary, except at x = 0.4, the dielectric constant decreases as the nickel concentration increases. According to the findings of this research work, nanoparticles composed of Ni₀.₄ Co₀.₄ Fe₂ O₄ have demonstrated a promising value against S. aureus and E. coli, and it suggests a proposed model for their potential use as a new source of antibacterial agents.

Keywords: antimicrobial, band gap, citrate precursor, dielectric, nanoparticle

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Authors: Md. Danish Eqbal, Venkat Gundabala

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Microparticles and microcapsules are basically used as a carrier for cells, tissues, drugs, and chemicals. Due to its biocompatibility, non-toxicity and biodegradability, alginate based microparticles have numerous applications in drug delivery, tissue engineering, organ repair and transplantation, etc. The production of uniform monodispersed microparticles was a challenge for the past few decades. However, emergence of microfluidics has provided controlled methods for the generation of the uniform monodispersed microparticles. In this work, we present a successful method for the generation of both microparticles and microcapsules (single and double core) using merging approach of two droplets, completely inside the microfluidic device. We have fabricated hybrid glass- PDMS (polydimethylsiloxane) based microfluidic device which has coflow geometry as well as the T junction channel. Coflow is used to generate the single as well as double oil-alginate emulsion in oil and T junction helps to form the calcium chloride droplets in oil. The basic idea is to match the frequency of the alginate droplets and calcium chloride droplets perfectly for controlled generation. Using the merging of droplets technique, we have successfully generated the microparticles and the microcapsules having single core as well as double and multiple cores. The cores in the microcapsules are very stable, well separated from each other and very intact as seen through cross-sectional confocal images. The size and the number of the cores along with the thickness of the shell can be easily controlled by controlling the flowrate of the liquids.

Keywords: double-core, droplets, microcapsules, microparticles

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Authors: Shalini Attri

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Silence has been 'scriptured' in women within dominating social structures, as the modes of speaking and behaving which deny women free investiture to language. A woman becomes the product of ideological constructions as language substantiates andro-centric bias. Constrained from writing/speaking in the public sphere, women have traditionally been confined to expressing themselves in writing private poetry, letters or diaries. The helplessness of a woman is revealed in the ways in which she is expected to speak a language, which, in fact, is man-made. There are visible binaries of coloniser- colonised; Western-Eastern; White-Black, Nature-Culture, even Male-Female that contribute significantly to our understanding of the concept of representation and its resultant politics. Normally, an author is labeled as feminist, humanist, or propagandist and this process of labeling correspond to a sense of politics besides his inclination to a particular field. One cannot even think of contemporary literature without this representational politics. Thus, each and every bit of analysis of a work of literature demands a political angle to be dealt with. Besides literature, the historical facts and manuscripts are also subject to this politics. The image of woman as someone either dependent on man or is exploited by him only provides half the picture of this representational politics. The present paper is an attempt to study Panchali’s (Draupadi of Mahabharata) voiceless articulation and her representation as a strong woman in Chitra Divakurani’s The Palace of Illusions.

Keywords: politics, representation, silence, social structures

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Authors: Hasan Ustun Basaran

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Diesel engines are widely used in transportation sector due to their high thermal efficiency. However, they also release high rates of NOₓ and PM (particulate matter) emissions into the environment which have hazardous effects on human health. Therefore, environmental protection agencies have issued strict emission regulations on automotive diesel engines. Recently, these regulations are even increasingly strengthened. Engine producers search novel on-engine methods such as advanced combustion techniques, utilization of renewable fuels, exhaust gas recirculation, advanced fuel injection methods or use exhaust after-treatment (EAT) systems in order to reduce emission rates on diesel engines. Although those aforementioned on-engine methods are effective to curb emission rates, they result in inefficiency or cannot decrease emission rates satisfactorily at all operating conditions. Therefore, engine manufacturers apply both on-engine techniques and EAT systems to meet the stringent emission norms. EAT systems are highly effective to diminish emission rates, however, they perform inefficiently at low loads due to low exhaust gas temperatures (below 250°C). Therefore, the objective of this study is to demonstrate that engine-out temperatures can be elevated above 250°C at low-loaded cases via cylinder disablement. The engine studied and modeled via Lotus Engine Simulation (LES) software is a six-cylinder turbocharged and intercooled diesel engine. Exhaust temperatures and mass flow rates are predicted at 1200 rpm engine speed and several low loaded conditions using LES program. It is seen that cylinder deactivation results in a considerable exhaust temperature rise (up to 100°C) at low loads which ensures effective EAT management. The method also improves fuel efficiency through reduced total pumping loss. Decreased total air induction due to inactive cylinders is thought to be responsible for improved engine pumping loss. The technique reduces exhaust gas flow rate as air flow is cut off on disabled cylinders. Still, heat transfer rates to the after-treatment catalyst bed do not decrease that much since exhaust temperatures are increased sufficiently. Simulation results are promising; however, further experimental studies are needed to identify the true potential of the method on fuel consumption and EAT improvement.

Keywords: cylinder disablement, diesel engines, exhaust after-treatment, exhaust temperature, fuel efficiency

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Authors: Ana Corberan-Vallet, Karen C. Florez, Ingrid C. Marino, Jose D. Bermudez

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In 2016, the Region of the Americas was declared free of measles, a viral disease that can cause severe health problems. However, since 2017, measles has reemerged in Venezuela and has subsequently reached neighboring countries. In 2018, twelve American countries reported confirmed cases of measles. Governmental and health authorities in Colombia, a country that shares the longest land boundary with Venezuela, are aware of the need for a strong response to restrict the expanse of the epidemic. In this work, we apply a Bayesian hierarchical Poisson model with an underlying cluster structure to describe disease incidence in Colombia. Concretely, the proposed methodology provides relative risk estimates at the department level and identifies clusters of disease, which facilitates the implementation of targeted public health interventions. Socio-demographic factors, such as the percentage of migrants, gross domestic product, and entry routes, are included in the model to better describe the incidence of disease. Since the model does not impose any spatial correlation at any level of the model hierarchy, it avoids the spatial confounding problem and provides a suitable framework to estimate the fixed-effect coefficients associated with spatially-structured covariates.

Keywords: Bayesian analysis, cluster identification, disease mapping, risk estimation

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Authors: Raúl Jiménez Vilches

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Native (L1) speakers can mark prosodically one part of an utterance and make it more relevant as opposed to the rest of the constituents. Conversely, non-native (L2) speakers encounter problems when it comes to marking prosodically information structure in English. In fact, the L2 speaker’s choice for the prosodic realization of focus is not so clear and often obscures the intended pragmatic meaning and the communicative value in general. This paper reports some of the findings obtained in an L2 prosodic training course for Spanish learners of English within the context of public speaking. More specifically, it analyses the effects of the course experiment in relation to the non-native production of the tonic syllable to mark focus and compares it with the public speeches delivered by native English speakers. The whole experimental training was executed throughout eighteen input sessions (1,440 minutes total time) and all the sessions took place in the classroom. In particular, the first part of the course provided explicit instruction on the recognition and production of the tonic syllable and how the tonic syllable is used to express focus. The non-native and native oral presentations were acoustically analyzed using Praat software for speech analysis (7,356 words in total). The investigation adopted mixed and embedded methodologies. Quantitative information is needed when measuring acoustically the phonetic realization of focus. Qualitative data such as questionnaires, interviews, and observations were also used to interpret the quantitative data. The embedded experiment design was implemented through the analysis of the public speeches before and after the intervention. Results indicate that, even after the L2 prosodic training course, Spanish learners of English still show some major inconsistencies in marking focus effectively. Although there was occasional improvement regarding the choice for location and word classes, Spanish learners were, in general, far from achieving similar results to the ones obtained by the English native speakers in the two types of focus. The prosodic realization of focus seems to be one of the hardest areas of the English prosodic system to be mastered by Spanish learners. A funded research project is in the process of moving the present classroom-based experiment to an online environment (mobile app) and determining whether there is a more effective focus usage through CAPT (Computer-Assisted Pronunciation) tools.

Keywords: focus, prosody, public speaking, Spanish learners of English

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Authors: Rahimah Saimin

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Previous research has shown that young children can learn from educational television programmes, videos or other technological media. However, the blending of any of these with traditional printed-based text appears to be omitted. Repeated viewing is an important factor in children's ability to comprehend the content or plot. The present study combined videos with traditional printed-based text and required repeated viewing and is original and distinctive. The first study was a pilot study to explore whether the intervention is implementable in ordinary classrooms. The second study explored whether the curricular embedding is important or whether the video with curricular embedding is effective. The third study explored the effect of “dosage”, i.e. whether a longer/ more intense intervention has a proportionately greater effect on outcomes. Both measured outcomes (comprehension, word sounds, and early word recognition) and unmeasured outcomes (engagement to reading traditional printed-based texts or/and multimodal texts) were obtained from this study. Observation indicated degree of engagement in reading. The theoretical framework was multimodality theory combined with Piaget’s and Vygotsky’s learning theories. An experimental design was used with 4-5-year-old children in nursery schools and primary schools. Six links to video clips exploring non-fiction science content were provided to teachers. The first session is whole-class and subsequent sessions small-group. The teacher then engaged the children in dialogue using supplementary materials. About half of each class was selected randomly for pre-post assessments. Two assessments were used the British Picture Vocabulary Scale (BPVSIII) and the York Assessment of Reading for Comprehension (YARC): Early Reading. Different programme fidelity means were deployed- observations, teacher self-reports attendance logs and post-delivery interviews. Data collection is in progress and results will be available shortly. If this multiphase study show effectiveness in one or other application, then teachers will have other tools which they can use to enhance vocabulary, letter knowledge and word reading. This would be a valuable addition to their repertoire.

Keywords: language skills, literacy skills, multimodality, video

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Authors: Nipin Kohli, Ravi Chand Singh

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Diabetes mellitus is a serious illness and can be life-threatening if left untreated. Acetone present in the exhaled breath of a diabetic person is a biomarker of patients suffering from diabetes mellitus and is higher than its usual concentration present in the breath of healthy people. In the present work, a portable gas sensor system based on chromium oxide (Cr₂O₃) nanoparticles has been developed that can analyze diabetic patient’s breath. Undoped and indium (In) doped Cr₂O₃ nanoparticles were synthesized by a chemical route and characterized by X-ray diffraction, scanning electron microscopy, Raman spectroscopy, UV-visible spectroscopy, and photoluminescence spectroscopy for their structural, morphological and optical properties. Thick film gas sensors were fabricated out of synthesized samples. To diagnose diabetes, the sensors’ response to low concentrations of acetone was measured, and it was found that the addition of indium dramatically enhances the acetone gas sensing response. Moreover, the fabricated sensors were highly stable, reproducible and resistant to humidity. Enhancement of sensor response of doped sensors towards acetone can be ascribed to increase in defects due to addition of a dopant, and it was found that in-doped Cr₂O₃ sensors are more useful for analysis of breath of diabetic patients.

Keywords: Diabetes mellitus, nanoparticles, raman spectroscopy, sensor

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Authors: Luvindran Sugumaran, Mohd Nashrul Mohd Zubir, Kazi Md Salim Newaz, Tuan Zaharinie Tuan Zahari, Suazlan Mt Aznam, Aiman Mohd Halil

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With the fast growth of integrated circuits and the trend towards making electronic devices smaller, the heat dissipation load of electronic devices has continued to go over the limit. The high heat flux element would not only harm the operation and lifetime of the equipment but would also impede the performance upgrade brought about by the iteration of technological updates, which would have a direct negative impact on the economic and production cost benefits of rising industries. Hence, in high-tech industries like radar, information and communication, electromagnetic power, and aerospace, the development and implementation of effective heat dissipation technologies were urgently required. Pool boiling is favored over other cooling methods because of its capacity to dissipate a high heat flux at a low wall superheat without the usage of mechanical components. Enhancing the pool boiling performance by increasing the heat transfer coefficient via surface modification techniques has received a lot of attention. There are several surface modification methods feasible today, but the stability and durability of surface modification are the greatest priority. Thus, laser machining is an interesting choice for surface modification due to its low production cost, high scalability, and repeatability. In this study, different patterns of laser-processed copper surfaces are fabricated to investigate the nucleate pool boiling heat transfer performance of distilled water. The investigation showed that there is a significant enhancement in the pool boiling heat transfer performance of the laser-processed surface compared to the reference surface due to the notable increase in nucleation frequency and nucleation site density. It was discovered that the heat transfer coefficients increased when both the surface area ratio and the ratio of peak-to-valley height of the microstructure were raised. It is believed that the development of microstructures on the surface as a result of laser processing is the primary factor in the enhancement of heat transfer performance.

Keywords: heat transfer coefficient, laser processing, micro structured surface, pool boiling

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Authors: Dana A. Thal, Heike Kahlert, Fritz Scholz

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Thiol molecules are known to easily form self-assembled monolayers (SAM) on Au surfaces. Depending on the thiol’s structure, surface modifications via SAM can be used for electrode sensor development. In the presented work, 1-decanethiol coated polycrystalline Au electrodes were applied to indirectly assess the radical scavenging potential of plant compounds and extracts. Different plant compounds with reported antioxidant properties as well as an extract from the plant Gynostemma pentaphyllum were tested for their effectiveness to prevent SAM degradation on the sensor electrodes via photolytically generated radicals in aqueous media. The SAM degradation was monitored over time by differential pulse voltammetry (DPV) measurements. The results were compared to established antioxidant assays. The obtained data showed an exposure time and concentration dependent degradation process of the SAM at the electrode’s surfaces. The tested substances differed in their capacity to prevent SAM degradation. Calculated radical scavenging activities of the tested plant compounds were different for different assays. The presented method poses a simple system for radical scavenging evaluation and, considering the importance of the test system in antioxidant activity evaluation, might be taken as a bridging tool between in-vivo and in-vitro antioxidant assay in order to obtain more biologically relevant results in antioxidant research.

Keywords: alkanethiol SAM, plant antioxidant, polycrystalline Au, radical scavenger

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Authors: Laidi Babouri

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The remarkable properties of steel, such as hardness and impact resistance, motivate their use in the automotive manufacturing industry. However, due to the very vulnerable environmental conditions of use, the steel that makes up the car body can corrode. This situation is motivating more and more automobile manufacturers to develop research to develop processes minimizing the rate of degradation of the physicomechanical properties of these materials. The present work falls within this perspective; it presents the results of a research study focused on the use of synthetic wax for the protection of steel, type XES (DC04), against corrosion in aggressive environments. The media used in this study are an acid medium with a pH=5.6, a 3% chloride medium, and a dry medium. Evaluation of the protective power of synthetic wax in different environments was carried out using mass loss techniques (immersion), completed by electrochemical techniques (stationary and transient). The results of the immersion of the steel samples, with a surface area of (1.44 cm²), in the various media, for a period of 30 days, using the immersion technique, showed high protective efficiency of synthetic wax in acidic and saline environments, with a lesser degree in a dry environment. Moreover, the study of the protective power, using electrochemical techniques, confirmed the results obtained in static mode (loss of mass), the protective efficiency of synthetic wax, against the corrosion of steel, in different environments, which reaches a maximum rate of 99.87% in a saline environment.

Keywords: corrosion, steel, industrial wax, environment, mass loss, electrochemical techniques

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Authors: Haowen Xi

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We propose and solve exactly a class of non-linear generalization of the Black-Scholes process of stochastic differential equations describing price bubble and crashes dynamics. As a result of nonlinear positive feedback, the faster-than-exponential price positive growth (bubble forming) and negative price growth (crash forming) are found to be the power-law finite-time singularity in which bubbles and crashes price formation ending at finite critical time tc. While most literature on the market bubble and crash process focuses on the nonlinear positive feedback mechanism aspect, very few studies concern the noise level on the same process. The present work adds to the market bubble and crashes literature by studying the external sources noise influence on the critical time tc of the bubble forming and crashes forming. Two main results will be discussed: (1) the analytical expression of expected value of the critical time is found and unexpected critical slowing down due to the coupling external noise is predicted; (2) numerical simulations of the nonlinear stochastic equation is presented, and the probability distribution of Prob(tc) is found to be the inverse gamma function.

Keywords: bubble, crash, finite-time-singular, numerical simulation, price dynamics, stochastic differential equations

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Authors: Ibrahim Hamidu Magem

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Employee engagement has continued to gain popularity among practitioners, consultants and academicians recent years. This is due to the fact that the engaged employees are central to organizational success in today’s highly competitive and rapidly changing business environment. Employee engagement depicts a situation whereby employee’s harnessed themselves to their work roles. The importance of employee engagement to organizations cannot be overemphasized in today’s rapidly changing business environment. Organizations both large and small are constantly striving to improve their performance, retain employees, reduce absenteeism, and create loyal customers among others. To be able to achieve these organizations need a team of highly engaged employees. In line with this, the study attempts to provide a valuable framework for understanding the antecedents and consequences of employee engagement in organizations. The paper categorizes the antecedents of employee engagement into individual and organizational factors which it is assumed that the existence of such factors could result into engaged employees that will be of benefit to organizations. Therefore, it is recommended that organizations should revisit and redesign its employee engagement system to enable them attain their organizational goals and objectives. In addition, organizations should note that engagement is personal but organizational engagement programmes should be about everyone in the organization. The findings from this paper adds to existing studies about employee engagement and also provide awareness to academics and practitioners about the importance of employee engagement to improve organizations efficiency and effectiveness, as well as to impact to overall firm performance.

Keywords: antecedents, employee engagement, job involvement, organization

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Authors: Fines Fatimah, SH. MH.

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Indonesia is one of the countries that has ratified the UNCRPD (United Nations Convention on the Rights of Persons with Disabilities). The ratification of this convention brings consequences on the adjustment of national legislation with the UNCRPD convention, where this ratification at the same time is a measure in the eyes of the international community that a state party could be consistent with the issues and problems of disability. Persons with disabilities often have little access to justice when they are forced to deal with the criminal justice system. Pursuit of justice through litigation are often not in their favor, therefore without any awareness of law enforcement/awareness of disability will further complicate access to justice for persons with disabilities. Under Article 13 of the UNCRPD, it appeared that the convention requires ratifying states to guarantee equal opportunity and treatment in justice for persons with disabilities. The States should also ensure that any judicial rules must be adapted to the circumstances of persons with disabilities so that people with disabilities can fully participate in all stages of the trial court and, for example, as a witness. Finally, the state must provide training to understand these persons with disabilities (for those who work in the judiciary institution such as police or prison officials). Further, this paper aims to describe problem faced by persons with intellectual disabilities to access justice in Indonesian Criminal Justice System. This paper tries to find and propose the alternative solutions to promote the quality of law enforcement in Indonesia, especially for persons with intellectual disabilities.

Keywords: access to justice, Indonesian criminal justice system, intellectual disability, ratifying states

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Authors: Madhushi Bandara, Dharshana Kasthurirathna, Danaja Maldeniya, Mahendra Piraveenan

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Community detection is an extremely useful technique in understanding the structure and function of a social network. Louvain algorithm, which is based on Newman-Girman modularity optimization technique, is extensively used as a computationally efficient method extract the communities in social networks. It has been suggested that the nodes that are in close geographical proximity have a higher tendency of forming communities. Variants of the Newman-Girman modularity measure such as dist-modularity try to normalize the effect of geographical proximity to extract geographically dispersed communities, at the expense of losing the information about the geographically proximate communities. In this work, we propose a method to extract geographically dispersed communities while preserving the information about the geographically proximate communities, by analyzing the ‘community network’, where the centroids of communities would be considered as network nodes. We suggest that the inter-community link strengths, which are normalized over the community sizes, may be used to identify and extract the ‘overlay communities’. The overlay communities would have relatively higher link strengths, despite being relatively apart in their spatial distribution. We apply this method to the Gowalla online social network, which contains the geographical signatures of its users, and identify the overlay communities within it.

Keywords: social networks, community detection, modularity optimization, geographically dispersed communities

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Authors: Abdulbaset Saad, Adel Younis, Zuomin Dong

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For design optimization with high-dimensional expensive problems, an effective and efficient optimization methodology is desired. This work proposes a series of modification to the Differential Evolution (DE) algorithm for solving computation Intensive Black-Box Problems. The proposed methodology is called Radial Basis Meta-Model Algorithm Assisted Differential Evolutionary (RBF-DE), which is a global optimization algorithm based on the meta-modeling techniques. A meta-modeling assisted DE is proposed to solve computationally expensive optimization problems. The Radial Basis Function (RBF) model is used as a surrogate model to approximate the expensive objective function, while DE employs a mechanism to dynamically select the best performing combination of parameters such as differential rate, cross over probability, and population size. The proposed algorithm is tested on benchmark functions and real life practical applications and problems. The test results demonstrate that the proposed algorithm is promising and performs well compared to other optimization algorithms. The proposed algorithm is capable of converging to acceptable and good solutions in terms of accuracy, number of evaluations, and time needed to converge.

Keywords: differential evolution, engineering design, expensive computations, meta-modeling, radial basis function, optimization

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Authors: Merina Islam

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In this paper, an attempt is made to draw out the contemporary relevance of philosophy in school education of India. This paper attempt is made to inquire into the importance of philosophy for schoolchildren in the Indian cultural context. As education in philosophy for children is useful for teaching the acquisition of knowledge from the information provided, for questioning of rules in different contexts, and for the analysis of facts encountered in daily life. Ethical attitudes can neither be derived from the information provided about the moral rules, nor do they result from a practice of unquestioning obedience It includes some studies done in this field and also reports on philosophy. Many European countries emphasise on the above said theme. There are lots of work and research done by many philosophers on philosophy for children. Indian values system is different from the West and more important than others. Education has become a tool to achieve efficiency in all walks of human life whether social, political, religious or philosophical. Every nation started developing its own specific set of educational values. For India it is very necessary to increase philosophical thinking study and research. Philosophy could make significant contribution, particularly in relation to children's moral development because the Indian curriculum currently neglects this aim. A teacher can play an important role in promoting this discussion because a teacher has the capacity to influence students with their thoughts and personality and engages them in these activities. Philosophy needs to be included in the curriculum and have demonstrated cognitive and social gains in children who were explored to philosophy in their schooling.

Keywords: education, ethical attitude, moral value, philosophy

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Authors: J. C. Iwuchukwu, K. C. Okwor

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In recent time and in the study area, yam farmers are moving into less laborious and more economical crops and very few yam farmers are growing trifoliate yam. In yam markets, little or no bitter yam is displayed or sold. The work was therefore designed to ascertain trend and causes of decline in trifoliate yam production in Enugu state. Three agricultural zones, six blocks, eighteen circles and one hundred and eight trifoliate yam farmers that were purposively selected constituted sample for the study. An interview schedule was used to collect data while percentage, mean score and standard deviation were used for data analysis. Findings of the study revealed that the respondents had no extension contact, Majority (90.7%) sourced information on trifoliate yam from neighbours/friends/relatives and produced mainly for consumption (67.6%) during rainy season (70.4%). Trifoliate yam was produced manually(71.3%) and organically (58.3%) in a mixture of other crops (87%) using indigenous/local varieties (73.1%). Mean size of land allocated to trifoliate yam production was relatively steady, mean cost of input and income were increasing while output was decreasing within the years under consideration (before 2001 to 2014). Poor/lack of finance(M=1.8) and drudgery associated with trifoliate yam product(M=1.72) were some of the causes of decline in trifoliate yam production in the area. The study recommended that more research and public enlightenment campaigns on the importance of trifoliate yam should be carried out to encourage and consolidate farmers and the masses effort in production and consumption of the crop so that it will not go extinct and then contribute to food security.

Keywords: causes, decline, trend, trifoliate yam

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Authors: Nalan Kaya, Gonca Ozan, Elif Erdem, Neriman Colakoglu, Enver Ozan

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The toxic effects of tobacco smoke exposure have been detected in numerous studies. Ellagic acid (EA), (2,3,7,8-tetrahydroxy [1]-benzopyranol [5,4,3-cde] benzopyran 5,10-dione), a natural phenolic lactone compound, is found in various plant species including pomegranate, grape, strawberries, blackberries and raspberries. Similar to the other effective antioxidants, EA can safely interact with the free radicals and reduces oxidative stress through the phenolic ring and hydroxyl components in its structure. The aim of the present study was to examine the protective effects of ellagic acid against oxidative damage on lung tissues of rats induced by tobacco smoke. Twenty-four male adult (8 weeks old) Spraque-Dawley rats were divided randomly into 4 equal groups: group I (Control), group II (Tobacco smoke), group III (Tobacco smoke + corn oil) and group IV (Tobacco smoke + ellagic acid). The rats in group II, III and IV, were exposed to tobacco smoke 1 hour twice a day for 12 weeks. In addition to tobacco smoke exposure, 12 mg/kg ellagic acid (dissolved in corn oil), was applied to the rats in group IV by oral gavage. Equal amount of corn oil used in solving ellagic acid was applied to the rats by oral gavage in group III. At the end of the experimental period, rats were decapitated. Lung tissues and blood samples were taken. The lung slides were stained by H&E and Masson’s Trichrome methods. Also, galactin-3 stain was applied. Biochemical analyzes were performed. Vascular congestion and inflammatory cell infiltration in pulmonary interstitium, thickness in interalveolar septum, cytoplasmic vacuolation in some macrophages and galactin-3 positive cells were observed in histological examination of tobacco smoke group. In addition to these findings, hemorrhage in pulmonary interstitium and bronchial lumen was detected in tobacco smoke + corn oil group. Reduced vascular congestion and hemorrhage in pulmoner interstitium and rarely thickness in interalveolar septum were shown in tobacco smoke + EA group. Compared to group-I, group-II GSH level was decreased and MDA level was increased significantly. Nevertheless group-IV GSH level was higher and MDA level was lower than group-II. The results indicate that ellagic acid could protect the lung tissue from the tobacco smoke harmful effects.

Keywords: ellagic acid, lung, rat, tobacco smoke

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Authors: Mai Nguyen-Phuong-Mai

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This paper incorporates insight from various models, studies and disciplines to construct a framework called the Inverted Pyramid Model. It is argued that such a framework has several advantages: (1) it reduces the shortcomings of the problem-focused approach that dominates the mainstream theories of cross-cultural management. With contributing insight from neuroscience, it suggests that training in business cross-cultural awareness should start with potential synergy emerged from differences instead of the traditional approach that focuses on the liability of foreigners and negative consequences of cultural distance. (2) The framework supports a dynamic and holistic way of analyzing cultural diversity by analyzing four major cultural units (global, national, organizational and group culture). (3) The framework emphasizes the role of individuals –an aspect of culture that is often ignored or regarded as a non-issue in the traditional approach. It is based on the notion that people don’t do business with a country, but work (in)directly with a unique person. And it is at this individual level that culture is made, personally, dynamically, and contextually. Insight from neuroscience provides significant evidence that a person can develop a multicultural mind, confirm and contradict, follow and reshape a culture, even when (s)he was previously an outsider to this culture. With this insight, the paper proposes a revision of the old adage (Think global – Act local) and change it into Think global – Plan local – Act individual.

Keywords: static–dynamic paradigm, cultural diversity, multicultural mind, neuroscience

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Authors: Vedanki Khandenwal, Pawan Srivastava, Kartick Tarafder, Subhasis Ghosh

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We present here the experimental realization of controlled doping of graphene monolayers through charge transfer by trapping selected organic molecules between the graphene layer and underlying substrates. This charge transfer between graphene and trapped molecule leads to controlled n-type or p-type doping in monolayer graphene (MLG), depending on whether the trapped molecule acts as an electron donor or an electron acceptor. Doping controllability has been validated by a shift in corresponding Raman peak positions and a shift in Dirac points. In the transfer characteristics of field effect transistors, a significant shift of Dirac point towards positive or negative gate voltage region provides the signature of p-type or n-type doping of graphene, respectively, as a result of the charge transfer between graphene and the organic molecules trapped within it. In order to facilitate the charge transfer interaction, it is crucial for the trapped molecules to be situated in close proximity to the graphene surface, as demonstrated by findings in Raman and infrared spectroscopies. However, the mechanism responsible for this charge transfer interaction has remained unclear at the microscopic level. Generally, it is accepted that the dipole moment of adsorbed molecules plays a crucial role in determining the charge-transfer interaction between molecules and graphene. However, our findings clearly illustrate that the doping effect primarily depends on the reactivity of the constituent atoms in the adsorbed molecules rather than just their dipole moment. This has been illustrated by trapping various molecules at the graphene−substrate interface. Dopant molecules such as acetone (containing highly reactive oxygen atoms) promote adsorption across the entire graphene surface. In contrast, molecules with less reactive atoms, such as acetonitrile, tend to adsorb at the edges due to the presence of reactive dangling bonds. In the case of low-dipole moment molecules like toluene, there is a lack of substantial adsorption anywhere on the graphene surface. Observation of (i) the emergence of the Raman D peak exclusively at the edges for trapped molecules without reactive atoms and throughout the entire basal plane for those with reactive atoms, and (ii) variations in the density of attached molecules (with and without reactive atoms) to graphene with their respective dipole moments provides compelling evidence to support our claim. Additionally, these observations were supported by first principle density functional calculations.

Keywords: graphene, doping, charge transfer, liquid phase exfoliation

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Authors: Murray Olowa

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This article examines the studies investigating the Mathematical Knowledge for Teaching (MKT) of secondary preservice teachers in Papua New Guinea based on probabilities. This research was conducted due to the continuous issues faced in the country in both primary and secondary education, like changes in curriculum, emphasis on mathematics and science education, and a decline in mathematics performance. Moreover, the mathematics curriculum doesn’t capture Pedagogical Content Knowledge (PCK) or Subject Matter Knowledge (SMK). The two main domains that have been identified are SMK and PCK, which have been further sub-divided into Common Content Knowledge (CCK), Specialised Content Knowledge (SCK) and Horizon Content Knowledge (HCK), and Knowledge of Content and Students (KCS), Knowledge of Content and Teaching (KCT) and Knowledge of Content and Curriculum (KCC), respectively. The data collected from 15-_year-_ ones and 15-_year-_fours conducted at St Peter Chanel Secondary Teachers College revealed that there is no significant difference in subject matter knowledge between year one and year four since the P-value of 0.22>0.05. However, it was revealed that year fours have higher pedagogical content knowledge than year one since P-value was 0.007<0.05. Finally, the research has proven that year fours have higher MKT than year one. This difference occurred due to final year preservice teachers’ hard work and engagement in mathematics curriculum and teaching practice.

Keywords: mathematical knowledge for teaching, subject matter knowledge, pedagogical content knowledge, Papua New Guinea, preservice teachers, probability

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Authors: Racholsan Raj Nirmal, B. S. V. Patnaik, R. Jayaganthan

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The deformation behaviour of additively manufactured AlSi10Mg alloy under low strains, high strain rates and elevated temperature conditions is essential to analyse and predict its response against dynamic loading such as impact and thermomechanical fatigue. The constitutive relation of Johnson-Cook is used to capture the strain rate sensitivity and thermal softening effect in AlSi10Mg alloy. Johnson-Cook failure model is widely used for exploring damage mechanics and predicting the fracture in many materials. In this present work, Johnson-Cook material and damage model parameters for additively manufactured AlSi10Mg alloy have been determined numerically from four types of uniaxial tensile test. Three different uniaxial tensile tests with dynamic strain rates (0.1, 1, 10, 50, and 100 s^-1) and elevated temperature tensile test with three different temperature conditions (450 K, 500 K and 550 K) were performed on 3D printed AlSi10Mg alloy in ABAQUS/Explicit. Hexahedral elements are used to discretize tensile specimens and fracture energy value of 43.6 kN/m was used for damage initiation. Levenberg Marquardt optimization method was used for the evaluation of Johnson-Cook model parameters. It was observed that additively manufactured AlSi10Mg alloy has shown relatively higher strain rate sensitivity and lower thermal stability as compared to the other Al alloys.

Keywords: ABAQUS, additive manufacturing, AlSi10Mg, Johnson-Cook model

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Authors: Abigail Gragg

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The goal of this research study was to adjudicate if implementing Howard Gardner’s multiple levels of intelligence would enhance student achievement levels in an Algebra 1 College Preparatory class. This was conducted within every class by incorporating one level of the eight levels of intelligence into small group work in stations. Every class was conducted utilizing small-group instruction. Achievement levels were measured through various forms of collected data that expressed student understandings in class through formative assessments versus student understandings on summative assessments. The data samples included: assessments (i.e. summative and formative assessments), observable data, video recordings, a daily log book, student surveys, and checklists kept during the observation periods. Formative assessments were analyzed during each class period to measure in-class understanding. Summative assessments were dissected per question per accuracy to review the effects of each intelligence implemented. The data was collated into a coding workbook for further analysis to conclude the resulting themes of the research. These themes include 1) there was no correlation to multiple levels of intelligence enhancing student achievement, 2) bodily-kinesthetic intelligence showed to be the intelligence that had the most improvement on test questions and 3) out of all of the bits of intelligence, interpersonal intelligence enhanced student understanding in class.

Keywords: stations, small group instruction, multiple levels of intelligence, Mathematics, Algebra 1, student achievement, secondary school, instructional Pedagogies

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Authors: Roman Knizek, Denisa Knizkova, Vladimir Bajzik

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Nowadays there are countless kinds of bedsheets or mattress covers for little children which should stop any liquid getting into the mattress. It is quite easy to wash the cover of the mattress, but it is almost impossible to clean the body of a mattress which is made of latex foam, wool or synthetic materials. Children bedsheets or mattress covers are often made with plastic coating which is not steam or air permeable and therefore is not very hygienic. This is our goal: by laminating a nanofiber membrane to a suitable bedsheet textile material, we can create a bedsheet which is waterproof but at the same time steam permeable and also partially breathable, thanks to the membrane. For the same reason, nanofiber membranes are widely used in outdoor clothing. The comfort properties and durability of the new nano-membrane bedsheet were studied. The following comfort properties were investigated: steam permeability - measured in accordance with Standard ISO 11902 hydrostatic resistances - measured in accordance with Standard ISO 811 and air permeability - measured in accordance with Standard ISO 9237. The durability or more precisely the wash resistance of the nano-membrane bedsheet was also measured by submitting the sheet to 30 washing cycles. The result of our work is a children's bedsheet with a nano-membrane. The nano-membrane is made of polyurethane to keep maximum flexibility and elasticity which are essential for this product. The comfort properties of this new bedsheet are very good especially its steam permeability and hydrostatic resistance.

Keywords: bed sheet, hydrostatic resistance, nanofiber membrane, water vapour permeable

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Authors: Saleh B. Mohamed, Mohamed H. Elhsnawi, Mesbah M. Salem

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Current and future applications of small gas turbine engines annular type combustors have requirements presenting difficult disputes to the combustor designer. Reduced cost and fuel consumption and improved durability and reliability as well as higher temperatures and pressures for such application are forecast. Coupled with these performance requirements, irrespective of the engine size, is the demand to control the pollutant emissions, namely the oxides of nitrogen, carbon monoxide, smoke and unburned hydrocarbons. These technical and environmental challenges have made the design of small size combustion system a very hard task. Thus, the main target of this work is to generalize a calculation method of annular type combustors for small gas turbine engines that enables to understand the fundamental concepts of the coupled processes and to identify the proper procedure that formulates and solves the problems in combustion fields in as much simplified and accurate manner as possible. The combustion chamber in task is designed with central vaporizing unit and to deliver 516.3 KW of power. The geometrical constraints are 142 mm & 140 mm overall length and casing diameter, respectively, while the airflow rate is 0.8 kg/sec and the fuel flow rate is 0.012 kg/sec. The relevant design equations are programmed by using MathCAD language for ease and speed up of the calculation process.

Keywords: design of gas turbine, small engine design, annular type combustors, mechanical engineering

Procedia PDF Downloads 406

Authors: Shujun Xie, Shirong Zhang, Shenglin Ma

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Background: Chronic inflammation might lead to many malignancies, and inadequate resolution could play a crucial role in tumor invasion, progression, and metastases. A randomised, double-blind, placebo-controlled trial shows that IL-1β inhibition with canakinumab could reduce incident lung cancer and lung cancer mortality in patients with atherosclerosis. The process and secretion of proinflammatory cytokine IL-1β are controlled by the inflammasome. Here we showed the correlation of the innate immune system and afatinib, a tyrosine kinase inhibitor targeting epidermal growth factor receptor (EGFR) in non-small cell lung cancer. Methods: Murine Bone marrow derived macrophages (BMDMs), peritoneal macrophages (PMs) and THP-1 were used to check the effect of afatinib on the activation of NLRP3 inflammasome. The assembly of NLRP3 inflammasome was check by co-immunoprecipitation of NLRP3 and apoptosis-associated speck-like protein containing CARD (ASC), disuccinimidyl suberate (DSS)-cross link of ASC. Lipopolysaccharide (LPS)-induced sepsis and Alum-induced peritonitis were conducted to confirm that afatinib could inhibit the activation of NLRP3 in vivo. Peripheral blood mononuclear cells (PBMCs) from non-small cell lung cancer (NSCLC) patients before or after taking afatinib were used to check that afatinib inhibits inflammation in NSCLC therapy. Results: Our data showed that afatinib could inhibit the secretion of IL-1β in a dose-dependent manner in macrophage. Moreover, afatinib could inhibit the maturation of IL-1β and caspase-1 without affecting the precursors of IL-1β and caspase-1. Next, we found that afatinib could block the assembly of NLRP3 inflammasome and the ASC speck by blocking the interaction of the sensor protein NLRP3 and the adaptor protein ASC. We also found that afatinib was able to alleviate the LPS-induced sepsis in vivo. Conclusion: Our study found that afatinib could inhibit the activation of NLRP3 inflammasome in macrophage, providing new evidence that afatinib could target the innate immune system to control chronic inflammation. These investigations will provide significant experimental evidence in afatinib as therapeutic drug for non-small cell lung cancer or other tumors and NLRP3-related diseases and will explore new targets for afatinib.

Keywords: inflammasome, afatinib, inflammation, tyrosine kinase inhibitor

Procedia PDF Downloads 115

Authors: Zerzouri Nora, Benalia Nadia, Bensiali Nadia

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This paper presents a grid-connected wind power generation scheme using Doubly Fed Induction Generator (DFIG). This can supply power at constant voltage and constant frequency with the rotor speed varying. This makes it suitable for variable speed wind energy application. The DFIG system consists of wind turbine, asynchronous wound rotor induction generator, and inverter with Space Vector Modulation (SVM) controller. In which the stator is connected directly to the grid and the rotor winding is in interface with rotor converter and grid converter. The use of back-to-back SVM converter in the rotor circuit results in low distortion current, reactive power control and operate at variable speed. Mathematical modeling of the DFIG is done in order to analyze the performance of the systems and they are simulated using MATLAB. The simulation results for the system are obtained and hence it shows that the system can operate at variable speed with low harmonic current distortion. The objective is to track and extract maximum power from the wind energy system and transfer it to the grid for useful work.

Keywords: Doubly Fed Induction Generator, Wind Energy Conversion Systems, Space Vector Modulation, distortion harmonics

Procedia PDF Downloads 479

Authors: Tero Huhtala, Minna Pikkarainen, Saila Saraniemi

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Information technology has long been used as an enabler of exchange for goods and services. Services are evolving from generic to personalized, and the reverse use of customer data has been discussed in both academia and industry for the past few years. This article presents the results of an empirical case study in the area of preventive health care services. The primary data were gathered in workshops, in which future personal data-based services were conceptualized by analyzing future scenarios from a business perspective. The aim of this study is to understand business model transformation in emerging personal data ecosystems. The work was done as a case study in the context of occupational healthcare. The results have implications to theory and practice, indicating that adopting personal data management principles requires transformation of the business model, which, if successfully managed, may provide access to more resources, potential to offer better value, and additional customer channels. These advantages correlate with the broadening of the business ecosystem. Expanding the scope of this study to include more actors would improve the validity of the research. The results draw from existing literature and are based on findings from a case study and the economic properties of the healthcare industry in Finland.

Keywords: ecosystem, business model, personal data, preventive healthcare

Procedia PDF Downloads 246

Authors: Ezeonu, Chukwuma Stephen, Onwurah, Ikechukwu Noel Emmanuel

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Pure strains of Aspergillus fumigatus (AF), aspergillus niger (AN), aspergillus oryzae (AO), trichophyton mentagrophyte (TM), trichophyton rubrum (TR) and Trichophyton soudanense (TS) were isolated from decomposing rice husk. Freshly processed rice husk in Mandle’s medium were heat pre-treated using an autoclave at 121oC for 20 minutes. The isolated fungi as monoculture and di-culture combinations were inoculated into each of the pre-treated rice husk with the exception of two controls. Seven days hydrolysis was followed by estimation of carbohydrate, reducing sugar and non-reducing sugar. Fungal treated rice husks were left to ferment for 7 days with introduction of both baker’s and palm wine yeast. The result obtained in the work gave the highest carbohydrate (20.53 ± 2.73 %) from rice husks treated with TS + TR di-culture. The highest soluble reducing sugar (2.66 ± 0.14 %) was obtained from rice husk treated with TM. The highest soluble nonreducing sugar (18.08 ± 2.61 %) was from AF. The introduction of yeasts from palm wine gave the highest bio-ethanol (12.82 ± 0.39 %) from AO. The highest bio-ethanol (6.60 ± 0.10 %) from baker's yeast fermentation was in AO + TS treated rice husk. There was increased availability of sugar and moderate yield of bio-ethanol, especially from palm wine yeast.

Keywords: fungi, rice husk, carbohydrate, reducing sugar, non-reducing sugar, ethanol, fermentation

Procedia PDF Downloads 435